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Worklog #2: Marantz Model 32 Restoration

aokman

aokman

Marantz horder...
Well it didn't take long but i found another Marantz to add to the collection :banana: had to pay a bit for it but it was worth it i think along with a wooden sleeve and a Model 23 tuner...

Overall looks in good condition except for the 110v:

Current readings out of the terminals:

Left: 225mv
Right: 110mv

Current Plans:

Cleanup of chassis
Recapping
Look into replacing relay, some resistors + other bits to be found
Convert transformer to 240v
Usual adjustments

 
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Have fun with your next project! :tresbon:

I can't wait to do my next Marantz also. But no free time at the moment.)-: I think I became a collector already. :sigh::scratch2:

Thought you were living in the US.

:beerchug:
 
Oooh, that's purdy! :drool: This will be an interesting worklog, don't see the Model 32 very often.
 
Well i couldn't resist having a play around with it today...

Managed to get the power supply out and found 1 cap about to fail along with 2 blistered resistors cooking the PCB. Similar results with the resistors on the amp boards aswell.

Still have to source caps for the unit but there are only about 4 electrolytics in the whole thing, rest are films. Looking at replacing all of them though... not sure what the black caps scattered on the amp boards are yet tho?

One front lamp is on the way out so im going to just replace both with a single WB series CREE LED. Will easily light up the whole face.

Primary filter caps are:

Sangamd Vinylclad 6800uf - 50v (35mm x 105mm) screw type

So far:

- Converted transformer to 240v so no more stepdown transformer :)
- Removed and stripped/cleaned power supply board
- Replaced 1.5A 1N5393 rectifier diodes with 3A 1N5404
- Replaced relay with new type and rerouted connectors
- Replaced 2W 1.5k resistors with 5W 1.5k and elevated off PCB





 
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I would be happy to but it might be a bit prohibitive for you since im in Australia and i thought you have quite a few techs over there :scratch2:

Capacitor hunting is fun for this model 32 aswell, most values are hard to match for the black caps on the amp modules and im a little hesitant about changing them until i know the exact type, anyone have an idea of what type of film they are? They are all 250v-300v aswell
 
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Hi Aokman, looks good thus far! what are you planning to do with the timber sleeve? restore it or get a replica made?
 
didnt get alot done today due to work but i managed to get started on the chassis, the bottom was quite discoloured and lots of corrosion spots so ive decided to refinish it back to bare metal and bring it up again :)



On another note i finally discovered what the black caps were around the amp boards as ive never seen them used them before and now i know why, they are Silver Mica Caps, US Marantz certainly didn't stuff around with these units and went for the best. Just 4 x 2700pf and 4 x 1000pf Mica caps cost $35 and i doubt would need replacing anyway due to their build (rated to 125c and very long life)
 
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Another little update, people have asked me how i rewired the relay to suit the old design, basically i swapped the relay coil contacts with the speaker contacts internally :) i used copper desolder braid wound up tightly to extend the coil wires :)

The old coil looked like nice quality but i think its passed its prime now...

also the chassis is almost done, not a perfect finish but better than before :)

Just about to put the order in for caps, replacing the filter caps with 10,000uf 63v RIFA caps.

 
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I love that chassis, beautiful polish job...what did you use to achieve that high quality finish? :yes:

Thank's

Phil
 
Basically it was one of those jobs i wish i never started LOL as it can be just so time consuming... Started with a 240grit around the chassis with a orbital to remove the top layer then worked up to 1200grit and alternated steel wool with some other techniques :) its not perfect like i said but its much better than the factory corroded finish. I would have rathered had the entire inside electroplated but aparently it cannot be done without stripping the inside and outside of the amp which is out of the question obviously :tears:

I may end up getting panasonic caps from Digikey instead as i have a Bose 1801 monster arriving soon that will need some hefty caps so it would make another order from digikey cost effective :)
 
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most definately :) just waiting on my parts shipment to arrive which has the parts for this and the Bose 1801 im working on. Been delayed because of the holiday period :(

much more to come shortly :D
 
aokman said:
Basically it was one of those jobs i wish i never started LOL as it can be just so time consuming... Started with a 240grit around the chassis with a orbital to remove the top layer then worked up to 1200grit and alternated steel wool with some other techniques :) its not perfect like i said but its much better than the factory corroded finish. I would have rathered had the entire inside electroplated but aparently it cannot be done without stripping the inside and outside of the amp which is out of the question obviously :tears:

I may end up getting panasonic caps from Digikey instead as i have a Bose 1801 monster arriving soon that will need some hefty caps so it would make another order from digikey cost effective :)
Click to expand...

I just did the same thing with a heavily corroded model 3800 (Marantz) - and I stripped the whole thing in order to get it re- yellow-chromatized. I honestly think that you should do the same. The plate is now unprotected and can very easily corrode - much worse than before, allthough it look very nice by now.

best regards
Freddy
 
fredmarantz said:
I just did the same thing with a heavily corroded model 3800 (Marantz) - and I stripped the whole thing in order to get it re- yellow-chromatized. I honestly think that you should do the same. The plate is now unprotected and can very easily corrode - much worse than before, allthough it look very nice by now.

best regards
Freddy
Click to expand...

i would love to believe me :) but i dont want to loose the factory markings on the outside :(
 
I do understand that very much ! But is there a way to protect the surfaces from moist and oxygen? some spray or something?

Fortunately the 3800 of mine is constructed in a way, that allows all chassis expect the back-plate with that lettering to be plated.
I had mine yellow-chromatized and that also meant that they had to strip all the paintwork on the outside (black structure with some sort of flake in it.) I'm sure you know that type of paint. I found a good painter, who usually paints medical factory equipment and paints for a famous electronic company, to do the job. He thought, that that particular paint would be easy to restore. Right now the Chassis-parts are at him - and I should get it back within a week or so.

Btw: Your other work on the 32 looks very very good and I think this baby will come back in busines!

best regards
Freddy
 
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