[sdiy] Frozen DX7IID

[Ullrich Peter]

Hi!

You can have a look at the datasheet of the PL version here: page 155
http://bitsavers.informatik.uni-stuttgart.de/pdf/toshiba/_dataBooks/1982_Toshiba_MOS_Memory.pdf

The first page of the APL datasheet is here:
http://www.cryptomuseum.com/spy/fs5000/files/TC5564.pdf

The typical standby current definition seems to be the difference on the first look, but the maximum standby current seems to be the same...

Ciao
Peter

http://www.ullrich.at.tt
________________________________________
Von: synth-diy-bounces at dropmix.xs4all.nl [synth-diy-bounces at dropmix.xs4all.nl]" im Auftrag von "greg at gzifcak.net [greg at gzifcak.net]
Gesendet: Freitag, 22. August 2014 23:39
An: MTG
Cc: synth-diy at dropmix.xs4all.nl
Betreff: Re: [sdiy] Frozen DX7IID

Thanks for the insight; I hope this isn't the case because I haven't been
able to find replacements with the exact suffix. If that is what's causing
it I'll just take them back out and live with a functioning synth with no
patch memory. I usually program it from scratch anyway, but it would be
nice to be able to save.

> If it's anything like the vanilla DX7 they require almost exact
> replacements. There is something funky going on with the memory
> addressing or the assertion or de-assertion of the control lines but
> I've never really had the time to examine it. On the regular DX7 I had a
> bad SRAM and tried quite a few standard types that *should* work but
> they don't. I had to resort to buying a new one of pretty much the exact
> type (manufacturer too).
>
> Maybe someone knows what Yamaha is doing that makes it so picky. There
> are so many expansion boards out there (E! et al) that someone obviously
> knows.
>
> GB
>
>
> On 8/21/2014 1:37 PM, greg at gzifcak.net wrote:
>> Hello,
>>
>> I just replaced the RAM in my DX7II. I swapped the existing Toshiba
>> TC5564PL-15 chips for TC5564APL-15 since this is all I could find
>> available. I searched for info on the meaning of the suffix but couldn't
>> find anything.
>>
>> Anyway, I did not try powering it on before I did the repair, but it
>> worked fine (aside from the RAM) when I last used it about a month ago
>> or
>> so.
>>
>> When I powered it on after replacing the RAM chips, all lights came on
>> and
>> the screen is blank except for the top row, which is showing solid bars.
>> It is making no sound and no panel controls have any effect.
>>
>> I probed around with my scope and the sub-CPU and main CPU are both
>> receiving clock and show approximately 5v on the power pins.
>>
>> Any ideas what else to check or should I hunt for replacement CPUs?
>>
>> Thanks in advance,
>> Greg
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>
>>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>


_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy



The information contained in this e-mail message is privileged and confidential and is for the exclusive use of the addressee. The person who receives this message and who is not the addressee, one of his employees or an agent entitled to hand it over to the addressee, is informed that he may not use, disclose or reproduce the contents thereof, and is kindly asked to notify the sender and delete the e-mail immediately.