Re: RE: Techtoolslist Digest, Vol 4, Issue 7

<x-flowed>Once I added the RESET jumper to the 68B21 the pod worked flawlessly.
It's a 68B09E CPU by the way...

however the board is not working in the game - but if I force a reset
it does. Yet the game MPU IS sending the RESET signal, but I think
the original powerup should have a proper RESET on the audio board.
SO I shall experiment with a NOR or NAND gated Supervisor IC to see
if that makes it work better. However, first I'll secure the boards
to get the ground path solid...

I must be missing something!

John :-#)#

At 11:54 AM -0800 2/23/05, Tony Gonzalez wrote:
>Maybe the Z80 pod may also have some kind of similar
>issue as well?
>
>Tony
>
>--- John Robertson <jrr@flippers.com> wrote:
>
>> It's starting to look like a design flaw. The
>> 68B21's RESET line is
>> simply tied to Vcc through a pull-up resistor. I've
>> now jumpered that
>> to the board RESET line and I get a clean start up
>> almost every time
>> (I have substituted a good 68B21 to no avail
>> previously).
>>
>> Sooo, if this works in the game, another Tech Tip
>> will appear on RGP I guess.
>>
>> John :-#)#
>>
>> At 11:51 AM -0600 2/23/05, Robert C. Bullock wrote:
>> >John:
>> >
>> >-----
>> >However when I replaced the suspect 175, no sounds,
>> and when I put the
>> >original 175 back in the (now socketed) PCB, I
>> don't get the sounds even
>> >with the Bugtrap the same way.
>> >-----
>> >
>> >Hmm, the only similar thing I've seen is a bad -5V
>> reg (7905) on Atari
>> >Roadblasters in the sound section. Putting my logic
>> comparator on one of the
>> >chips fixed a problem with the scrolling playfield,
>> but killed the sound.
>> >Take it off, it scrolls again, sound works.
>> >
>> >Replacing the voltage regulator fixed it. The
>> voltage on the pulse to sync
>> >that section of the board was low.
>> >
>> >You'll have to Google this or give me a deal on
>> that pinout cart :) and I'll
>> >dig the particulars back out. This sounds somewhat
>> similar.
>> >
>> >
>> >_______________________________________________
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>> >Techtoolslist@flippers.com
>>
>>http://seven.pairlist.net/mailman/listinfo/techtoolslist
>>
>>
>> --
>> 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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>>
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>>
>
>
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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"
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