Hp 1955

[terminatorX]

Re: Hp 1955

O.L means no connection good you're asking to be sure=)
So I first cleaned out the old solder and to be honest I kind of had my suspicion against it. But it was still as dead as before. So I soldered a small isolated copper wire between point 2 and 3 now the circiut is complete.
I tested the big cap and it showes 321.1V. So obviously no problem with the big cap. As I can see the function of the switch seem to be bypassed to an permanent on-state. Don't really care about that though. I guess the question now is, is it safe to mount it back and test the whole monitor?

[selldoor]

Re: Hp 1955

You could leave the switch in by soldering the wire as I said , but that is your choice.

As a further intermediate test you can check the low voltages at the connector.

You can re assemble to test or "bench test" making sure the boards dont touch each other.

[terminatorX]

Re: Hp 1955

Think it was my misstake the switch is in on it.

Not sure exactly what you want me to do when checking the "low voltage"..

Not sure about the "bench test" either....

Really just want to know if it's green light for putting the power board back into the monitor and using it as normal if it works now....

[selldoor]

Re: Hp 1955

I was just trying to save you having to take it apart again if it doesnt work.

Low voltage is testing along the connector -cn701 will reveal the output
from the power board to the main/ logic board

Bench Test is connecting all the parts together electrically to see if it is going to work , without putting it all back together. Sometimes the boards have to be isolated from each other by putting cardboard between them.

That said, just put it together and go for it - please report what happens.

[terminatorX]

Re: Hp 1955

Ok I "benched" it. So I get low volume high pitched sound from the back.
The monitor shows a picture for like o moment the it goes black but all leds are lit, it's really only the picture going out. If I turn off then on the same repeats. Picture for a second then black. No flickering. But the switch seem to work.

[selldoor]

Re: Hp 1955

Seem to be getting closer BUT have you re- soldered the joints yet as you promised you would weeks ago?

[terminatorX]

Re: Hp 1955

So I think we have solved it all.
First I desoldered the c5707 transistors and tested them. Nothing wrong here...
So I did a more close up inspection on the area and who could have thought there was a real crack in the solder, so much that when pushing from the other side it went through. Resoldered only the crack. Well I first melted the original solder and also added some new solder. Now it's working like a charm at least the time tested.
Made a picture on that so you can se for your selves, also some of the resoldered transistors are in view.
I will leave this screen on for a while and see if it can hadle being on.
If it passes then I guess I'll have to say thank you all for the help!

[selldoor]

Re: Hp 1955

Great Result
How many times did we suggest cold joints - resoldering?

[terminatorX]

Re: Hp 1955

Ending with sarcasm doesn't sound nice....(but I see your point).
Lot of reasons I didn't initially resolder. As I see it it wasn't the only problem here.
Anyways it's solved now and thats the only thing that matters.