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Compaq s910 standby

I have a Compaq s910 which works fully except for a clicking sound from it when the monitor enters standby mode. What I know so far is that the clicking is just the degauser relay (nothing arcing). The monitor can only enter standby mode for a split second before powering up the transformer and tube etc, then a split second later goes back to standby mode and repeats the process forever.

There is a IC (3843B) on the board which is cauing the main transformer to kick in, but don't know if its the problem or just a side effect. I have measured voltages from around the place and firstly have to say that I don't understand how the aforementioned IC can even function in that AC enviroment.

I have got the schematics for everything. The important bits:

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Reply to
Michael Collard
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Hello

I got a compaq S910 from a friend, its manuf in 2000 and has the sam

symptoms: standby click power on/off (with blinkin led) and sometime it just wont turn on from the power button, I can hear a very fain tick inside and then randomly 30sec-5min it goes KA-BOING and turn on :lol:

As it is, the monitor is useless since I dont want to keep

fire-hazard inside my house or anybody elses

I already sent the darn thing to a tv repair shop and the guy sai

there wasnt any problems. So I got it home and it wouldnt turn on an then when it did, I turned off the pc and the standby click was there

Did the original poster manage to fix this? I'm about to give up o this, getting tired of hauling its heavy *ss around

Reply to
Joergen

very well may be No, it didn't. But I don't care anyway for that function so someon else can tackle that. TNX BTW to Michael Collard for the schematics Without those it would have been a lot harder to fix it. I may no even have started the repair :D

It is kinda weird though that these two faults seem to go together..

Reply to
Fietsbroek

The failure to come on is caused by the controller UC3843 (IC801) not having its startup voltage. This is derived from the chain C843, C844, R100 and D822. In my case C843 had lost its capacitance. Eventually, due to the leakage through it the monitor will start up after a long wait. I don't know yet if this solves the clicking standby fault, but it very well may be. I fixed it by removing C843 and C844 and replacing it with one of those EMC capacitors. The value is not very important, should be around 0.5 uF but in my case was 0.15 uF/275 VAC. The display started up happily after this. It has a very crisp picture, so I'm happy now!

Steven

Reply to
Fietsbroek

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