Heater display Falcon 38 Junior dead/not working

[CRD]

Due to an earlier unnoticed inkleak in the pump the flat cable from the heater board to the heater display was damaged. The white parts on both sides of the cable had come loose and exposed the metal. During the pump change I might have actually shorted the exposed cable wires when removing and installing the heater control panel again.
The display was dead so I switched it OFF directly and I pulled the flatcable on the heater board in the machine. The heaters still work and stay at the last used setting of 50 degrees celsius. I took the cable out and cleaned it. With a knife I removed the damaged white parts and cleaned the metal wires. Took a piece of high tack vinyl and pressed the metal wires evenly spaced at one side. Then put an other piece of vinyl at the other side. Checked the cable for end to end conenction and for ohmic shortage between the wires but the cable is 100%.
Reconnecting the cable between heater board and display still no display or button press acceptance. Heaters still work to the 50 degrees setting stored in the machine.

Any one ever had the heater display board or heater main board gone bad and might guide me to either one of them instead of both.

Thanks, Paco

 

[chorca]

it sounds like you're pretty tech savvy, have you had a quick look through the photos on my blog post to see if you're putting the cables in right? They should be pretty easy to get in there, and I had one of my cables damaged by ink as well, but luckily they didn't short.

Ribbon Cables

 

[CRD]

Chorca,

Yes I am an technical engineer.
I forgot when removing the cable to check if the blue tabside should be to the front of the machine.
I know how the cable goes into the heat board display and I checked you rebuild (wonderfull write up).
The cable in the main board should go with the contacts to the rear (blue in the front) of the machine? I checked with a small mirror for the contacts. Also the bending of the cable made me believe I was correct.
If not let me know! Do not know what happens if the cable is put reverse except no contact from connector to cable.....

Paco

 

[chorca]

Yeah, it sounds like you did it right. Looking at the picture i took, the pins are going to be on the backside, so the blue tape should go towards the front of the machine.

If it did short, who knows what might have been damaged by it.. Seems maybe something on the heater control panel or one of the interface chips, since the heaters are still working, that means the SSRs and all that on the board are operational. Not sure if there's fuses anywhere for it.

 

[CRD]

If I have time I can take the heater main board out to check for fuses. I gues they would only be ther efor the high current lines to the heaters. But all works except for the temp keys not responding and the blank display.
With 4 keys it should take four lines from the 26 line cable then plus and minus take one also so 20 left for the display.
If I had electric schematics it would more simpler to track the problem.
I can try to measure if there is anything at all at the heater display concerning voltages.

Paco