[sdiy] Andromeda A6 repair?

Barry Klein Barry.L.Klein at wdc.com
Tue Jan 13 22:32:32 CET 2015


Nope - a K6T4016V3B-TB70. 
http://pdf.datasheetcatalog.com/datasheet/SamsungElectronic/mXvvstq.pdf
Separate coin-cell backup battery.
TSOP44 package  - not nearly as small SMT as the stuff I normally deal with.
Schematic date is 2002 but I think the synth was made to 2010.
The chip selects are sent by a Lattice programmable logic chip  - ISP LSI 1016E-80LT
http://www.latticesemi.com/~/media/Documents/DataSheets/ispLSI/ispLSI1016DataSheet.PDF
I was soooo scared this may have been bad - but looks to be issuing the CS's.  It has 5V VDD, outputs around 4V.  Most other stuff is 3.3V.
Alesis had a problem with one brand SRAM and recommended replacing any seen - but my unit has the approved brand.
They are IS61LV25616-15T:
http://www.cs.columbia.edu/~sedwards/classes/2008/4840/ISSI-IS61LV25616-SRAM.pdf
Should I look for a faster part if I replace?

Barry




-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of MTG
Sent: Tuesday, January 13, 2015 12:48 PM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Andromeda A6 repair?

Hi Barry,


NV SRAM being what?  A DIP with a battery built in?  Do you have a part number for that?

I've seen SRAM of just about every flavour fail at one time or other, but if there are mis-matched logic families that might account for a lot of really hard-to-put-a-finger-on trouble.

I wonder if the CS with the resistor might be better served with a diode?  What year is this thing ... are we talking mostly SMD?

GB


On 1/13/2015 11:00 AM, Barry Klein wrote:
> No SPI, old school parallel busses.
>
> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl 
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of 
> gordonjcp at gjcp.net
> Sent: Tuesday, January 13, 2015 10:51 AM
> To: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] Andromeda A6 repair?
>
> On Tue, Jan 13, 2015 at 06:40:40PM +0000, Barry Klein wrote:
>> I am a bit confused though about the memory management.
>> There is a Flash, NV SRAM, and two "high speed" SRAM chips.
>> Would an issue with the NV SRAM chip be responsible for a hang on the write to flash?
>
> Yes, if they share a common SPI bus (or parts of it).
>
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