Re: Amplifone DEFLECTION QUESTION

In almost all cases, when the vectors are only drawn in a certain quarter of
it, the amps are probably good but there is one supply voltage gone. The X
and Y amps need a + voltage to move to one side, and a - voltage to move the
beam to the other side. so when only one of the two supplies is available,
everything gets drawn in one particular quarter because there is only one
quarter in the monitor where only ont type of supply is needed:

for example, if the monitor uses a positive voltage to move the beam up and
right, that is the only quater of the screen that would work if there is no
negative supply:

-+ | ++
     |
-----------
     |
-- | --

I don't have an amplifone :( (Need one for my Star Wars) so I am not sure if
this is as the screen is layed out on that type of monitor but you get the
idea. Check the positive and negative supplies, preferrably at the power
transistors.

Mendel

----- Original Message -----
From: Daniel Piraino <dpiraino@twcny.rr.com>
To: <vectorlist@synthcom.com>
Sent: Friday, October 05, 2001 6:22 AM
Subject: VECTOR: Amplifone DEFLECTION QUESTION

>
> I have been working on an Amplifone board that I have gotten to the point
of running
> without blowing transistors. I found the culprit and fixed it but there is
a problem
> im not sure of. The screen is sqewd. To explain what it looks like it
would be like
> if you took the top left corner of the screen and pulled it to the middle
of the
> screen. Nothing is draw to the top of the screen or to the left side of
the screen.
> Everything is being drawn to the bottom right of the screen. I was
wondering if it
> could be a capacitor that went bad. I havent checked them yet but I will.
If you
> understand what Im saying and have an idea let me know.
> Thanks,
> Dan Piraino
>
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Received on Fri Oct 5 09:40:47 2001