CurtPalme.com Home Theater Forum

[Diesel 90]

Hi people,

I'm having some Marquee 8500 powerup issues and need some help working through this.

First occurrence happened about a year ago. Projector would not startup and LVPS light came on. At the time I replaced all the caps in the LVPS and all appeared well again and it worked until a couple of days ago.

This time it initially would power up and run for a few minutes then the LVPS relay(s) would click off and the LVPS led came on at the back of the projector. The problem got worse in the space of 3 or 4 retries where the power would come on for progressively shorter times and then click off with the resultant LVPS led on the back.

At the moment the tubes don't even have time to light up before the relays start clicking in accelerating frequency and then gives up trying. No diagnostic leds light up on the LVPS itself.

I tried pulling a number of boards to see if that would lessen the load but no change observed. I did not pull the neck boards or the back panel. I replaced the battery on the CLM about 10 months ago so I don't suspect it would be the source of this issue.

The only other observation I have is that high humidity, about one or two days out of the year here, has caused some powerup issues in the past but that would stabilize quickly after a few on-off-on cycles.

Questions:

1) Did I overlook a troubleshooting step that could potentially point to a different source for this problem (for instance, the projector may have a fault tripping up the LVPS such as bad caps on another board, etc)?

2) Has anyone observed similar symptoms and it turned out not to be the LVPS?

3) Are there accessible test points on the chassis to check if the voltages are coming up or are bring pulled down by a short?

4) Does anyone have an LVPS they are willing to sell, preferably from Canada or US?

The projector has given us 17 years of service with pretty much daily use as our main video source in a house that had up to 5 people. It would be nice to get it going again as we don't have a TV in the house as a fall back.

Thanks for any assistance with this.

RT

[ronaldus]

Hi Diesel,

I had something similar but it was a mosfet in the standby circuit of the LVPS.

Does the standby voltage still work? (the filament voltage should be reduced to around 3V when plugged in but not switched on)

It could also be a problem on the HDM (bad contact) maybe reseat the board?

I don't know if this helps.

Regards,

Ronaldus

[Diesel 90]

Ronaldus,

Thank you for the tips, I will see if I can get power long enough to get it into standby. I will also have a look at the MOSFETS. Does anyone know if the LVPS can be bench tested outside of the chassis?

I reseated the HDM and focus board, that has been the cause of some glitches in the past but not this time around.

RT

[ronaldus]

Hi diesel,

What I mean with standby is that you simply plug in the projector in the mains and you should have the fans running at very low speed and the filament voltage should be around 3 V

here is the thread where we discuss about it

http://www.curtpalme.com/forum/viewtopic.php?p=484211&highlight=#484211

please read until the end because the the beginning is about another problem

I hope this helps.

Regards,

Ronaldus

[Diesel 90]

Ronaldus,

That's an informative thread, thanks for the link.

My projector is set to power up as soon as it's plugged in to mains so I may not have time to put it into standby mode by pressing the button for 3 seconds. I control it through a remote controlled power bar.

I will try disconnecting the neck boards and back cover boards next to see if there was a short there.

RT

[Diesel 90]

I put this issue aside for a while and came back to it last week only to have the projector work correctly without changing a thing. At this point the problem appears correlated with periods of high ambient humidity. Does anyone know of an issue that would cause an LVPS fault related to ambient humidity?

RT

[Tim in Phoenix]

Guys

When did you last open the lvps and blow the dust out? Use an air hose or canned air. Clean also the edge connector at the rear and the bulkhead socket it plugs into.

[Diesel 90]

Thanks Tim, I did clean out the LVPS when I replaced the capacitors but perhaps the rest of the projector needs the same treatment.

RT