[dark006]

The TV at hand is a 21" Toshiba CF20D40. The chassis number TAC is 9402. Made in 1994.
When I hit the power button I can hear it turn on, but there are no lights (Green or Red), audio, or video. It just sounds like it powers up and shuts right down within a second. After a while in complete silence of turning it on/off, on/off I'm 100% that it just shuts down like immediately after its turned on. I can hear its the same sound each time I power it on. You can hear a very tiny "pop" from the speakers as well, but no sign of video on the screen.
I took the back off and tried to vacuum up some of the dust, took the fuses out to check and clean the terminals? So it still does the same thing. I found two fuses and both looked okay yet. One had a very very tiny wire in it and it was mounted diagnally, but stayed put in that position. Could it be broken and just stuck or would the fuse link purposely be in that position?
What is the next step I should look into? I've got my multimeter in hand. I can solder, but dont have that much experience with capacitors and TV internals. I'm VERY motivated to get this thing back up and working; I found it in the dumpster at work! Any advice or guidance would be greatly appreciated!

[n2gun]

do a resistance check on fuses as long as you have a meter. other than that probably little you can do.

[dark006]

What readings and I looking for on fuses, resistance right? How do I know how much to check for on fuses and capacitors and what setting do should I put my multimeter to?

[wacor]

The ohm meter settings for the capicitors would depend upon the capacitor. and really you need a capacitor tester to get an answer. the ohm meter won't give much of a picture on them. would indicate if open or shorted but not the accuracy you need otherwise.

as to the fuses most any ohm meter setting should work. if there is continuity the fuse should be good. i have seen some odd occasions where a fuse won't carry the voltage thru it on a load but that is quite rare.

[dark006]

Well I just found this. Is this big enough to disrupt a circuit?

[wacor]

How the heck did that crack?

Looks like the break is in part of the circuit built into the board. I would think it would easily cause issues.

There are some guys here who work on tvs so hopefully they can tell you.

[Frank4d]

Look closely at the right end of the crack. Is the copper trace cracked? I don't see a problem if it is not.

In your first post you mentioned there are two fuses, and one has a thin wire through it. Be advised BOTH should have have wires through them. An ohm meter should show close to 0 ohms for both. (Set the multimeter to ohms or resistance. The omega symbol is also sometimes used).

You need to be careful working inside a TV. The voltage on the CRT anode wire and around the flyback transformer is very high (as high as 30,000 volts).

[dark006]

Well it doesnt completely split a trace, it just goes into one only about 0.5mm. None of the caps are fried and everything looks physically okay on the board. Somebody else said something about a a 3-prong transformer on a verticle heatsink close to the flyback transformer.

[Space Cowboy]

I'm currently working on a Samsung 21" CRT and like Frank said you need to be VERY careful.

To Short out the voltage that the capacitors can hold you get a lead with two INSULATED Clips and connect one to ground. The other end of the clip to a long, thin, RUBBER handled screwdriver and slowly insert the screwdriver under the rubber sucktion cup on the back of the main tube. You may see or hear a spark.

Then .. what I do is VERY carefully remove the cup and two fragile leads that are under the cup and clip the leads to them and ground while I work on it. Usually I leave the tube plugged in but OFF when I do this. Then connect to ground at the monitors metal frame. Then unplug the monitor and work on it with the lead still in place.

Be very careful .. That voltage will knock you on your fanny or into the room nextdoor if your not.

To check a fuse correctly you really need to have one end unattached to anything. IF it's soldered on a circuitboard you may get false readings.

I just got mine opened .. checked the fuses .. which were showing values all over the place .. Then decided to hold off because I don't have anywhere to tear it apart as much as I'm going to have to.

That crack in the solder joint is easy to repair if you have a good iron and some good solder/flux. I'd use a 50 watt iron .. let it get good and hot.. tin the tip and clean it.. then just hit it with a touch of new solder and get on and off that sucker quick. You want a mirror like bubble of solder on the joint.

I have power to mine just no picture. No neck glow either. It maybe heading for the dumpster. Hard to tell yet.

Good luck
David

[dark006]

Thanks for the advice! I'll make sure to be real careful. I'm going to go solder that joint up right after this, but I've got a few more pictures to show.

First off, I noticed some light scratches on the board. I dont know if this is enough to effect it; I'm sure it all depends on how deep the scratches are? Take a look.


Second, what are these lever type tabs by the neck. They move, which I'm sure most of you know, but what do they do?


Okay! Big update, hopefully this is something distictive. I noticed that when I do turn it on, it is actually on and staying on. I know this because when I press the on button, I can hear the speaker pop along with a very quiet static from the speakers. However, I cannot turn the volume up to increase the loudness of the static. I've got the back of the tv off when I turn it on and I can see anything, I can just hear a click.

So then as soon as I turn it off, that static goes away. Sound like anything specific?