Re: Tempest Color Vectors

Meh – those 74s289n’sat P9 are a bit expensive. Alright I’ll give it a whirl. I did find a few so I ordered just to have some on hand.
From: Kevin Moore
Sent: Saturday, December 08, 2012 3:45 PM
To: vectorlist@vectorlist.org
Subject: Re: VECTOR: Tempest Color Vectors

I would remove the color ram from both boards, socket, and try the unknown in the known good board. Should take all of 10 mins and then you will know.

On Sat, Dec 8, 2012 at 2:07 PM, Rodney Massman <rmassman@hotmail.com> wrote:

  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 17:50:23 2012