[sdiy] DX7 Memory Problem

[Neil Johnson]

Hi,

The CY7C185-20PXC looks compatible.  Available from Farnell too:

http://uk.farnell.com/cypress-semiconductor/cy7c185-20pxc/ic-sram-64k-8kx8-20ns-dip28/dp/1688740

The address lines are in a different order, but that won't matter.

If the chips truly are toast, cut them off the board first, then
desolder the remaining bits of pin.  Much easier than trying to remove
a 28-pin DIP - you want to keep the PCB intact.

And then fit sockets :)

Cheers
Neil

On 20 August 2012 14:15, gregory zifcak <zifcak at hotmail.com> wrote:
>
> Thanks for the tip, unfortunately they are not socketed.
>
> ----------------------------------------
>> Date: Sun, 19 Aug 2012 00:20:39 -0700
>> From: dmarv at dop.com
>> To: synth-diy at dropmix.xs4all.nl
>> Subject: Re: [sdiy] DX7 Memory Problem
>>
>> On 8/18/2012 11:39 PM, gregory zifcak wrote:
>>> Cool, thanks for the info. Yeah I have memory protect off. I found the self-test procedure and it fails at the RAM check. I will check the chip enable lines as you said; I'm guessing one or both of the RAM chips died. The chips are 8k, part number TC5564PL-15. That would be great if you have some spares.
>>> Greg
>>>
>>>
>> Greg,
>> If the RAM is in a socket, try reseating it before replacement. I'm in
>> Southern California and have seen lots of problems from corrosion on
>> sockets.
>>
>> Dale
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>
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