Gossen T4 80 1 Capacitor Replacement

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.


Cable grommet

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.

Inside Look

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

See Also