> I'm trying to find IC CTS 02701-011.
> Proprietary to Arp.
> Any suggestions for a source?
That chip is completely unobtainable. Unless you take it from another instrument.
Do you mean Z14 in DAC?
Yes, that is the one.
That's probably not possible to get anywhere,
but as you can see in Service Manual, it's only resistor array, you
can substitute it with resistors. The only problem is they have rather
non-standard values, so it must be done with some resistor
combinations, or with trimmers.
Correct. I have just repaired a ProDGX (my own) where this chip failed. I tried with a lot of precision resistor, but that was not precise enough, probably also because it is difficult to read the original values in the service manual. I will have to re-do the work, this time with a lot of trimmers. Unfortunately that is the only solution. You will have to fine-tune the trimmers by ear or a tuner, as the purpose of this chip is in the D/A converter, taking the digital keyboard lines and converting them into CV for the VCO.