ID what I think is some type of tempco or thermistor from a vintage synth?

[Midphase]

I'm working on a Cat synthesizer by Octave from the mid-70's.

There are two CA3046 Transistor Arrays that are used for the VCO's, and on top of that appear these bonded components which are labeled TEL LABS on one side and 2K 1% with an additional set of numbers 33-76 which likely refers to the manufacturing date.

I'm attaching some pics and the relevant section of the schematic to see if y'all have some ideas on what I can use as replacement.

Thank you in advance for any insights that you might be able to offer.

[TimFox]

I don’t know a direct replacement.
Those specified tempco resistors were commonly used for analog log or anti log amplifiers to bias the circuit to exploit the (temperature-sensitive) V_be logarithmic dependence on current of a BJT junction. Note that its circuit supplies a relatively small DC bias to the next BJT in the VCO.

[edavid]

Yes, they are Tel Labs Q81 thermistors that are used to compensate for the temperature dependence of V_BE of the transistors in the log amp stage.

You can buy equivalents from synthesizer suppliers, for example:

https://smallbear-electronics.mybigcommerce.com/tempco-resistor-thermistor-krl-bantry-riedon-1kohm-2kohm-1-87kohm/

Why do you think they are bad?

[Midphase]

I don't think they are necessarily bad, but I do need to replace the CA3046's and I figured that it might make sense to swap the whole assembly.

The paste that they used to attach it to the IC has hardened and is brittle and cracking, and I figured I'd use some thermal paste to replace it, but it would be nicer to be working with clean components.

But yeah, I just wanted to replace these 50 year old parts with something newer that would hopefully have better performance specs. But the old ones are probably ok.