CurtPalme.com Home Theater Forum

ronaldus · Joined: 25 Dec 2010 Posts: 183 Location: france

Hi Everybody,

I see now and then (once every two films) that my HV goes off and comes back on (without any loud ticks or sparks).

I can see it comming because I can see the blooming increase a little bit and it looks as if the image becomes slightly overexposed then it's a question of a few minutes and the image goes dark and comes back out of focus and becomes sharp again. It's then stable for the rest of the movie.

I think when the blooming increases this means that the HV increasing too much and then is switched off by security. If it would drop the picture would become darker i guess.

The defocussing effect is also due to the HV changing because higher HV means the electrons have more energy and the focussing strength of the focus coils is less effective. On the other hand lower HV means the electrons have les energy and the focussing strength is too high and we also get a defocusing effect.

What do you guys think about this theory?

I have not mofified the HVPS yet so maby it's the right moment to do that.

Regards,

Ron.

**Curt Palme** · Posted: Mon Mar 03, 2014 3:24 pm Post subject:

It is probably that the HV is decreasing. you'd have to measure it to make sure. THe rest of the set can only turn the HVPS on or off, so it makes sense that what you're seeing is coming from within the HVPS. I'll bet it's a problem within the potted section. you can try to mod the exposed LV section, but I don't think it will change anything.

DarthZorG · Joined: 04 Mar 2014 Posts: 2

I had.. or actually have the same problem, it started like yours did and then suddenly the HVPS died with the typical burn electronics smoke. I contacted Curt for a HVPS replacement and i also discovered my tube bellows were leaking so i got new bellows which took forever to get to me, long story short i finally put the new bellows on, cleaned the tubes and put the new HVPS in place... but the problem is still there Crying or Very sad

It still seems a HV related problem, maybe it's the splitter, or maybe the LVPS (the HVPS source comes form the LVPS right ? ), anyway in my case the control board doesn't show any error condition Sad

ronaldus · Joined: 25 Dec 2010 Posts: 183 Location: france

Hi again,

I also had the problem when i change the Vertical size of the image (I think it was vertical but it's a long time ago that I adjusted that) as soon as the size decreased to much (or increased to much i don't remember) the HV stopped and came back on. Could this be a protection (scan fail or something) problem?

DartZorch maybe this could be some hint for you?

regards,

Ron.

**Curt Palme** · Posted: Tue Mar 04, 2014 4:31 pm Post subject:

Ron, if you have the V modification done, I've had the odd time where the HV protect will shut down due to the image being too short. I wouldn't worry about that.

ronaldus · Joined: 25 Dec 2010 Posts: 183 Location: france

Thanks Curt,

Regards,

Ron.

DarthZorG · Joined: 04 Mar 2014 Posts: 2

Thanks Ron, i will try that, it still seems weird as I've been watching movies for over 2 years with that setup before the problem started showing up, also i'm kinda worried as i already lost one HVPS i wouldn't want to get another one burned, so I'd like to try to pinpoint the problem before attempting something.

gjaky · Joined: 05 Jun 2010 Posts: 2802 Location: Budapest, Hungary

Well you guys should try to remove one tube at a time (pull the HV lead) and see if the problem is related to a certain tube, or any two of the three will work fine (or still acting up?). This would help to decide wether this is tube related problem or the HVPS has trouble with the load.

1031 · Joined: 22 Mar 2006 Posts: 657 Location: Finland

My 9500 had similar symtptoms, cannot remember what was culprit ( it was 2-3 years ago) but somehow i think that was HDM-module or contact issue with HDM-MOBO.

**Curt Palme** · Posted: Tue Mar 04, 2014 7:58 pm Post subject:

Do not only disconnect the HV lead, disconnect the cable between the CRT socket and the motherboard. That will completely isolate each tube from the set.

tanwn · Joined: 26 Dec 2006 Posts: 104

yes i have a barco cine9 that used to do it too and found out that the cause was the HDM module. Swap it out and now it works perfectly.

ronaldus · Joined: 25 Dec 2010 Posts: 183 Location: france

Hi everybody,

I would like to give some feedback about my HV problem.

during holidays I finally managed to do all the maintenance upgrades. I thought it would be nice to give my opinion about the improvement that I could see.

Caps an resistor upgrade on all STIG VERT and CONV board:
No improvement in image quality (bandwidth wise) but Conv stability is allmost perfect now. after about 15 minutes everything is stable. Worth the effort!

Caps an chip upgrade on FOCUS board:
No visible improvements.

Caps upgrade on HDM and daughter board
No vissible improvements

Caps upgrade on VIM
no visual improvements

Caps upgrade on NECKBOARDS:
clear improvement in sharpness Worth the effort!
chips (EL16XXXx see nashous tread) upgrade on NECKBOARDS:
loss in sharpness. When putting the old chip (HF1100) back sharpness didn't improve to old value

LVPS:
Wima caps on output and increase CAP for heater circuit:
No visual improvements

HVPS:
replace all carbon resistors with OHMITES
Much cleaner image less noise and brighter image (probably G2 voltages changed due to resistor change)
Worth the effort!

CLM:
upgrade yellow tantallium and other caps:
no visual improvement or stability increase (everything worked allready fine)

I had a small HV leak (tick every 3 seconds) on the HV lead of the red tube (covered everything with a silicon hose and problem is solved.

Result of all this:

No HV cuts during the film and improved image and convergence stability.

The only problem that's left is that sometimes my to and bottom bow are off when i switch on my projector.

I'll open a new thread on it.

Conclusion: Well worth the effort