PROMs and EPROMs, specifically 2332/2532/2732

[John Robertson]

On 10/24/2015 5:43 AM, Adrian Graham wrote:
> Hi folks,
>
> PET4032 repair continues with all ROMs, video RAM and dodgy sockets removed
> thanks to a hot air gun. Holes cleaned and I have new turned pin sockets for
> everything I've removed which I'll be fitting this afternoon.
>
> Since the ROMs came out OK I'm trying to dump them using my Pinmaster48
> programmer, being from the 90s it doesn't read 2332/2532 PROMs but it WILL
> read a lot of variants of 2732 so I've made an adapter as found thanks to
> google and USENET:
>
> 2332 pin 18 to 2732 pin 21 (A11)
> 2332 pin 20 to 2732 pin 18 (Chip enable/Power Down)
> 2332 pin 21 to 2732 pins 20 and 24 via diodes with banding at the 2332 end
> (2332 Vpp)
>
> Wiring checks out and the diodes are aligned correctly so pins 20 and 24
> don't interfere with each other, however the pinmaster continually gives me
> "continuity error on pin 20"
>
> Have I goofed somewhere?
>
> Cheers,
>
You just tie pin 21 of the 2332 to Vcc (+5) - Pin 24 of the 2732 - to read.

There are only two modifications needed normally for reading a 2532/2332 
in a 2732 socket.

2332

Pin 21 - Vcc (2732 Pin 24)
Pin 18 - A11 (2732 Pin 21)

If your reader coughs up a /OE error then use diodes:

2332

Pin 20 - 2 Diodes, one to 2732 pin 20, the other to 2732 pin 18. Banded 
end to these pins, and you will also need a pullup resistor on the 
2532/2332 socket pin 20 so /CE (2332/2532) goes high when not selected. 
2K2 would do fine. Anything from your junk box between 1K and 4K7 should 
work though.

I don't think you will need the diodes though.

John :-#)#

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