Toshiba SA-20Y Unanswered Questions

[Anaxas]

Hello,

I've acquired a Toshiba SA-20Y that looks like it's had a hard life. Sadly, the only resource that I found that listed the service manual was stereomanuals.com and after some further reading I don't believe the business has continued. The SA-15Y has manuals online, so I'm OK for some technical items, but for specifics to the 20Y I'll need help from the community.

I'm in the process of giving it a once over before I try to dim-bulb power up and I've found a couple of minor things that pop out that I'm minorly concerned about.
- There is a thin black wire that is soldered to the chassis of the variable tuning capacitor (left side / towards the bottom, facing the receiver) that was loose on the other near the coupling capacitors. I'm not sure where the other end is supposed to be attached to.
- The output transistors appear to have been removed / replaced at some point in it's life - The ones there are labeled "ES31" - The SA-15Y has them as 2SC793 in the service manual - I'm not sure what they are supposed to be for the 20Y (or know what's installed - picture below)

All the capacitors and other internals appear to be original - I haven't found anything that appears burnt or bulged. I'll give it a good cleaning and hook up a dummy load to measure some voltages since it's cap coupled.

If anyone can help with my initial questions , I'd be very grateful.

 

[Anaxas]

One mystery down .. I traced down the thin black wire to the traumatized AM antenna in the back.

Cleaned the pots and switches and the unit powered up OK, passed the DBT, nothing blew up - I was worried that the relay didn't click, but it appears that the relay opens when it detects a fault. Sound is about 1/3 lower on the right channel, but I didn't investigate. Speaker / sound started to oscillate/thump when I moved the Bass knob , something is definitely temperamental.

Whatever 4 outputs are installed, they do work - But it would still be nice to know what the originals were and the part #

Time to step up my game and I will probably spend too much time on this one. Will report back anything I find.

 

[Anaxas]

Found a service manual, not the best quality , but together with the SA-15Y one available online it's sufficient. Original transistors are 2SC793 just like in the 15Y - Some small differences in the power section, and some additional 'filter' boards , but mostly the same. I tracked down the thumping / motorboating to a bad capacitor on the pre-amp / tone board SAF-16 (33uf reading as 3nf). The current ES31 outputs sound fine, so they stay. Replacing the caps is a slow process since all the leads are folded and soldered along all the traces. Once done I'll make another thread about the restoration.

 

[Thomas Ryan]

Hi Anaxas,

I am working on one of these and find the available SA 15Y service manual (hifiengine) to be only marginally useful
(especially the schematics which are poorly scanned/unreadable).

Did you find a source for the SA 20Y pdf?

thanks,

Tom

 

[Thomas Ryan]

OK - I downloaded a decent SA 20Y service manual off the "Sam's Technical Publishing" website. (no affiliation)
Not very many pages, but has the tuner alignment procedures, board diagrams and a readable schematic.

Tom

 

[Anaxas]

Sorry for the delay .. I had found the SAMS SA-20Y manual as well. I used it together with the SA-15Y service manual for certain items.