EAI Pace TA-10

. Thanks for the pointers Evan, On checking in the net I have now found a TR-20 maintenance manual. The TR-10 PSU doesn't have the test points, but otherwise I think it's the same. It certainly produces the same voltages. There is also a reference voltage generator, which sits next to the PSU which is identical to the TR-20. So I have now checked my PSU and the reference voltages and they are correct. It looks like I had a faulty DVM, rather than the PSU being faulty. I popped it on a 9V battery and got 12Volts which can't be right. Having sorted that out I have now started checking the modules. Out of 8 amplifier modules only two seem to work correctly, but as each module contains 2 amplifiers that's enough to get started with. Given that I don't have a module where one works and one doesn't I am inclined to blame the chopper relay as that is the only common component. I think the next step might be to swap the chopper relays between a duff and a working board and see if that helps, but to be honest despite reading several articles on it, I still don't understand how a chopper stabilizer works.. Dave G4UGM