Bachmann Controller Gone Bad

[Yet_Another]

I just pulled out my old grey basic Bachmann controller to run in a new DMU, and I thought I was going to have to send it back. The motor was making a horrible growling noise, but not going anywhere.

Then I noticed that all of the lights were on a both ends.

Off to the shed, to find my Kato SX controller. Plug that in instead, and all is well.

While the DMU was running in, I got the multi-meter on the Bachmann controller, and it seems to be outputting 12-14V AC.

This controller came from the old class 24 newspapers set (370-065), which came out in 2013, so it's about 12-13 years old.

No damage done, apparently, but it was a little unnerving! The controller is heading for the recycling.

[ntpntpntp]

The basic grey box controller?

Did you use the correct power supply - there are different similar-looking versions, I believe some of those controllers may require a DC power supply and some use an AC supply.  If you used an AC supply with a unit that takes DC that might explain the AC output.  What are the markings for the power input socket on the controller? 

[crewearpley40]

Will this help?
Not really clear markings. Very basic controller and mine ended up in a bin.
https://tinyurl.com/32mzh9pn
Nick s comment re ac supply being used with a dc may suggest indeed  issues
Chris

[Yet_Another]

The basic grey box controller?

Did you use the correct power supply - there are different similar-looking versions, I believe some of those controllers may require a DC power supply and some use an AC supply.  If you used an AC supply with a unit that takes DC that might explain the AC output.  What are the markings for the power input socket on the controller?

Yes, it's the correct power supply, they have lived together since they were unpacked. 16V AC out of the wall wart, input on the grey controller is labelled 16V AC.

I've just had a quick look inside, and I can't see anything burned or otherwise damaged. One for the tip. I think I may still have another one: I own two of that set. I wonder where I put the boxes?

[ntpntpntp]

OK, it was just a thought    Seems odd though, if you saw AC on the track output that would seem to imply a problem with the bridge rectifier diode(s). Diagnose using the continuity test setting on your multimeter across each diode in turn, and simple/cheap to replace if that is indeed the cause.

[Yet_Another]

I did have that thought, but there's no obvious diode bridge. Looks more like half wave rectification with some large capacitors for smoothing. But you can't get at everything because there's a large heat sink bolted over the back of the PCB, and taking it off will compromise the power transistors. I might have a play, so I won't chuck it out immediately.