[Elecraft] Elecraft ATU T1 stopped working

[Hajo Dezelski]

Hello,
 
After almost 18 years, my workhorse the Elecraft ATU T1 stopped working:
 
- I used it continuously with max. 10w usually 2-5 watts.
- I broadcast on the 40, 30, 20m and sometimes 80m bands.
- When I press the "Tune" button, there are no LEDs.
- The other modes do not work either.
 
What I have done:
 
- changed Battery (9 V).
- cleaned/roughened Battery contacts .
- Visual inspection of electronics - rough cleaning
- replaced cable.
- checked external wiring to antenna
- removed temporarily MCU to check corrosion
- used external PWR/TUNE switch / pulling J3-ring to ground to enable auto-tuning:

  This worked in so far as the yellow LED started blinking and the SWR showed a mismatch, but transmitting (on several bands )
  didn't trigger the circuit or any reaction. The Atu does not look for another combination.

One thing for sure: I have to change the two switches.
 
I know the T1 is old, but it worked until now every day and I do not have the feeling that something is really broken, for from time to time it works.
Any ideas how to proceed?

73 de
Hajo DL1SDZ