This is the first of these sets I've even thought about looking at.

It's a Philips 27PT563537A with a chassis # L01.1UAC-7638

When I power it up, all I get is the green indicator light. I've got 180v on the collector of the horizontal output transistor when the light is on. Around 91 when it is off.

I think this is one of the sets that I really need to diagnose on a computer, but am not sure.

I found a copy of the troubleshooting proceedures. Unfortunately, the remote to this set is sitting in Matthews, NC right now, and I have nothing here this new to operate the set.

Have any of you here had any luck with one of these newer sets?

It won't be a big deal if the set doesent get fixed. I'm just doing these folks a favor by looking at it. They already got a flat screen for a replacement.

If I can get it running, I will give it to a friend of mine that has a 26" RCA set from the early 1980's with a lovely green image. The CRT is about gone.

Thank you in advance for having a look at this.

Bruce

You probably need a "Horizontal driver kit". It will contain 2 new driver transistors, a capacitor, a new driver transformer and a couple of resistors and instructions on which one to use for a given chassis. I have worked on MANY of these sets--and the H-drive area is THE most common problem.

take a heat gun (hair dryer will do) and aim it at some caps near the center of the main board, then try it. Or if you could prob use an ESR meter to test them in circuit. I had a late model phillips that would come on if I preheated the cap, thats how I found it, replaced it and all good.

funny what RCA just posted, the guy I got it from had just had it serviced, with the above kit installed. Worked for a week, then did the same thing. I personally think they soaked him for the horz fix (it would come on if he repeatedly tried it, then it would play, in fact he had just left it on for a month and then turned it off).

I dont think he needed the kit since it had HV when warmed up, just would take several repeated attempts to start it.

here it is

http://www.videokarma.org/showthread.php?t=246769&page=2

Interesting reading, Dave. 25uf capacitor?

It simply couldn't be that easy, could it?

I buttoned it back up until next weekend when I can work on it some more.

Thanks for ALL and ANY suggestions!

Bruce

Replace C2455, a 47uf, 25V cap in the horizontal drive circuit. If you keep trying to power up the set with this bad cap still in there, you will eventually short the HOT. I had one of these sets come my way that had been in another shop for months. They told the owner that it needed a voltage regulator and that the part was NLA. The owner finally picked up his set and brought it to me for repair. After replacing the cap, the set worked fine.

yes it can be as simple as a cap, dumb cheapo caps these days.

I just had a DTV converter box go south on me (apex I think) the green led would flicker, it would come on after repeated attempts, eventually no more.

I pulled it apart, found a 330 uf 16v cap with a dome shaped top, pulled it, yep bad, replaced with a 470uf (all I had) 35v rat shack and it worked fine.

the 330uf was TINY like about 1/4 wide by 3/8 tall. This is why I am hesitant to replace old E caps in a lot of stuff made in the 1960's and later. They ofter test fine (value and leakage at rated value) and even though they are old I sometimes wonder if modern caps are a good idea if the old ones out ok.

The Techassist board (still running?) had lots of great info on these in their heyday.

http://www.freelists.org/post/techassist/Philips-Model-27PT543S37A-Chassis-L011U,2

Yes, the 47uf cap WILL fix most sets. It's a MUST replace part, unless it's been replaced before.

We used to scope the horiz drive, verify the bad cap, and let the sets run for the rest of the day, sit idle overnite and see if they'd start up in the morning from cold. If so, the set was considered fixed.

Lightning/surge ops usually killed the HOTs and regulators. Seems yours are ok.

Cheers,

OK. Replaced C4255. It had not been replaced before. Same condition. Green power light comes on and burns steady. Pull the cord, and the green light continues to burn until the power supply goes down.

There is no click of the relay or anything. No degauss, nothing.

Any other suggestions?

Thanks!

Bruce

did you try the hair dryer, aim at the little cap near the center of the board.

did you try the hair dryer, aim at the little cap near the center of the board.

No, Dave, I didnt. I'll give it a whack tomorrow.

the best way would be to get an ESR meter and just go thru it, but I am too cheap to pop for on of those. It seems most of the times the new caps fail but going up in ESR vs leakage like the old caps. the heat seems to make them recover enough to work so you can find them. when I replaced the bad cap on mine I hooked it up to the cap tester, and did the heat thing, worked like a thermostat...

OK. Replaced C4255. It had not been replaced before. Same condition. Green power light comes on and burns steady. Pull the cord, and the green light continues to burn until the power supply goes down.

There is no click of the relay or anything. No degauss, nothing.

Any other suggestions?

Thanks!

Bruce

IF someone replaced the two driver transistors without replacing that cap...it WILL take them out AGAIN!! Been there...done that.

Looking at the soldering, there has been no work done on this set. The previous owners stated this, too. They went to turn it on one night, and got the green LED and nothing else.

I found my heat gun. I'll bring the set back in the house this evening. I've had to stick it in the shed due to lack of space, again. There are too many really valuable sets here to keep this Philips in the house.

IIRC the cap i had issues with was near a heat sinked devise that I think was a voltage regulater, near the center of the board.

I started by just heating up different sections, the plugging in and trying it out (not heating with it pluged in). Of course this only worked since it was just a cap and it happened to be only high esr (not completly open or shorted).

Hope it works.

BINGO!!

Horizontal drive kit, like you guys suggested, and replaced the output, which was leaky. It's working. The new output is barely warm after 2 hours playing.

Now, get it back together, and let it run for 24 hours and see if it does as it should.

My friend will really like this set, I think.