Fixing Mimaki JFX200 - SYSTEM HALT (1) 13d: PCB SLRY-F3

[DustinH]

I recently had a catastrophic failure for my JFX200 printer and had to pioneer a fix because there was no information about the problem. For the benefit of the community I am documenting the process in case it helps anyone in the future even though this is a somewhat advanced fix. It did however save the slider relay board, which has worked well since.

The Problem (Symptoms)​

The trouble started mid-print. The machine suddenly stopped while the carriage was moving, threw a SYSTEM HALT error, and—dumped all the ink out of the heads.

We saw a mix of confusing errors:

1. JFXT PRINT (SCAN DIR.): The freeze happened specifically while the carriage was moving.
2. SYSTEM HALT (1) 13d: PCB SLRY-F3: The printer claimed the heater fuse (F3) was blown.
   • The deceptive clue: The LED next to F3 on the slider relay board was faintly lit. We initially thought this meant the fuse was blown, but it actually meant the voltage rail itself was "browning out" (starving for power) because the diode feeding it had failed.
3. SYSTEM HALT (6) 811: FW/SIO read: This popped up when we bridged over the J601 diode (explained later), killing the LCD backlight and crashing the brain of the machine.

The Investigation (Finding the Short)​

We chased the F3 error for a while, but the fuse tested fine (zero ohm resistance). The real issue was that Diode J601—located right next to Fuse F3 on the Slider Relay Board failed. The diodes we replaced it with also failed.

The breakthrough happened when we realized the crash was triggered by motion. We physically inspected the carriage wiring and found the culprit: A crooked FFC (Flat Flexible Cable) connected to CN2 on the HDC PCB (Head Control Board).

Because the cable was crooked (or had conductive ink fuzz in it), the vibration of the carriage moving caused the pins to cross. This sent a massive short-circuit spike through the system.

• Why the ink drained: It wasn't a solenoid failure; the short caused the printer's "brain" (CPU) to crash instantly. When the brain dies, the negative pressure system loses control, and gravity takes over, emptying the ink.

The "Frankenstein" Circuit Repair​

The component J601 is a Dual Schottky Diode with two input legs and one large output tab. Mimaki designed this with two parallel power channels to split the heavy electrical load (Amps) required by the heaters.

Since J601 is hard to fully desolder without damaging the board, we improvised a solution using two separate SR5100 Diodes (5A/100V) found on Amazon.

The Procedure:

1. Disconnecting the Old: We used a soldering iron to lift (disconnect) the two input legs of the old J601, effectively taking it out of the circuit without removing the chip body. This is probably not required, but I wanted to be safe.
2. Mounting the New Diodes:
   • The Output (Silver Band): We soldered the silver-band side (Cathode) of both new diodes directly onto the large, exposed heat-sink tab of the old J601.
   • The Input (Black Side):
     • Diode 1: Soldered to the remaining good pad where the old leg used to be.
     • Diode 2 (The Flywire): Since the second pad was ripped off after the first repair attempt, we traced the circuit back to the input. We found a set of Vias (small holes) right next to the FFC connector coming from the Main PCB. After confirming with a multimeter that these vias were directly connected to the power input, we ran a "flywire" (jumper wire) from the Diode 2 input leg directly to these vias.

This restores the original design: two parallel power paths sharing the load, keeping the diodes cool and the power stable.

The Expensive Lesson (The Main PCB)​

Early in the troubleshooting process, we made a critical mistake: We thought it would be okay to bypass the blown J601 diode with a simple jumper wire. Turns out the diode is a safty to protect against shorts like this. When we bridged it with a wire, we removed that protection. The next time the short circuit occurred, the electrical spike traveled backward down the line and fried the 36V Power Regulator on the Main PCB. We had to purchase a replacement Main PCB. Fortunately, we found one that came with the firmware pre-loaded, so we avoided the nightmare of having to flash a blank board.

Final Summary​

• Root Cause: Crooked FFC on the HDC Board shorting during movement.
• Casualties: Diode J601 (twice) and the original Main PCB (due to the jumper wire mistake).
• Solution: Re-seated the FFC to clear the short, and installed dual SR5100 diodes with a flywire to handle the power load safely.

 

[damonCA21]

Well done on the repair, but yes, never replace a diode with a direct connection, they are there for a reason! I have worked on boards where people have soldered in wires to replace fuses - fine until you get a short and that voltage goes where it shouldnt

 

[Smoke_Jaguar]

Avoid components from Amazon like the plague. Legit good stuff from Mouser and Digikey tends to be cheaper, way more reliable and tends to arrive pretty quickly.

 

[netsol]

I recently had a catastrophic failure for my JFX200 printer and had to pioneer a fix because there was no information about the problem. For the benefit of the community I am documenting the process in case it helps anyone in the future even though this is a somewhat advanced fix. It did however save the slider relay board, which has worked well since.

The Problem (Symptoms)​

The trouble started mid-print. The machine suddenly stopped while the carriage was moving, threw a SYSTEM HALT error, and—dumped all the ink out of the heads.

We saw a mix of confusing errors:

1. JFXT PRINT (SCAN DIR.): The freeze happened specifically while the carriage was moving.
2. SYSTEM HALT (1) 13d: PCB SLRY-F3: The printer claimed the heater fuse (F3) was blown.
   • The deceptive clue: The LED next to F3 on the slider relay board was faintly lit. We initially thought this meant the fuse was blown, but it actually meant the voltage rail itself was "browning out" (starving for power) because the diode feeding it had failed.
3. SYSTEM HALT (6) 811: FW/SIO read: This popped up when we bridged over the J601 diode (explained later), killing the LCD backlight and crashing the brain of the machine.

The Investigation (Finding the Short)​

We chased the F3 error for a while, but the fuse tested fine (zero ohm resistance). The real issue was that Diode J601—located right next to Fuse F3 on the Slider Relay Board failed. The diodes we replaced it with also failed.

The breakthrough happened when we realized the crash was triggered by motion. We physically inspected the carriage wiring and found the culprit: A crooked FFC (Flat Flexible Cable) connected to CN2 on the HDC PCB (Head Control Board).

Because the cable was crooked (or had conductive ink fuzz in it), the vibration of the carriage moving caused the pins to cross. This sent a massive short-circuit spike through the system.

• Why the ink drained: It wasn't a solenoid failure; the short caused the printer's "brain" (CPU) to crash instantly. When the brain dies, the negative pressure system loses control, and gravity takes over, emptying the ink.

The "Frankenstein" Circuit Repair​

The component J601 is a Dual Schottky Diode with two input legs and one large output tab. Mimaki designed this with two parallel power channels to split the heavy electrical load (Amps) required by the heaters.

Since J601 is hard to fully desolder without damaging the board, we improvised a solution using two separate SR5100 Diodes (5A/100V) found on Amazon.

The Procedure:

1. Disconnecting the Old: We used a soldering iron to lift (disconnect) the two input legs of the old J601, effectively taking it out of the circuit without removing the chip body. This is probably not required, but I wanted to be safe.
2. Mounting the New Diodes:
   • The Output (Silver Band): We soldered the silver-band side (Cathode) of both new diodes directly onto the large, exposed heat-sink tab of the old J601.
   • The Input (Black Side):
     • Diode 1: Soldered to the remaining good pad where the old leg used to be.
     • Diode 2 (The Flywire): Since the second pad was ripped off after the first repair attempt, we traced the circuit back to the input. We found a set of Vias (small holes) right next to the FFC connector coming from the Main PCB. After confirming with a multimeter that these vias were directly connected to the power input, we ran a "flywire" (jumper wire) from the Diode 2 input leg directly to these vias.

This restores the original design: two parallel power paths sharing the load, keeping the diodes cool and the power stable.

The Expensive Lesson (The Main PCB)​

Early in the troubleshooting process, we made a critical mistake: We thought it would be okay to bypass the blown J601 diode with a simple jumper wire. Turns out the diode is a safty to protect against shorts like this. When we bridged it with a wire, we removed that protection. The next time the short circuit occurred, the electrical spike traveled backward down the line and fried the 36V Power Regulator on the Main PCB. We had to purchase a replacement Main PCB. Fortunately, we found one that came with the firmware pre-loaded, so we avoided the nightmare of having to flash a blank board.

Final Summary​

• Root Cause: Crooked FFC on the HDC Board shorting during movement.
• Casualties: Diode J601 (twice) and the original Main PCB (due to the jumper wire mistake).
• Solution: Re-seated the FFC to clear the short, and installed dual SR5100 diodes with a flywire to handle the power load safely.

and you didn't trash that cable?

what i would generally do, is CUT THE CABLE INTO 3 PIECES and throw them away
(one of my employees used to take cables that looked OK out of the garbage and hang them up with the new ones)