Jam Code 10-02 is a Manual Bypass Tray registration loop forming failure on Konica Minolta bizhub machines. The official Konica Minolta description is precise and technically meaningful: For paper fed from the manual bypass tray, loop forming has not been complete before a sheet enters the registration roller because the rise timing of load to perform registration is earlier than the rise timing of load to form a loop.

Translated into field language: bypass paper did physically reach the registration roller area — it triggered the detection sensor — but it arrived too slowly. By the time the paper leading edge reached the registration roller nip, the machine’s internal timing sequence had already commanded the registration roller to begin driving the paper into the imaging section, before the controlled buckle (the loop) that straightens the paper leading edge had time to fully form. The machine detects this timing failure, halts the feed cycle, and records 10-02.

This is the critical distinction that separates 10-02 from 10-01: 10-01 means paper never reached the sensor. 10-02 means paper did reach the sensor area, but arrived late. Both share many of the same components and causes, but 10-02 points more specifically to a sluggish or marginal feed mechanism — a bypass drive that is not failing completely, but is not delivering paper fast enough to meet the machine’s timing window. This subtle difference shapes the entire diagnostic approach.

Field	Details
Jam Code	10-02
Description	Manual bypass tray registration loop forming failure — paper reached the registration roller area but arrived late, preventing complete loop formation before registration timing fired
Key Distinction from 10-01	Paper did reach the detection sensor (PS1, PS9, or PS4 depending on model) — the feed mechanism is not completely dead. The failure is marginal feed speed, not total feed failure
Detection Logic	The registration sensor (PS1 / PS9) or Tray 1 VT sensor (PS4) was activated by the bypass paper leading edge, but the controlled buckle (loop) forming sequence in front of the registration roller nip was not complete before the rise timing of the registration load (CL4 on CL7/SD1 models, or the registration motor sequence on M27 models) occurred
Why Loop Forming Matters	The paper loop — a deliberate 3–5 mm buckle formed against the stationary registration roller nip — is the mechanical method bizhub machines use to ensure the paper leading edge is perfectly square to the imaging path before it enters the transfer section. A loop that is too small or not formed at all causes skewed or distorted print output on the leading edge, and the machine detects this as a timing fault
Key Components	Registration sensor (PS1 / PS9 / PS4); bypass paper feed clutch (CL7 / CL2 on compact i-series); bypass pickup solenoid (SD1); bypass pickup roller solenoid (SD6, i-series); bypass paper feed motor (M27, high-volume models); registration clutch (CL4); transport motor (M1 / M22 / M24); bypass pickup roller; bypass feed roller; bypass separation roller/pad; vertical transport one-way spring clutch gear (high-volume models); registration loop adjustment (service mode); control board (BASEB / MFPB / FRB / EXCB / PFTDB)
Severity	High — bypass tray disabled; commonly intermittent (1 in 20–50 pages) before becoming consistent; may produce skewed leading edges or toner smear on affected prints before jamming
Related Jam Codes	10-01 (Bypass primary misfeed — paper never reached sensor), 10-04 (Registration sensor/2 PS72 not activated — bizhub 658e/558e only), 10-40 (Bypass image write signal timeout), 11-02 (Tray 1 registration loop forming failure — same components, same mechanism, different tray source)

All Affected Models and Exact Component References

The components involved in 10-02 differ significantly across model families. Two distinct architectural groups exist: CL7/SD1 models (BASEB, MFPB, FRB, PRCB-based machines) where the bypass feed clutch, lift solenoid, and shared transport motor are the key drive components; and M27 models (PFTDB-based high-volume machines) where a dedicated bypass motor drives both the lift mechanism and the feed rollers independently. The registration clutch (CL4) and registration sensor (PS1/PS9/PS4) are common to all platforms.

bizhub Models	Detection Sensor	Bypass Feed Clutch	Lift Solenoid	Pickup Solenoid	Reg. Clutch	Transport Motor	Sensor Check	CL4 Check	Feed Clutch Check	SD1 Check	M1 Check	Board
C250i / C300i / C360i / 250i / 300i / 360i	PS1	CL7	SD1	SD6	CL4	M1	BASEB CN15E-9 (ON), 4-C	CC: 21, MC: 2, BASEB CN15E-2 (ON), 3-C	CC: 20, MC: 3, BASEB CN26EA-12 (ON), 10-K	CC: 23, MC: 3, BASEB CN26EA-9 (ON), 10-K	CC: 40, MC: 1,4,5 BASEB CN19EA-1 to 5, 1-C	BASEB
C3350i / C4000i / C4050i	PS9	CL2	SD1	—	CL4	M1	BASEB CN22EA-13 (ON), 13-C	CC: 21, MC: 3, BASEB CN22EA-3 (ON), 12-C	CC: 20, MC: 4, BASEB CN23E-10 (ON), 9-K	Refer to SM	CC: 40, MC: 1,2 BASEB CN17E-1 to 5, 1-C	BASEB
C258 / C308 / C368 / C227 / C287 / C367	PS1	CL7	SD1	—	CL4	M1	FRB CN8-3 (ON), 6-L	CC: 21, MC: 2, FRB CN8-7 (CL4_REM), 5-L	CC: 20, MC: 3, MFPB (refer to SM)	CC: 23, MC: 3, MFPB (refer to SM)	CC: 40, MC: 1–4 MFPB CN8E-3 (REM), 2-C	MFPB + FRB
368e / 308e	PS1	CL7	SD1	—	CL4	M1, M22	FRB CN8-3 (ON), 6-L	CC: 21, MC: 2, FRB CN8-7 (CL4_24V), 5-L	CC: 20, MC: 3, MFPB CN18E-8 (ON), 22-J	CC: 23, MC: 3, MFPB CN18E-10 (ON), 22-J	CC: 40, MC: 1–4 MFPB CN8E-3 (REM), 2-C	MFPB + FRB
C458 / C558 / C658 / 458e / 558e / 658e	PS1 (PS72 on 658e/558e)	CL7	SD1	—	CL4	M1 (M22, M24 on 658e)	EXCB CN6-3 (ON), 26-P	CC: 21, MC: 2, FRB CN8-7 (CL4_REM), 4-K	CC: 20, MC: 3, MFPB CN19E-7 (ON), 22-I	CC: 23, MC: 3, MFPB CN19E-9 (ON), 22-I	CC: 40, MC: 1–4 MFPB CN14E-3 (REM), 1-C	MFPB + FRB + EXCB
C450i / C550i / C650i / 458i / 558i / 658i	PS1	CL7	SD1	—	CL4	M1, M22, M24	Refer to SM	Refer to SM	Refer to SM	Refer to SM	Refer to SM	MFPB + EXCB + FRB + BASEB
C224e / C284e / C364e / C224 / C284 / C364	PS1	CL7	SD1	—	CL4	M1	PRCB or MFPB (refer to SM)	Refer to SM	Refer to SM	Refer to SM	Refer to SM	PRCB / MFPB
223 / 283 / 363 / 423 / C454 / C554	PS1	CL7	SD1	—	CL4	M1	Refer to SM	Refer to SM	Refer to SM	Refer to SM	Refer to SM	PRCB
654e / 754e / 758 / 808 / 958	PS4 (Tray 1 VT sensor)	— (M27 dedicated motor)	— (M27 drives lift cam)	—	CL4 (via PFTDB)	M27 (bypass), M22 (main)	PFTDB CN14-8 (ON), 1-P	Refer to SM	— (M27 drives all bypass functions)	—	M27: PFTDB CN9-1 to 4 (654e/754e), CN9-3 to 6 (758/808/958)	PFTDB + MFPB
C659 / C759	PS4	— (M27 dedicated motor)	—	—	CL4	M27 (bypass)	PFTDB CN14-8 (ON), 1-P	Refer to SM	—	—	M27: CC: 28, MC: 1–4, PFTDB CN9-3 to 6, 12-P	PFTDB + MFPB

CC = Check Code, MC = Multi Code, SM = Service Manual

ℹ️ Why 10-02 and 11-02 often appear together: When Jam Code 10-02 (bypass) and 11-02 (Tray 1) appear simultaneously or alternately, the root cause is almost always in the shared main paper path — specifically the vertical transport one-way spring clutch gear, the registration clutch (CL4), or the transport motor (M1) — not in two independent tray feed assembly failures. Both bypass and Tray 1 paper merges into the same main transport path before the registration roller, and a sluggish shared drive component produces late paper arrival from both sources. This co-occurrence is the single strongest diagnostic indicator that the fault is in the shared path, not in the bypass tray mechanism itself.

Understanding the Loop Forming Sequence — Why Timing Is Everything

To diagnose 10-02 correctly, understanding the loop forming sequence is essential. This is the one bizhub jam code where the machine is reporting a timing failure rather than a component failure — and the distinction changes what you look for.

The loop forming sequence for bypass paper works as follows:

1. The bypass feed cycle begins: SD1 energizes (lift plate rises), SD6 energizes on i-series (pickup roller drops), CL7 or CL2 engages (feed rollers receive drive from M1 or M27 runs on PFTDB models)
2. The pickup roller grips the top sheet and drives it through the feed/separation roller nip into the main paper path
3. The paper leading edge reaches the registration roller nip. At this moment, the registration roller is stationary — CL4 (registration clutch) has not yet been commanded to engage. The paper leading edge hits the stationary nip and the sheet continues to be pushed forward by the bypass feed rollers behind it
4. This continued forward push against a stationary nip causes the paper to buckle slightly — forming the controlled loop between the feed rollers and the registration roller nip. This buckle is the loop. It is typically 3–5 mm deep and ensures the paper leading edge is forced into full, even contact across its width with the registration roller nip line
5. Once the loop is fully formed (the buckle has straightened the leading edge perfectly square to the nip), the machine fires CL4 and the registration roller pair engages, driving the paper cleanly into the imaging section
6. 10-02 fires when: the paper leading edge reaches the registration nip and the loop begins to form, but the paper arrives so late that the machine’s predetermined CL4 engagement timing fires before the loop is complete. The registration roller starts turning while the paper leading edge is still catching up to the nip — there is no time to form the corrective buckle — and the paper enters the imaging section skewed or with a misaligned leading edge, triggering the jam code

The key insight for 10-02 diagnosis is: the paper is moving, but not fast enough. Every component in the bypass path that can cause sluggish paper delivery — a marginally worn pickup roller, a barely engaging CL7, a CL4 that engages slightly early, an SD1 that actuates with a slight delay, or a one-way spring clutch that is slipping in the shared vertical transport path — can produce 10-02 without producing 10-01, because the paper does arrive at the sensor, just 10–50 milliseconds too late.

There are five root cause categories for 10-02:

• Category 1 — Marginally worn bypass rollers: The pickup roller or feed roller has not completely glazed (which would cause 10-01) but has lost enough surface texture that it delivers the paper at 85–95% of the expected speed. Paper arrives at the registration roller just past the loop-forming window. This is the most common cause on machines with moderate-to-high bypass usage
• Category 2 — Bypass feed clutch (CL7 / CL2) engaging sluggishly: The electromagnetic clutch engages successfully but with a slight delay from a worn or contaminated clutch face, or the clutch is receiving a marginal drive signal. The initial 15–30 ms delay cascades into a paper arrival that misses the loop timing window
• Category 3 — Bypass lift solenoid (SD1) actuating slowly: SD1 energizes but the lift plate mechanism takes slightly longer than specified to complete the full lift stroke, delaying the moment when the pickup roller contacts the paper. This adds latency to the entire feed cycle and shifts paper arrival time past the loop formation window
• Category 4 — Vertical transport one-way spring clutch gear slipping (high-volume models with shared VT path): On older high-volume bizhub models (C452, C552, C652, and the shared-path section of PFTDB models), a one-way spring clutch gear in the vertical transport section between the bypass/Tray 1 path and the registration roller partially slips. The paper enters this zone at the correct speed but exits it at reduced speed — arriving at the registration roller too late for loop formation. This is the most commonly missed field cause of persistent 10-02 and 11-02 on machines above 800k–1M copies. The gear looks like a normal drive gear in the parts catalog, but it contains an internal spring clutch. When the spring weakens, the gear drives the transport roller at reduced torque and the paper slips through at reduced speed
• Category 5 — Registration clutch (CL4) engaging early or out of calibrated timing: CL4 fires earlier than expected relative to paper arrival — a timing drift caused by the registration loop adjustment setting having drifted, a worn or electrically degraded CL4 that changes its engagement lag, or a board-level timing anomaly. The loop window closes before the paper has time to form the buckle

Step 1 — Check Paper and Bypass Tray Condition

Before entering service mode for 10-02, eliminate paper and tray condition as a cause. Paper condition issues specifically cause late paper delivery — not zero paper delivery — and produce 10-02 rather than 10-01 for exactly this reason.

1. Remove all paper from the bypass tray and inspect:
   • Paper curl: Curled paper — particularly paper curled downward at the leading edge — slows entry into the registration nip because the edge is being pushed against the nip line at an angle rather than making full-width simultaneous contact. The paper leading edge must work against the curl to enter the nip cleanly. Reverse-curl the stack by hand and reload
   • Paper weight: Heavier stock (150 g/m² and above) requires more drive force from the feed rollers to maintain speed through the bypass path. Marginally worn feed rollers that perform acceptably on 80 g/m² copy paper will slip on 200 g/m² card stock, producing 10-02 specifically on heavy media. Always test with the same media the customer is using when troubleshooting 10-02
   • Paper dampness: Humid or damp paper from improperly stored reams has reduced stiffness, causing it to buckle and slow between the feed rollers and the registration nip more than dry paper. Fan and air out the stack before reloading
   • Overloaded bypass tray: Too many sheets on the bypass tray increases the pickup roller spring load and can cause the top sheet to slightly bind against the sheet below it during pickup, slowing initial acceleration. Reduce the stack to 10–15 sheets for heavy stock and 50 sheets for standard paper
2. Reload fresh paper in a reduced stack and run a 10-page test. If 10-02 does not recur with fresh, dry, uncurled paper, the cause is paper condition

Step 2 — Inspect and Clean the Bypass Tray Pickup Roller and Feed Roller

Marginally worn bypass rollers are the most common mechanical cause of 10-02 across all bizhub model families. Unlike 10-01, which requires the roller to be severely glazed (complete failure), 10-02 occurs when the roller has lost enough surface texture to slow paper delivery by 10–15% — enough to miss the loop timing window while still occasionally feeding paper successfully.

1. With the bypass tray open, inspect the pickup roller surface — it should be visibly textured and dark. Even light glazing (the surface appears slightly shiny but not mirror-smooth) is sufficient to cause 10-02 on smooth or heavier paper stocks
2. Clean the pickup roller thoroughly with a damp lint-free cloth. Use a slightly damp cotton swab to clean the contact area more aggressively if the surface appears glazed — occasionally cleaning restores enough texture to eliminate 10-02 on standard copy paper, but a roller that requires cleaning to feed reliably is at end-of-life and should be replaced at the next PM
3. Access the bypass feed roller and separation roller/pad:
   • Feed roller: Inspect and clean. A partially glazed feed roller that grips paper intermittently produces 10-02 that varies by paper type — working on rough bond paper but failing on smooth coated stock
   • Separation retard pad or roller: A retard pad that has become partially collapsed or excessively hard may grip the bottom of the single sheet being fed, slightly slowing it. Inspect the pad surface — it should be firm but compliant. A pad that is clearly worn, glazed, or shows a distinct hollow groove where it contacts the feed roller should be replaced even if it appears to be maintaining some retard function
4. After cleaning, run a 20-page bypass test with the same paper stock that is producing 10-02. If the code is eliminated, cleaning was sufficient. If it recurs within 50–100 pages of the cleaning, the roller is at end-of-life — replace the full roller set at the next PM or immediately if the customer relies on the bypass tray

Step 3 — Adjust the Registration Loop Value in Service Mode

The registration loop adjustment is a service mode calibration parameter that controls how long the machine waits after detecting paper at the registration sensor before firing CL4 (the registration clutch that starts the roller driving). A larger loop value gives more time for the paper buckle to form before registration begins. A smaller value reduces the window.

This adjustment is the fastest non-mechanical resolution for 10-02 when the bypass mechanism is marginally slower than specification but mechanically intact — and it is the correct first intervention before replacing any component when 10-02 is intermittent and related to paper type or environment.

1. Enter Service Mode (refer to model-specific service manual for access procedure)
2. Navigate to the paper adjustment / registration section. The parameter is typically labeled:
   • BASEB models (C250i/C360i/C3350i/C4050i): Look for “Bypass tray: Registration loop” or “Manual bypass loop” adjustment parameter under the paper feed adjustment section
   • MFPB/FRB models (C258/C368/C458/C658/368e/658e): Look for “Bypass loop adjustment” or “Bypass tray loop value” in the adjustment section
   • PFTDB models (654e/754e/758/808/958/C659/C759): Look for the bypass tray loop adjustment in the PFTDB-related paper transport adjustment section
3. The default value is typically 0. The adjustment range is typically -5 to +5 (or -3 to +3 on some models), where:
   • Positive values (+1 to +5): Increase the loop wait time — the machine waits longer before firing CL4, giving slower-arriving paper more time to form the loop. This is the correct direction for 10-02
   • Negative values: Reduce the loop wait time — used for jam codes where paper is arriving early and forming an excessive loop that causes crumpling
4. Increase the bypass registration loop value by +1 or +2 from the current setting. Save the change and run a 20-page bypass test with the specific paper stock that was producing 10-02
5. If 10-02 continues, increase by another +1 and retest. Continue until the jam resolves or the maximum value is reached
6. If the maximum positive loop value does not resolve 10-02, the timing deficit is too large to be compensated by adjustment alone — the root cause is mechanical (worn roller, sluggish CL7, failing SD1, or slipping one-way spring clutch gear). Proceed to the mechanical steps below

⚠️ Do not set the loop adjustment to maximum (+5) as a permanent fix without addressing the mechanical root cause. A maximum-positive loop adjustment compensates for a progressively degrading mechanical component and will stop working as the component continues to wear. The correct use of the loop adjustment is as a temporary measure while waiting for a PM visit, or as a fine-tuning parameter after the mechanical issue has been addressed. A machine running at maximum loop adjustment needs a roller replacement or clutch service — not just a parameter change.

Step 4 — Check the Bypass Lift-Up Solenoid (SD1) in Service Mode

For 10-02, the SD1 check focuses not just on whether SD1 energizes (which covers 10-01) but on whether SD1 completes the full lift stroke in the correct time. A solenoid that pulls slowly — due to a weakening coil, reduced supply voltage from a degraded connector, or a mechanically sluggish plunger — delays the moment when the paper stack reaches the pickup roller, cascading into late paper arrival at the registration sensor.

1. Enter Service Mode and navigate to the solenoid / load operation check section
2. Command SD1 to energize using the model-specific signal from the table above
3. With the bypass tray open, observe the lift plate rising when SD1 is commanded — it should rise crisply and fully to the top position. A lift plate that moves slowly, stops partway, or requires a moment to start moving is the sign of a sluggish SD1 or a mechanically binding lift plate mechanism
4. Also inspect the SD1 plunger and linkage:
   • The SD1 plunger should snap into the pulled position immediately when the solenoid energizes. A slow or soft pull indicates a weakening solenoid coil or reduced supply voltage at the solenoid connector
   • Test the connector between SD1 and the board for any pin that is partially pulled back or corroded — a connection with higher-than-normal resistance reduces the voltage available to SD1 and slows the pull-in force
   • Check the lift plate pivot arm for any binding, bent pivot, or hardened grease that is increasing the mechanical load on the SD1 plunger
5. On i-series models (C250i/C300i/C360i): also check SD6 (bypass pickup roller press solenoid) using Check code: 23, Multi code: 3, Signal: BASEB CN26EA-7. An SD6 that engages slowly delays the pickup roller drop-down and introduces the same latency to the feed cycle as a slow SD1

Step 5 — Check the Bypass Paper Feed Clutch (CL7 / CL2) in Service Mode

The bypass paper feed clutch (CL7 or CL2 on compact i-series) is the component most directly responsible for how quickly the bypass feed rollers accelerate from zero speed to full paper transport speed when a feed cycle begins. A clutch that is engaging correctly but with a 20–40 ms additional lag — due to a worn clutch face, a slightly under-voltage drive signal, or a connector with marginal contact — is sufficient to cause 10-02 without causing 10-01, because paper still arrives at the sensor, just slightly late.

1. In Service Mode, navigate to the clutch load operation check section
2. Command CL7 (or CL2 on C3350i/C4050i) to engage using the model-specific signal from the table above
3. Listen and feel for the clutch engaging — it should produce a crisp, solid click immediately when commanded. A soft click, a delayed click (audible lag of more than 50ms after the command), or a click that requires a second attempt in service mode indicates a marginal clutch
4. With the bypass tray removed, manually rotate the feed roller shaft — it should lock solid immediately when CL7 is commanded. A shaft that locks with a slight rotational lag (it spins slightly before catching) indicates clutch face wear
5. Check the connector between CL7 and the board:
   • Test the voltage at the CL7 connector pins during energization — it should be within 10% of the rated 24V. A low voltage from a degraded connector or pin causes the clutch coil to produce less pull-in force and engage with added latency
   • Reseat the CL7 connector fully and run a 20-page bypass test. A connector that was marginally seated can cause the voltage drop that produces intermittent 10-02
6. If CL7 engages correctly in service mode but 10-02 continues: the clutch face has worn and is mechanically slipping during the initial engagement transient — replacing CL7 is the correct fix when this diagnosis is confirmed

Step 6 — Check the Registration Clutch (CL4) in Service Mode

The registration clutch (CL4) is the other side of the loop forming timing equation. Even when bypass paper arrives at the registration nip on time, a CL4 that engages slightly earlier than its nominal timing — or one that engages so aggressively it pulls the paper before the loop is complete — can cause 10-02 from the registration side of the timing window rather than the paper delivery side.

1. In Service Mode, navigate to the clutch load operation check section
2. Command CL4 to engage using the model-specific signal from the table above
3. Listen for a crisp, immediate click. CL4 is a high-precision clutch because its engagement timing directly controls print registration — it should respond with no audible lag when commanded in service mode
4. Also check the registration roller nip condition:
   • Remove the right-side cover to access the registration roller pair. Manually rotate the registration roller with CL4 de-energized — it should turn freely with light, even resistance
   • Check both rollers for wear grooves, glazing, or debris buildup on the roller surface. A registration roller with a debris ring on the rubber surface grips the paper unevenly, causing the leading edge to buckle asymmetrically and taking longer to complete the loop — this produces intermittent 10-02 that appears random but is actually correlated to paper alignment relative to the worn groove on the roller
   • Clean the registration roller surfaces with a damp lint-free cloth. If the rubber is worn to a visible groove, the registration roller pair should be replaced
5. If CL4 engages correctly and the registration rollers are clean, CL4 is not the cause. Proceed to Step 7

Step 7 — Inspect the Vertical Transport One-Way Spring Clutch Gear (High-Volume and Older Series Models)

This step addresses the most commonly missed field cause of persistent 10-02 (and simultaneous 11-02) on high-volume bizhub machines. It is field-validated by experienced technicians as the root cause on machines above 800k–1M+ copies where roller replacement, clutch replacement, and loop value adjustment have all been performed without resolving the intermittent registration delay.

In the vertical transport section between the Tray 1/bypass feed area and the registration roller, there is a drive gear on the vertical transport roller shaft that contains an internal one-way spring clutch. This spring clutch allows the roller to free-spin in one direction (preventing paper double-feeding on reverse transport) while locking firmly in the drive direction to carry paper upward to the registration roller at full speed. Over time — typically at 800k–1.75M copies depending on machine usage pattern — the internal spring weakens and the gear begins to partially slip in the drive direction. This means the vertical transport roller is no longer driving paper at full motor speed; it is delivering paper at 85–95% speed, consistently arriving at the registration nip just outside the loop formation window.

This part appears as a plain gear in the parts catalog on some model families (with no indication that it contains an internal spring clutch), which is why it is frequently overlooked. Field technicians on copytechnet.com have explicitly documented this part as the solution for persistent 10-02 / 11-02 after all other components have been replaced.

1. Access the vertical transport section — typically accessed through the right-side cover area of the machine body. On most bizhub models, the vertical transport roller is the roller that guides paper from the Tray 1/bypass feed area upward to the main transport path leading to the registration roller
2. Locate the one-way spring clutch gear on the vertical transport roller shaft. On bizhub C452/C552/C652 and similar platforms, this is referenced as a 22T gear in the parts catalog but functions as a spring clutch. On other model generations, the equivalent gear is in the same general position — on the vertical transport roller shaft that bridges the feed section and the registration section
3. To test whether this gear is slipping: with the machine powered off, manually rotate the vertical transport roller shaft in the drive direction (the direction paper would be pushed). If the gear on the shaft turns freely in the drive direction rather than locking, the spring clutch has failed — it should resist rotation in the drive direction with firm, even resistance
4. There are typically two of these spring clutch gears on this shaft — replace both as a pair. Replacing one and leaving a worn one produces an unbalanced transport roller nip that causes paper skew in addition to timing delay
5. When fitting the replacement gears, confirm the drive direction orientation before pressing them onto the shaft — an incorrectly oriented spring clutch gear prevents all drive to the transport roller and produces 10-01 (not 10-02) from both bypass and Tray 1
6. After replacement, run a 30-page test from the bypass tray and a 30-page test from Tray 1. If both 10-02 and 11-02 were present before, both should clear after replacing these gears — confirmation that the shared vertical transport gear was the common root cause

ℹ️ Field note on the spring clutch gear diagnosis: When a bizhub is producing intermittent 10-02 from the bypass AND intermittent 11-02 from Tray 1, and the jam interval is approximately every 20–40 pages, and standard roller/clutch/solenoid replacement has not resolved it — the vertical transport one-way spring clutch gear is almost certainly the root cause. The ~20–40 page interval corresponds to the spring clutch slipping at a specific paper-transport load point repeatedly. Adjusting the registration loop value to maximum (+5) typically extends the jam interval but does not eliminate it. Replacing the spring clutch gears eliminates the jam entirely. These gears should be carried as a standard spare part by any technician servicing high-volume bizhub machines.

Step 8 — Check the Transport Motor (M1 / M22 / M27) in Service Mode

A transport motor running at reduced speed delivers bypass paper late to the registration sensor, directly causing 10-02. Unlike a failed motor (which causes 10-01 with no paper movement), a motor running at 90–95% of rated speed delivers paper that is consistently 15–30 ms late — exactly the pattern that causes registration loop timing failures.

1. In Service Mode, navigate to the motor load check section
2. Command the transport motor using the model-specific check signal from the table above:
   • BASEB models (C250i/C360i/C3350i): M1, Check code: 40, Signal: BASEB CN19EA-1 to 5 or BASEB CN17E-1 to 5
   • MFPB+FRB models (C258/C368/368e/C458/658e): M1, Check code: 40, Signal: MFPB CN8E-3 or MFPB CN14E-3
   • PFTDB models (654e/754e/758/808/958/C659/C759): M27, Signal: PFTDB CN9-1 to 4 or CN9-3 to 6; also check M22 (paper feed motor) at PFTDB CN10-1 to 4
3. Listen carefully while the motor runs. Normal motor operation produces a clean, even hum. Signs of a degrading motor include:
   • Irregular speed — audible speed variations during the run check
   • Grinding — bearing wear in the motor assembly
   • Hesitation — momentary stalls during the run cycle, indicating winding degradation
4. Also monitor the motor LOCK signal (speed feedback) at the motor connector during the run check — an unstable LOCK signal that flickers between valid and invalid indicates the motor speed feedback encoder or the motor winding is producing intermittent signals, causing the board to vary motor speed as it attempts to correct to setpoint
5. Check the motor drive connector for proper pin contact. A partially seated motor connector causes intermittent drive voltage drops that allow the motor to run at variable speed — producing intermittent 10-02 rather than a consistent failure that would be easier to identify
6. If the motor runs erratically or produces abnormal noise, replace M1 or M27 as appropriate. Before motor replacement, check the board-level ICP or fuse protecting the motor circuit — a partially blown protection component is the correct diagnosis when the motor shows intermittent speed anomalies

Step 9 — Check the Registration Sensor (PS1 / PS9 / PS4) Response Speed

For 10-02, the registration sensor check focuses on response timing rather than basic switching function. A sensor that activates correctly but with a slight mechanical delay — due to a sticky actuator flag, a contaminated sensor slot, or a flag that is slightly bent and must travel further to interrupt the beam — reports paper arrival later than the actual paper position, which from the machine’s perspective looks identical to paper arriving late.

1. In Service Mode, navigate to the sensor I/O check section
2. Monitor the registration sensor using the model-specific signal from the table above
3. Physically inspect the sensor slot and actuator flag:
   • Open the right-side cover to access the registration sensor area. Inspect the sensor beam slot for any paper dust, toner dust, or paper fiber accumulation — a partially obstructed beam slot causes the sensor to register activation later in the paper’s travel than it should
   • Clean the sensor slot with a puff of compressed air followed by a lint-free cloth wipe
   • Check the sensor actuator flag — the small plastic pivot arm that crosses the beam when paper arrives. The flag should pivot freely and snap back immediately when paper passes. A flag with sticky or stiff pivot action delays the beam interruption relative to actual paper position. Clean the pivot point and confirm free movement
4. Manually advance a sheet of paper into the bypass path and watch for the sensor signal transition in service mode — it should switch instantly (no visible lag) as the leading edge crosses the beam. A delayed or slow transition that is visible in service mode display confirms sensor contamination or flag stiffness as a contributing timing factor to 10-02

Step 10 — Replace the Control Board (Last Resort)

If all mechanical components are confirmed functional, the registration loop adjustment is at maximum positive value, sensor response is clean, and 10-02 still fires consistently from the bypass tray, a board-level timing fault in the clutch engagement sequencing circuit is the remaining cause. Board replacement is the last resort after all mechanical and adjustment options are exhausted.

• Replace BASEB — bizhub C250i/C300i/C360i, C3350i, C4000i, C4050i
• Replace FRB, then MFPB — bizhub C258/C308/C368, C458/C558/C658, 458e/558e/658e, 368e/308e (try FRB before MFPB — FRB controls CL4 and CL7 timing signals on these models)
• Replace MFPB — bizhub C224e/C284e/C364e, C224/C284/C364
• Replace PRCB or MFPB — bizhub 223/283/363/423, C454/C554
• Replace PFTDB, then MFPB — bizhub 654e/754e, 758/808/958/PRO 958, C659/C759 (PFTDB controls M27 and all bypass timing on these models; try PFTDB before MFPB for isolated 10-02 codes)
• Replace EXCB, then FRB, then MFPB — bizhub C450i/C550i/C650i, 458i/558i/658i

Quick Reference — Troubleshooting by Symptom

Symptom	Most Likely Cause	First Action
10-02 intermittently — bypass works fine for 20–50 pages then jams	Marginally worn bypass pickup roller or feed roller; or vertical transport one-way spring clutch gear slipping on high-volume machines	Clean bypass pickup roller; increase registration loop adjustment by +1 to +2; if no improvement, inspect vertical transport spring clutch gear
10-02 only on heavy card, labels, or coated paper — standard copy paper feeds fine	Bypass pickup roller or feed roller surface texture insufficient for heavier/smoother stock	Clean bypass rollers thoroughly; test with the problem media; if 10-02 recurs within 50 pages of cleaning, replace the full roller set
10-02 only when bypass tray is fully loaded — works fine with 20 or fewer sheets	Excessive bypass stack compressing top sheets and slowing pickup roller initial engagement; or pickup roller spring pressure too heavy from over-full tray	Reduce bypass stack to 15–20 sheets for the specific media type; if still intermittent with reduced load, inspect pickup roller surface
10-02 AND 11-02 both firing — bypass and Tray 1 both producing registration delays	Vertical transport one-way spring clutch gear slipping in shared main transport path (dominant field-confirmed cause)	Inspect vertical transport spring clutch gear on the shared VT roller shaft; test for slipping by manual rotation in drive direction; replace both gears as a pair
10-02 with slight paper skew on leading edge of affected prints before jamming	Vertical transport roller one-way spring clutch gear partially slipping asymmetrically; or registration roller surface worn with a groove	Inspect vertical transport spring clutch gears (replace as pair); inspect registration roller surfaces for wear groove; clean registration rollers
10-02 in high-humidity environment or after environmental change	Paper moisture causing reduced sheet stiffness; damp paper slows through the registration path and takes longer to form the loop buckle	Fan and air out paper stack; switch to fresh sealed ream; try paper from a different ream; increase loop adjustment by +1 temporarily
10-02 after bypass roller replacement — jam codes started after PM	Loop adjustment value not reset after roller replacement (new rollers may feed slightly faster, changing loop timing); or incorrect roller installed	Check registration loop adjustment setting and reduce by -1 from current value if positive; confirm correct roller part numbers for the machine
SD1 audibly slow or lift plate rising sluggishly on service mode test	SD1 coil weakening; degraded SD1 connector causing reduced supply voltage; mechanical binding on lift plate pivot	Reseat SD1 connector and test voltage at pins; inspect lift plate pivot for binding; replace SD1 if sluggish pull-in confirmed with good connector
CL7 engaging with audible lag in service mode check	CL7 clutch face worn; marginal connector contact causing voltage drop at coil	Reseat CL7 connector; test voltage at coil connector pins during energization; replace CL7 if engagement lag confirmed with good connector voltage
10-02 persists after roller replacement, spring clutch gear replacement, maximum loop adjustment, and confirmed component function in service mode	FRB (on MFPB+FRB models) or PFTDB (on PFTDB models) board-level clutch timing sequencing fault	Replace FRB before MFPB on applicable models; replace PFTDB before MFPB on high-volume models; replace BASEB on i-series

Understanding the -02 Loop Forming Jam Code Family

Jam Code 10-02 belongs to a family of loop forming failure codes that share identical detection logic but apply to different paper sources. Understanding this family is essential for interpreting combinations of codes and for correctly identifying shared-path root causes:

• 10-02 — Bypass tray registration loop forming failure. Paper from the manual bypass tray reached the registration area but arrived too late for the loop to form before CL4 fired. This article
• 11-02 — Tray 1 registration loop forming failure. Identical detection logic and identical timing mechanism as 10-02, but originating from Tray 1. When 10-02 and 11-02 appear together, the fault is in the shared main transport path between the feed sections and the registration roller — specifically the vertical transport one-way spring clutch gear. Simultaneous 10-02 and 11-02 should never be diagnosed as two independent feed assembly failures
• 12-02 / 20-02 — Tray 2 and vertical transport section loop forming failures. Same detection logic, further upstream in the paper path. When 20-02 accompanies 10-02 and 11-02 simultaneously, the fault is in the registration section itself — typically a CL4 that is engaging abnormally early, or a board-level timing anomaly affecting the registration engagement sequence
• 10-01 — Bypass tray primary misfeed. Paper never reached the detection sensor. Unlike 10-02, this code indicates a complete bypass feed failure — no paper movement, not late paper movement. The distinction is critical: 10-01 requires a different diagnostic approach (solenoid/clutch/motor completely failing) versus 10-02 (solenoid/clutch/motor working but marginally slower than required)
• 10-04 — Bypass tray registration sensor/2 (PS72) not activated — bizhub 658e/558e models only. PS72 is the second registration sensor on these models that confirms the full paper width has entered the registration nip. 10-04 alongside 10-02 on these models points to paper skewing in the bypass path, which is consistent with a partially slipping vertical transport spring clutch gear causing asymmetric paper delivery

Preventing Jam Code 10-02 From Recurring

• Include the bypass pickup roller in every PM regardless of bypass usage level. The bypass roller glazes from intermittent high-stress feeding — heavy card, labels, letterhead — faster than the consistent copy paper feeding that tray rollers receive. A bypass roller that is lightly glazed will produce 10-02 on smooth or heavy stock before it looks visibly worn. Clean or replace it at every PM
• Check and document the registration loop adjustment value at every PM. The loop value drifts as rollers and clutches wear. At each PM, note the current setting, perform roller and clutch replacement as needed, and reset the loop value to 0 or to the value that provided best performance after replacement. A machine running at +4 or +5 after a PM is telling you the mechanical components are still marginal after replacement
• Inspect the vertical transport one-way spring clutch gear at every major PM on high-volume machines above 600k copies. Add this to the standard checklist for machines that process above 8,000–10,000 pages per month. A simple manual rotation test (30 seconds) confirms whether the spring clutch is still locking in the drive direction. Replace both gears as a pair at the 800k–1M copy mark as a proactive measure on busy machines rather than waiting for 10-02 and 11-02 to appear
• Advise customers to use uncurled, correctly specified paper in the bypass tray. The majority of recurring 10-02 calls between PM visits in office environments are caused by curled or incorrectly specified paper. A brief customer education at each PM visit — covering the importance of un-curling paper before loading, reducing stack size for heavy stock, and using fresh paper from sealed reams — significantly reduces between-PM 10-02 occurrence
• Run the post-PM bypass test with the same media type the customer uses, not standard copy paper. A machine that passes a post-PM test on 80 g/m² copy paper but produces 10-02 on the customer’s 200 g/m² card stock has not been correctly tested. Always run the post-PM bypass test on the heaviest or smoothest stock the customer uses regularly from the bypass tray

Professional Technician Summary

Jam Code 10-02 is the bypass tray’s timing-sensitive registration loop forming failure — a code that is frequently more frustrating to diagnose than 10-01 precisely because the bypass mechanism appears to be working. Paper is moving. The sensor is activating. The clutches are engaging. Everything looks functional in isolation, yet the jam code persists.

The key to efficient 10-02 diagnosis is remembering that 10-02 is a marginal timing failure, not a component failure. Every component in the path is working, but one or more are working 10–15% slower than specification. The diagnostic task is identifying which component is introducing the latency.

For isolated bypass 10-02 with no Tray 1 involvement: Start with the bypass roller surfaces (clean or replace), then check the registration loop adjustment and increase it by +1 or +2, then verify SD1 actuates crisply (not sluggishly), then verify CL7 engages immediately (not with lag). These four interventions resolve the majority of isolated bypass 10-02 calls.

For simultaneous 10-02 and 11-02 from both bypass and Tray 1: Go directly to the vertical transport one-way spring clutch gear before touching any individual tray component. This shared-path component is the field-confirmed root cause when both trays produce registration timing failures simultaneously, particularly on machines above 800k–1M copies. Experienced technicians carry these gears as a standard spare and report them as a top-five recurring failure item on high-volume bizhub installations. Replacing these gears while the rollers, clutches, and loop adjustment are already within serviceable range resolves the combined 10-02 and 11-02 pattern immediately and completely.

Board replacement is a genuine last resort for 10-02. The component interactions involved in loop forming timing are mechanical and well-documented, and every mechanical and adjustment option should be exhausted before condemning a board for a timing-based jam code on the bypass tray.