Re: cbm 8032 motherboard + atx power supply

From: Gerrit Heitsch <>
Date: Sun, 21 Aug 2016 19:14:45 +0200
Message-ID: <>
On 08/19/2016 04:52 PM, Ethan Dicks wrote:
> On Fri, Aug 19, 2016 at 10:37 AM, David Wood <> wrote:
>> Is anyone familiar with what -5v is used for on PETs?
> Negative bias voltage for the 4116 DRAMs, a few dozen mA, IIRC.
> (if you have socketed DRAM and..) if you did the pinballer hack of
> modding 4164s for use in 4116 sockets (lift out the -5V pin from the
> socket, and run a jumper over the top of the chip to the high address
> bit are the steps from memory), you might not require -5V at all.  The
> schematics are out on and shouldn't take long to verify
> that's the only use.

The 4164 don't like +12V, so there is a bit more rewiring necessary. 
Also, not all 4164 use a 7Bit refresh but some want 8 Bit. If you use 
them as 4116-Replacement, that shouldn't matter, but I'm not 100% sure.


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Received on 2016-08-21 18:00:03

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