Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

[SurrealMustard]

I've been working on this early RCA DLP television (circa 2003) and trying to bring it back to operational spec. It was sitting in a garage for a while and upon initial examination, the lamp was apparently broken. Upon replacing the lamp, the set fired right up! Everything seemed fine at first, but closer examination revealed some ghosting and minor distortion (green and pinkish, mostly on the left side) in the picture (although it does show up in the menus too), as shown here:





With no video source hooked up, the menus look okay aside from the ghosting (which is present, but hardly visible in this picture):



When you add a video source however, things get really weird! The menu becomes distorted and the distortions be changed by navigating the menu or displaying moving pictures through the video input.





Now, on to the troubleshooting. To begin with, I entered the service menu and displayed the test patterns, which according to the service guide are generated by the light engine itself, and as such did not exhibit any ghosting or distortions at all, narrowing down the suspects to one of the four boards in the chassis side of the set (the power supply, DM2CR digital module, input board, audio board (not pictured), or formatter board (also not pictured)) -
(see the attachments section for full resolution pictures)







A visual inspection revealed no puffed up capacitors or obviously damaged components. Any ideas as to where to look next?


TL;DR? Distorted menus, minor PQ problems, and ghosting as pictured above, light engine not the culprit, no puffed capacitors in any of the usual places. What should I check next?

[R_J]

Re: Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

I would say by looking at the picture there are a couple bad caps, most likely one of the small ones in the video circuit. They won't show as bulged or even leak they just dry up and don't do their job. A scope would track it down quickly, or cap checker/esr meter would help. When a video signal is applied it is upsetting a circuit somewhere, most likely a low value decoupling cap somwhere.
or it could be a bad cap in the low voltage supply around u1360h u13609 etc.
Just a guess.

[SurrealMustard]

u1360h and u13609

I would say by looking at the picture there are a couple bad caps, most likely one of the small ones in the video circuit. They won't show as bulged or even leak they just dry up and don't do their job. A scope would track it down quickly, or cap checker/esr meter would help. When a video signal is applied it is upsetting a circuit somewhere, most likely a low value decoupling cap somwhere.
or it could be a bad cap in the low voltage supply around u1360h u13609 etc.
Just a guess.

I see. Now when you talk about the low voltage supply and u1360h and u13609, are you referring to those four green capacitors in the DM2CR module shown in the second to last picture? I ask because I'm having a bit of a tough time reading some of the labels in the picture .
When you talk about the small caps in the video circuit, are you talking about the small green ones toward the back of the input board or the blue ones (or both)?

[R_J]

Re: Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

I was refering to these outlined in yellow, or maybe one of the small caps on the last picture could be causing it.
These are just guess's but I have seen the fault before on other tv's and its usually a bad cap.

[SurrealMustard]

Format

I finally got a look at the previously unseen formatter board and there isn't too much going on with it. The three larger surface mount capacitors on there did catch my eye though. Do those look like they might be cause for concern (bulged) or is that normal for those?

[SurrealMustard]

must be something else

(TL;DWR? skip to the bottom of the post)

I ended up replacing the most probable suspects (the four 680μF capacitors) on the DM2CR digital module, and while it didn't end up solving the problem, I didn't make it any worse, and I learned a few tricks for removing old, crusty, "un-meltable" solder with the help of a heat gun.

From here, I've taken a closer look at the service guide and discovered contrary to what I posted earlier that most of the test patterns are actually generated by the formatter board and only one is generated by the light engine, meaning I can pretty much rule out the formatter as a possible cause of the problem after all.

Back to the repair action: According to the service guide, "Any 2H component (YPrPb) that is input to the A/V In/Out CBA is routed directly to the formatter.". This tells me that if the DM2CR is the cause of the problem, said problem should vanish when displaying 2H (480p) content and be present for everything else, but this is not the case, as the ghosting and color distortion is present at all resolutions. If this is true, I can only assume that the DM2CR is fine and that the input board was at fault all along. This makes sense until we consider the distorted menus, which if generated by a functional DM2CR and sent straight to the formatter, wouldn't be distorted, unless of course they take a stop at the defective video input board first. Could there possibly be a power supply issue?


TL;DR? Capacitor replacement on DM2CR successful, but no change. Found possibly helpful information in the service guide, but still unsure. I'll move on to capacitors on the video input board unless someone thinks it could possibly be a power supply issue.

[SurrealMustard]

progress

After further testing, deliberation, and perusal of the service guide, I am officially taking back what I said before about the formatter board being fine. As a matter of fact, I now believe it may be suspect. If video from the input board that bypasses the DM2CR digital module exhibits artifacts as well as video straight from the DM2CR that bypasses the input module, a common problem on the formatter would seem more likely than a compound problem on both the input board as well as the DM2CR.

I will further examine the formatter for repair or replacement.

[R_J]

Re: Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

I bet they are bad. I've repaired these modules before. You will know when you go to unsolder them, you usually get a very fishy smell.
You can use regular radial lead caps to replace them if you don't have the same surface mount ones.
and use care when removing them so you don't take a trace with them, a lot of times when they leak the solder pad also becomes loose from the board.

[SurrealMustard]

good idea

I bet they are bad...
You can use regular radial lead caps to replace them if you don't have the same surface mount ones.
and use care when removing them so you don't take a trace with them, a lot of times when they leak the solder pad also becomes loose from the board.

The capacitors on the formatter? It makes sense and I've already got some 16 volt 680μF tankers leftover from my attempted repair of the DM2CR, so all I'd need are a couple 6.3volt 1500μF ones (according to the informational sheet for those surface mount capacitors, the number in the middle represents the capacitance and the letter represents the voltage - "j" is 6.3 and "c" is 16). I'll look into getting some of those and report back.

I've repaired these modules before. You will know when you go to unsolder them, you usually get a very fishy smell.

Interesting. Was it an early RCA brand DLP set too?

[R_J]

Re: Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

Early crt rear projection Toshiba's had problems in a video processor module, and I did repair some rca's also but its been a while.
This is where a scope comes in handy.
You could solder a 680/16 in place of the surface mount just to confirm that it will fix it. even replacing a bad 1500 with a good 680 would most likely cure the problem. then you could replace them with the surface mounts when you get them.

[SurrealMustard]

issues starting out

...
and use care when removing them so you don't take a trace with them, a lot of times when they leak the solder pad also becomes loose from the board.

Well, I went to start removing the capacitors today and I accidentally tore a couple of the solder pads right off and cracked a couple others. Did I screw my board or can I blob some extra solder from the leg of the new capacitor over to the holes where the old pads made contact with?

[R_J]

Re: Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

Look where the trace goes and run a wire from the next closest solder point, or you can try and scrape a bit of the covering off the copper trace and solder to it.
I usually use thin (28-30Ga) wire wrap wire for this. if the brake in the trace is close just use one strand from some stranded wire.

try adding some fresh solder to the solder on the cap. first. this can help transfer the heat better and the cap should come off easier. and heat one side then the other alternating between them helps. Heating both connections at the same time would work better but you can't always do that unless you have a tweezer type solder iron.

[SurrealMustard]

good save, but still no dice

Look where the trace goes and run a wire from the next closest solder point, or you can try and scrape a bit of the covering off the copper trace and solder to it.
I usually use thin (28-30Ga) wire wrap wire for this. if the brake in the trace is close just use one strand from some stranded wire.

try adding some fresh solder to the solder on the cap. first. this can help transfer the heat better and the cap should come off easier. and heat one side then the other alternating between them helps. Heating both connections at the same time would work better but you can't always do that unless you have a tweezer type solder iron.

Good call on the scraping, that did the trick. I got the capacitors on successfully and the board reinstalled, but there is still no change - the ghosting and waviness are still present . I'm thinking the whole formatter board is going to just have to be replaced. I saw some on eBay with a slightly different model number, but they look the same, so I might just go with one of those.

[R_J]

Re: Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

did you replace all the caps or only a few?

[SurrealMustard]

replaced

did you replace all the caps or only a few?

All three of the larger ones.

[R_J]

Re: Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

I would get a cap say around 47uf and solder it accross each of the 47 - 100 uf caps on that board, you can try one at a time or solder a couple at a time, that way you don't have to remove the original cap untill you know wich one is bad. without a cap checker or a scope its about the only way short of replacing all the elec. caps.
There are 2 100uf 6v in the corner that look like they may be around a regulator. ther is also one cw614 that lookslike its part of a voltage regulator circuit. try temporarly soldering a cap accross it and see if that helps. again you can use something close to the 100uf, Im sure a 47uf accross it would get rid of the lines if that cap was bad.

[SurrealMustard]

alternative capacitor

I would get a cap say around 47uf and solder it accross each of the 47 - 100 uf caps on that board, you can try one at a time or solder a couple at a time, that way you don't have to remove the original cap untill you know wich one is bad. without a cap checker or a scope its about the only way short of replacing all the elec. caps.
There are 2 100uf 6v in the corner that look like they may be around a regulator. ther is also one cw614 that lookslike it's part of a voltage regulator circuit. try temporarily soldering a cap across it and see if that helps. again you can use something close to the 100uf, Im sure a 47uf across it would get rid of the lines if that cap was bad.

I haven't got any 47μF or 100μF capacitors handy, but I do have a whole bag of 330μFs from a previous project. Do you think those would be close enough for this circuit?

[R_J]

Re: Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

You could try the 330 in place of the 100 if you don't leave them in. or find an old board with some used ones on it.

[SurrealMustard]

request for clarification

You could try the 330 in place of the 100 if you don't leave them in. or find an old board with some used ones on it.

By "if you don't leave them in", you are referring to the capacitors that are already on the board?

[R_J]

Re: Ghosting and wavy menus on RCA DLP Projection TV (HD61LPW42)

no, I ment to just put them in parallel with the one thats on the board but just to try and see if it fixes the problem, if it does'nt then remove it and try it on another one. If it does fix the problem then get the correct cap to replace the bad one.
on the 47 uf ones I would use something smaller, 10 to maybe 100 but not much higher.