Panasonic TX-24A1UN CRT Sound and Input problem.

[hugocarmo]

Hi.

I´ve been given an old CRT from Panasonic, it´s almost new, it was storaged and almost not used since bought.
It is imaculate inside, almost no dust or debris inside.
The picture is good, but I have no left sound channel, I tried all the inputs, outputs, even on headphone jack. In AV2 I hear sound from right channel but no image, on tv tuner only right sound channel, the same for AV1.
So I started to look for a service manual, I found one, and started from the beginning.
Most of the times the caps are the problem so I orderer all the caps for all boards, wich I replaced, one by one, not all because I misunderstood some of them and ordered polarized when they were non polarized, of course those I didn´t replaced, but I can say that I have 70% of all boards, with new capacitors, all almost nichicon.
Well, the problems remains, no left sound channel, no image in AV2, only on AV1...
Some of You have any experience with this model? It´s a Alpha 2 Chassis, I will upload some pictures and the service manual.

Thank You all in advance,

Hugo from Portugal!!

[CapLeaker]

I would start to poke around that AV switching IC. There are series capacitors and of course that IC itself.

[KYBOSH]

Impressive undertaking.
Good luck and Im following along for the ride.

[hugocarmo]

Hi.

I have some updates about this repair.
As I said I was waiting to receive the original remote that I found online.
After receiving it it didn´t work.
I opened it, tested all components, replaced the two capacitors, and came to the conclusion that was the crystal ressonator that was bad.
It is a CSB420P, I ordered one and after replacing it, the remote started to work perfectly!
The remote has some tracks that are in bad shape, I scraped the lacker and applied new one, I think it will last for a few years!!

Now, the sound problem... I ordered some IC´s, STK4392, AN5836, TDA3803A, M51321P, and PCD8582DP, I found them cheap so ordered all.
After replacement of all of them, I resolved the sound problem.
Now I have sound on both channels, this tv has a great sound quality indeed!
But the AV2 scart input remains with the problem that only sound is heared.
The screen is gray with no picture at all, only sound.
Something curious, when I have AV1 connected if I go to any channel in tuner the image is the same as AV1, is it normal?
I post images and a video in the end of the post.

Thank You very much!

Hugo.

https://freeimage.host/i/3sKs0ba
https://freeimage.host/i/3sf3511
https://freeimage.host/i/3sf3adg
https://freeimage.host/i/3sf37rF
https://vimeo.com/1085978165?share=copy