Re: Amplifone monitor - still stumped on bright dot in middle.

John, good to hear you got it going again. 3.1 million on your first game?
You must have those trenches memorized! Use the force and get all the towers
every time?

Jordan B

On Fri, Aug 5, 2011 at 11:38 AM, John Huie <jehuie@sbcglobal.net> wrote:

> Thank you to EVERYONE who helped or attempted to help me get this amplifone
> going. It is now up and running and I played my first game of Star Wars on
> it this morning (level 14, 3.1 million) and it looks good. I need to do
> some minor adjustment on brightness levels of the colors and such but
> otherwise it's very nice.
>
> Several people mentioned possible issues with the spot-killer circuit and
> that was apparently what the problem was. An extra thanks to Mr. William
> Boucher for providing the helpful details! I replaced Q10, Q11, Q26 and the
> 4.3 volt zener diode this morning (somewhat arbitrarily) and fired it up!
>
> Thanks again for all of your tips. I may be slow but with your help it's
> back to life!
>
> --- On *Tue, 8/2/11, William Boucher <wboucher6@cogeco.ca>* wrote:
>
>
> From: William Boucher <wboucher6@cogeco.ca>
>
> Subject: Re: VECTOR: Amplifone monitor - still stumped on bright dot in
> middle.
> To: vectorlist@vectorlist.org
> Date: Tuesday, August 2, 2011, 8:58 AM
>
>
> Assuming there is not a CRT problem, I still think that the problem is
> related to a component that is common to all 3 color Z drives.
> I took a look at the Amplifone schematic this morning to see what else I
> could find.
> Refer to the attached marked-up schematic and PCB photo for component
> locations.
> Mark-ups are in red and blue.
> Here are a couple of things that you can check...
>
> 1) Check for 12V at the cathode of CR20. If this zener is shorted, the
> color drive will be extremely weak or non-existant. An open (or partially
> open) R71 can also cause the same issue.
>
> 2) Check the cathode of CR19 for 4.3V. If this zener is shorted (or
> leaking a lot), the Z drives will be weak or cut off.
>
> 3) Just because the spot killer (SK) LED is off doesn't mean that the SK
> output transistor (Q26) is okay. You can check Q26 to be sure that it is
> really off (maybe by seeing 4.3V is present) or just replace it to be 100%
> sure.
>
>
>
>
>
> Just to clarify, when you stated "W jumpers are all long gone.", we assume
> that you meant that the old "0 ohm resistors" were replaced with solid
> wires.
>
>
> William Boucher
> http://www.biltronix.com
>
> ----- Original Message -----
> *From:* John Huie <http://mc/compose?to=jehuie@sbcglobal.net>
> *To:* vectorlist_at_vectorlist.org<http://mc/compose?to=vectorlist@vectorlist.org>
> *Sent:* Saturday, July 23, 2011 8:05 PM
> *Subject:* VECTOR: Amplifone monitor - still stumped on bright dot in
> middle.
>
> Just to refresh...this monitor on this Star Wars works good and the
> graphics are all there and everything but there's a constant bright dot in
> the middle. If I turn the brightness down enough for the dot to go away
> then I can't see the other graphics at all.
>
> Here's what I've tried so far:
>
> - Bought a whole slew of components from Bob Roberts to rebuild the
> deflection board and HV board
> - HV is good.
> - B+ is good.
> - Adjusting color drives doesn't help. Brightness down and the color
> drives up still won't let me turn down dot enough to see graphics well.
> - I don't have any spare parts to swap in. I only have 6100 vectors other
> than this.
> - double checked continuity from focus block wiring, all connections under
> boots are good. Good continuity back to HV board and color drives on
> deflection board are good.
> - Pins on neck not shorted to heater pins. (Except pin 4 which isn't used
> - could this be a problem?)
> - W jumpers are all long gone.
> - Resistors in neck board/ring are good.
> - Does same thing with known working PCB set.
> - Reflowed J103 and tested continuity along wires.
> - Ground to neck board/ring is good.
>
> Still not sure how to check Z signal. What components should I be looking
> at that are common to all 3 colors that could be causing this?
>
> Any other idea?
>
> Thanks everyone. I'm working on this for a friend of mine and just about at
> the end of my rope.
>
>

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Received on Fri Aug 5 15:11:58 2011