CurtPalme.com Home Theater Forum

[HK-Steve]

This is a revision of the other thread, steps are not in order, just a review of all done to solve the problem.
https://www.curtpalme.com/forum_archived/viewtopic.php@t=22010.html

Marquee Ultra 2004, Ceiling mounted.

Original Revision B HVPS Fuse exploded 2 times, and now is not repairable,
Tried 2 more B Revision HVPS, both blew the fuse same as the first. Also became un-repairable.
Pulled HDM, FCM and LVPS, all tested OK.
VNB also checked and tested OK.
Tubes are LUG with about 1500hrs on them,

After checking everything, even taking the projector down from the ceiling, re-installing everything in my workshop,
worked perfectly for the 2 months I had it running 4hrs a day,

re-installed at Michaels, ran after the re-install for 4 months, then exactly the same problem, blown HVPS fuse.



Things I have done so far,

Tested the tubes with Sencore unit, tested all ok.
replace the fuse in HVPS, blew straight away.
replaced mosfets, plus other parts, fuse blew again.
tested voltage of the power outlet, 231volts, with no spikes.
HVPS fuse was correctly rated, OEM.
checked 390volt output from LVPS, tested at 383volts.
Changed LVPS,
Splitter replaced,
Cleaned all the HV cables and connectors to splitter.
Physical check of each tube for cracks or glycol leaks. Heater filaments all glow.
G2 voltages are all good,
Replaced the full wiring loom and connectors,
checked both LVPS and HVPS connectors and pcb connections, no burn marks or contact problems.
HV cables visually checked, found nothing, but installed clear sleeve anyway, made no diffence. Fuses still blew.
VNB's all checked and tested, no problems.
Ground, or earth system is all good, measured at 0.01ohms.
Measured HVPS G2 resistances, all ok.
34Kv HVPS was used, was suggested that it had better protection, all ran no problems.

I think that pretty much covers the other thread, suggestions and advice from you all.


Now I have a Revision A7 HVPS running currently with no problems since sunday,

Cheers
Steve

[geisemann]

-I replace neck cards. WE have some in stock I will sell cheap. Spark gaps can fail.

HV ARC can happen when humidity level drops and you will not see it until it hits the right value.

-Remove the tubes and put a nice thick goop of silicone around the HV cups. Possibly remove the HV cables and replace with new ones. Internal arcs can happen you will not see.

-Replace all 3 tubes with some good used ones see if problem comes back.

What is the humidity level in your home.?
Greg

www.eisemann-theater.com

[draganm]

So I did my best to re-read the other thread. IT seems like we're looking at the 2 different problems right?

1) The fuse for the G2 section / Mosfets keeps blowing which would indicate a problem with the electron guns. However tested with Sencore and gates /filaments check good?

2)A section of the HV circuit is blowing and scorching the potting compound. This we're pretty sure has to to with the Diode/multiplier section and is not related to the G2 section at all?

at this point it has to be tube related I think. I broke open a tube and was expecting to see an actual grid but "HV Grid" is just a silver/metallic coating on the inside of the bell. IT's connected to the HV glass-metal transition that the HV lead under the boot clips into. Is there any way to check the resistance of the Grid inside the tube? As in removing the HV boots and testing the pass-through?

[Nashou66]

Does NIDI have any type of power conditioner in the Mix?

Athanasios

[HK-Steve]

Humidity is not an issue, it is about 15%, would see high humidity more of a problem than low humidity.
The HV connection to the tube has lots of silicon when newly installed.


Tubes were tested with Sencore unit, tested all good. plus the 3 tubes had nearly identical reading.


No power conditioner, the power here in Switzerland is very stable,


Just seem to be chasing my tail, everything runs well for nearly 6 months, then boom, same problem,
With everything tested, proven to be good, and no place to point the finger for the actual cause.


Appreciate the help and comments.

Cheers

[HK-Steve]

Hi Everyone, just checking in from my holiday in Australia,

I have not heard anything from Michael, so all looks good once again.
Hopefully Michael will drop in and post the status of his projector.


Cheers