YES! I get!!! SM-80 ! ;)

So, I cleaned up my SM80 a little bit. Made a list of the can caps on top. Next I'll make a list of the lytics underneath and order what I need. If these tubes I've ordered come in, it should be pretty quick to get some kind of sound out of it.

Here's a picture of it after a lazy man's clean up. The top and bottom cabinet have to be painted and the panel worked on a bit to make it pretty. I don't have any knobs that look right. I'll just have to use what I can and keep looking.
 

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Slow progress - detected that power transformer was rotate on 180 degr. from normal position ;) Fix it and thinking about change old rectifier diodes (on anode voltage) with new ones - I have a few UF4004 diodes (1A, 400V, 50nanosec)
 

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Hi all!
Today I have finished anode voltage rectifier with replaced old diode by fast new one - see pics, also I check caps in voltage doubler - its 2 200uFx180V - one have 300uF and 0,3 Ohm ESR, other have 247 uF and 3,2 Ohm ESR, so what are thinking - should I need replace this caps(mid 60s productoin I think ) or stay with it? I have a new EPCOS 220uFx450V whith suitable dimensions....
 

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I would never trust an electrolytic that was 50 years old. I say use the new ones. The chance of going bad and causing a problem and damaging tubes or irreplaceable transformers is just too great.
 
Well I got all the caps from Antique Radio supply. I've changed out most of the caps on the underside. These Suzuki caps do blow up. Here's a picture of another one. This one was in the treble tone circuit.

Just a few more to change underneath, and then I will be changing out all the can caps on top. That will probably be the hardest part of this whole restore. I also got some knobs that actually look pretty good, nothing like the originals, but match the others pretty well. They're not quite tall enough, or the shafts are too long, however you want to look at it. I think what I'll do is put some spacers between the chassis and the pots, which will recess them more into the chassis.

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Wow! Nice caps, congratulations! Im also looking on 50-50 uF JJ ;) But it seems that 20-20-20-40 uF caps much more in diameter than original 20-20-20?
 
The knobs on yours are different than mine.

I'd love to find some original knobs like you have, but since yours and Mike's are the only other two SM80's I've ever even heard of, I'll just make do with those cream colored guitar knobs for now. The one's on Mike's are just like yours, but looks like he's missing an insert and a knob or two..
 
Wow! Nice caps, congratulations! Im also looking on 50-50 uF JJ ;) But it seems that 20-20-20-40 uF caps much more in diameter than original 20-20-20?

Yes, they are much fatter cans. I have plenty of clamps so I will just set them up a bit higher and run the wires down through the hole. It'll probably work ok.

I looked all through Antique Electronic Supply catalog and couldn't find any 20-20-20 can cap that was the right size. My SM80 will not be a beautiful restored original, so... I can live with it. I'll make it look pretty good on the outside.
 
I'd love to find some original knobs like you have, but since yours and Mike's are the only other two SM80's I've ever even heard of, I'll just make do with those cream colored guitar knobs for now. The one's on Mike's are just like yours, but looks like he's missing an insert and a knob or two..
Those look fine, I'd think one would have to be told they were replacements.
 
Hi all!
My caps set for SM-80 PS - I planing stay old 200uF 180V Nichicon case on chassis and install new EPCOS caps inside Nichicon for the authentic look ;)
 

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That's the way to do it!! Your SM80 will look completely original. Not an easy task.
Keep up the good work.
 
Some update - open old big Nichicon caps and cooking new home for EPCOS :) As always at the most inopportune moment thermo-glue ended....
 

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Excellent. We have a new method for removing Cap innards.... With a wine bottle opener!!! Great idea.

We just did this for a 919 and the insides did not come out easily. Always glad to see another method.
 
Thanks, Jim! I warm inner content about 10 minutes under hot water in my bathroom, I think our japan friends specially made diameter of the capacitor equal to the diameter of a wine bottle to make our work easy in 50 years :cool:
 
Thanks, Jim! I warm inner content about 10 minutes under hot water in my bathroom, I think our japan friends specially made diameter of the capacitor equal to the diameter of a wine bottle to make our work easy in 50 years :cool:

You make me laugh.

I have replaced all the caps in my SM80. Not an easy task. Easier than a 1000A, though. Of course... the can caps on top were the hardest. I replaced all 5 cans on the back row with JJ units. They even look nice. The one double can with two 200uf @25v near the front, I replaced with a couple 220uf@25v caps underneath the chassis, and left the stock can where it was.

Tomorrow, I will check everything out and hopefully screw up the courage to power up and see if it will make music. I will use the variac at first, and monitor voltages as I bring it up. If it works, I will then concentrate on the front panel and cabinet, try to make it look as good as I can. I still need to add a FM audio output that I can feed to an Eico MX99, which I will bring back in on the FM Mpx inputs. I also would like to get both tuners working, and all three bands on the right hand one.

I plan on taking the cabinet with me to the local hardware store to see if I can match the stock colors with some spray paint. Here's some pictures of my severely corroded SM80 with all the caps replaced.

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Well, fired it up today. Brought it up on the variac, slowly. All voltages came up and it looked pretty good. Nothing on the speakers though.

The heaters were not heating in the 4 output tubes. Were they all bad? Took me a minute to remember that the output tube heaters are in series, and one of them was likely bad. Put in all new tubes and voila!! audio came out the other end.

Spent about an hour figuring out and adjusting proper bias, had to look up these weird tubes. Seems they were originally made for Horizontal deflection in TV's. They can take up to 7Kv on the plates. Wow! Plate dissipation was not that high at 10w, but hey, I set it for about 75-80% bias. Then to listen.

Besides the usual exercising of the bad switches, something was really wrong. Sounded weird and the bass control did weird things when adjusted. Eventually realized that I had made a mistake when replacing the caps in the bass control circuitry. I had been short the 0.003uf caps and had to wait a week to get them and then another week to get the time to do it, and had put them in wrong.

OK, now we were cooking. Played first from my Ipod. Bela fleck and Tariketh. On my bench speakers. Justin was in the shop and after he left, I hooked it up to the big speakers and cranked it up. It seemed quite clean, but there was something I didn't like about it. Kept fooling with it, and finally put the output on the scope.

Well, I was running it into total clipping. It was so clean, it just seemed I could turn it up lots more. Turned it down to where it's running just below clipping. Very clean with powerful bass.

That got me curious so I measured the output just before clipping and did the math. Hmmm, puts out 38-39 wpc or so. Impressive. I was expecting 20-25 wpc.

So, it's been cranked for a couple hours. OPT's get a little warm, but that's all. Power transformer the same, just a little warm. Wow, cool amp. And I don't just mean temperature wise. When I read about the tubes I was skeptical. Can't nothing that was made to drive a TV screen sound very good. But I am happily wrong about that.

I'll have to listen for longer to really form an opinion, but... with this little time listening, I would rate my CA303/BA303 combination a little better and seemingly a little more power, but damn close. Sansui knows, or knew, how to make tube gear.

I'm gonna try bypassing the tone section and see how it sounds. It's a very simple very rudimentary circuit and it might sound better with it out.

Nothing from either one of the tuner sections. I'm not surprised, some of those tubes don't even get warm. I definitely wanna get that stuff working, but not a priority right now.

The picture is from testing it on my workbench. Variac on the left.

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