CurtPalme.com Home Theater Forum

massimo · Joined: 25 Jan 2022 Posts: 15

Hi guys, I'm here again asking you for advice that has never happened to me until now..
I am a happy owner of a barco cine 7, an electrohome ECP 3100 and finally now also a fantastic SONY VPH-1271Q.

in the latter I found a defect, if I raise the contrast or brightness above 50% the image blurs, this has never happened to me with my previous projectors ... even trying to fix it with the focus control on the card does not change anything.. it almost seems that it receives too much current and distorts the image.. what do you think I should do?

I state that the projector has been stopped many times, but it has always been kept in a dry and not humid place.
I also state that the projector can be seen below 50% brightness and contrast, it could (in my opinion) be seen better but in any case it can be seen quite well ... I await your kind reply, thanks to all Smile

**Curt Palme** · Posted: Tue May 02, 2023 2:19 pm Post subject:

It sounds like bad HV regulation, or the focus voltage is changing as you change the contrast. Or, it could be weak tubes, but that would seem unlikely, especially if all 3 are doing it. As you ramp the contrast up and down, does the image change size at all? If so, then it's HV regulation problems.

The HV regulation is done on the PA board, however in the dozens of 12XX series I serviced, I never had any HV problems outside of arcing due to bad HV leads. Also, each PA board is calibrated to each set, so you can't take a PA board from another 12XX and put it into the set, as it will most likely be out of calibration.

massimo · Joined: 25 Jan 2022 Posts: 15

Thanks for the reply!
The size of the image does not change and the defect occurs on all three tubes ( more on the blue one )
Now that I actually look carefully at the electronic fire I can never reach it perfectly, but first I still have to finish calibrating the astigmatism.
If I can tomorrow I'll take a couple of pictures for you to understand better.

**Curt Palme** · Posted: Thu May 04, 2023 3:12 am Post subject:

Have you adjusted the focus pots on the focus/G2 block? DO NOT touch the G2 settings, they are critical, but crank up the contrast, and set the focus controls for best focusing. If it's still bad, but there is a point on each control where the focus is the best, and then gets blurrier on either side, I will suggest bad tubes.
I had that once on a Barco 800 that uses the same tubes. No matter what I did, I could not get the focus good on any tube. I changed all 3 tubes, and the problem was solved.

massimo · Joined: 25 Jan 2022 Posts: 15

Ok thanks, in the next few days I will try the procedure you told me and I will let you know.
I don't think about the tubes, he calculates that this projector belonged to a gentleman who used it regularly for a certain period, then later sold it to me, when we turned it on he did this trick of the focus but according to him years before he didn't did, the image in the tubes was very sharp... Is it probable that after all these years something has changed in the circuit? Any capacitors leaking? Any oxidized trimmers? Or the pipes deteriorates or even standing still?

IF I wanted to "calibrate" the G2 voltage to be able to give it a tweak, how could I do it? I saw that on the Barco cine 7 there is a procedure, that's why I haven't read anything yet...

I hate to leave it alone because I ordered about 2 weeks ago the HDMI add-on card that you sell..

**Curt Palme** · Posted: Thu May 04, 2023 4:32 pm Post subject:

Just drifting of the G2 controls is the most common. Check the hour count once you're in the service menu. The G2 calibration is in the service manual as well.

massimo · Joined: 25 Jan 2022 Posts: 15

Many thanks, I'll do everything on Saturday and then I'll let you know. The hours of the crts are around 1700h from what I remember, however under 2000 hours

massimo · Joined: 25 Jan 2022 Posts: 15

Here I am back, after having redone the tests hundreds of times and having calibrated everything properly, finally the projector no longer blurs as the contrast increases.
List of works performed:

- reset the projector to factory settings

- mechanical centering of the tubes

- alignment (level) of the three tubes by moving the deflection yoke

- calibration of the g2 grid as per the service manual

-Retouched red tube astigmatism (the other two are fine in my opinion)

- installation of the new HDMI card bought right here on the site.

After all this work, however, I'm still not satisfied... The image is always blurry and not very clear, I tried to compensate both the mechanical and the electronic focus by the trimmers but it is still too blurry.
To understand this, it is as if a 480p video is reproduced from YouTube on a 4k television, I see the video ... colors, depth, etc., but I don't see it clearly.
What can I do to get an excellent result also on detail and sharpness? Surely I'm doing something wrong, please enlighten me!

**Curt Palme** · Posted: Sun May 07, 2023 2:25 pm Post subject:

It's a 35 year old ES focusing set. They simply don't focus as well as EM focusing sets, which is why EM focusing sets became more popular, or at least more in demand than ES ones. Tubes do age, esp if they are ES focusing sets, and it could also be that the set is a 11,700 hour set, as the hour meter rolls over to 0000 after 9999. The focus electron grid does age if the set has been in standby mode without a picture being displayed, so that could be the problem as well. My guess would be bad tubes as I mentioned earlier.

massimo · Joined: 25 Jan 2022 Posts: 15

ok now i get it, so curt what would you recommend to do? Replace the tubes of the permitted set if there are still decent tubes around or just change the whole set with something more performing?