Help me diagnose my CRT

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8-bit afterparty
Posts: 3
Joined: Sat Apr 10, 2021 7:12 am

Help me diagnose my CRT

Post by 8-bit afterparty »

Hey guys, I just found this forum and hope this post is in the right category. I like the old wooden console style tvs and found one in excellent shape. I was excited to see it had composite jacks (I know) on the back because I was just expecting coaxial. The picture is bright and seemingly perfect via coaxial but upon plugging in my super famicom and switching to the AUX input, I get sound but no picture.

I replaced all the electrolytics and reflowed all the IC pins thinking that would surely solve the problem but no, same result.

When AUX is displayed on the screen, the top half of the word is cut off (1st pic), and when I turn the brightness up on the flyback, I see this (2nd pic). I feel like a seasoned pro would be able to diagnose this in about 10 minutes but I'm pretty new to CRTs. Could anybody point me in the right direction on what to check or replace? Thanks, looks like a great forum here!

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Last edited by 8-bit afterparty on Sat Apr 24, 2021 9:43 pm, edited 1 time in total.
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Josh128
Posts: 2247
Joined: Thu Jan 16, 2014 9:01 am

Re: Help me diagnose my CRT

Post by Josh128 »

Pics are missing.
8-bit afterparty
Posts: 3
Joined: Sat Apr 10, 2021 7:12 am

Re: Help me diagnose my CRT

Post by 8-bit afterparty »

Should be good now. My apologies if those pics are too big, I’ve never posted images in this way before.

A couple of other things I’ve learned that may be helpful...

I’m getting high voltage static on the screen / the high frequency noise even in AUX mode with the blank screen, so that’s good at least. The screen appears to be not quite black, but sort of a flickering black / gray. The OSD also appears to shake slightly when I pull up the menus, although this may just be normal.

Some noteworthy ICs I’ve looked up the pin outs to:

TMP47C634N-R328
TDA4504A
TDA3569 (Pinout came from a cross referenced NTE7048)

I’ve been following traces from juicy sounding pins and pulling / testing components but so far no dice.
8-bit afterparty
Posts: 3
Joined: Sat Apr 10, 2021 7:12 am

Re: Help me diagnose my CRT

Post by 8-bit afterparty »

I’ve been unsuccessful so far at finding schematics for this model number RK4916 PE04, but there is a fairly simplified diagram on the inside of the chassis that has been a bit helpful as well.

J601 on the diagram is where the 2 pin connector responsible for video from the rca jack daughterboard plugs in.

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