Mimaki UCJV300 "Error 1db" - Need help diagnosing and fixing

[HGdesign]

Not sure if this is a related question, but I am not clear what the second Sub Power switch is for on the printer? Referring to the main 120V power coming in, and two main rocker switches. The main one seems to power up everything, and supplies the Power supply. I see the manual says to switch off the Sub switch first when powering down. But I am not clear what that second sub power line does inside the machine.

So far I can confirm that 36V is at the start of the station iv PCB, and on both sides of Fuse 1. The 5v power supply is outputting 5v, but I have not been able to confirm 5v at this PCB yet. I believe F2 is supposed to have 5V, but has 0. I will work on trying to understand the path it is coming going and checking these voltages you both suggested today and reply back.
Thank you!

 

[HGdesign]

Update with some more data

 

[Smoke_Jaguar]

Second switch/power socket is usually not connected, as it's just a generic one for bed heaters on the solvent printer variants. On later models it is blocked off.

 

[HGdesign]

Here is what I can confirm so far:
-Main PS 36V consistent 35.9 whenever I check
- Small 5V PS also seems good at 5V output

For Main PCB , I have EPL3 version:
- 5V at CN14 coming into top right of board
- 5V at F1 Fuse
- 5V at F8 nano fuse

Station IV PCB:
- 36V at CN2 connector coming into board
- 36V at both sides of Fuse 1
- 36V across large capacitor to the right of CN24
- 22mV at F2 fuse <---- I believe this should be 5V ---
- 22mv at the round coil ferrite buck to the left of F2 -- thinking this should be 5V as well.
- OV at all other round coils
- 0 LED's lit on this board
- For the missing 5V at this PCB, I am not clear if that is supplied via the FFC cable from the main PCB. It seems like it is according to diagram 2.1 attached.
- I don't see any other direct 5v supply being noted for this PCB
- I am taking Voltage measurements with a meter from ground to various points on PCB's noted above where I expect there to be certain voltage.

- I am not sure what pin 5V would be coming from across the FCC and not sure if I can use a meter and take a voltage reading at each output wire on that FCC or do I risk damaging the main PCB using that approach?
Thank you

 

[HGdesign]

 

[HGdesign]

 

[kehall]

I think you're on the right approach to see if you're getting 5V from main pcb CN9 - you could measure from F1 and the conductors on the other end of cable (unplugged from CN1 on Sta4 pcb) - looks like there's 36V via there too (from F4), and also the ground to check.

Even if you get continuity to F1, it doesn't mean the cable is good, as I have found. Get a new 20 pin FFC of the same type and swap it. Not going to say it'll work (it's not subject to movement really is it), but it's cheap and easy to rule out.

 

[HGdesign]

I think you're on the right approach to see if you're getting 5V from main pcb CN9 - you could measure from F1 and the conductors on the other end of cable (unplugged from CN1 on Sta4 pcb) - looks like there's 36V via there too (from F4), and also the ground to check.

Even if you get continuity to F1, it doesn't mean the cable is good, as I have found. Get a new 20 pin FFC of the same type and swap it. Not going to say it'll work (it's not subject to movement really is it), but it's cheap and easy to rule out.

Ok, I will go ahead and measure the FCC and reply back. Is there a way to know which pins on the FCC should have voltages, or should I just check each one?
- I did try calling some mamiki sellers including my local supplier and am surprised how so many part numbers are not stocked and have long lead times.. Currently still waiting for simple flushing solution 07 to arrive. Is this your experience as well?
- Any recomndations where to buy the FCC cables, or should I just wait for Mimaki dealer
- As for getting PCBs, I am being told it may take a few weeks, and seeing some Aliibaba sellers saying it would cost less and likely get here faster. Have you guys tried any reliable sources on Alibaba, or stay local for everything?
Thank you

 

[Smoke_Jaguar]

In most instances, Chinese sellers and eBay seem to be higher than ordering parts through a dealer. Can try hitting up AmCad in Dallas, they tend to be pretty reasonable and parts will arrive quicker (and also tend to be current versions, as AliExpress ones might be obsolete versions).

 

[kehall]

Ok, I will go ahead and measure the FCC and reply back. Is there a way to know which pins on the FCC should have voltages, or should I just check each one?

You can check continuity when powered off from the fuses to the ends of the cable (and check grounds too) to find out. What it won't tell you is if the connection is poor when cable is inserted (e.g. high resistance), which can happen. It may help you locate some test points on the inbound side of the various voltages on the Sta4 board though, so you can check when next powered up.

I've not seen any Mimaki docs get to level of schematics I'm afraid. Seems to be the way of the world now, at one time you'd get a schematic with the equipment - nowadays service manuals are all 'replace board' rubbish with no detail which is terrible given a good portion of faults could be just a single component for pence. Board replacement is quick though so where downtime costs money, the expense could possibly be justified.

You can get FFC cables almost anywhere. You know the number of "pins", so just check the length, pitch (e.g. 1mm) and type/direction - there are A-A and A-B types sometimes called forward/reverse (the exposed conductors are either same side or opposite sides when laid out flat).

 

[HGdesign]

Some updates:
I did a number of tests using this technique and seemed like continuity is there back to the main PCB. Checking voltages made me suspect the the MOSFET on the back of the station 4 board may be the issue because it has 36V at the source before powering up, but then 36V at the Gate after power up. I am not sure, but think that is not right. I think the Gate is supposed to have 5V to control the MOSFET and then the 36V should go thru to the Drain, but that shows zero.
- Anyway, I had ordered some parts just incase it came down to that and some of them arrive today including a new station 4 board
- I am nervous about something downstream being the problem. So I put it in and only connected the two minimum connections: CN1 (36V) and CN9 ( from the main PCB)
- The good news is that upon powering up from the front panel, I finally got a series of LEDs light up on this new Station IV board
- The "potentially bad" news is that within about 15 seconds into boot up, the machine cut off the power by itself and the power supply went silent, and the LCD turned off
- Do you know if this is a normal safety feature because I have about 10 other connectors not hooked up to the station 4 board?
- Or do you think I may have damaged the new board or something else in this process
- To be safe, I have not reconnected or tested again and hoping to get some feedback from you veterans before trying again.
I appreciate any guidance, on how to proceed. My hope was to connect only one thing at a time, and work my way up to all connections begin made. Again my fear: Could there be something downstream that caused the PCB damage, and if so, how can I find it, and how can I avoid it from repeating.
Thank you!

 

[kehall]

The mosfet is likely P-channel that needs the gate driving negative in respect of the source voltage to activate, so it's 'OFF' state is with the gate at the same potential as the source with a pullup resistor - it's probably driven from a tiny NPN bipolar transistor to pull the gate to ground via a 10k resistor or so. I wouldn't worry about that so much (it'll probably be activated by the FPGA once all the other preliminary startup tests complete)...

As for the shutdown I don't know if that is expected behaviour or not, but I think it could be worth a second try, I've certainly tested things without other stuff attached on the UJF - typically results in other errors though, not a shutdown.

Stupid question, is there a separate power switch at the front like on the UJF that needs to be on - I've had the UJF come on with main power, only to shut down a short time later because the front power switch was in the off position (it's a 'soft' power control)..

 

[HGdesign]

The mosfet is likely P-channel that needs the gate driving negative in respect of the source voltage to activate, so it's 'OFF' state is with the gate at the same potential as the source with a pullup resistor - it's probably driven from a tiny NPN bipolar transistor to pull the gate to ground via a 10k resistor or so. I wouldn't worry about that so much (it'll probably be activated by the FPGA once all the other preliminary startup tests complete)...

As for the shutdown I don't know if that is expected behaviour or not, but I think it could be worth a second try, I've certainly tested things without other stuff attached on the UJF - typically results in other errors though, not a shutdown.

Stupid question, is there a separate power switch at the front like on the UJF that needs to be on - I've had the UJF come on with main power, only to shut down a short time later because the front power switch was in the off position (it's a 'soft' power control)..

I have not been able to find another switch on the front. That said, on the keypad, there is a "Enter" button that lights up in blue when the machine is turned on. That continued to be blue after the power seemed to shut down and screen turned off.
(And I think it is Pchannel based on part number)

Have you ever had PCB's need replacement? One of the things that continues to worry me, is do PCB's tend to just fail sometimes and simply need to be replaced without there being an external cause. I would love to hook up everything and power it up but concerned if a component external to the PCB on one of the connectors may be shorted, etc. and cause a repeat board failure. It does appear that my station 4 PCB certainly had some issue based on the new one at least powering up. Just trying to think if there are other preventive steps I can take before trying again just incase. The boards being hefty priced and long lead times being the reason.

2 additional questions:
- During the boot up, does the machine go thru any steps such as trying to move carriage, pump inks, circulation pumps, etc. ? If it does do some kind of startup routine, then trying to think which items I can try to manually check first to make sure they don't have shorts, or spin freely, etc. This machine had been sitting unused for many months before it they powered up to sell and I was told thats when this error occurred. Not being the original owner, I have limited knowledge of its history. Wondering if the lines, valves, pumps, heads etc. could be clogged, and if the machine tries to run those during startup if that could have caused a failure to the PCB / PCB's

- And is there a way to save/ store the parameters from the machine main board when I can't fully boot up? Just incase I mess up something and need to replace the mainboard I would need to restore parameters.

Thank you again!

 

[HGdesign]

I have some good news. I tried to add a few more connectors and boot again and it repeated the earlier test with lights on the new station iv PCB followed by shutdown about out 15 seconds.
I decided to go ahead and connect the CT board, and remaining connectors and try again and, thank God, the machine powered up and stayed on this time!
Here is what it went thru on the screen:
- Boot
- RTC-IC Ok, Ether Ok, Very quickly with a beep sound
- UCJV300 Start-up
2.2
This stayed on the screen for about 20seconds
The large curved smile shaped led at the bottom of the control panel started flashing red color
- Then it switched to a screen with blue tab across the top : F/W UPDATING *TRANSMIT START *
- Then about 10 seconds later, 3 orange tabs went by " EXPIRATION 1 month, 2 month, --- ( these I think I referring to the inks being expired as expected)
- And then in a few more seconds it returned to the Blue tab : F/W Updating as noted above.
The tabs on this screen corresponding to "Func1", "Func2", "Func3" buttons are all grey and pressing them did not do anything
- I waited about a minute and then powered off the machine by holding down the END/Power button that changed the screen to "Mimaki logo -- Power Off 2.2"
I am attaching pictures of the screens

--My thought is the the blue screen is regarding a firmware update ? Not sure what I need to do. If this is normal, good, bad?
-- Very grateful to see the machine power up. Still nervous what caused the issues to begin with and how to proceed from here.
Looking forward to any guidance from you all. Thank you so much once again!

 

[HGdesign]

 

[HGdesign]

I was able to make further progress today. There was another forum here that stated the "F/W updating..." error has to do with the keyboard enter key stuck. That pointed me in the right direction, although none of my keys were stuck, but turns out the pcb is very sensitive to contaminants on the surface. I took the front panel apart, checked buttons and FCC with a meter, and everything looked clean and to be in good order. With the problem not going away, I decided to clean that keyboard pcb with isopropyl alcohol and cleanroom swabs. I was able to take off a fine residue on its front face which I thought would not accomplish anything, but thankfully it allowed the machine to finsih booting up without the error. I am now able to boot up the machine and navigate the menus etc. with all the keys responding.
There are 2 ink bottles that are expired, and I get an "I can't print / BOTTLE" error on the Home Screen.
- I am not ready to print yet anyway as I want to carefully clean out the ink supply to the heads as best I can to avoid damage from clogs since the printer has been sitting a long time.
- It seems the menu will not let me run some of the head wash etc. yet either. Wondering if that is due to the expired ink error above?
- I tried booting into service mode by holding the "Fun1" and "Func3" keys during boot up, but failed to get into service mode. I was able to get into parameters mode by holding the right and left arrow keys during power up. Please let me know if there are different versions that were made to get into the service mode and precise set of key press / timing etc. that I need to follow? My machine is on firmware 2.2, model UCJV300 with the EPL3 mainboard
- I want to reset the clock, and also save all the parameters incase something gores wrong and I need them.
Thank you!

 

[Smoke_Jaguar]

Ancient firmware, 3.4 is current.

 

[HGdesign]

Ancient firmware, 3.4 is current.

I'll wait some days before trying to do firmware updates just to make sure the machine is operating in a stable manner and not going to hang in the middle of an update.
Any suggestions on the process to get into the service mode on the 2.2 version and reset the clock
Thank you

 

[Smoke_Jaguar]

Func1 and Func 3 when booting up, wait until you hear a beep and let go. Will give you access to #ADJUST menu so you can set time/date. If a chip is flagged as expired, this will NOT clear that state.

 

[HGdesign]

Func1 and Func 3 when booting up, wait until you hear a beep and let go. Will give you access to #ADJUST menu so you can set time/date. If a chip is flagged as expired, this will NOT clear that state.

I tried Func1 & 3 without success. Tried to do about 15 attempts including letting go at the beep, letting go after, holding power as well (but then no beep occurred) ... Each time it powers up into the main Home Screen with the ink levels at the bottom
- Is there a particular timing that I have to hit to make it work?
- Do I hold down the F1 & 3 button, and then press the power button
- Do I need to hold the power button as well, or release that right away
Not seeing what I am missing.