ILX lighwave LDC-3742 repair

[h.bashar]

Hello EEVblog community, my first post here! My name is Hasanain and I am a control engineer from Sheffield/UK, I recently acquired a non-functioning ILX-Lightwave LDC-3742 laser diode driver unit, the unit powers up with error code E-413, checking the operation manual the code has to do with serial eeprom checksum error presumably on the TEC unit.
Unfortunately, a search on google failed to return a service manual for the unit and before I attempt removing the actual TEC module for inspection I was wondering if there are any laser aficionados here on the forum that may have scan of the service manual.

Best wishes

Update! I have examined the digital board and it does not contain any serial eeproms so I removed the TEC module and bingo! found the faulty (perhaps) 8 pin socketed chip by national semi 93C06EN, I am not sure if a replacement will render this unit functioning again , I suspect it holds some sort of calibration data or some look up tables for the temperature sensors. I will pick up one of these chips and give it ago and try to hack into the data on the faulty eerprom (6 x 16bit spi)and see what it contains. I have also attached some picture of the unit tear-down. If you guys have any input on this by all means leave a comment.

cheers

2nd Update!: I have dismantled the unit down to the power supply board, and measured all the voltages and they all appear to be correct, so it appears that the eeprom in question is indeed faulty!

3rd Update: At last some real progress!, the problem is not the eeprom, its the optoisolater connecting the TEC module to the MCU board, confirmed by swapping around the socketed 6n136, the unit no longer display the error code. I  have ordered several of those and will update soon.

[joaomcferreira]

Hi  Hasanain

I hope you have managed to repair your controller.
I have just come across your post  while searching a service manual for a similar equipment, LDC-3714B.
I was calibrating the quipment, according to User Manual and I found a problem with the measurement of the laser voltage, it always reads zero, either in the display or using GPIB interface. I would like to repair it.

Have you got any schematics, service manual or any usefull information that you can share with me?

Looking forward to hear from you.
Best regards, Joao