Monitor 1081 problem

[Jan]

Sometimes and without any warning my Commodore 1081 monitor completely loses its picture. It's like somebody pulled the plug, the screen goes black, but the sound still works. After punching and hitting the monitor a little (just a little! ;) ), the screen often returns, but only to go black after a while again.

When I opened the case I noticed a spool which is glowing when the monitor works correctly, but once the screen goes black, the glowing stops. Somewhere in the monitor there must be a loose contact that is causing this picture failure. Somebody told me that this monitor has certain solder spots that often broke, which could cause this problem. But does anybody know where these spots are?

Maybe somebody has experienced the same problem on his monitor or just heard about this problem and can help me here? :)

[Toni Wilen]

Resolder line output transformer's connections (=large transformer that is connected to tube with fat red wire)

This is very very common problem..

[LordBug]

Be very careful playing near the fly-back transformer (the one Toni mentioned). It has about 15000 volts coming off of it. Some parts near it (like the capicitors) might be charged that high too. Let it sit unplugged for a few days before doing anything.

[Jan]

Yeah I have a lot of respect for these monitors :D . My uncle is an electrician and he told me that they sometimes even after days still contain enough electricity to blow your lights out forever :D . So I'll be careful, and thanks for your help :) .

[Jan]

Hmm, seems I need some more help as I can't figure out what Toni's referring to. I've attached a picture of my 1081, can anyone tell me what needs to be fixed?

[Toni Wilen]

Oops. It is gray not red wire. (I forgot because most tv's and monitor's use red wire) Follow the wire from tube's "suction cup"-connector and you'll find the transformer :)

Monitor is safe to operate if you don't go near the "suction cup"-connector. (it could still have 20+kv high voltage..)

[Jan]

Just to be on the safe side here :)

http://www.deissen.de/jan/dscf0007.jpg

If I'm not mistaken, this should be the transformer, right?
And these...

http://www.deissen.de/jan/dscf0008.jpg

...solder spots inside the square should be the ones that I have to re-solder? All spots? That's strange because I don't see anything broken there. Is it just that I have to put solder on all those spots again and everything should be fine?

[Toni Wilen]

solder spots inside the square should be the ones that I have to re-solder? All spots? That's strange because I don't see anything broken there. Is it just that I have to put solder on all those spots again and everything should be fine?

Usually but not always there are visible circular cracks in solder. Resolder them and also look other nearby larger solder pads with magnifying class. (especially those that connect to heatsinked components)