Robin Whittle's list of unavailable 303 parts

From: Robin Whittle 
To: Analogue Heaven 
Subject: [AH] TB-303 parts - grim outlook


Today I got a reply from the Roland Australia spare parts chap - who was
very helpful.  I asked him about the key TB-303 parts - and he
interrogated a central database of what is available from Japan.

Here are the results:

The following are "No longer available, no subsitute part."

15179126  CPU Chip: uPCD650C-133 
                                       
13219331  Pot, Tuning and Accent: K161B0-50kB   (50k linear.)

13219340  Pot, Cut Off and Env Mod: K161BO-50kA (50k log.)

13219339  Pot, Decay: K161BO-1MA                (1Meg log.)  

13219775  Pot (dual), Resonance: K162T00W-50kBx2 (50k linear, dual.)
          Note - the part number (13219774) in the the TB-303
          manual is incorrect.                


This one is apparently available from Japan:

13429607  5 pin Din connector with integral dual pole switch:
          TCS0737-01-010  
          Note: the service manual gives the  part number incorrectly as
          "13429706".


At some stage, it will be necessary to scrap TB-303s to keep others
going. The pots have not been manufactured by Alps for ten years or
more.  The CPU chip is not replacable - it is a "mask programmed"
(computer program built into the chip when it is manufactured) version
of an obsolete NEC 4 bit microcontroller.  

There are some small Spectrol pots which should fit in the same space,
including some dual pots.  They have a splined shaft, but are a bit
shorter and have a smaller body, and completely different pin
arrangements.  In desparation, if I can get some of these at the correct
values, perhaps these could be used.  The dual pot is a "180" series,
but this is not mentioned on the Spectrol web site.  I got one, but not
a suitable value, from http://www.farnell.com, part number 307-1248.

  - Robin


===============================================================

Robin Whittle    rw@firstpr.com.au  http://www.firstpr.com.au
                 Heidelberg Heights, Melbourne, Australia 

First Principles Research and expression: Consulting and 
                 technical writing. Music. Internet music 
                 marketing. Telecommunications. Consumer 
                 advocacy in telecommunications, especially 
                 privacy. M-F relationships. Kinetic sculpture.
                  
Real World       Electronics and software for music including:
Interfaces       Devil Fish mods for the TB-303, Akai sampler 
                 memory and Csound synthesis software. 

===============================================================