Viewsonic P810 ribbon cable
 

Hi. Strange problem. I have a Viewsonic P810 set that was sitting around
waiting on a component (video amplifier IC) for about a year. I replaced
the component along with some caps, all on the neck board. When I went to
power the set up for checking, the SMPS wouldn't do anything (one tweet
when power applied, one tweet when power removed). If I remove the flat
ribbon cable that connects the neck board to the deflection area, the
monitor powers up nice and detects a video signal, but no picture is
displayed. I can only imagine that something went wrong in my repair, but
I don't know what - it was just an IC and five electrolytic caps.

Is anyone familiar enough with this set or the related Panasonic sets to
know what signals are on this ribbon cable and where I should be looking
for the problem? I have a copy of the service manual, and it doesn't seem
to contain any schematic of the neck board. I'm really at a loss to
explain what I did wrong if anything - I went over all my joints again and
checked connections just in case. The best I can come up with is that I
nicked or torched something unrelated during surgery. That damn neck
board is just packed with tiny SMD stuff.

Thanks.

Look in the schematic, since you have it, to where the ribbon cable connects
on the chassis. From there you should be able to work out what the signals
are.

Most likely you have another short on the CRT board, or the CRT itself is
shorted in the electron gun assy. I have had bad CRT's on these. This is
why, when I get a CRT monitor, if it gets too involved, I scrap the monitor.
They are very low in cost now. If I spend a few hours on a CRT monitor, and
start adding parts, the job can easily exceed its replacement cost.

--

Jerry G.
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"Ryan Underwood" wrote in message
...
Hi. Strange problem. I have a Viewsonic P810 set that was sitting around
waiting on a component (video amplifier IC) for about a year. I replaced
the component along with some caps, all on the neck board. When I went to
power the set up for checking, the SMPS wouldn't do anything (one tweet
when power applied, one tweet when power removed). If I remove the flat
ribbon cable that connects the neck board to the deflection area, the
monitor powers up nice and detects a video signal, but no picture is
displayed. I can only imagine that something went wrong in my repair, but
I don't know what - it was just an IC and five electrolytic caps.

Is anyone familiar enough with this set or the related Panasonic sets to
know what signals are on this ribbon cable and where I should be looking
for the problem? I have a copy of the service manual, and it doesn't seem
to contain any schematic of the neck board. I'm really at a loss to
explain what I did wrong if anything - I went over all my joints again and
checked connections just in case. The best I can come up with is that I
nicked or torched something unrelated during surgery. That damn neck
board is just packed with tiny SMD stuff.

Thanks.

Ryan:
Which P810 do you have ? There are about 4 or 5 different ones.
I have a schematic on the one using the HV8SA main board.
I think there is a "1M" after the full model number (starts with a VC).
You did not put any of the capacitors in backward, did you ?
John

you may have done something that is triggering xray protection, other than
that i wouldnt know why it would not turn on only when the neck is
connected. im not sure but i think if the guns in the tube are over
energized or a spark is arcing somewhere the xray circut will power some
or all of the functions down to prevent excessive radiaton.