Tatung Monitor

[Wayne Fitzner]

I have a Tatung TCM-1002 monitor. When turned on a green light by the power
switch flashes but no picture. If I hold hair dryer on one corner of smaller
circuit board it comes on and stays on. Any ideas?

 

[Dave D]

I have a Tatung TCM-1002 monitor. When turned on a green light by the power
switch flashes but no picture. If I hold hair dryer on one corner of
smaller circuit board it comes on and stays on. Any ideas?

Are there any electrolytic capacitors in that area, and is it the power
supply section? Electrolytic capacitors are notorious for causing this sort
of problem.

Let the monitor cool and heat each component in the area with the tip of a
soldering iron, taking care not to damage them. Try and power it on between
times. That should help you pinpoint the offending part.

Dave

 

[Jamie]

I have a Tatung TCM-1002 monitor. When turned on a green light by the power
switch flashes but no picture. If I hold hair dryer on one corner of smaller
circuit board it comes on and stays on. Any ideas?

cracked solder joint.
get your mag glass out and iron..

 

[Wayne Fitzner]

I did what you said and found the capacitor. Got new one at Radio Shack and
now it powers up like it should. Thanks!!!

 

[Dave D]

I did what you said and found the capacitor. Got new one at Radio Shack and
now it powers up like it should. Thanks!!!

Well done

You may find other capacitors will fail soon, but at least you know what to
look for next time and they are very cheap components to replace..

Dave

 

[Mr. Land]

Well done

You may find other capacitors will fail soon, but at least you know what to
look for next time and they are very cheap components to replace..

Dave

PMFBI, but I found this thread pretty interesting. Are you saying that
the 'lytics in this set are notorious, or of this brand, or in general?

What is it about an electrolytic that would make it fail at room
temperature but work OK when hot? I thought the can-types were just a
couple of long sheets of aluminum foil w/ an insulator between?
Thanks.

 

[James Sweet]

PMFBI, but I found this thread pretty interesting. Are you saying that
the 'lytics in this set are notorious, or of this brand, or in general?

In general they're a common failure, for a while it was really bad due
to counterfeit electrolyte circulating.

What is it about an electrolytic that would make it fail at room
temperature but work OK when hot? I thought the can-types were just a
couple of long sheets of aluminum foil w/ an insulator between?
Thanks.

I don't know why, but that's the usual failure mode, they dry up and the
ESR increases. Cold temperature also causes it to increase so they tend
to act up first when cold, then they dry up further and don't work
anymore at all.

 

[Dave D]

PMFBI, but I found this thread pretty interesting. Are you saying that
the 'lytics in this set are notorious, or of this brand, or in general?

Electrolytics are IME the least reliable component in general, particularly
in switchmode power supplies. Any 'strange' fault qualifies for close
attention to electrolytics IMO.

What is it about an electrolytic that would make it fail at room
temperature but work OK when hot? I thought the can-types were just a
couple of long sheets of aluminum foil w/ an insulator between?

With an electrolyte paste.

Maybe the electrolyte partially dries up and the heating process temporarily
reactivates and/or redistributes it, but that is a pure guess on my part.

Dave