8 blinks in power supply:Magnavox 42mf237s/37

[geminidpr]

Magnavox 42mf237s/37 doesn't turn on but the power supply has a small board on it that has a green led blinking 8 times every few seconds. Any help will be appreciated. Thanx.

[tom66]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

Can we have some pictures of the boards inside the TV, and one of the overall layout?
Is this a plasma display?

[geminidpr]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

Yes it is a Plasma. PDP module is S42AX-YB08. I will post pics soon.Thanx.

[geminidpr]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

[tom66]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

OK, so this is a plasma display, with the plasma panel being a Samsung part. The left hand board (from your first picture) is the Y-Main, the right hand board is the X-Main.

Disconnect all power & wait 1 minute.
Unplug the Y-Main (main power connector going to PSU, second pic.)
Power up -- does it complete power up sequence (you will have no visible image.)
Disconnect all power & wait 1 minute.
Unplug the X-Main.
Power up -- does it complete power up sequence (you will have no visible image.)
Disconnect all power & wait 1 minute.
Plug in both boards again for future tests.

[geminidpr]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

I did what u asked and it didn't power up on any of the attempts. All I get is the relay clicking and a green Led blinking 8 times on the power supply board.


I forgot to mention that instead of using two separate filter caps valued at 680mf at 50volts (DC8404 and DC8405) I used just one 2200mf at 50volts. I did the same with DC8407 and DC8524. I did this cause each of the two pairs were connected in parallel and I didn't have four 680mf at 50volts.

[tom66]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

What make and series of capacitor did you use? And where did you buy them?
Example: Panasonic "FC"

[geminidpr]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

Japan 85 degree C
It has an M mark on it and M logo.
I bought it at a local repair shop.

I plan on ordering those caps soon, do u think that can be the cause?


Which type do u recommend and where can I get them?

[tom66]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

Those are most likely Panasonic (Matshushita-Panasonic Electronic Components) but they are not low ESR capacitors if they are light blue.

A power supply would need low ESR capacitors to function well. Low ESR capacitors include Panasonic FC, FM, FR, and Rubycon YXF, ZL, ZLJ, ZLH, among many, many others.

Were the originals failed?
I'm guessing the symptoms remain the same?

I would advise swapping out the capacitors for low ESR replacements. It might not fix the issue, but they might also be causing the problem. So we need to rule them out.

[geminidpr]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

The original caps were bloated. They have V9A and "Samwha" WB on them and are rated at 105 deg C.

Where do u recommend for me to order the low ECR caps?

[rayrod81]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

The power supply should have a diagnostic legend printed on it which will tell you which circuit on the board is faulty. I can't quite see it in pictures of the power supply. It is directly beneath or next to the board with the blinking LED. From other pictures I have seen it looks as though it may be a thermal fault.

[tom66]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

Ah, Samwha. I have replaced well over 30 of those.
You can buy low ESR capacitors from Digikey by searching for "Panasonic FR" (or FM, or FC) and then selecting desired capacitance and voltage rating.

[geminidpr]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

Tom....I just ordered the panasonic FC caps. Thanx.

Ray.....Ur right about the Legend. It is just below the small module and 8 blinks indicate thermal. Any idea how to find the cause? Thanx.

[rayrod81]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

I am guessing that there is a thermal fuse on the board that may be blown. Without a schematic it would be hard to pin point. Usually they are inside one of the transformers on the board.

[geminidpr]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

[geminidpr]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

I checked that thermal fuse and it read 70 ohms. I also heated it with a heat gun and the resistance did go up. There are no visible marks on it for me to check the specs on it. Any idea what I should try next?

I added the legend to show that 8 blinks means there is a thermal problem.

[tom66]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

Is there a part # on the board so we can look up a schematic?

We need to trace where the thermal signal is coming from and maybe we'll find we can temporarily override it to find what is overheating or where the problem is.

[geminidpr]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

These are the numbers on the power supply board which is made by Samsung:

Model No: PS-507-PHN
LJ41-05253A
LJ92-01513A

[kmx200]

Re: 8 blinks in power supply:Magnavox 42mf237s/37

Is there a part # on the board so we can look up a schematic?

We need to trace where the thermal signal is coming from and maybe we'll find we can temporarily override it to find what is overheating or where the problem is.

I know that this is an old post, but I was wondering if you finally found a schematic for that power supply.
I have a similar problem with the same power supply.
Thank you in advance!