I recently got this 80V/1A Gossen (SIEMENS branded) T4-80-1. It was in original condition and some of the capacitors did not look quite so good.
The rubber cable grommet started to become oil after all these years, so I cut it out and replaced it with a new one after cleaning the mess up.
Some picture of the inside, I really like the manually wire wound power resistors.
I did not find any schematics, for reference here is what I measured:
- Zeners: the black Zener diode at top next to the 2N3441 is 6.66-6.7V, the one at the bottom above the 1000uF capacitor is 7.2V. The two ones in a V-shape are 6.8V and the remaining is 12V.
- Wire wound resistors: The four on the power transistor board and the current shunt are 1Ω. The curvy one is 0.09Ω-0.1Ω. The inrush limiter for the main reservoir capacitor (value not critical) is 0.4Ω. (Measured using 4-wire on both my HP 3478a and Keithley 196 for reference)
Replacing the capacitors
I left the main storage capacitor in place but put it out of circuit.
I used the following capacitors:
- Würth 1000uF/200V 861221084017
- CDE 1000uF/50V 108TTA050M
- CDE 100uF/160V 107TTA160M
- CDE 47uF/160V 476TTA160M