CurtPalme.com Home Theater Forum

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

I have been using the retro for the main veiwing "TV" for quite a few years. It has been working great and only needs tweeking about once every six months. But lately it has been having an issue with the focus. It is very random and length of time varies. The picture will be perfect and then turn blurry for a few seconds then back to perfect. I removed and reseated the focus/G2 board and made little change. I did notice it happens most often when there is a lot of white on the screen. Darker shots never seem to change but Very bright scenes almost always go blurry. I reduced the contrast some and it helped but did not cure it. Contrast was at 51 and now it is at 46. The set has about 12,000 hours on it. It only had 1040 hrs when I got it.
I think something is about to fail. Just having a hard time keeping up with the demands of all 3 tubes fully lit.

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

OK I have been paying more attention to what is happening and one of the reasons it gets so blurry. It is because the brighter and whiter the screen gets. The farther the convergence goes off.
What can cause the convergence to change with picture intensity?

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

That happens also when you ramp up contrast I bet. Is it on all colors? Put up a grid and mark a piece of painters tape next to a grid line. Shut all but one color off and ramp the contrast and see if that corresponding grid moves against the reference tape mark.

Athanasios

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

When I put up a grid with just one color. There is no movement at all when ramping up contrast. But blurring when it gets over 80. With two colors any two, there is some movement as contrast goes up. And blurr at about 70. When all three tubes are on there is drastic movement. And blurr starts at around 50

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

I'm not a barco expert, but it sounds LVPS problem to me.

km987654 · Posted: Mon Oct 08, 2012 5:48 am Post subject:

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

OK, I swapped out the LVPS and there is ZERO change. Still goes blurry and off convergence with bright scenes.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

When you say movement do you mean the entire grid moves? Like a shift adjustment. If so then it may be a high voltage issue. Does that have a focus/ shift board? If so, pull it and check for bad solder joints.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

I just did some checking and the focus and shift are separate. So, you may have to look at the HV board, again checking for bad solder joints.

**Curt Palme** · Posted: Tue Oct 16, 2012 6:01 am Post subject:

Sounds like either your HV board isn't regulating properly, or the G2/focus board is drifting itself. It's not an LVPS issue as you found out.

It could also be the quad or HV splitter, but I doubt it.

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

I will try swapping them out to see what is causing it.

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

I tried each one separate and as a pair.The HV board and Focus/G2. No change still drifts convergence and focus with bright scenes.

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

Neck boards? Bad contact or leaking glycol on the neck board (especially conjunction with G3 -focus- pin) can cause various focusing problems.

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

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

If it looses the focus how could you tell so sure how far the convergence goes off, turning simply the focus pot makes the convergence off that is why the electronic focus is in the first steps of the set up procedure.
Anyway just thought it might worth a try, since you've changed literally everything else.

barclay66 · Posted: Wed Oct 17, 2012 9:47 am Post subject:

Hi,

The source of this problem seems to be some tough little bitch!

I took a look at the schematics and this is what came to my mind:

- If convergence doesn't have a stable output, this often is related to the convergence amplifier's power supply not being stable
- The major supply for the convergence amplifiers is generated on the SMPS (+17V and -17V)
- The SMPS has already been swapped without change (presumably OK)
- Nevertheless those power rails could be affected by other boards putting load on them

With this in mind I would measure both rails and would check if their voltages change according to the effect on screen. If so, I would start swapping the boards which draw most of the current on these rails: H-Deflection, Sync+Vert. Deflection and Convergence Output board.

Regards,
barclay66

**Curt Palme** · Posted: Wed Oct 17, 2012 11:27 am Post subject:

I still say you have HV issues. Convergence will be affected as the HV changes. It could be a glycol leak out of a tube onto the motherboard, I had my own retro 808s do a massive smoke show 5 years ago due to that. I'd suspect a quad or the HV splitter.

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

I will check for leaks tonight and see what I find.

It happened rather quick, not a gradual change. Although it seems to be getting worse.

papalek · Joined: 08 Mar 2006 Posts: 1536 Location: Longs SC

No leaks anywhere. I pulled all the neck boards and they are dry, even in the pin holes. Now the pic is also going black. The set is on but no pic. It will do this after about 15 minutes of use. The only way to get the pic back is to turn it off and back on. Then the pic will stay for hours.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Do you have a quad to try?