A single KRL 1% C-2AQ Tempco resistor.
1K, 2K and 1.87K available.
1.87K is a replacement part for classic ARP synths including the 2600, four of these tempcos are used in the TTSH project.
One for each oscillator and one for the filter.
3500ppm. 1/4W. PTC – Positive Temperature Coefficient.
Datasheet (This part is in the ‘Q’ range)