Toshiba 42HP66 - Pulsing -Vy

[capkid]

Re: Toshiba 42HP66 - Pulsing -Vy

I found the PS101 module for $10 on eBay, so I decided to replace it. The replacement did not do the trick - not sure if it's faulty, but I doubt it. One thing I noticed both before and after replacing PS101 is that the voltages fluctuate a couple volts on the Y-Sus. Also, the VS voltage drops several volts at the fuse. I checked the VS voltage on the PSU without the Y-Sus connected, and it's right on spec (184V). I'm probably going to check the IPM next.

[Shinju]

Re: Toshiba 42HP66 - Pulsing -Vy

I would sell you my whole unmolested 42HP66 for what I paid for it if you want.

It has audio no picture. but between the 2 maybe you can make one working?!

[capkid]

Re: Toshiba 42HP66 - Pulsing -Vy

I would sell you my whole unmolested 42HP66 for what I paid for it if you want.

It has audio no picture. but between the 2 maybe you can make one working?!

I sent you a PM.

[freakaftr8]

Re: Toshiba 42HP66 - Pulsing -Vy

when you get this fixed keep us informed I'm interested in your findings I have an LG plasma that is very much the same as E TV you have internally and I have an uncontrollable -vy as well after an IPM replacement

[capkid]

Re: Toshiba 42HP66 - Pulsing -Vy

when you get this fixed keep us informed I'm interested in your findings I have an LG plasma that is very much the same as E TV you have internally and I have an uncontrollable -vy as well after an IPM replacement

I hope I can figure this out. Thanks for mentioning that you had the fluctuation after replacing the IPM - good clue that the IPM may not be faulty.

[capkid]

Re: Toshiba 42HP66 - Pulsing -Vy

Quick update: I compared the Y-Sus IPM readings to the Z-Sus, and the readings were identical. So, I'm moving on to looking at other possibilities.

I did find this thread for the Vizio P42HDTV10A, which uses a similar Y-Sus. I've already replaced three of the five mosfets on the heat sink, which brought back the picture; the other two mosfets appear to be fine: https://www.badcaps.net/forum/showth...ght=p42hdtv10a

[capkid]

Re: Toshiba 42HP66 - Pulsing -Vy

Comedy of errors: I shorted the IPM while probing a diode under less than optimal lighting. I'd picked up another 42HP66 from Shinju that had a bad Y-Sus IPM, so I removed the IPMs from both boards and spent a couple hours comparing component readings. Removing just a couple components in the -Vy circuit, I couldn't find anything questionable. My suspicion is that a bad surface-mount diode is causing the -Vy fluctuation issues, but I'm not sure I want to spend more time trying to find the bad component.

I was able to confirm that the Y-Sus is back to where I started by replacing the IPM with one of the good used IPMs I've accumulated over the years. I'll be swapping the Y-Sus from the other 42HP66 and installing a brand new IPM to get my friend's TV out the door.

[capkid]

Re: Toshiba 42HP66 - Pulsing -Vy

Ok, this first 42HP66 is done. The control board has been flashed to removed the sparkles. I'm starting to think the other Y-Sus has a leaking SMD cap, but who knows.

[capkid]

Re: Toshiba 42HP66 - Pulsing -Vy

I'm determined to figure out the issue with this second Y-Sus; I feel like I'm getting close.

I checked about 20 SMD caps on the Y-Sus using my analog meter on the X10K scale and watching the needle flick. Most are not in the -Vy circuit, but I wanted to get a gauge for whether the test would give me something on which to consistently rely. Of the 20 caps I tested, two caps (C3 and C20), which just happen to be in the -Vy circuit and in series, registered nothing. All others returned a reading. I then checked the resistance of the two caps with my digital meter - nothing. Hmm... I'm off to see if I can find a parts list somewhere - long shot for the Y-Sus.

[capkid]

Re: Toshiba 42HP66 - Pulsing -Vy

Well, I decided to bag fixing the Y-Sus. I was able to find a "broken" Y-Sus on eBay for $25, incl. shipping. The mal-discharge was absolutely horrible after I replaced the IPM (screen was full of red sparkles), but flashing the control board cleared up the picture.