CurtPalme.com Home Theater Forum

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

I've moved on from my reliable and ancient 8000 to what I'd hoped was a "better" 8500. It is a pretty recent example, made in 1998, so far its not as good as my ancient 8000. It has a "pulse" to it, and sometimes loses synch entirely. The image wavers, expanding and contracting a small amount. It is very distracting and I'm sure it is a pre-cursor to a violent failure of some kind.

What will cause this ?

I have virtually all boards to swap in for diagnostics, so far the LVPS and FCM and CLM made no difference.

Rather than me just go through the tedious task of swapping them all out, can someone point me to the right board to swap ?

Thanks...

stefuel · Posted: Sun Feb 08, 2009 10:28 pm Post subject:

Not sure what you mean by pulse but if the image is changing in size, I'd suspect the HVPS.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

first off did you do the mandatory cleaning of all boards and especially the chips on the CLM and DPB? also check the daughter board on the HDM.
When every getting a marquee cleaning all contacts is something you should always do

but like chip asked what is it doing exactly? it does sound like a HVPS issue, maybe not a bad HVPS bit something is causing HV to pulse. Does the image go in and out of focus also? the CLM form the 8000 is not the same so Id clean the 8500's CLm chips. the U7 chip on the DPB can cause lots of wierd things, the DPB microprocessor U7 reads sync for H and V from the VIM. if this chip cant get a clean read it will do wierd things like your describing. The older CLM from your 8500 might cause the same thing to happen, some times older CLMs from an 8000 work on the 8500's sometimes they don't. Mostly they work for a bit then loose sync from my own experience.

Athanasios

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

Thanks for the replies, all the boards I have for swapping are 8500 boards. While I do have some 8000 boards left around, the old reliable beast is long gone and any boards I've bought have been for an 8500...

Yes I've cleaned and reseated all the chips and contacts, first thing I did with the 8500 when I got it...

It must be my HVPS, it just winked out on me...

What kills these HVPS's ?? This is at least the second one in this particular chassis...

stefuel · Posted: Mon Feb 09, 2009 12:30 am Post subject:

"What kills these HVPS's ?? This is at least the second one in this particular chassis... "

Look at the name on the supply. I'll bet it has something in common with AmPro. Na Na Na Na Na.....

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

My second HVPS just did the same thing, this time with a different VIM. Something else is causing this, any ideas ???

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Paul. 2 things. Did you try another HDM and 2, does it act up with the menus or internal test patterns?

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

OK. How about convergence board or splitter? Convergence board maybe for size changing but sync?????? Hmmmmm

Is focus going out also like already asked? Any change in brightness?

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

A bad tube or CRT socket can also cause this. Even the G2 connection on the CRT card.

Also check the HV connector under the red tube.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Have you changed any of the VNB's? You may be able to disconnect the black umbilical cord form the VNB's and fire up the PJ, the VNBs connected will light up the tubes, Do one at a time and see what happens. it could be A bad VNB, if the Spotkill circuit on the VNB goes bad or something else on VNB is not right it can cause the EHT inhinit, SpotKill, G2- Inhibit, these will all turn off video. if the OVER-I Circuit on the VNB, which triggers the spotkill, goes over 2.5V it causes the vidoe to shut off. I had a bad vnb where soemtimes the image would flicker then go out and other times it cause HV shut down. These signals are sent to the VIM from the VNB. You'll need an extender card to look vfor the voltages.

Now you might not be able to start the PJ with the VNB umbilicals not cinnected, some vims can allow this some cant, and it s usually for only a few minuts before it will shut off the PJ.

But check the VNB's one at a time by leaving only one connected

Voltage points on VIM Link Courtesy of TSE

http://www.curtpalme.com/forum/download.php?id=5599

Athanasios

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

LVPS drives the HVPS, I would check the voltage on that rail. The later 8500's with newer ribbon cables don't have an insulating strip or the white ground wire, that's normal.

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

Two different LVPS's and the issue remains.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

yes one bad VNB can cause what your describing as the same thing was going on with my 8500, once i changed the VNB it was ok.

Like in the HVPS description that McGyv posted a bad CRT socket(VNB) can cause it/.

Athanasios

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

I should change the title of this thread...the action of this thing has changed....

Now, it fires up, runs fine for a few minutes, then the video blinks out, but the raster remains ??

I've now changed out EVERY board, except the neckboards, and motherboard and backplane...the HV connector under the red tube appears fine upon visual inspection.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY