Vectorlist Archives: Re: Asteroids vectors that don't join up pr

From: COLIN DAVIES <colin.w.davies_at_btopenworld.com>
Date: Mon Mar 02 2009 - 07:51:59 EST

Hi Chris.

Double check your XY output on a scope. Looks more of a PCB issue then a monitor one to me at least.

I had a similar issue with my HV cage, the screen will expand, and then just go off.....(HV is dropping off when it expands) A 'calibrated tap' on the side of the cab would bring it back (Just like we did to the TV's when we were kids !!).

My issue is probably either a dry joint, bad connection,bad pot, bad diode, bad diode caps or lopt is on its way out or the wires are corroded where they come out of the lopt and onto the soldertags on the 'carrier'. You may have similar issues here.

I'll be buying some spare Transformers if they are ever repro'd as I have a number of HV cages and monitors to check out.

Cheers, Colin

--- On Mon, 2/3/09, Chris Hardy <chris@hardys.plus.com> wrote:

From: Chris Hardy <chris@hardys.plus.com>
Subject: VECTOR: Asteroids vectors that don't join up properly..
To: vectorlist@vectorlist.org
Date: Monday, 2 March, 2009, 9:47 AM

I've got a strange problem with my Alca Planet cab. (Asteroids bootleg).

The vectors don't seem to be long enough and don't join up.

I got the cab all working nicely when the original Toei XY monitor chassis
decided to let some magic smoke out.

Fortunately I had a spare chassis which I put in the cab and all was fine,
except for the fact that the vectors didn't seem to join up properly.

I re-capped the chassis but the problem persisted.

http://hardys.kol.co.nz/asteroids/DSCN4602.JPG shows the problem. The
vectors in the letters are too short.

When I put the pcb into test mode, the corners of the screen don't join up
either.

The asteroids pcb is fine as it was working fine on the original monitor
chassis.

The other problem with the chassis is that the screen randomly expands and
shrinks slightly. It's not a major problem but noticeable. According to
the
XY FAQ it's usually the HT diode but I can't find it anywhere on the HT
wire. Hopefully it's not inside the LOPT if this is the problem. (I suppose
I could always transplant the LOPT from the other chassis to see if this is
the problem).

It doesn't seem to matter if the cab has been on for a while as I left it
on
for a couple of hours today and no change.

Suggestions?

Thanks

Chris

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Re: Asteroids vectors that don't join up properly..