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Vintage Synth Repair

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obsolete component part sourcing

obsolete component part sourcing

2008-05-19 by Scott Nordlund

I'm looking to get a rather unusual SRAM chip (4M x 1 bit, 5V, asynchronous, parallel interface) for a project I'm working on (Yamaha VSS-200). These chips were produced by several companies, but they're all obsolete now and all the stock seems to have been bought by "$250 minimum order, send request for quote" type places. Does anyone know of any possible alternative source for these (I tried all the usual suppliers that I could think of- mouser/digikey/jameco/etc.) or any clever way to trick someone into selling single/small quantities for a reasonable price?

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Re: [vintagesynthrepair] obsolete component part sourcing

2008-05-19 by Russell Rose

what's the manufacturer part#?what's the yamaha part#?
On May 19, 2008, at 5:50 PM, Scott Nordlund wrote:

I'm looking to get a rather unusual SRAM chip (4M x 1 bit, 5V, asynchronous, parallel interface) for a project I'm working on (Yamaha VSS-200). These chips were produced by several companies, but they're all obsolete now and all the stock seems to have been bought by "$250 minimum order, send request for quote" type places. Does anyone know of any possible alternative source for these (I tried all the usual suppliers that I could think of- mouser/digikey/jameco/etc.) or any clever way to trick someone into selling single/small quantities for a reasonable price?

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Re: obsolete component part sourcing

2008-05-20 by thirteentech

What is the chip number and do you know what machines used them?

--- In vintagesynthrepair@yahoogroups.com, Russell Rose <russrose@...> wrote:
Show quoted textHide quoted text
>
> what's the manufacturer part#?what's the yamaha part#?
> On May 19, 2008, at 5:50 PM, Scott Nordlund wrote:
> 
> > I'm looking to get a rather unusual SRAM chip (4M x 1 bit, 5V,  
> > asynchronous, parallel interface) for a project I'm working on  
> > (Yamaha VSS-200).  These chips were produced by several companies,  
> > but they're all obsolete now and all the stock seems to have been  
> > bought by "$250 minimum order, send request for quote" type  
> > places.  Does anyone know of any possible alternative source for  
> > these (I tried all the usual suppliers that I could think of-  
> > mouser/digikey/jameco/etc.) or any clever way to trick someone into  
> > selling single/small quantities for a reasonable price?
> >
> > Give to a good cause with every e-mail. Join the i'm Initiative  
> > from Microsoft.
>

RE: [vintagesynthrepair] obsolete component part sourcing

2008-05-20 by Scott Nordlund

This is a (drastic) modification rather than a repair, so it's not a stock part. The stock part is a 21256 256K x 1 bit DRAM, and I am attempting to replace it with a larger SRAM (with latches to separate the row and column addresses and a banana jack patch bay to make all address lines available for arbitrary rearrangement).

I have several part numbers that I'm looking for- NEC UPD444001 or UPD434001, Hitachi HM621400H, Toshiba TC551402J, and maybe (haven't found a datasheet to confirm) Mitsubisihi M5M54R01. DIP package would be nice, but probably I'll have to settle for SOJ-32. Any variant on these would work as long as it's 5V and big enough to be soldered by hand. The speed rating isn't important (as the original chip is considerably slower).

There is a smaller (1M) and rather expensive chip available from Digikey, and I can settle for this if necessary, but it won't be quite as amazing as a 4M chip. I have also found a 16M 3.3V chip. The biggest problem here is finding a 54 pin TSOP-II to DIP adapter for a sane price.
Show quoted textHide quoted text
To: vintagesynthrepair@yahoogroups.com
From: russrose@mindspring.com
Date: Mon, 19 May 2008 19:27:23 -0400
Subject: Re: [vintagesynthrepair] obsolete component part sourcing

what's the manufacturer part#?what's the yamaha part#?

On May 19, 2008, at 5:50 PM, Scott Nordlund wrote:

I'm looking to get a rather unusual SRAM chip (4M x 1 bit, 5V, asynchronous, parallel interface) for a project I'm working on (Yamaha VSS-200). These chips were produced by several companies, but they're all obsolete now and all the stock seems to have been bought by "$250 minimum order, send request for quote" type places. Does anyone know of any possible alternative source for these (I tried all the usual suppliers that I could think of- mouser/digikey/jameco/etc.) or any clever way to trick someone into selling single/small quantities for a reasonable price?

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Re: [vintagesynthrepair] obsolete component part sourcing

2008-05-20 by John Loffink

You want to look for surplus part vendors.  The one I've used in the 
past, Great Plains Electronics, has many obsolete memory parts, most 
older than the one you're searching, but had none of the parts you were 
looking for.

http://www.greatplainselectronics.com/default.asp

Scott Nordlund wrote:
> This is a (drastic) modification rather than a repair, so it's not a 
> stock part.  The stock part is a 21256 256K x 1 bit DRAM, and I am 
> attempting to replace it with a larger SRAM (with latches to separate 
> the row and column addresses and a banana jack patch bay to make all 
> address lines available for arbitrary rearrangement).
>
> I have several part numbers that I'm looking for- NEC UPD444001 or 
> UPD434001, Hitachi HM621400H, Toshiba TC551402J, and maybe (haven't 
> found a datasheet to confirm) Mitsubisihi M5M54R01.  DIP package would 
> be nice, but probably I'll have to settle for SOJ-32.  Any variant on 
> these would work as long as it's 5V and big enough to be soldered by 
> hand.  The speed rating isn't important (as the original chip is 
> considerably slower).
>
> There is a smaller (1M) and rather expensive chip available from 
> Digikey, and I can settle for this if necessary, but it won't be quite 
> as amazing as a 4M chip.  I have also found a 16M 3.3V chip.  The 
> biggest problem here is finding a 54 pin TSOP-II to DIP adapter for a 
> sane price.

-- 
John Loffink
The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com
The Wavemakers Synthesizer Web Site
http://www.wavemakers-synth.com

RE: [vintagesynthrepair] obsolete component part sourcing

2008-05-20 by Scott Nordlund

> You want to look for surplus part vendors. The one I've used in the
> past, Great Plains Electronics, has many obsolete memory parts, most
> older than the one you're searching, but had none of the parts you were
> looking for.
>
> http://www.greatplainselectronics.com/default.asp

Right, the problem is finding surplus vendors that actually have the part and will sell it in quantities of less than 1000. The particular chips I'm looking for were introduced in the late 90's and subsequently seem to have disappeared into a black hole.

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