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Old 04-23-2015, 11:49 AM   #1
SHADOW3277
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Default Toshiba 42HP66 Plasma Voltage Help

Picked up this TV from CL. It had an inky looking picture. Took the back off and found a blown fuse on the ZSUS. Replaced the fuse and TV wouldn't power on. Put the old blown fuse back in and TV would power on with the bad image. Ordered a new ZSUS from TSM and now get a much better picture but there are some scenes where it appears to be strobing. For instance a scene with ceiling florescents, the lights appear to be strobing and sometimes the face color will show sparkles.

I checked voltages and they were off but every time I try to adjust them I get a worse or no picture.

Panel voltages: 186 VS 60 VA -200 -Vy 120 VSC Zbias 100
Actual: 157 VS 60 VA -267 -Vy 98 VSC Zbias 100

When I try to adjust VS up the picture gets real bad with sparkles at around 160 and gets progressively worse the higher I go. I cannot get VSC to adjust up as it is turned all the way clockwise and I can't get -Vy to come down.

There is a setup and a setdn but I do not have a scope that can check those. Looking to see if anyone has had this happen before.
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Old 04-23-2015, 12:04 PM   #2
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Default Re: Toshiba 42HP66 Plasma Voltage Help

Some pics.
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Old 04-23-2015, 07:57 PM   #3
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Default Re: Toshiba 42HP66 Plasma Voltage Help

If your VS and VA voltages can be adjusted to spec, you may have issues with the YSus. BTW, the original ZSus probably has a blown IPM (large module under the heat sink).
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Old 04-24-2015, 10:16 AM   #4
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Default Re: Toshiba 42HP66 Plasma Voltage Help

The -Vy and VSC are derived from the Vs supply via dc/dc converters.

You'll not be able to set these if the Vs is as low as you say it is. Vs needs to be at least 180V for correct panel and system operation. Usually with Vs this low--The set would shut-down anyway.....

Set Vs, Va Then set everything else up, only check the picture when all Voltages are right.

IF there's summit wrong with the picture then, There's a fault or a panel issue.
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Last edited by Alastair E; 04-24-2015 at 10:18 AM..
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Old 04-25-2015, 09:18 AM   #5
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Default Re: Toshiba 42HP66 Plasma Voltage Help

Appreciate the responses. I set VS to 186, VA was at 60. The picture was really bad. Tried setting -VY and VSC but still couldn't set those to panel voltages. Also, VS was not stable, it kept fluctuating 1-2 volts difference. While the screen was playing with the bad picture it went out completely (still have sound). So I guess the YSUS was bad too and it finally went?
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Old 04-25-2015, 09:57 AM   #6
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Default Re: Toshiba 42HP66 Plasma Voltage Help

Yes, it sounds like the YSus died; the IPM most likely is shot. Generally, it's recommended that both ZSus and YSus IPMs be replaced at the same time because of similar wear rates. If you're going to buy a used YSus, definitely go back to ShopJimmy to make a purchase to take advantage of the warranty protection they offer.

If you're adventurous...not an easy fix without a desoldering gun (e.g. Hakko 808): https://www.youtube.com/watch?v=Y8MNQYXw8E0
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Old 04-25-2015, 11:19 AM   #7
Alastair E
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Default Re: Toshiba 42HP66 Plasma Voltage Help

Personally--With such an old set--I would only replace the one dead IPM.--This tactic has served me well dealing with these sets.

Reason being--You can ONLY Get Used IPM's anyway! NEW IPM were Never available, and still are not.

In your case--There's summit badly wrong with that Y-SUS if those voltages don't set, so whole board replacement would be recommended......
--Shame you're other side of the world, I have a fair few parts for these series (V8/X3) panels

The running of the set with low Vs was merely masking the fault somewhat--the 'strobing' effect was a function of low Vs I expect....
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Old 04-25-2015, 11:30 AM   #8
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Default Re: Toshiba 42HP66 Plasma Voltage Help

Yes, I agree - I only replace one IPM at a time, also. However, the owner should expect that the second IPM can go at any time.
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