CurtPalme.com Home Theater Forum

blu86 · Joined: 28 Dec 2006 Posts: 23 Location: New York/New Jersey

Hi all! Haven't posted in a while, but am a regular reader Smile

I have an Ampro 4600, and am running Blu-ray 1080p through it with the HDFury. Have been achieving great images, so finally ceiling mounted the projector. My issue is I'm getting serious defocusing/image destabilization problems. The problem is on the raster (occurs with both internal patterns and an external source). The image will defocus and then blow up and shrink in size every few seconds. The amount of time this goes on for seems to have to have no pattern, and sometimes it does not occur at all. It seems to be happening more often since being ceiling mounted (it went on for over 30 minutes last night until I gave up and turned the projector off). Also, when I FIRST start the projector it is often okay for a minute or two, then the problem starts, which lends me to believe it is not a warmup issue. Any ideas?

**Curt Palme** · Posted: Mon Dec 22, 2008 9:52 pm Post subject:

Sounds like the focus board is kicking in and out. THat's pretty common to 4600s. THere's a shutoff switch right on the focus board heatsink. Let me know if you hear it click in and out when it defocuses and kicks back in. Check the belly fans for dirty filters/clogged air passage.

stefuel · Posted: Mon Dec 22, 2008 11:52 pm Post subject:

I know Pete's lurking around here someplace Wink

blu86 · Joined: 28 Dec 2006 Posts: 23 Location: New York/New Jersey

Thanks Curt. Just fired it up and the problem is still occurring. Listened very closely for the shutoff switch but couldn't hear anything. Is it a loud click? All the filters are clean. Were you asking about my clogged filters because it is an issue with overheating? Asking this because in the past the problem has gone away after leaving the machine on for some time, which wouldn't seem consistent with overheating. Is there something I am overlooking?

**Curt Palme** · Posted: Tue Dec 23, 2008 2:14 am Post subject:

It's pretty soft. THere's a thermostat looking thing with 2 wires coming out of it that's bolted to the focus board heatsink. That's where it would click.

Otherwise the focus board is probably just defective. I have stock...

Mark_A_W · Posted: Tue Dec 23, 2008 3:33 am Post subject:

Sounds like HV to me.

It's losing focus AND the image is getting bigger.

The HV supply is failing.

Disclaimer: I know nothing about Ampros..

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

blu86 · Joined: 28 Dec 2006 Posts: 23 Location: New York/New Jersey

Thank you Mark, Macgyver, and Curt. The image definitely fluctuates in size when the problem is occurring. Macgyver- I located the thermal switch and will try what you suggested tomorrow, it sounds like a great way to test Curt's theory. Though I would be surprised if it is an overheating issue; after leaving the projector on for about an hour tonight the problem went away. Would that be consistent with a failing HVPS?

stefuel · Posted: Tue Dec 23, 2008 9:23 am Post subject:

Check the remote for errors when it's acting up or turn on the on screen display. Check your HV re-start count to see if it is increasing in number. I'm in the HVPS camp way of thinking.

**Curt Palme** · Posted: Tue Dec 23, 2008 1:24 pm Post subject:

Yeah, I changed my mind. HVPS is bad. I don't have a spare right now, but might be able to repair yours.

blu86 · Joined: 28 Dec 2006 Posts: 23 Location: New York/New Jersey

Update! Just started the projector and while the image size was fluctuating I checked the diagnostics (thank you stefuel) and got "-25 VOLTS HI". Does this indicate a problem with the HVPS? If so the next two questions would be 1) is there any way to repair it myself? 2) if not- Curt, I assume you wouldn't know until you saw it but do you have any estimate as to repair costs? And any guess as to what turnaround time might be?

Want to add that I noted a slight crack/chip that runs the length of what appears to be the gray rubber/foam covering of the HV splitter, but again, it appears to only affect the covering. Is this anything to worry about?

Z-Photo · Posted: Tue Dec 23, 2008 7:23 pm Post subject:

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Unfortunately the -25 volt high is a common readout when registration is turned on. When your getting the -25v high try turning off registration(code 55 if I remember correctly) and see if the -25v goes away.

blu86 · Joined: 28 Dec 2006 Posts: 23 Location: New York/New Jersey

just checked, the -25 VOLT HI is showing up with registration on or off

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Well the -25v line only feeds the CPU and the registration amp so I cant really see it causing your problem. But that line probably should be checked anyways just to see what the actual voltage is there.

tse · Joined: 03 May 2006 Posts: 1014 Location: Sweatbucket, Fl.

There is a chance this is caused by a simple bad connection between the HV supply and the splitter. Check the "Hobson" connector that plugs into the Spellman for cracks or worn locking tabs in the cap part. Remember to unplug projector from AC line and wait a few minutes for discharge before messing with HV stuff.

Scott

Z-Photo · Posted: Wed Dec 24, 2008 2:50 pm Post subject:

blu86 · Joined: 28 Dec 2006 Posts: 23 Location: New York/New Jersey

I am going to check the HVPS and connections today, the projector has been unplugged all night. I read some past posts about repairing broken solder connections in the HVPS with high-temp solder and finding success. Guess I won't know until I take a look. Would be great if it was as simple as that Smile

stefuel · Posted: Wed Dec 24, 2008 9:12 pm Post subject:

Should you decide to take it on your self be aware that there are about 25 screws to remove and not all the same length but the same size and yes it does matter. As long as the problem is not in the potted section, it should be repairable. Curt knows where all the trouble spots are and can repair it.

blu86 · Joined: 28 Dec 2006 Posts: 23 Location: New York/New Jersey

MERRY CHRISTMAS EVERYONE!!!!