CRT TV Not Turning On

The place for all discussion on gaming hardware
Post Reply
TetsuoXLI
Posts: 48
Joined: Tue Jan 04, 2022 7:07 pm

CRT TV Not Turning On

Post by TetsuoXLI »

I RGB modded my Sony KV-13M10. I turned on the TV for the first time after the modifications and it looked great. I was playing games on it for about 20 minutes. Then I turned the TV off. After a little while, I tried turning the TV back on but no video would show. Now every time I turn it on, the TV powers on but instantly shuts off with a small pop and then a crackling sound occurs. Should I give up on it? What could have caused this? I don't think I made any modifications that were invasive enough to prevent the TV from fully turning on. Maybe the TV just died from years of use. I tried adjusting the screen voltage but that didn't work. Here is a video:

https://drive.google.com/file/d/1pqooSH ... sp=sharing
KPackratt2k
Posts: 211
Joined: Sun Apr 04, 2021 11:02 pm
Location: Seattle, WA, USA

Re: CRT TV Not Turning On

Post by KPackratt2k »

I'd get a multimeter and start testing components (i.e. resistors, diodes, and capacitors) to see if anything is faulty. I'd start with attempting to turn the TV on with the back cover removed and pay close attention to the main board while it tries to turn on, chances are you'll find the component that's popping. If you manage to identify the problematic part, look at the component list in the service manual for information on the part and order a replacement part.

I know someone who had the same issue that you had, the problem in his case was a bad diode.
TetsuoXLI
Posts: 48
Joined: Tue Jan 04, 2022 7:07 pm

Re: CRT TV Not Turning On

Post by TetsuoXLI »

Thanks for the reply! I have tried turning the TV on with the back cover off and I couldn't see anything suspicious. I am fairly new to this so how would I go about safely testing the components. What setting would I use on the multimeter?
Dreamcazman
Posts: 63
Joined: Thu Feb 24, 2022 11:07 pm

Re: CRT TV Not Turning On

Post by Dreamcazman »

I'm not certain, but it may be the flyback transformer making the arcing sound (the black component with the red cable coming out the top).

Try to listen closely to that to see if that's where the noise is coming from.
TetsuoXLI
Posts: 48
Joined: Tue Jan 04, 2022 7:07 pm

Re: CRT TV Not Turning On

Post by TetsuoXLI »

I couldn't see anything obvious.
TetsuoXLI
Posts: 48
Joined: Tue Jan 04, 2022 7:07 pm

Re: CRT TV Not Turning On

Post by TetsuoXLI »

What on the crt holds the dangerous charge when unplugged? Is it the metal piece beneith the anode cap? or is it the tube itself (where the anode cap goes)? I have heard that even once you discharge a CRT, it can build up charge again. Someone suggested that once you have discharged, you should connect it to ground still. But I'm not sure exactly what to connect to ground. The cap or the tube?
Dreamcazman
Posts: 63
Joined: Thu Feb 24, 2022 11:07 pm

Re: CRT TV Not Turning On

Post by Dreamcazman »

TetsuoXLI wrote:The cap or the tube?
Most late model CRTs have a discharge circuit, so the tubes and capacitors discharge themselves if the set is left unplugged for a while, but don't rely on that alone.

The tube acts as a huge capacitor, so to discharge it properly, make a tool (flat screwdriver with a wire connected to ground) and slip it under the cap which connects to the tube.

Pull it out, leave it a few minutes, then do it again, then you should be safe to take the cap off.

I was a nervous wreck the first time I did it, also wore thick leather gloves too, can't be too safe.
TetsuoXLI
Posts: 48
Joined: Tue Jan 04, 2022 7:07 pm

Re: CRT TV Not Turning On

Post by TetsuoXLI »

I'm sorry, I was unclear. I meant "The anode cap or the tube itself?"
Dreamcazman
Posts: 63
Joined: Thu Feb 24, 2022 11:07 pm

Re: CRT TV Not Turning On

Post by Dreamcazman »

TetsuoXLI wrote:I'm sorry, I was unclear. I meant "The anode cap or the tube itself?"
Doesn't really matter, the cap is connected to the tube.

It's the tube that holds the charge, but you have to discharge it before even attempting to remove the cap.
TetsuoXLI
Posts: 48
Joined: Tue Jan 04, 2022 7:07 pm

Re: CRT TV Not Turning On

Post by TetsuoXLI »

Thanks for the reply. The reason I ask is because someone told me that the charge can build up even after discharging and suggested that I run a wire to ground so that there is no chance of a build up of charge. Was this person correct? I just asked because I needed to know where the charge is actually held so that I could run wire from that point to ground.

Now, back to my original problem, I have dissasembled the TV again and am in the process of testing components. What components are most likely the cause? Probably capacitors right? Upon further inspection, I discovered a pad that had been lifted. However, this was done after the TV stopped working, I could still use some advice for how to fix it though...

Here is a picture:
https://imgur.com/a/IAMLtva

Let me explain this picture. As you can see a pad is missing and has taken a bit of trace with it. Since I had already made the cut (show in purple) the trace was not pulled any farther. Also, you can see a bit of copper trace (shown in red). But now I have two questions: (1) I have circled the white square in blue. What is under that white square? Is there just the one trace that runs between the cut and the pulled pad? Or, is there more traces that run under that white box that have been split because of the trace that was pulled up. Can I just ignore that missing trace since cut it anyway? (2) Can I just slap a bit of solder onto the exposed trace and call it a day? If not, how should I fix it?

Thanks in advance for any help!
Dreamcazman
Posts: 63
Joined: Thu Feb 24, 2022 11:07 pm

Re: CRT TV Not Turning On

Post by Dreamcazman »

TetsuoXLI wrote:What is under that white square?
There won't be anything under the square, that's just part of the screen printing, like the numbers printed next to it. TV circuit boards are single layer only, not like PC or console boards which are generally multilayered.

If there were any traces underneath, you'd be able to see them as they would be slightly raised due to the copper.

You can put a touch of solder on the exposed copper to stop it oxidising or if you have some solder mask/conformal coating, use that instead.
TetsuoXLI
Posts: 48
Joined: Tue Jan 04, 2022 7:07 pm

Re: CRT TV Not Turning On

Post by TetsuoXLI »

Thanks for the help! Wil that tiny contact area be enough to get a good connection?
Post Reply