Kieran
Joined: 17 Jan 2010
Posts: 1
Location: london
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| Posted: Sun Jan 17, 2010 12:47 pm Post subject: Help needed with data 800 Scan fail diagnosis |
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A bit of background, the projector is a 1993 vintage Data 800 with just over 2200 hours of use.
I hadn’t used it for about 6 months until a couple of weeks ago. Previously when in use the projector would sometimes make a pop or click sound, the picture would be lost (projector still running). I was able to re gain the picture by switching to standby and then back on.
The problem I have is that the projector did its “pop” and “click” trick and is now showing a “scan fail” fault which suggests the problem is with either the horizontal or vertical control boards. When switching inputs the red LED on the Vertical board lights up for a second or two, the LED on the Horizontal board is never lights up when changing input.
I have downloaded the service manuals, which have some cryptic notes written on them on them. For example the Vertical board schematic has –ve = good, +ve = bad, but nothing about where to look if bad (have a +ve at the point which says bad).
So far I have checked the +17v reference (showed 16.96v)
All power supply LED’s are ON + scan fail
The red LED (hold down?) on the EHT board is OFF
Pulled the convergence board, and powered up, no change
Pulled the EHT board and powered up with the Vertical board removed, still showed scan fail, tried the same with the Horizontal O/P board, same result.
I am not sure where to start looking, can anyone suggest a good place to start and what signals/voltages I should be looking for on the boards to try and diagnose the problem.
I cant see any burnt /damaged components, there are no burning smells to go on either. I replaced some of the caps on the SMPS and the convergence module 7 years ago.
Thanks
Kieran.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Sun Jan 17, 2010 1:34 pm Post subject: |
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Sounds like short in tube, some crap between cathode and heater for example. First it was partial short and it snapped every now and then.
Now it's probably full short, if projector goes to SF.
Remove one tube HV cable and neck board+rgb amp at time to see if it helps.
Other option is HV problem caused by arching...
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