Re: Tempest twisting images...

Version 3 of the ROMs fixes this problem.
What happens is the input protection board only see deflection in one
direction and shuts down the inputs.
Version 3 puts a copyright at the bottom of the screen and keeps the picture
balanced, preventing the collapse.

On 6/14/06, John Robertson <pinball@telus.net> wrote:
>
> Found the problem. Turns out the replacement XY driver board I had left
> (from my parts stock) is a version P327 with the input protection circuit. I
> found that this circuit was the cause of the twisting by hooking my scope to
> the inputs of Q600 and Q700 and getting the same twisting, but not at the X
> & Y outputs on the motherboard. Hence something was a problem in this
> circuit. Replaced the two transistors Q804 & Q805, plus two of the diodes
> D806 & D808 (Germanium I think) with 1N914s.
>
> Same problem. Poked around for another 1/2 hour...
>
> Gave up and clipped R810 & R811 - inputs to the protection circuit - and
> now the picture is fine.
>
> As Tempest originally worked without the protection circuit I am going to
> leave it disabled here - I suspect this circuit simply can't handle the
> patterns that Tempest throws up, or the capacitors are too low (88ufd
> instead of 100ufd, within spec +10/-20% for caps.). Still it looks great and
> I have to move on...
>
> I made a MPEG of the twisting image, if anyone wants a copy let me know.
>
> John :-#)#
>
> At 2:13 PM -0700 6/12/06, John Robertson wrote:
>
> Yes, I tried tightening the pins on the sockets. Now that I think of it
> the plug feels a little un-tight. I'll check stock to see if I have a plug
> assembly with better bite. I did do the exchange power transistor plug with
> the X transistors - the Y group won't reach - to make sure the problem
> wasn't on those two. Forgot to fully test the Y plug!
>
>
> Will come back with part two tomorrow when I get back to the shop -
> currently I'm in the warehouse digging around:
> http://flippers.com/TimeTravelWarehouse.htm
>
>
> There are a number of vector games there folks, good time to get good
> deals...bulk buys encouraged!
>
>
> John :-#)#
>
>
> At 9:58 PM +0100 6/12/06, simon wrote:
>
> John
>
> I had some strange image problems with bad Deflection transistor sockets,
> check they are good.
>
> Cheers
>
> Simon
>
> ----- Original Message -----
>
> *From:* John Robertson <pinball@telus.net>
>
> *To:* vectorlist@vectorlist.org
>
> *Sent:* Monday, June 12, 2006 8:39 PM
>
> *Subject:* VECTOR: Tempest twisting images...
>
>
> Ok, I'm lazy enough, but has anyone seen a situation with a Tempest
> monitor where the picture twists (+ Y axis) upon the display of the TEMPEST
> name for a second? Rather interesting distortion, I originally thought it
> was Q606 (2N3716) that was having life issues, but no, replacing it didn't
> change this distortion, then I tried the driver - MPUSU57 - again not the
> problem.
>
>
> Understand that I've re-capped the HV (stable voltages) and installed the
> LV2000 kit - stable +/- B voltages. Grounds are excellent, tried jumper
> wires to double check. Game seems happy otherwise, no smoke...connectors all
> inspected and solder built up on the monitor driver board pins as usual.
>
>
> There is also a twisting wave that appears in the picture on various
> levels - only during play, not in the attract mode - curiouser and
> curiouser.
>
>
>
> I thought it had to do with the speakers as it seemed to be most prominent
> when the sounds were very active (lots of shots, explosions), so I unplugged
> the speakers - no change.
>
>
> Yeah, pictures will be nice, but I'm off the warehouse right now to deal
> with other issues. Perhaps I can get them tomorrow and post them somewhere.
>
>
> Archives have nothing under twist or distortion that I can find relating
> to this...closest I found was "Tempest Boardset Barreling" by Dave Langley
> back a few years.
>
>
> John :-#(#
>
> --
>
> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
> www.flippers.com
> "Old pinballers never die, they just flip out"
>
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>
>
> --
>
> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
> www.flippers.com
>
> "Old pinballers never die, they just flip out"
>
>
>
> --
>
> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
> www.flippers.com
> "Old pinballers never die, they just flip out"
>

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Received on Wed Jun 14 14:43:22 2006