EAI Pace TA-10

[Dave G4UGM]

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Evan
> Koblentz
> Sent: 14 November 2014 13:35
> To: General at classiccmp.org; Discussion at classiccmp.org:On-Topic and Off-
> Topic Posts
> Subject: Re: EAI Pace TA-10
> 
> 
> > Folks,
> >
> > I have just bought one of these and it is behaving oddly. I think the
> > PSU regulation is faulty. Does any one have a schematic of the PSU, or
> > even just the regulator board. I think the US and UK actually have the
> > same PSU as my UK version has 2 x 110 Volt primaries strapped in series.
.
> >
> > Dave Wade
> >
> > G4UGM
> 
> Happen to know if it's the same PSU as the TR-20? (MARCH has the -20 and a
> decent set of documentation.)

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