Next up is an AU-X901 from Tony (@sansui au719 ) in his initial listening tests he was very happy with how it sounds, but he knows it has the 'glue' problem, and wants it to work reliably & better if possible - hence the reconditioning request.
Opening it up for a look inside and well, it's very dirty,
there is also some brown smeary stuff that looks like flux residue on some parts of the chassis and the main amplifier board is covered in sandy coloured grime. Everywhere inside there are thin straw like fragments which I think are dried up flower petals. The glue is very dark brown and not too widely spread, but has damaged some components.
Yesterday I got round to giving it a check over, and found DC offset was 200mV+ on one channel and around 50mV on the other, bias was set (or had drifted) to very low levels around 1mV or lower for each of the 4 settings. So I reset the these as best I could with the old trimmers and had a listen, sounds nice but lacking that top end clarity and dynamic feel that I know it is capable of. Interestingly I find the only thing obviously wrong is that the 'Speakers B' selector switch works - but no relay click, ('Speakers A' works fine), I file that away in my mind for future investigation.
So I begin dismantling the amplifier because I want to completely remove the main amplifier board to clean it properly, and the heatsinks so I can re-do the bias tracking transistor mounting which looks a mess. I get to the rear panel and start removing screws - then a fragment of black plastic falls out of the unit. More screws removed - and then I notice it, a crack in the protection board! Further dismantling reveals that this amplifier has had a big impact to the speaker terminals, which has bowed in the rear panel, cracked the protection board, and bent the speaker terminal connecting posts like bananas.
I'll take some pictures and post them up so you can see for yourselves.
I think I can repair this,
but I need to remove the speaker terminals from the board so I can get a proper look. 
Opening it up for a look inside and well, it's very dirty,
there is also some brown smeary stuff that looks like flux residue on some parts of the chassis and the main amplifier board is covered in sandy coloured grime. Everywhere inside there are thin straw like fragments which I think are dried up flower petals. The glue is very dark brown and not too widely spread, but has damaged some components.Yesterday I got round to giving it a check over, and found DC offset was 200mV+ on one channel and around 50mV on the other, bias was set (or had drifted) to very low levels around 1mV or lower for each of the 4 settings. So I reset the these as best I could with the old trimmers and had a listen, sounds nice but lacking that top end clarity and dynamic feel that I know it is capable of. Interestingly I find the only thing obviously wrong is that the 'Speakers B' selector switch works - but no relay click, ('Speakers A' works fine), I file that away in my mind for future investigation.
So I begin dismantling the amplifier because I want to completely remove the main amplifier board to clean it properly, and the heatsinks so I can re-do the bias tracking transistor mounting which looks a mess. I get to the rear panel and start removing screws - then a fragment of black plastic falls out of the unit. More screws removed - and then I notice it, a crack in the protection board! Further dismantling reveals that this amplifier has had a big impact to the speaker terminals, which has bowed in the rear panel, cracked the protection board, and bent the speaker terminal connecting posts like bananas.
I'll take some pictures and post them up so you can see for yourselves.
I think I can repair this,
but I need to remove the speaker terminals from the board so I can get a proper look.
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