Fujitsu Siemens P19-2 Rev.04 no power/led goes nuts; Part ID?

[mobby_6kl]

I'm trying to fix this monitor which, upon being powered up, either does nothing at all, or the power LED starts blinking randomly. I popped it open to find what appears to be the 715G1643 power supply board like this one: http://www.aliexpress.com/store/prod...890399457.html however I wasn't able to find any schematics for it.

The caps are a weird combination of Elite, Hermei, and Rubycon stuff, all of which look ok visually (I don't have an ESR meter). However, I think I identified another likely culprit by the scorch marks on the PCB in the output section, in the bottom-left of the front photo and bottom-right of the back.

The part in question appears to be either a zener or maybe TVS diode, but I can't tell which it is, let alone what its specs are. There was some gunk over it so I did my best to clean it up - it appears to say 81B (which is a zener diode... in a completely wrong packaging: https://cdn.badcaps-static.com/pdfs/...e22b7af3b5.pdf) though the marking can be interpreted in more ways, I suppose. I tried various permutations, but none seem to correspond to any actual component codes.

The monitor is quite old and honestly not worth anyone putting too much effort, hence I'd just rather quickly replace all the cheap parts than buy equipment or spend hours measuring stuff. Any ideas what the hell that thing could be? Thanks!

[mobby_6kl]

Re: Fujitsu Siemens P19-2 Rev.04 no power/led goes nuts; Part ID?

Welp, my second P19 just started to exhibit the 2 seconds to black symptoms!

But only sometimes, like it turned on fine just now. However at other times it will do all the classic stuff, turn on for a bit and then go dark, with the image visible under external light. I'll just go through the guide for now though. Might end up making one working monitor out of these two.

Any ideas about that diode though? A might be able to see the marking better in the second monitor but this is far from guaranteed.

[budm]

Re: Fujitsu Siemens P19-2 Rev.04 no power/led goes nuts; Part ID?

TVS 8.1V. The example circuit uses 12V and 5V so the difference between the two Voltage is 7V so they use 9.1V. What is your Voltages? Most power supply does not put in TVS in that section.
The circuit is setup similar to the diagram (HP L1706) attached. 8.1V may not have enough head room.
2-second to black can be those two transistors (drive the inverter transformer), rectangular grey tuning cap lost its capacitance, inverter transformer, lamps, etc.