CurtPalme.com Home Theater Forum

[ronaldus]

Hi Again,

My focus problem is back again.

I've made a little film.

Switching on off still works (that was the original problem why i opened the thread)

Suggestions anybody?

regards,

Ron.

[Nashou66]

Hmm Weird, is it on all colors?

Nashou

[ronaldus]

Hi again,

Yes it's on all colors but not necessarily at the same time and not the same defocusing on every color. Red could be good when green is out of focus and when I increase the contrast then red could be out of focus etc.

I've switched the projector off (but still plugged in) and 10 minutes later when switching back on everything was good again and no problems during my short movie session.

It must be some bad contact. I'll try to measure some voltages on the focus board. and maybe also on the stig amp?

regards,

Ron.

[Nashou66]

I wonder if its the HVPS? Can you pull it out and in a few times? Might be dirty connector.

Athanasios

[ronaldus]

Hi Nashou,

Why would it be the HVPS? Is it used for the focus system?

Regards,

Ron.

[haireez]

Hi, do you have a spare HVPS? If yes, you should give it a try as I do have a similar problem like you but after I changed with my spare HVPS, the focus is back to normal. Before that, there was an intermittent and the projector focus was quite bad out of sudden.

[Nashou66]

I asked about the HVPS just to see if you have the 34.9kv version and not the older 34KV version. Also like Haireez says try another HVPS, it does affect focus if going bad.

Athanasios

[ronaldus]

Hi again,

I don't know which HVPS I have by heart but I have Panasonic tubes if that helps. Unfortunatly I don't have another HVPS.

Would it be a problem in the potted section? I was planning to do the mods for the carbon resistors in the the non potted section but i don't know if that would help.

I dont know if you still rember but I had once an arc inside the projector that killed one channel of the CVA because I had not connected the earth strips from the neckboard to the back heatsink. Could that be the cause of the problem?

I also have a spare focus board but i have not tried that one.

regards,

Ron.

[ronaldus]

Hi everybody,

It's me again. I was very busy lately but I still have the same focus issue. However i discovered something that could be interesting.

I now have to switch the projector on and off at least 6 times before I get good focus. This afternoon I switched on the projector and off course the focus was bad. I thought let's go into the service menu and try to adjust the astig. Then i discovered stigmator: not installed. So I think there might be a bad connection between the CLM and the ASTIG board because it doesn't recognise the board alltough it is installed!

I'll flip open the heatsink tonight to have a look for a bad connector. It must be something like that.

By the way the problem of the projector not switching on never reappeared after I cleaned the contacts of the LVPS so i must have cleaned all the contacts well.

Any other thoughts?

[Nashou66]

Check the fusible resistors on the SAB, R103,203,303 etc.

Athanasios

[ronaldus]

Hi Athanasios,

I played a little bit this evening and I made some further tests. While the focus was still bad I lowered the contrast a few notches and went back to the astig menu and bingo it was back and i could adjust it and it reacted normal. After a few on of cycles i got good focus (that didn't change while ramping the contrast) i went again to the stigmator menu and it was again not installed. I think I have two problems still pending:
1 the focus not good when starting up and it changes while ramping the contrast.
2 the astig board is not always recognised.

I have a spare astig board so I will change that to see if it makes a difference.
But I still think it could be a power/connector problem I'll also check some voltages.

I know i just have to open the projector up and repair it but i just want to put all the sympthoms here. In case somebody has the same problems he could maybe profit from it.

I'll keep you informed.

[Nashou66]

Re connect the SWB on the CLM too. Might be that contact.

Athanasios

[thewolfman]

[draganm]

considering the machines are mostly over 15 years old now removing everything and cleaning with Caig deoxit is going ot be your best repair tool.
When I get these machines in now the connectors are so oxidized they're hard ot get off and make a crunchy-grindy noise as you pull them on. After brushing on de-oxit they slide back together so smoothly it's amazing

[ronaldus]

Is this deoxit much different then normal contact cleaner? i've used contact spray for all the connectors.

[Nashou66]

[ronaldus]

Hi everybody,

I finally had some time to work on my projector a little bit and I think i solved the issue with the focus.

I took out the control board, cleaned the two white connectors at the end and put it back in. Bingo!

Start up without problems and the focus is now good again also in the corners. I have the impression that the image is sharper. This should be normal because the problem I had was with the stigmator circuit.

I must say that in order to do this I had to move the projector forward and i have some mechanical system with a turning threaded rod to do this (see my photo album) . In order to make this rod turn i used an electric 1/2' wrench driver (like they use for car wheels) This thing makes quite some vibrations so i don't know if this helped also shaking every connector in the marquee

Since I had to move the projector forward by 25cm I checked if I could increase the image without touching the side of the tube face and I could! So maybe this helped also increasing sharpness. I think I will leave the projector where it is now.

I just wanted to let you know as some feedback

Regards,

Ron