Rant trying to fix a mutoh 1204a

[netsol]

i want to give out an award for worst service manual i have seen in 50 years in the electronic repair industry. (better than 35 yrs experience with wide format printing)

the 390 page mutoh service manual does not mention A SINGLE VOLTAGE OR TEST POINT in the entire service manual

for what it is worth, my machine would appear completely dead, except the data light flashes ONCE after pressing power button, power led does not light.

with back cover removed i can see led's lighting on main board and one of the others. nothing on heater board

led's go on and off with the power button, so i assume we have some sort of switched 5v.

no cycling of motors, etc

i am going to solder a test extension on to the fuses that are obviously not for the drive circuit for the printheads & fabricate an insulated bracket to allow me to flip the power board upside down &
make things reachable with an oscilloscope

i understand that marking testpoints is not a priority for the manufacturer since they have access to the inventory of replacement panels, but damn, they do not make it easy

if anyone has a drawing or any notes regarding voltage testing, it would be greatly appreciated

 

[Solventinkjet]

As a certified Mutoh tech for over 13 years, I agree. Although they tend to be better translated than Mimaki manuals, Mimaki at least has electronic troubleshooting guides for each machine. Mutoh's philosophy seems to be, if you get this error code, replace this part and don't ask questions.

As for your issue, if you're getting the data light to flash, a lot of the time you just need to take the memory out, air dust everything, and re-install. It's a quirk with the 1204s. That and there is a red ceramic fuse that sometimes blows and takes out the panel. I believe the power supply should be out putting 42, 24 and 5 volts. Sounds like you have the skills to test for that. Good luck!