Lotem 800V Errors


Well-known member
Hi guys,

We have a Lotem 800V, 48 diodes, app ver. 3.20.01

Following startup, the machine arrives at READY state.
After a while we get "ATTENTION" errors:
"Left Tec Card doesn't respond (Opcode 23)."
"The operation "Put" on left Tec Card failed."
If we try to perform Laser Diode Calibration or try to Expose, we get an additional error:
"DDB Card" doesn't respond (Opcode 80)."
"The operation "Put" on DDB Card failed."

My ex-Scitex technician tried to isolate the source by replacing (one at a time) TEC, DDB and NUC boards TWICE.
Going further, we checked continuity on the 50 pin cable connecting the L-Box to the E-Box (DDB to NUC), still getting the same errors.

We are now discussing ways to proceed.
Since we noticed the LEDs on the 3 Power Supplies in the L-Box didn't light up, we wonder if this may indicate a source to the problem.
We intend to find if the PS's get any AC power and later possibly replace the PS's.
Does anyone know which of the 3 PS's (+5V, -5V or +/-12V) should we try to replace first?

Any other possible source to this problem?

Any comment welcome.


Well-known member
Hi, Sir
By my Strong experience, if you have Faulty the power supply Nothing will be going ON,
Repair the power supply or Replace. of course the troubleshooting, indicate that you must test the output of secondary of
Transformer and fuses. See for Colder +Dry Joint in the power supply board. If the LED Not GOING ON, is very sure that you
have Faulty Board, but however test first as indicated before.
Have Schematic ??
Let me kno.


Well-known member
Thank you Chock,
By now we know that LEDs on 2 PS's should have lit after startup, but they didn't.
We are still investigating...


Well-known member
Hi Chock,
The schematics I have are Function/Block Diagrams, not detailed enough.
Many thanks for your readiness to help, but I believe that only a veteran ex-Scitex/Creo/Kodak Lotem service person may have the know-how and prior experience required in this case.
BTW, I am told that the 5 volt power supply in the L-box is the prime suspect and may need to be replaced.
Thanks again.


Well-known member
Hope you are well. Function/Block Diagrams is enough
However the Troubleshooting as my experience 45 years as electrical and electronic engineer BSEE , P.E
i saw Thousands of Machines, and Boards from All tipes, and always there are a Common Denominator: Power supply
if is Missing =Machine will NOT work. Now retired.
In your case the lack of Power supply +5vcc is very critical, since they control IC, from TTL circuit. By that reason
any board can do the o.k job.
Star by replacing or repair the PCB respectively. Of course you must sure if another p.supply PBC is missing like +12 for IC CMOS
or 3.3V LSCMOS circuit.
Thank you in advance, and let me know any question
or send me email.


Well-known member
Hello ReprpPro, Have you checked the blowers in the upper area of the LDD box for proper funcioning? Also make sure that the metal screen on the LDD box is clean and allows for air circulation in the box. All this just to make sure that the electronics in the LLD box are cooled properly.


Well-known member
Additionally, please let me know in case that you would need any parts for your Lotem 800V2. We have them all available :)


Well-known member
Hi Peter,
You are correct - the blowers in the L-Box do not function.
We realized we need to go upstream from there.
However, trying to resolve this problem took up too much time, so I decided to let this Lotem rest and moved out the (single functioning) DDB card to the our second Lotem.
After we get the replacement DDB card next week, we shall resume our tracking the problems on this Lotem.
Having 2 (nearly identical) Lotems allows us such margin of freedom...

I'll certainly get back to you for any parts, should I need any.
TIA for any assistance.


Well-known member
Replacing the Interlock board fixed the problem.
This should have been obvious to the first Tec guy, strangely he ignored it...
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