1986 RCA Console TV Model G25343WK

[JohnCT]

Originally Posted by Console User

I guess, I talked to a Local TV Repairman and he told me not to run the set too much until I get the connections at my tuner fixed. He said it may make the e prom go out totally.

He's right. Also, there are two heatsinks with solder ground tabs: the horiz output and LV regulator IC heatsinks. Cracks on the solder will corrupt those faster than even the tuner grounds will.

I still have a couple of dozen of those stupid eeproms if something goes wrong. Most were the same except for features. I used to stock most of the higher featured ones to cover all the models.

John

[Console User]

I think, my Parents 1991 Zenith Console Set had a somewhat similar issue with the tuner ground. I can remember how it worked and worked with no known issues. Then one day in about 2011 or so we turned it on and we had a picture then in a few minutes when to snow. I fiddled around with the tuner on the main board and could get a picture if I propped up the tuner with a pencil or something. I can remember it was all going good until I was going to take it to a TV Shop. Then I somehow messed with it and hit something and the set went totally dead. We ended up having a replacement main board put in it. It ran for several more years after that. This set will only go to snow or start rolling, etc. usually after it's been on a few minutes the first thing in the morning. Then it seems to not act up the other times during the day when it's turned back on. I can't get it in the Shop until next week. I was hoping to get by with it until then?

[Console User]

Originally Posted by JohnCT

He's right. Also, there are two heatsinks with solder ground tabs: the horiz output and LV regulator IC heatsinks. Cracks on the solder will corrupt those faster than even the tuner grounds will.

I still have a couple of dozen of those stupid eeproms if something goes wrong. Most were the same except for features. I used to stock most of the higher featured ones to cover all the models.

John

The TV seems to work okay and not turn to snow or a blank screen if I use the RCA hookup on the back of TV versus the Coaxial Hookup. If this is the case will it be okay to use the TV this way until I get it into the shop or will it still be at risk of having the set go totally out before connections etc. are repaired?

Thanks.

[JohnCT]

Originally Posted by Console User

The TV seems to work okay and not turn to snow or a blank screen if I use the RCA hookup on the back of TV versus the Coaxial Hookup. If this is the case will it be okay to use the TV this way until I get it into the shop or will it still be at risk of having the set go totally out before connections etc. are repaired?

Thanks.

Hmm.. not 100% sure about the tuner connections, but I am positive the two heatsink tabs will corrupt the eeprom regardless of what input it's on.

I remember the first time we saw one of these in warranty shortly after they were in production- it came in with no sound. Back then, we didn't have the tricks we used later to recover the eeprom but just replaced the chip. It came back a week later with no sound. I changed the eeprom again and while it was running, I tapped the chassis board with the back end of a 1/4" driver like I did for years. The picture blinked and came back, but sound went out. Eeprom corrupted again. I called RCA tech support and they told me about resoldering the two heatsink tabs. This was before the tuners started acted up. Later on they issued a "goldenrod" bulletin on that.


John

EDIT: it's time consuming, but as long as the TV is running, I'd go in the service menu and write down every value, particularly the tuner parameters if you ever plan to use the tuner again. There were places selling "pre-programmed" eeproms but there is no such thing. On an analogue TV, every one is unique and quite different. If your eeprom goes bad, you can certainly readjust the grey scale, horiz osc, vert, etc., but the tuner will need to be aligned with a generator. RCA equipped the ASCs with a very clever device (frequency agile generator) that would output any channel on VHF Lo, Hi, UHF, and all cable bands. It had three attenuator switches and all you needed was a voltmeter to do a perfect tuner alignment. Using the attenuators, you could actually do it by eye. I still have the tuner aligner, one of the few things I didn't toss when we switched from CRTs to flats virtually overnight.

[Console User]

Originally Posted by JohnCT

He's right. Also, there are two heatsinks with solder ground tabs: the horiz output and LV regulator IC heatsinks. Cracks on the solder will corrupt those faster than even the tuner grounds will.

I still have a couple of dozen of those stupid eeproms if something goes wrong. Most were the same except for features. I used to stock most of the higher featured ones to cover all the models.

John

Would the issue with the tuner have anything to do with me getting a Blue Outline around dark hairline, dark clothing, etc. on the edges? It's like if you were to take a blue marker and trace around an object that is dark with a blue marker. Also, noticeable on black stenciled letters on a certain background. I believe, someone thought this may be a convergence issue and that they were always this way. I have had several RCA Sets but never dealt with this issue in the past.

Thanks.

[JohnCT]

Originally Posted by Console User

Would the issue with the tuner have anything to do with me getting a Blue Outline around dark hairline, dark clothing, etc. on the edges? It's like if you were to take a blue marker and trace around an object that is dark with a blue marker. Also, noticeable on black stenciled letters on a certain background. I believe, someone thought this may be a convergence issue and that they were always this way. I have had several RCA Sets but never dealt with this issue in the past.

Thanks.

If you can take a real good picture of what you're talking about, I can get a better idea.

Those RCAs were built for cost, but I have to tell you, design wise they were very well sorted. There were no "that's just the way they are" performance issues. Even when put behind a 35" tube, they produced a very nice artifact free picture.

As far as convergence, all RCAs of that era used a pre-yammed yoke and a flexible magnetic convergence/purity band in place of the mechanical beam bender that everyone else used, and I can state categorically that in the thousands of those I had repaired over the years, I never had a convergence issue on any of them.

Generally, a blue outline is a weak CRT, but the halo would not be static: it would change and flare outward with contrast and brightness level. If you see the halo at very low brightness levels, I would say it's not a weak tube.

If the tube is strong, I'd lean towards a bad jungle IC causing that. Uncommon but I've seen them. I can't think of anything in the eeprom that would cause that.

John

[Console User]

Originally Posted by JohnCT

If you can take a real good picture of what you're talking about, I can get a better idea.

Those RCAs were built for cost, but I have to tell you, design wise they were very well sorted. There were no "that's just the way they are" performance issues. Even when put behind a 35" tube, they produced a very nice artifact free picture.

As far as convergence, all RCAs of that era used a pre-yammed yoke and a flexible magnetic convergence/purity band in place of the mechanical beam bender that everyone else used, and I can state categorically that in the thousands of those I had repaired over the years, I never had a convergence issue on any of them.

Generally, a blue outline is a weak CRT, but the halo would not be static: it would change and flare outward with contrast and brightness level. If you see the halo at very low brightness levels, I would say it's not a weak tube.

If the tube is strong, I'd lean towards a bad jungle IC causing that. Uncommon but I've seen them. I can't think of anything in the eeprom that would cause that.

John

I took a picture of my issue. It's in my Album under my User Name. It shows a lot of blue everywhere. I have found, that no matter how much I turn down the Picture and or Brightness it never really goes away. It just maybe helps to make it not so noticeable in the screen shots.

[JohnCT]

OK, I see the pic. If you put an image on and freeze frame it (like a DVD), and the blue flaring does not change with brightness/contrast or G2 changes, then it's not the tube (huzzah).

Just to be sure it's not convergence, can you take a pic of the problem showing graphics? With regard to convergence, make sure the picture tube wasn't changed. We were supposed to install a mechanical beam bender when the tube was changed, but lots of us just reused the flexible magnetic tape. You would be surprised how easily the convergence and purity fell into place by rotating and then taping the magnetic strip back down..

I have those schematics at work, when I get there I'll check to see what's involved in the RGB system. IIRC, there are three transistors (r,g,b) off the jungle which drive the three TO-220 transistors on the CRT socket board.

I also may have seen this before and logged it.

It looks like the blue has very low bandwidth and is causing the blue flare.

A trick to split the problem between the main chassis and the CRT socket board or CRT itself is to swap the blue and (say) red wire inputs to the CRT board and see if the flare swaps to red (turn the chroma down). If it stays on the blue, the main board is OK and the problem is at the socket board or tube itself. If the flaring changes to red, we have to work backward to the main board.

John

[JohnCT]

The output from the jungle IC goes directly to the kine output board - there are no drivers between them.

At the CRT board, there are three input wires (prob color coded) for the kine drives - E1 (red), E2 (blue) and E3 (green). Remove the blue wire at point E2 and swap it with either E3 or E1 and see if the problem switches color.

The only parts on the main board connected between E2 and the jungle IC are a 100 ohm resistor, a 220 pf surface mount capacitor, and a 2.2 uh coil.

If the flaring switches from blue to red or green when you swap the wires, you have a problem on the main board, and I'd bet that it's the jungle IC (or what RCA called the T-Chip).

BTW, if you put the TV on a blank input and activate the menus, does the blue flaring show up on the menus as well?

John

[Console User]

Originally Posted by JohnCT

The output from the jungle IC goes directly to the kine output board - there are no drivers between them.

At the CRT board, there are three input wires (prob color coded) for the kine drives - E1 (red), E2 (blue) and E3 (green). Remove the blue wire at point E2 and swap it with either E3 or E1 and see if the problem switches color.

The only parts on the main board connected between E2 and the jungle IC are a 100 ohm resistor, a 220 pf surface mount capacitor, and a 2.2 uh coil.

If the flaring switches from blue to red or green when you swap the wires, you have a problem on the main board, and I'd bet that it's the jungle IC (or what RCA called the T-Chip).

BTW, if you put the TV on a blank input and activate the menus, does the blue flaring show up on the menus as well?

John

There is no evidence of blue flaring when put on a blank screen say in Video Source and pull up the menu items.

[Console User]

Turning down the G2 does seem to help some. However, still a little bit visible.

[Console User]

I went back into the Service Menu and adjusted the Drive Adjustments. I turned the blue down, and adjusted the Green and Red as well. I do not seem to have as much blue flare in the picture. It doesn't even seem visible from a distance now. It may have dimmed my picture some and the white isn't as pure by increasing the green and lessening the blue. However, I feel it's better than the blue flare. I will post a picture in my Album of a screen shot now.