Found an RCa CTC203AD5. Sound but no picture.

[MRX37]

I found a 25 inch RCA CTC203AD5 TV made in 2001. It turns on, and I can hear a station through the speakers, but there's no picture. There is also no H/V scanning sound... that sound that a CRT makes when it's drawing the raster is not present.

When I turn the TV on, I can hear it degaussing, then a moment or two later I hear the sound from the speakers. There are no other sounds. No flyback whine, no CRT scanning noise. Nothing.

Any ideas?

[radiotvnut]

There is a small coil that is connected to the base of the horizontal output transistor. Resolder this coil. The best thing to do is remove the coil, scrape any glue off the leads, remove any glue that is on the PC board, clean the foil, and resolder the coil. Also, it wouldn't hurt to resolder everything between the horizontal driver transformer and the flyback. If soldering does not correct the fault, check for B+ to the flyback. I don't recall exactly what it should be; but, look for at least 125 volts.

[MRX37]

Originally Posted by radiotvnut

There is a small coil that is connected to the base of the horizontal output transistor. Resolder this coil. The best thing to do is remove the coil, scrape any glue off the leads, remove any glue that is on the PC board, clean the foil, and resolder the coil. Also, it wouldn't hurt to resolder everything between the horizontal driver transformer and the flyback. If soldering does not correct the fault, check for B+ to the flyback. I don't recall exactly what it should be; but, look for at least 125 volts.

Okay. I'll do this tomorrow and let you guys know if that brings it back.

I did try slapping the TV to see if it did anything, no luck.

[MRX37]

What does this coil look like? Is it housed inside a casing?

So far I've replaced the degaussing thermistor, because the old one broke off, and I either checked or resoldered all the connections in the area near the HOT.

Also, where on this TV can I connect leads to test the B+ voltage?

[radiotvnut]

The coil is not housed in anything. It's a small round ferrite rod with several turns of wire wrapped around it. It's located behind the HOT heatsink. That coil can look like it's soldered OK but still not make good connection.

You can clip your negative meter lead to the tuner shield, vert. output heatsink, etc. Don't clip it to the heatsink with the power supply switching regulator on it. This is hot ground and will give you false readings. Set your meter to read at least 200 VDC and check the voltage at the collector of the HOT. If you get at least 120 volts or so but no HV; you've either got loose connections or a loss of horizontal drive. Loss of horizontal drive can be caused by, but not limited to, a defective horizontal driver transistor, a defective horizontal drive transformer, or the jungle IC. No B+ will indicate a power supply fault.

[MRX37]

radiotvnut: You were right. It was the coil. It's alive now. Thanks a lot!

[radiotvnut]

Originally Posted by MRX37

radiotvnut: You were right. It was the coil. It's alive now. Thanks a lot!

Glad it's fixed. Actually, you were very lucky! Usually, the loose connections on the coil will take out the HOT. Many times when the HOT shorts, it will overload the switching power supply and blow several parts in that area.

[MRX37]

Well it's fixed now. Not a great picture on it, but it's sellable. Typical fuzzy corners and shitty HV regulation. Just crap that I notice, but as I've learned by now, the people who buy em from me couldn't care less.

[radiotvnut]

Originally Posted by MRX37

Well it's fixed now. Not a great picture on it, but it's sellable. Typical fuzzy corners and shitty HV regulation. Just crap that I notice, but as I've learned by now, the people who buy em from me couldn't care less.

It's strange that I've had more than one TV for sale at once and, fairly often, they'll buy the one with the worst picture and talk about how great it looks. A friend who used to fix TV's told me that he never adjusted the picture unless the customer complained about the picture being bad. He said that too many times, he's adjusted someone's set as part of the repair and they'd ask "what the hell did you do to my TV, it looks terrible". To prevent this, if a TV came in dead; he'd fix that and if the picture was too green or whatever, he left it alone.

[MRX37]

I've gotten to the point now where if I'm not going to keep the TV, the most I'll adjust is the screen and focus voltages. If there's anything else wrong with the CRT, I either don't bother with it, or if it's bad enough, I pull the chassis and shit can the rest of the TV.

This TV has the fuzzy corners and whatnot, but lots of brightness left on that CRT. No color bleeding and no tinted B/W picture. I'm sure it'll be snapped up pretty fast.

[MRX37]

Yep. Someone bought it off of me. They took one look at it and it was love at first sight.