Re: G05 issue

thanks bill, its the bottom as i have monitor on the floor in back of the cabinet. i'll check what you suggested.. pretty sure i replaced at least one of the small transistors in -y.
on the brightness i will pay more attention to what it does as it was secondary to really look at over that other issue but who knows, they may be related....

Sent from my Samsung Captivate

William Boucher <wboucher6@cogeco.ca> wrote:

So strange, I thought that would have been it.  Have you tried replacing the Y axis TO-3 power transistors yet.  I had previously assumed so.  Something is either stopping on of them from turning on enough to reach full deflection or the transistor itself is failing somehow when it tries to turn on that much.  The image squishes into a line simply because the driver for that side of Y cannot turn on all the way.  Have you replaced the small transistors in the Y preamp?
 
You said the image was squished at the bottom right?  That's the monitor's bottom and not the bottom of the image you see in the mirror?  I'm trying to determine if we are talking about the positive supplied half of the screen or the negative supplied half.  Knowing that narrows it to just one TO-3 power transistor and fewer components in the Y amp.  For example, if it's the negative side, then focus on Q609 and if it's for sure okay, then move backwards to Q607 and check R615 isn't burned, check R616 and D608.  Also check D606 and D607. 
 
If it's the positive half, then Q608, Q606, and Q605.
 
If the problem is further back even than that, then Q602, Q603, and Q604.
 
Very sorry I cannot be more specific.  You can try swapping a specific transistor in the Y amp with the same one in the X amp.  When you hit the right one, the squished bottom will become a squished side and you'll have found the problem.
 
As for the brightness issue, I don't know why it would be unstable unless there's a flakey pot or diode (R517, R514, D506.  Obviously Q504 or Q503 could have an issue.  Brightness is such a subtle thing, it's hard to scope it out because the Z drive is mainly working overall regardless of a small change in brightness.  I mean, the Z voltage will be lower if the beam is brighter but it doesn't have to be all that much lower to look just a bit too bright.  My first attempt to fix it would likely be to replace the two pots and the two transistors.  Since you said the contrast appeared wider (some lines are too bright, others too dim) on powerup, that might be pointing right at the contrast pot R517.  Does the contrast go back to normal after it warms up again or does it stay that way?
 
Bill Boucher
http://www.biltronix.com
----- Original Message -----
From: andre
To: vectorlist@vectorlist.org
Sent: Saturday, February 25, 2012 11:34 AM
Subject: Re: VECTOR: G05 issue

I replaced R602 even though it seemed ok, but still had the same issue. I checked B+/- and both are at 39v. There is a fair amount of ac on those lines (.3mV if I recall correctly from yesterday) so I replaced both the 6800 caps with new ones. No difference in the AC ripple, or the image. All other caps are new as well.
I did find out though, that if I adjust R602 and R601 (think that is the other Y pot) down to their minimum, that the image is fine if it is squished into a band in the center of the screen that does not include that 1/4-1/3 band along the bottom of the crt. As soon as the image enters that area, it starts to vibrate and gets distorted.
- I put in another known working deflection and the image is great, so its not a crt or HV issue.
- I again re-soldered all the connector posts, pushing them all down a couple mm into the pcb so I for sure had a post on the opposite side that was soldered well.
- The bad deflection also seems to be bright on startup. What I mean is I can adjust it so the bright/contrast is good for omega race with the 2 intensities. But if I turn the cab off and on, it seems the bright vectors are too bright again, and the lower ones quite dim. I did check everything in the guide that mentions vectors being too bright and all was ok. Heater voltage I adjusted right onto 6v and it is steady.
 
thanks

From: "wboucher6@cogeco.ca" <wboucher6@cogeco.ca>
To: vectorlist@vectorlist.org
Sent: Tuesday, February 21, 2012 5:07:28 PM
Subject: re: VECTOR: G05 issue

Sounds like R602 pot is misadjusted or broken.  The input clamping circuit may be limiting Y.

Another possibility, check the positive and negative DC supply levels B+ and B-.  One of those rails may be too low.
The one to check is indicated by which half of the screen has the problem.  I forget off the top of my head which is
which or I'd just say.

Bill Boucher
http://www.biltronix.com

>
>
> I had a similar isse back in 2008 with a g05, but I don't have a clue what the solution was. Well fast forward to
> today and I have a new battlezone basketcase I just got. The deflection was in bad shape. I recapped everything, new
> side transistors, a nd went to work on verifying all else as the monitor just would not function in any respect. One of
> the connectors had the metal posts come off the pcb. So the guy soldered wire on the underside to join the bottom of
> the posts to positions on the pcb. The wiring is done correctly and should work. A couple of the posts were not
> completely through the pcb and had lost some contact so I melted the solder, and pushed the posts through the pcb so I
> could fasten them a lot better. After all of this, the monitor now finally works, but I have the same issue as below,
> only it is the bottom that is compressed. Its maybe 1/4 to 1/3 of the bottom of the screen that is compressed into a
> line that vibrates much like a
>  loose connection would cause.. but I have verified all the connector posts for continuity. The top 3/4-2/3 of the
> screen is rendered absolutely fine. Is there anything other than a connector issue that could cause this?  
> ---------------------------------original post 2008------------------------------------
> This monitor was working fine, then a bunch of resistors in the Y section fried after a 3906 died. I replaced all the
> burnt resistors, the 3906 and tested every other transistor and diode..all were fine. Put deflection back in and only
> got a thin line across the center horizontally.. threw in another deflection and it worked, so HV and frame
> transistors were good.. Well after pulling out my hair, went through every resistor and found the large 2ohm wirewound
> one in the Y was in the meg-ohms.. something must have happened to it.. so swapped out with another one, and it looked
> like the monitor was working when I fired up Omega Race..until the text wrote out to full screen.. I still have an
> issue.. When something is displayed over the whole screen, I have a bout the top 1/3 compressed into a horizontal
> line..but the rest is fine. It is more than half the screen as the center box in Omega Race is complete..another inch
> or two above that box is where it   compresses... I've verified pretty well everything I can on that side of the
> deflection.. does this point to anything I can maybe re-check?
>
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Received on Sat Feb 25 14:24:47 2012