Thanks, yes I sprayed the selector today with contact cleaner and reflowed most of the inputs and it's already better, will need to order the DP relay you advised and then hopefully it's good for a few more years. Thanks so much for your help and advice.
So my amp is working fine now thanks, but I bought another faulty one cheap as a practice run (a PM30SE) which I might sell on, and am wondering if you ever had problems with the contacts inside the slider switch becoming bent out of shape and then difficulties getting them back so they fit back in properly. They fell out when I took the black housing off the switch inside the metal cover, and then must have not gone back in correctly after I cleaned the oxide off the switch. Is it possible to get replacements do you know? Thanks again in advance.
Hi the switch is made by Alps and is now obsolete, many Amplifiers of this time period used Alps switches.
It does not have to be a ribbon actuated type, as the internal sliders will be the same.
This switch is available for sale
https://www.ebay.co.uk/itm/Alps-Sli...2349624.m46890.l49286&mkrid=710-127635-2958-0
Thanks that's great, so are you recommending I buy any ALPS style switch to rob the sliders from (and try not to break them this time!)? Thanks.
I don't see any other option, if possible it's worth taking photos before and during disassembly of parts. That way it makes reassembly easier, with this type of switch you can fit the to metal case then operate the switch with a flat blade screw driver before pressing the metal tabs back in place and clipping back on the ribbon slide.
By testing it you can confirm with your multimeter on continuity that it's working correctly.
The metal tabs become brittle if bent to many times.
Thanks that makes sense, and I know there are other workarounds but ideally I'd like to salvage the original switch if possible. Thanks as always for your help and advice it's much appreciated.
Bit of a late update on this!
So I got a bit sidetracked for a year and came back to this amp a couple of weeks ago, and also my original one which I'd started with and still wasn't 100%. My own one's lingering snags were just down to one dry joint on the selector and the volume pot needing cleaning and is now all good.
The other one, for which I was trying to find replacement brushes (for the ones I'd damaged while removing to clean) for the ALPS selector switch, led to a dead end as several switches I bought all had different sized brushes (see second picture where they're smaller & don't make good contact). So I only had the options of changing to a dial switch or to unmangle the original brushes. I chose the latter and to my surprise I managed to get them back into pretty good shape and, along with repairing another dry joint & replacing the protection relay, it's now working spot-on. Thanks again for your help, I started with one broken amp & now have three fully working, great learning process.
