Re: Overclocked Deluxe - limited success

-----Original Message-----
From: Neil Bradley <neil@synthcom.com>
To: vectorlist@synthcom.com
Date: Thu, 26 Apr 2001 13:24:07 -0700 (PDT)
Subject: VECTOR: Overclocked Deluxe - limited success

>
> Well, I tried overclocking the Asteroids Deluxe board and here's what I've
> found. I cut the trace between the CPU and the solder points so I'm not
> increasing the clock to any other circuitry - only the processor. Then I
> jumpered pin 37 of the CPU (clock) to pin 14 (6Mhz), pin 13 (3Mhz) and
> eventually back to its original home at pin 12 (1.5Mhz) on chip C3.
>
> @ 3Mhz - I get 5 high tones then 1 low tone, and this cycle completes. I
> don't have a diag manual for Asteroids Deluxe. Anyone know what this
> means? RAM Error perhaps?
>
> @ 6Mhz - Nothing happens.
>
> I'm not sure what the problem is, but I have a few hunches:
>
> * How fast can the 2114s on this board actually run? Is 6Mhz too fast for
> them to keep up? Hm.... 6Mhz=166ns if it can do a SRAM every clock. Is
> this possible? I've found some 2114s that are rated to 200ns. Is it
> worthwhile to swap them out?
>

I repair a lot of galaxian pcb's,
experience has told me that 2114 rams are shit,
there is just no other word for it!

2114's are 1k x 4, they are usually used in pairs.

i replace them with a 6116.
these run much faster,they also have the same pinouts as a 2716 eprom.
if you are removing all the roms and putting in 1 big rom,
then put a 6116 in one of the unused sockets and bend-up the enable and r/w pins.

in games that use 4 2114's to get a 2k ram block in the memmory map you can replace all 4 with one i.c.

make sure your eprom is 150ns or faster.

IF YOU REALLY WANT SPEED - make an adapter-card and drop-in a 68b09.
then decompile the roms,edit a few commands and recompile with tasm.

the 6809 was designed from the start as a high power replacement for the 6502.
that is probably why it was used on starwars.

have-fun.

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Received on Fri Apr 27 07:07:41 2001