View Full Version : newish phillips TV problem


DaveWM
12-23-2009, 12:24 PM
I have no exp with modern SS sets. A buddy got himself a flat screen and gave me a 32" phillips. It was working when I picked it up. He tells me it takes a long time to get it to come one, repeatedly pushing the on button upwards of dozens of times. Once on it is fine. He had it repaired a month ago, was told it was a flyback problem... anyway it worked for a week then same deal.

any insight as to what is going on?

radiotvnut
12-23-2009, 01:28 PM
Some of the newer Philips sets have an electrolytic cap in the horizontal drive circuit that can cause this problem and it will take out the HOT if not replaced. My memory is taking a break; but, it's either a 22uf or 47uf and it's located somewhere around the center of the chassis with a couple of small transistors next to the cap.

DaveWM
12-23-2009, 01:32 PM
Roger that I will check it out.

radiotvnut
12-23-2009, 08:56 PM
I think it's C2455, a 47uf25V cap.

DaveWM
12-24-2009, 07:42 AM
great thanks again!

DaveWM
12-25-2009, 11:39 AM
Got it in the house today, plugged in, when turned on I get a 3-5-11 flash sequence on the green led. I assume this has some signifigance.

DaveWM
12-25-2009, 01:44 PM
C2510 (47uf/50v) had indeed been replaced (sloppy, left the leads full length, looked like they had folded over, I had hoped that was it, cut the leads, prob still there). The pcb trace had lifted, I jumped it with a small piece of wire.

I tested the cap, the replacement was good, but I wonder if when it was possilibly shorted if that took something out. There is a big bridge rec, I get 158vdc on it.

when starting up, the green light comes on, and I hear the HV start up (HV crackle0 thats when the green led goes out, then starts the blink sequence.

model # 32PT9100D/37

radiotvnut
12-25-2009, 02:17 PM
There are a couple small transistors close to that cap that may be bad. In fact, MAT electronics sells a kit that contains the HOT, the two transistors, and the cap for these sets. As you've found out, it doesn't take much to wreck that PC board - very cheap made. If the HV comes up, if only for a second, the HOT is good. I'd probably check/replace those two transistors close to that cap. The vertical output IC may be shorted. I haven't seen it in these sets; but, I have seen them short in other newer sets and cause the power supply to shut down. Just remove the IC and see if the set comes on with no vertical deflection. If it does, replace the IC and electrolytic caps associated with it. There could also be a shorted diode off the flyback transformer or secondary of the switching transformer. IIRC, these sets will also shutdown if the G2 control on the flyback is not set correctly. I'm sure those blinks are an error code; but, I have no idea what it means. If these steps don't correct the trouble, I'd probably forget it. Philips/Magnavox sets really took a nosedive in quality in the late '90's and they've only gotten worse since then.

DaveWM
12-25-2009, 04:49 PM
thinking this baby is curbside material. Anything worth keeping? what a piece of junk, it was made in 2005. has a energy star on it :roll eyes: you bet it saves energy, stops working after a few years. I have it sitting on my 1983 mitsubishi which still is going fine after 25 years. It is amazing how small the yoke is on these newer sets, compared to my old mid sixties sets that is. Guess it has to do with the way the gun is made, If I read correctly modern CRTs do not use 3 guns but rather a single gun that sweeps across 3 color dots.

radiotvnut
12-25-2009, 05:30 PM
You might pull the chassis just in case you need something off of it. That's what I usually do when I discard a newer TV. It's about to the point where if I can't fix a newer TV out of my junk, it's not worth fooling with. I just tossed a later model 36" Sharp with a shorted diode and a blown apart regulator IC in the power supply. I could have gotten the parts for around $7; but, what else would have been wrong with it? Even if those parts were the only thing wrong, it would have stayed here forever because it's not flat enough for most folks these days. Like I said, newer ones around here usually don't get fixed unless I have the part in my junk.

radiotvnut
12-25-2009, 05:49 PM
And, it's not just that TV. There has not been too many CRT sets made in the past ten years that weren't cheap made junk. As far as the "budget" sets, Sanyo was probably the best one.

jeyurkon
12-25-2009, 07:35 PM
If the HOT started up for even a second be very careful of the anode HV. Although I followed the manual for discharging it I managed to get zapped a few times by my Pioneer.

John

DaveWM
12-25-2009, 08:31 PM
anyreason to save the CRT?

radiotvnut
12-25-2009, 08:55 PM
Probably no need to save the CRT unless you think you'll need it. Of course, I never needed many of the CRT's that I saved until after I threw them out.

DaveWM
12-25-2009, 09:55 PM
I will prob give it one more try, I was just getting tired of it, not the best way to spend Christmas!

DaveWM
12-28-2009, 06:54 PM
On a hunch (the guy said it would evenually start and then be ok) that the recent cold weather may be an issue, I got out the heat gun and began aiming it around the board. At 1st no joy so I started different spots and then tried it again. This time I heard the very distinctive degaussing noise and pop the screen comes alive. :banana:

So now I have to check some stuff out. I have a funny feeling it may be the silly variester that may be part of the deguassing. Anyway at least I have a plan. I will try a few more times to see if I can isolate the spot that needs the heat.

DaveWM
12-28-2009, 07:31 PM
turned it off, would not come on, tried spot heat, no joy, I can see this is going to take some time....

re heated the whole back and got it going again.

argh...

well at least I CAN get it started. gotta find the part that likes the heat.

I did try shooting cold spray all over, no effect.

I will just have to keep at it.

DaveWM
12-28-2009, 07:40 PM
off and a quick on results in the nice degaussing noise and a pic. Now to see how long an interval between off and on.

ctc17
12-28-2009, 07:44 PM
My dads panasonic was doing the exact same thing. It was touch sensitivity as well as heat sensitive so it is most likely a cracked solder somewhere. After hours of looking I came to the conclusion it had to be one of the connections under one of the BGA mounted chips.
He wanted one of those new led flat screens and the power consumption was half of that big crt so I told him go for it.
This new lead free solder is such a bunch of trash.

DaveWM
12-28-2009, 08:02 PM
well maybe getting close, after severl trys I aimed it at some caps (look like polyfilm) near by the flyback, heat there and it came on. Good point about the solder, I will examine that area closely, will also try pushing around that area to see.

DaveWM
12-28-2009, 08:11 PM
getting repeatable results :banana:

gonna try it a few more time, not sure but there are a couple small resistors right by the problem area. Think I do some resistance checks there.

DaveWM
12-28-2009, 10:03 PM
got to give it a rest, I cant seem to isolate it to a specific part, but there is a rather large value electro cap right in the trouble area (very close to the flyback). I cant tell the value, but a guess is a 500-1000uf cap.

I dont know if a cold cap could be diff than a warm cap (leaky/open) but its not hard to get at so will do that one. I will have to be careful about polarity, cant see from the bottom any markings and will not know from the top until I get it out, so will be sure to note the way it is in now.

It does have the built in digital tuner, and I must say the pic is excellant even with the cheap rabbit ears, but it will not pic up channels that my DTV converter gets just fine with the same set of rabbit ears. Oh well that will be the next issue if I ever get this thing going. Getting late time for "tombs of the blind dead" (dvd I got for Christmas), good stuff IIRC have not seen it in over 25-30 years...

last nite it was planet of vampires, boy did allien rip that one off big time. I hope they paid some kind of royalities...

DaveWM
12-30-2009, 11:39 PM
this thing is makiing me crazy. I checked all the caps in the heated area, all good. will try some SS devices with more pin point heat and cold to see if I can find it. Agrh...

DaveWM
12-31-2009, 03:25 PM
ok, seems one of the codes (3) had to do with a xray warning :scratch2:

I tried reducting the HV till it cut off, then turned it back until the pic was just normal. turned off with the remote waited 10 seconds turned on. maybe I am on to something here...

If they replaced the fly (as they claim) and did not reset it right maybe that is the issue? Still dont know why the heat would effect that.

DaveWM
12-31-2009, 03:26 PM
going for an extened turn off will wait a couple minutes, keep your fingers crossed for me.

DaveWM
12-31-2009, 03:37 PM
no joy

3 min off and would not come on again. Heat gun around part by fly and all good again.

DaveWM
01-01-2010, 03:14 PM
BINGO!!

check yet another cap near the heating point, a little 25uf job. not leaking but had to turn the power factor all the way up on the cap checker. replace it and it works perfect.

Just for grins I put the bad cap on the tester, leave it hooked up, heat it up, an sure enough it value changed some, but the power factor was able to be cranked way back for max eye opening.

anyway now I can watch the gators on my NEW to me TV

:banana:

DaveWM
01-01-2010, 03:38 PM
in my internet searching I found this a common problem, I wonder how many TV's get trashed (not to mention people getting repairs they don't need).

It also make we wonder about the wisdom of shot gun replacement of old caps that are working and test fine with new ones. I mean the old ones are 40-50 years old and sometimes test fine (talking electrols here). While these were only 5 yrs old. I also wonder if it has to do with the tiny sizes they are made, and the life expectancy of "modern" consumer grade electronics.

DaveWM
01-01-2010, 04:03 PM
Talked to the guy that gave to to me, he said the orig proposed 300$ fix was to replace the whole board, yep that would have done it since the cap was on the board, sorta like replacing the whole engine because a spark plug is bad. He was going to take it home, but they insisted they could fix it for 200$ but he had to wait 3 weeks for the parts... oy vey... then he got it back worked for 3 days and then same deal and oh yea no warrenty at all.

radiotvnut
01-01-2010, 05:31 PM
You'd be surprised at the number of TV's that have come to me from repair shops that told the owners that it couldn't be fixed, would need a whole board, or would cost five fortunes to repair. Many of said sets only needed minor repairs. Either the shop didn't know what they were doing, wanted to make a killing, or had the customer pegged as a deadbeat who probably wouldn't pay.

DaveWM
01-01-2010, 06:10 PM
I am still turning it off and on to my amazement. My buddy had it on for a couple of MONTHs he would not turn it off until he got his replacement.

DaveWM
01-01-2010, 11:00 PM
A little more research tells me that I should get an ESR meter if I plan to do much work on more modern electronics that have a lot of these small electro caps. From what I have read it prob would have found this bad cap in a snap.