[sdiy] Re: [AH] Synth DIY Chip question?

[mirwin at qouest.net]

Tim,
Haven't seen the Hohner schematic but this info may be useful:

The MK50241 is a TOG (top-octave generator) chip - if you are getting 
notes out at all (even if quieter than they should be) the chip is 
probably fine. If one note is missing (and is missing from each octave 
of the keyboard) there may be a problem with either the TOG or whatever 
keyer-divider chips are used...  a connection problem. The MK50241 could 
be replaced with the more easily obtainable MK50240 with little effect 
on the sound.

LM3900.... common chip... should be replaceable with no problems.

TCA350Y.... a now-rare BBD chip,  three of which are used to create the 
"ensemble" sound from the raw "organ-like" sound. If one of the three 
wasn't working, you would probably still hear some of the effect.

Don't know what keyer-divider chips are used... I have pdf datasheets 
for the  TDA0470 (used in Solina), the S10430 (used in Korg Lambda) and 
TDA1008 (Crumar and various) if those would be helpful.
Cheers, Mike