Re: Tempest Color Vectors

From: Rodney Massman <rmassman_at_hotmail.com>
Date: Sat Dec 08 2012 - 15:07:43 EST

Hrm, if blue, in fact is on all the time, I'm going to have to look through
the schematics
to find out which transistor is blue. I'd think it highly unlikely
replacing all 3 transistors
in the first place, that the replacement component is bad. All 3904's.
I eyeballed and metered every suspect trace on the board. H8 has a lot of
leg rust but
scoping comparisons between the two boards indicates it's fine.
I don't think my original repair of the trace between K3 and K5 is within
the realm of a possiblity,
but I did look those traces over again as well.
I'm thinking if anything, it almost has to be a bad TTL somewhere.

-----Original Message-----
From: Andrew Welburn
Sent: Saturday, December 08, 2012 1:30 PM
To: vectorlist@vectorlist.org
Subject: Re: VECTOR: Tempest Color Vectors

You're looking at it the wrong way, your red contains blue (giving
magenta), your green contains blue (giving cyan) your yellow contains
blue (giving white) according to your photos...

to me, this means blue is on all the time. Time to recheck those
transistors, or concentrate on why your blue is on all the time.

Andrew Welburn
http://www.andys-arcade.com

On 08/12/2012 14:57, Rodney Massman wrote:
> Checked it with both a logic probe and scope. I’m getting like signals
> in comparison with the good working board and bad.
> Getting the same analog signals from 4,6,10,12. Digital type signals
> from 5,7,9,11. I’ve got some ic’s coming to piggyback, but that’s not
> one of them. Couldn’t source it.
> I think what’s throwing my scope and probe signals is that I am getting
> one, just not the right color.
> Ordered a stock of:
> SN74LS175N
> SN74LS139AN
> SN74LS32N
> SN74LS399N
> SN74LS164N
> SN74LS174N
> I don’t have much of a stock of TTL’s to test with. Hoping they
> piggyback well.
> *From:* Kevin Moore <mailto:talon.k@gmail.com>
> *Sent:* Saturday, December 08, 2012 6:58 AM
> *To:* vectorlist@vectorlist.org <mailto:vectorlist@vectorlist.org>
> *Subject:* Re: VECTOR: Tempest Color Vectors
> Have you checked the color ram at P9?
>
>
> On Sat, Dec 8, 2012 at 5:17 AM, Rodney Massman <rmassman@hotmail.com
> <mailto:rmassman@hotmail.com>> wrote:
>
> Been working on a Tempest for a friend. At first there was no video
> but the game played fine.
> I found a broken trace between K5 and K3 as someone long ago
> attempted to replace a 2114
> and in the process, burnt a trace.
> So I got video back, however have come across the most peculiar
> problem. At first I thought it
> was a simple issue of the color transistors, so I replaced Q2-4.
> Nothing changed. I also replaced Q8-10.
> I am completely missing Red, Green and Yellow. Has anyone else come
> across this problem?
> Bad color vectors:
> http://i269.photobucket.com/albums/jj63/rmassman/IMG_3111.jpg
> http://i269.photobucket.com/albums/jj63/rmassman/IMG_3146.jpg
> What it should look like:
> http://i269.photobucket.com/albums/jj63/rmassman/IMG_3112.jpg
> http://i269.photobucket.com/albums/jj63/rmassman/IMG_3149.jpg
> Thanks for any help.
> Rodney
>
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Received on Sat Dec 8 15:08:19 2012

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