Latest recap and Upgrade amp - Yamaha M-70

Someone might sell recapping kits. I prefer to determine the capacitors I want to use and order them from the parts houses mentioned (Mouser, Digikey, Newark,...). Those places don't compile and sell kits as far as I know.

The M70 and C70 are not the easiest amplifiers to restore/recap. They are built very sturdy and are great amplifiers but Yamaha used a lot wire wrapping inside that makes it more difficult to get to all of the places you need if you are replacing all of the electrolytic capacitors. I'm not saying not to do it but be aware there is a little more involved if you haven't looked inside yet. They are not units I would recommend for a first time restoration. I recently restored one of my C70 preamplifiers. You can look at the restoration here to get an idea of what is involved with that unit. I have an M70 that I need to restore but have quite a few other projects ahead of it. I have looked at the M70 and it looks like it will be a little more work than the C70.

I usually build my list of replacement parts by comparing what is actually in the unit with the service manual schematic and the parts list. Often times there are differences. When there is, I normally go with what is actually in the unit...unless it looks suspicious like someone else already replaced the original part. In those cases take a picture and post it on the forum so someone can compare it to theirs.
 
ok, Found the M70/C70/ system dropped one speaker and sometimes 2 speakers. Isolated the problem to the C-70 pre amp jacks....either the solder joints are cracked or the jack assembly is bad. They have some play. Anyone else run into this? The info I have is location PJ501 P/n lb400980 (unavailable I suspect?) This part available from anyone?

I'm going to have to pull the board (unless accessible from the bottom - haven't looked yet.) If I have to remove this board..any suggestions on caps. I was a board repair tech in the 80's.....but its been awhile. Recommendations on soldering iron wattage etc?

Anything to be aware of when removing the bottom cover? More screws than I would have suspected.

Thanks
 
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The DSBG is on the front vertically mounted power circuit board where you can't easily spot the issue. You should also have the .22uf X2 cap on the Control 1 power supply board looked after.

I'm still trying to decide if the M-70 or M-80 has the worst binding posts ever... :D It's a shame as they are all such nice sounding amps.

What are the speaker binding post "Manufacturer, Part Number"?
What are the RCA binding post "Vampire, Part Number"?
Caps "Manufacturer, Part Numbers"

What do you make of the statement of Sony adhesive failure? What exactly is this referring to? Are they talking about the heat sink paste?
 
What do you make of the statement of Sony adhesive failure? What exactly is this referring to?
( DSBG) Damn SONY Bond Glue. A lot of japanese manufactures and others. Used a glue to fasten down larger components such as heatsinks and large capacitors. By now the glue is all or mostly crusty dark brown/black. It attracts and retains moisture. If it is in contact with jumper wires or component leads it will eventually oxidize the leads/jumpers to the point of failure.Best to eradicate the stuff...

No it is not heatsink compound...
 
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( DSBG) Damn SONY Bond Glue. A lot of japanese manufactures and others. Used a glue to fasten down larger components such as heatsinks and large capacitors. By now the glue is all or mostly crusty dark brown/black. It attracts and retains moisture. If it is in contact with jumper wires or component leads it will eventually oxidize the leads/jumpers to the point of failure.Best to eradicate the stuff...

No it is not heatsink compound...

Did you see my last postings on the MX-A5000?
 
Hello! what capacitors was used for replacing the big 10000µF and 18000µF caps? i'm doing a recap of this unit at the moent and im not shure what caps to chose. Any help would be apreciated. Thanks!
 
I would prefere parts avalible at mouser, if anyone can send a link for suitable 10000µF and 18000µF replacement i would be greatfull.
 
I would prefere parts avalible at mouser, if anyone can send a link for suitable 10000µF and 18000µF replacement i would be greatfull.
May be a good idea to research the benefit of using higher uF caps in a power supply, Mundorf absolute quality and the high end parts supplier of Parts Connexion.
My opinion is the M-70 is one of the best Yamaha Amps ever built and deserves only the best parts.

Mouser is my primary supplier here in North Texas and never a complaint. Maybe they should be referred to as the WalMart of parts.
 
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