RE: Amplifone No HV

First thing to do is check the regs: +/- 30* in, +/- 24 out (*30 is
spec, you will typically up to +/- 33v).

http://www.classicade.com/temp/AmplifoneTestPoints.jpg

Also, replace all the zero ohm (brown) jumpers on the deflection board
as well. Don't forget the rudimentary: check for cold solder joints,
and resolder any harness wires that look frayed (the grounds on the HV
typically are stressed).

I'll wager that you HVT is bad, the red just doesn't last that long.
I'd recommend getting a WinTron ASAP, even if you do get the red up and
running, it is only a matter of time before it goes, and it will
probably take out a couple of components w/ it when it does go.

I've seen n/w HV boards semi-regularly on eBay -- typically fetch $80 or
so for red, $200+ for WinTron.

> -----Original Message-----
> From: owner-vectorlist@synthcom.com
> [mailto:owner-vectorlist@synthcom.com] On Behalf Of Dave Langley
> Sent: Saturday, August 17, 2002 4:12 PM
> To: Vector List
> Subject: VECTOR: Amplifone No HV
>
>
> Hi ...
>
> Finally after I've managed to get power on my Star Wars
> cockpit with 25"
> Amplifone for the first time (in 12 - 14 years!). I built up
> gradually,
> first testing the PSU block then the ARII and then the boards
> running with
> my 'scope as the monitor. All was well.
>
> Now the crunch. Power up my Amplifone.
>
> Before I powered up I verified all the diodes (except the
> LED), resistors
> and transistors.
> I recapped the board
> Removed the jumper and fitted some nice sold wire.
>
> I did not test the HVT (which is a red board serial No: XY
> 19025) as I
> don't have a tester.
> I did not test the regs (too lazy)
> I did not scope the wave form with the BU406D removed (too lazy)
>
> Upon power up I got:
> Game sounds and I could play blind.
> No static build up as if HV were there.
> No picture.
> There did not seem to be a heater glow but the room was brightly lit.
>
> I adjusted the screen control to no avail.
>
> So I've pulled the board and retested everything again.
> Nothing has changed, except the LED (CR2) did not test OK on
> diode test.
> Will this affect HV production in an otherwise working board?
>
> It's after midnight now (here in the UK) so I'll test the
> regs and scope
> the wave form at the BU406D in the morning. One thing I did
> not look at is
> to see if the Over voltage LED was lit. I've looked at the
> voltage cut off
> adjust pot and it is fully clockwise! Does this mean that it
> will cut off
> the HV really low? I don't have a HV probe so I cant set the HV ....
>
> So the main thrust of this post is:
>
> Is my LED OK?
> How should I set the two pots as I don't have a HV probe?
> If the Regs and waveform are OK it must be my HVT?
>
> Is it time to call wintron?
>
>
> Dave Langley
> www.robotron-2084.co.uk
>
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Received on Sat Aug 17 21:25:45 2002