Re: Tempest vector distortion

I couldn't view the video, not familiar with the file extension of it, but
the first thing that I thought of with respect to the curvy lines was the
XLIN and YLIN adjustment pots. Call up the test screen with the diagonal
cross hatch and adjust the pots to straighten the lines. There might be a
broken pot (or just a bad one). Another possibility may be a broken VDR
(0.5" long axial component) in the video pincushion correction section. A
bad MC1495 chip in the same section can make things curvy (bowed inward).
I am assuming that your monitor is the WG6100.
As Malcolm stated, turn down the screen pot (on the HV box) a little to
eliminate the center dot and retrace lines.

William Boucher
http://www.biltronix.com

----- Original Message -----
From: "Ken Sumrall" <k_lists@scrapheap.net>
To: <vectorlist@vectorlist.org>
Sent: Tuesday, August 09, 2011 6:53 PM
Subject: Re: VECTOR: Tempest vector distortion

> Really? They shipped the game with that error in the attract sequence?
> Or
> does it only happen on monitors that are marginal?
>
> I did notice what I thought was an odd EPROM configuration. There are
> only
> 3 EPROMs on the board. 2 are over by themselves, away from the CPU. Then
> there is an EPROM in a socket near the CPU with some wires running from it
> to various points on the board, and written on the label it says something
> like "Tempest 256K ROM". Is this a known hack to put most of the game in
> a single ROM? Should I just burn a new set of ROMs of the final version
> of
> the code?
>
> I'll get video of the curved vector lines and also of the EPROMs on
> the board and post them. Probably sometime tomorrow.
>
> ___
> Ken
>
>
> On 08/09/11 15:30, Malcolm Mackenzie wrote:
>> The foldover at the end of the attract sequence is a code error in early
>> revisions of the game.
>>
>> The faint lines you're seeing are indeed retrace lines. Adjusting the
>> brightness
>> should fix that. If not, you may have a problem in the z amp section of
>> the
>> monitor or board.
>>
>> The curving lines are a bit of a mystery...
>>
>> --- On *Tue, 8/9/11, Ken Sumrall /<k_lists@scrapheap.net>/* wrote:
>>
>>
>> From: Ken Sumrall <k_lists@scrapheap.net>
>> Subject: VECTOR: Tempest vector distortion
>> To: "vectorlist@vectorlist.org" <vectorlist@vectorlist.org>
>> Date: Tuesday, August 9, 2011, 3:14 PM
>>
>> Hello,
>>
>> We have a small arcade at work, and I recently got the cabaret
>> Tempest machine
>> there to work again. Basically I just pulled the logic board and
>> reseated all
>> the socketed chips and the interboard connector cable.
>>
>> It now comes up, stays up, and shaking the cabinet doesn't cause the
>> game to
>> crash. However, I'm seeing some vector distortion. When it displays
>> the
>> TEMPEST logo in the attract mode mode, near the end of the animation,
>> the
>> vectors foldover, and then (mostly) return to normal. You can see a
>> video
>> of it here:
>>
>> http://www.scrapheap.net/tempest/
>>
>> Also, on some levels (in particular, the one I call the staircase
>> level)
>> straight lines get drawn with a definite curve in them, and the
>> screen tends
>> to pulsate a bit with the size of the image growing larger and
>> smaller. My
>> first reaction is I need to work on the monitor, but then I thought
>> maybe I
>> need to adjust the X and Y size and position pots on the logic board.
>>
>> I also see some faint lines which I assume are the beam location
>> being moved
>> with the beam turned off. I assume I fix this by adjusting the screen
>> brightness.
>>
>> Suggestions anyone?
>>
>> Thanks in advance for your help!
>>
>> ___
>> Ken
>> ---------------------------------------------------------------------------
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>> </mc/compose?to=chris@westnet.com>
>>
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Received on Tue Aug 9 19:06:11 2011