RE: Tempest - Vector Generator RAM

Well, I got this working. However, my board comes back up and the text
shows up on the game, but all the gameplay vector graphics are all screwed
up. (ie. maze doesn't draw or showup and the enemies and my player (whatever
I am) blinks and appears once in awhile and I can see the other things off
and on). All the while the score displays and all other things not to do
with gameplay show up.
 
Also, I go to the test screen and it all is fine (including all the
cross-hatches, scaling mathbox etc). However, I do have a "M" for mathbox
in the text screen (I interchanged the back smaller board with one that is
known working and the "M" and vector problem still shows up. I checked the
connector and performed continuity tests across the connecter pins once
connected and they all checked out).
 
Any ideas?
 
A>

-----Original Message-----
From: Evrovski, Andrew [mailto:andy@cyberplex.com]
Sent: November 24, 2000 11:10
To: vectorlist@synthcom.com
Subject: VECTOR: Tempest - Vector Generator RAM

Folks,

        I have a problem with my Vector Gen RAM. I have socketted the RAM
and when booting up in test mode, I get a problem with RAM M3. I replace
this with a known working good 2114 and it still shows up as such (4 short
beeps and then 1 long beep). I conduct some continuity tests and according
to the schematic, I see connections between all appropriate pins on the RAM,
but I can see there is a problem with some of the RAM connections, but I
don't know what to do about it. What I mean is that on the schematic, pins
11-14 on RAMs J3,K3,L3,M3 are DVG3,DVG2,DVG1,DVG0 and J4,K4,L4,M4 are
DVG7,DVG6,DVG5,DVG4 and these behave differently than the address lines.
All the address lines are tied together on the RAMS, but the 11-14 are tied
together in BANKS (the 3's are together and the 4's are together) but they
are both tied to I/04, i/03, I/02, I/01. Here is the problem.... what the
HECK is I/0? Where are these connected? I measure impedance across pins
11-11, 12-12,13-13,14-14 across that I/0? barrier (across the 3's to 4's)
and I get 19K 11-11, 13-13, 14-14, but on pins 12-12, it is an open circuit.
I measure a known good working board and the impedance across all of the
pins above is the same (for all 4 pins INCLUDING pin 12) so I know that
there is something wrong with the connections on that pin, but until I know
*where* the connection is supposed to go, I will not know how to fix it.

        Can anyone shed some light on what the I/0? connections are
referring to?

Much appreciated.

Andrew Evrovski
HPC Development Director
Cyberplex
t: 902.429.4721 ext.109
f: 902.423.0899
www.cyberplex.com

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Received on Mon Nov 27 10:47:38 2000