JVC GM-V42UG plasma monitor problem

[Capz65]

Hi all. New to the board and new to plasma tv repair. I'm wondering if someone can have a look at the picture of my plasma screen below, and tell me which board might be bad. I've ordered the service manual and looked over the circuitry. I found no blown caps. Any ideas much appreciated.
Also, in the picture ignore the lines at the top. This is an old vcr on pause.

[Wizard]

Re: JVC GM-V42UG plasma monitor problem

Upper Y-drive IC failure in that band. Count your ICs of top and bottom Y-drive boards. is it 12 chips or 10, 8? Only fix is replace upper Y-Drive board. This is long narrow circuit board with square ICs, sometimes have heatsinks on each IC.

Hint: this is on your left side when viewed from behind with back cover removed like you are working on it.

BIG warning: this is highest voltage at enough current. Be careful.
Work on this with power cord *unplugged*. Don't touch any adjustments till this problem is fixed *first*. Then we can instruct you how to adjust if NECESSARY if you getting sparkles (usually red or green, rarely blue or dark sparkles in odd manner).

Cheers, Wizard

[Capz65]

Re: JVC GM-V42UG plasma monitor problem

Ok let me take a look through the service manual and get familiar with the boards and connectors. If it's the board I think you mean it has the ribbons going to the pdp. I assume I need to be careful not to damage those. Really man I can't thank you enough. This is the only solid answer I've had in two weeks on three forums.
If this was a newer tv I wouldn't hesitate to bring it to a pro. But as it's 6 years old and over 30000 hours, I really don't want to put too much money in it, aside from a board replacement. Thanks again, I'll check it out and get back.

[Capz65]

Re: JVC GM-V42UG plasma monitor problem

I got the Y-upper out carefully. It has 4 ICs on it with heatsinks. I found the board in stock at various merchants, priced from $50 to $90. However they don't say if it's new or refurbished. That probably means they're refurbs. I'd like to buy new. Is there a good source you guys use regularly?

[Krankshaft]

Re: JVC GM-V42UG plasma monitor problem

I use:

http://www.encompassparts.com (formerly Tritronics Inc).

[Capz65]

Re: JVC GM-V42UG plasma monitor problem

Now I'm not sure the Y-upper board is the problem. The problem I'm having is the colors are all psychedelic looking, not the horizontal lines across the top. Those are caused by the vcr. I just wanted to clarify. So the Y-upper failure would cause the color and pixel problems across the whole screen range?

[Wizard]

Re: JVC GM-V42UG plasma monitor problem

Remember the motto: GIGO.

Does this TV have s-video, component, DVI or HDMI? Use one of them.

And BIG caution, WARNING WARNING!!

If JVC have DVI or HDMI, do NOT PLUG IN POWER with back cover off till you find the light sensor on the DVI or HDMI RF shielding. Cover that hole WELL with BLACK electrical tape. It will look like a funny pipe in some case. One I found it too in a JVC LCD tv, I saw a foam pad in strange spot on the back cover where it was pressing against a light sensor hole when cover is on.

This is a WARNING. Look in your service manual on instructions to disable this.

Cheers, Wizard

[Capz65]

Re: JVC GM-V42UG plasma monitor problem

It does have component and RGB hookups. I connected my pc and the picture looked the same as the composite connectors. Should I bother getting component cables?

[Wizard]

Re: JVC GM-V42UG plasma monitor problem

Use your composite with audio cable to test on component.

red to red, green to yellow, blue to white and same on other end just to test.

Cheers, Wizard

[Capz65]

Re: JVC GM-V42UG plasma monitor problem

It's labeled component but the connector is like none I've used before. Picture below.

[Wizard]

Re: JVC GM-V42UG plasma monitor problem

These are called BNC connectors.

Bit spendy. Obtain five BNC to RCA adapters.

Cheers, Wizard

[Capz65]

Re: JVC GM-V42UG plasma monitor problem

Well I'm in it now, I'll go get them. I can obtain locally for a couple bucks apiece.

[Capz65]

Re: JVC GM-V42UG plasma monitor problem

I tried the component inputs and there's no change. Still grainy, washed out colors. Question, when a pdp is near the end of its life, what does the picture look like? The monitor has a lot of hours on it, however its labeled "Professional". Does that just mean the internal circuitry is more rugged or should the pdp last longer?

[Krankshaft]

Re: JVC GM-V42UG plasma monitor problem

Professional probably just means no frivolous stuff a Plasma monitor wouldn't need a digital tuner for example.

The buyer purchasing in quantity would probably save money on each unit not having certain parts they don't need as well.

[skisabeth]

Re: JVC GM-V42UG plasma monitor problem

Upper Y-drive IC failure in that band. Count your ICs of top and bottom Y-drive boards. is it 12 chips or 10, 8? Only fix is replace upper Y-Drive board. This is long narrow circuit board with square ICs, sometimes have heatsinks on each IC.

Hint: this is on your left side when viewed from behind with back cover removed like you are working on it.

BIG warning: this is highest voltage at enough current. Be careful.
Work on this with power cord *unplugged*. Don't touch any adjustments till this problem is fixed *first*. Then we can instruct you how to adjust if NECESSARY if you getting sparkles (usually red or green, rarely blue or dark sparkles in odd manner).

Cheers, Wizard

Attached is image of my JVC monitor.
I have no -70 volts at Vsca with Y-buf-upper and Lower PWB's connected.
all other voltages good replaced bad caps on SMPS PWB (Main power supply)
R5117 & R5118 are burnt up on Y-Main PWB.
With R5117 & 5118 removed -70 volts comes back but picture still looks bad
R5117 & R5118 measure 13.6Ohms in circuit & 27Ohms out any idea what they should be?

[skisabeth]

Re: JVC GM-V42UG plasma monitor problem

Now have -70 V back on Y-Main PWB by changing bad caps:
C5080 100@35V
C5081 100@25V
C5090 68 @250V
C5062 100@160V
But picture still the same.

[tom66]

Re: JVC GM-V42UG plasma monitor problem

Looks like Y-buffer fault.