Amplifone HV problem

I've been working on a bunch of suggestions that I have received reguarding
my Amplifone 25" in my SW cockpit. I still have problems mostly with what
I think is related to my low HV.

Red, green, blue inputs into the deflection board run .5v to 1v or so.
Red, green, blue inputs into the neck socket from deflection board vary as you
     look at them but in general range between 172v and 178v.
B+ is at 181.2v read at J104 connector on deflection board
G2 read from neck socket is at 457v.
Deflection board 50VAC rectifier diodes output as follows:
     CR14 32.2v (cathode), CR15 31.5v (cathode), CR16 32.0v (anode), and
     CR17 32.0v (anode). Opposite sides of these diodes swung all over but
     generally stayed in the millivolt range with occasional .1v readings.
7824cv output 26.2 volts
7924cv output -32.0 volts. (I've replaced this 4 times now and am sure it is
     insulated correctly. 2 seperate FAQs show this as an ok reading.)

With B+ set at around 180v I only get roughtly 14k HV. If I crank R7 all the
     way up as well as cranking up focus and brightness pots I end up with
     a white screen with the games vectors being displayed correctly. All
     retrace vectors can be seen however. But I get nothing with the B+ set
     at the correct level. Still the picture with all the pots up and the
     sound of the deflection chatter I have would indicate XY deflection is ok.

This is a new Wintron (bought last August). Cap kit was installed. Resistors
are origional I believe and test within 10% in circuit based on the color
codes of the ones there. I started to think that maybe someone in the past
could have put in a wrong resistor value so I wrote down the location and
colors to check at work. I think I made a mistake when I wrote them down
though. I have R11 as a 2.2k and R9 as a 22k which matches the schematic.
I then had R12 written in front of R9 meaning it had the same value as R9 or
22k (red, red, orange) but I rememeber mulitple (red, red, red) 2.2ks in there.
So I think I just added R12 in front of the wrong row. I'll double check
tonight. Anyone know if what I'm seeing could be caused by a 22k in R12
though? Not sure if it would turn the MPSU07 off or if it would still have
a smaller voltage going into the T1.

I see another post here now dealing with a low HV from a new Wintron. When
was that purchased? Any chance they changed something and that is now a
problem?

Greg

______________________________________________________________________________
Gregory Erway
(585) 924-7550 (work) gerway@redcom.com (work)
(585) 398-2672 (home) erway@rochester.rr.com (home)

           Classic Arcade Video Game Records (www.twingalaxies.com):
          Tapper World Champion - 1,263,625 6/3/01 (Tournament Rules)
      Rootbeer Tapper World Champion - 1,959,200 7/29/86 (Marathon Rules)
  M.A.C.H. 3 - Bomber Third-Place Champion - 353,200 3/22/86 (Factory Default)
  2001 Funspot/Twin Galaxies Classic Video Game World Championships 8th-place

Arcade Collection: http://www.vaps.org/members/ny/erway@rochester.rr.com.html
______________________________________________________________________________
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Received on Mon Mar 18 07:06:39 2002