I agree with the above post, Kevinkr has identified the highest priority changes.
Without those changes your amp will die, which is a shame because it is the cream of quality Japanese output with associated quality output transformers etc. I have the Sansui equivalent - they are fantastic items and will always be sought after and gain value.
Basically every single capacitor will need changing, but start with the ones kevinkr identifies. Also remember hot electrolytic capacitors can explode so the safety of you and your amp is in the balance. Try to wear glasses when working on these old amps.
Ironically paper-in-oil capacitors sound great and these beasts must have had awesome sound when new - but I can guarantee every single paper in oil will be leaking. In fact I fixed an old airband tube radio like that - it was silent but all the tubes lit up and after my Sansui experience I changed every single small cap out for polypropylene and it worked perfectly (and still works!).
Without those changes your amp will die, which is a shame because it is the cream of quality Japanese output with associated quality output transformers etc. I have the Sansui equivalent - they are fantastic items and will always be sought after and gain value.
Basically every single capacitor will need changing, but start with the ones kevinkr identifies. Also remember hot electrolytic capacitors can explode so the safety of you and your amp is in the balance. Try to wear glasses when working on these old amps.
Ironically paper-in-oil capacitors sound great and these beasts must have had awesome sound when new - but I can guarantee every single paper in oil will be leaking. In fact I fixed an old airband tube radio like that - it was silent but all the tubes lit up and after my Sansui experience I changed every single small cap out for polypropylene and it worked perfectly (and still works!).
I fully agree with the above: be prepared to change ALL the Suzuki branded (usually grey color) paper capacitors (if used) because they're all leaky now and responsible of all kind of troubles. Regarding the pots,they usually age very badly (open tracks,dead spots,mistracking,drifted value...) No cleaning will cure that and a replacement pot will be needed,which is usually impossible to find,especially in the tone control circuits. Looks like your MPX decoder need to be fixed/ re-aligned too,which requires specialized test equipment and good knowledge.
The main problem fixing vintage japanese audio gear is the inferior quality of the parts they used then ,especially if we compare them with US made gear from the same era. Capacitors leaks,resistors drifts and become noisy,potentiometers defective ,cheap switches,poor wiring, lousy workmanship,etc... Some have fairly good transformers but all the remaining is usually crap. Fully restoring vintage japanese tube receivers is a considerable job and doesn't usually worth the time and expense required. You'll end up replacing about 60-70% of the passive parts for a only average end result. Better to save the transformers and start building something from scratch.
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Totally agree. Japan in the tube era was similar to China today in IC era. However, transformers may be really good. Sansui for example used to wind transformers for other companies before they started building own stuff that may be characterized like topological mess, lots of unneeded capacitors, switches, and other bells and whistles. They even used electolytics as bypass capacitors in their tube gear!
Hello
I have, me too, a Pioneer SX-34
I have recap some parts and put new output tubes, and the amp sound very good.
The AM tuner work good.
But the FM tuner are silent (except a small white noise), today I've just test all the tuner tubes and they are fair to good.
I really don't see why the FM tuner are silent, (even with a good antenna).
Any hint ?
I still not sure If I will keep that receiver but it would be good if I can fix the FM tuner.
Btw, I have also a Sansui 500A tube receiver, working good, that monster weight 40lb
I even have a unknow tube amp, an Electra amp, single-ended output, but I never found any schematic for that one.
Thank
Bye
gaetan
I have, me too, a Pioneer SX-34
I have recap some parts and put new output tubes, and the amp sound very good.
The AM tuner work good.
But the FM tuner are silent (except a small white noise), today I've just test all the tuner tubes and they are fair to good.
I really don't see why the FM tuner are silent, (even with a good antenna).
Any hint ?
I still not sure If I will keep that receiver but it would be good if I can fix the FM tuner.
Btw, I have also a Sansui 500A tube receiver, working good, that monster weight 40lb
I even have a unknow tube amp, an Electra amp, single-ended output, but I never found any schematic for that one.
Thank
Bye
gaetan
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Back from Jentronics
Hi Everyone;
I'm back from the BIG CITY Halifax. A trip like this is quiet a big deal to me, however, I managed... found a place called >>> Jentronics <<<
I ordered all the caps you guys mentioned and I included the ones kevinkr added , C27, C32 and C35. Also the two 2-stage pots for bass and treble, 1 MOhm are in the order. I didn't order the volume/balance pot and it bothers me. May be I should have. (?)
Hey, and I bought a new tip for my old solder iron and a can of DeoxIT.
How am I going from here?
Should I have all the tubes tested? It is getting kind of expensive, the little can of deoxit was 17 $ and a couple of other things = $ 30 + $ 80 for gas for the van.
The tubes all light up, I might wait until the caps are changed and go from there, in order to save some money.
What do you guys say?
Okay, I look forward to read a reply or two on my concerns.
I'd like to rebuild this receiver properly, but if it is going to cost $ 500, I'd have re-think it.
Hi Everyone;
I'm back from the BIG CITY Halifax. A trip like this is quiet a big deal to me, however, I managed... found a place called >>> Jentronics <<<
I ordered all the caps you guys mentioned and I included the ones kevinkr added , C27, C32 and C35. Also the two 2-stage pots for bass and treble, 1 MOhm are in the order. I didn't order the volume/balance pot and it bothers me. May be I should have. (?)
Hey, and I bought a new tip for my old solder iron and a can of DeoxIT.
How am I going from here?
Should I have all the tubes tested? It is getting kind of expensive, the little can of deoxit was 17 $ and a couple of other things = $ 30 + $ 80 for gas for the van.
The tubes all light up, I might wait until the caps are changed and go from there, in order to save some money.
What do you guys say?
Okay, I look forward to read a reply or two on my concerns.
I'd like to rebuild this receiver properly, but if it is going to cost $ 500, I'd have re-think it.
Don't test if filaments glow when you may have some leaky interstage capacitors! You can damage your tubes such a way, while they will keep glowing. Also, old filter caps may explode and cover your walls by awfully smelling confetti!
Well, FWIW, unless you have an emotional or financial interest in a full restoration to original operating condition, which could easily approach or surpass the $500 by the time you account for a full realignment of the tuner (quite likely the most technically complicated part), I'd cast a third vote for salvaging what you can (probably the iron, and maybe chassis) and starting with a scratch build.
Many units of this vintage, regardless of their provenance and original build/parts quality, had far more complicated switching / tone / EQ and filtering etc., than would normally be required with the far fewer and generally higher quality of today's input sources.
Don't be surprised if over 75% of the schematic is dedicated to features and functions that you'd never use except to demonstrate that they still work.
When and if bypass for these function exist, they will still be comprised of extra wire, switching etc., that would need attention as part of a full restoration. In some units we're talking several hundred solder connections that would need to be at least reflowed, if not completely redone.
While I'm not at all familiar with this particular unit, there are owners or others far more experienced who could advise if the line/power stage audio circuitry is worth replicating on a potential stripped down hot-rod rebuild, or if most of the value is in the output and power transformers.
The latter was certainly the case with a couple of mid-late 50s Scott integrated amps that become organ donors for me a few years back. Both units had major problems with flaky switching / hum / noise from simple aging, or hastily executed previous repairs/mods - but once stripped down to the bare chassis and repurposed as basic power amps the quality of the output iron, and the masking effects of the complicated maze of redundant controls etc were revealed.
smelling confetties
Hi Wavebourn,
Thanks for the advise, I like the confetti part and I remember, that we bloow up these babies on purpose, when I was an apprentice.
You know what I mean, connect one with an overrated voltage, positive-negative, connected the wrong way, at a buddies desk 🙂.
No one got hurt..., these were the good old days.
No one thought about sueing one or another.
Hi Wavebourn,
Thanks for the advise, I like the confetti part and I remember, that we bloow up these babies on purpose, when I was an apprentice.
You know what I mean, connect one with an overrated voltage, positive-negative, connected the wrong way, at a buddies desk 🙂.
No one got hurt..., these were the good old days.
No one thought about sueing one or another.
Hi chrisb
I have read your comment and I really appreciate your thoughts or facts.
I probably will go all the way, it will take time and the money will spread, so I should be able to do it.
This receiver, I got in Montreal on a certain day, so it means a lot to me.
In addition I got a pair of Fisher Planar Planatex wall speakers, designed by Bertagni, Argentinia and the guy told me to use those speakers only very gently and best with a tube amp... and than he gave me the Pioneer SX-34.
However, I just tried to upload a picture of the speakers. Don't know whether it worked.
So, does anyone agree, to wait for the caps, replace them and go from there?
I have read your comment and I really appreciate your thoughts or facts.
I probably will go all the way, it will take time and the money will spread, so I should be able to do it.
This receiver, I got in Montreal on a certain day, so it means a lot to me.
In addition I got a pair of Fisher Planar Planatex wall speakers, designed by Bertagni, Argentinia and the guy told me to use those speakers only very gently and best with a tube amp... and than he gave me the Pioneer SX-34.
However, I just tried to upload a picture of the speakers. Don't know whether it worked.
So, does anyone agree, to wait for the caps, replace them and go from there?
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