Nick Danger's Yamaha M80 Amplifier Repair/ Restoration

[avionic]

Recommend you measure it as it can also be 180 pF 5% The capacitor manufacturers are quite inconsistent in their marking of capacitors. It could be either 18 or 180

According to Hoyle (M-80 service manual) There is not any 180pf caps on the main board. However there is a couple 18pf mica's.
But still won't hurt to double check it.

 

[Nick Danger]

Recommend you measure it as it can also be 180 pF 5% The capacitor manufacturers are quite inconsistent in their marking of capacitors. It could be either 18 or 180

According to Hoyle (M-80 service manual) There is not any 180pf caps on the main board. However there is a couple 18pf mica's.
But still won't hurt to double check it.

Thank you. I will figure out how to check it later today and will post my findings.

 

[laatsch55]

If you find a cheap cap checker that goes to picofarads let me know....

 

[Nick Danger]

If you find a cheap cap checker that goes to picofarads let me know....

Haven't been able to get a reading with my multimeter on this cap(boo). On this bright side, ordered a service manual . Resistors showed up so hopefully I will be able to get that sorted and a couple of jumpers made this century, too.

 

[laatsch55]

My Fluke 179 won't go to pico either. Doesn't mean they're bad. Just won't go that low..

 

[Nick Danger]

My Fluke 179 won't go to pico either. Doesn't mean they're bad. Just won't go that low..

Cheers, Lee. I take it meters to test these are a bit pricey or hard to come by?

 

[laatsch55]

It appears so..

 

[NavLinear]

Actually there are a number of LCR meters that would work. If capacitor testing is in you future you may want a meter with more bells and whistles versus needing a meter to check a cap now and again. On fleabay you can get some nice used ones.

 

[laatsch55]

Nav, you solved the hard to come by part , but not the pricey part....or have you??

 

[NavLinear]

Well - the price depends on what the meter can do and of course your budget. I would go with a meter that used the four wire Kelvin measurement method. The link below provides an explanation of how this works when making a resistance measurement.

http://www.allaboutcircuits.com/vol_1/chpt_8/9.html

A used HP would be on the top of my list but I like really nice test equipment. I have a BK meter that set me back a few hundred and it works quite well but I plan to use mine for many years and give it a work out for my hobbies. There are meters available that are more affordable that use the four wire Kelvin measurement technique but I have not used them so it would be a matter of looking at specs and pricing.

 

[Nick Danger]

Actually there are a number of LCR meters that would work. If capacitor testing is in you future you may want a meter with more bells and whistles versus needing a meter to check a cap now and again. On fleabay you can get some nice used ones.

This amp job is a litmus test for my aptitude to grind through some minor electronics repairs and maybe learn a thing or two. Success here may lead to me investing further in work bench gear.

Of course, if the amp goes up in flames and the copious amount of tears(mine) can't put it out, do not see needing anything outside of what I already own.

 

[laatsch55]

Every bencher will see some smoke eventually, don't let smoke on the first one deter you..

 

[laatsch55]

Also there is looking at the schematic and just ordering the correct one, they are pretty damn cheap..

 

[Nick Danger]

Also there is looking at the schematic and just ordering the correct one, they are pretty damn cheap..

Service manual on order. Figured it is going to come in handy and I really should have it for this job.

Every bencher will see some smoke eventually, don't let smoke on the first one deter you..

Thanks for the words of encouragement, Lee. Got to keep the Little Engine metality, no matter what the project is(I think I can, I think I can...).

 

[NavLinear]

This amp job is a litmus test for my aptitude to grind through some minor electronics repairs and maybe learn a thing or two. Success here may lead to me investing further in work bench gear.

Of course, if the amp goes up in flames and the copious amount of tears(mine) can't put it out, do not see needing anything outside of what I already own.

Letting a bit of smoke out is part of the learning curve - just don't do it too often. Using others to assist with something like this can get you through this process as it can be a challenge but the end result will be worth it. With Avionic and brutal along with others to provide guidance you'll make it through this.

Do you have a buddy that has a meter? Maybe you can borrow one to get familiar with it so when you're ready to purchase you'll have a better idea of the features that you'd want.

 

[Nick Danger]

Letting a bit of smoke out is part of the learning curve - just don't do it too often. Using others to assist with something like this can get you through this process as it can be a challenge but the end result will be worth it. With Avionic and brutal along with others to provide guidance you'll make it through this.

Do you have a buddy that has a meter? Maybe you can borrow one to get familiar with it so when you're ready to purchase you'll have a better idea of the features that you'd want.

As long is it not TOO much smoke I might not flip out terribly. I do have a couple of meters here, but they were pretty inexpensive. Will get some pics posted of them shortly. Thanks for watching this thread, Dennis.

Looks like Sunday I am going to try and get a bit more work done on it. Would like to get jumpers and busbars installed at the very least.

 

[Nick Danger]

Busbars, jumpers and transistors back on the board. Chance anybody has/ knows where I may grab a couple each of these capacitors? Any caps available that are considered an upgrade?

Thanks again, folks!

 

[NavLinear]

Busbars, jumpers and transistors back on the board. Chance anybody has/ knows where I may grab a couple each of these capacitors? Any caps available that are considered an upgrade?

Thanks again, folks!

Nichicon capacitors are on the top of the list for audio - at least for those of us that can't hear a gnat fart. The Black Gates you won't be able to find or if you the cost can be prohibitive. The Black Gates are sought after by audiophiles and they have not been manufactured for a number of years so if that one hasn't leaked you may reconsider replacing it. How old is your Yamaha?

In regards to the Nichicon you don't want to go below the rated voltage and capacitance. Do you know the part number for this guy? I'd guess that the footprint is important as it looks like it is soldered to a PCB.

 

[Nick Danger]

Thanks, Dennis for the input. I may end up reusing the caps as they have been tough to find for me.

 

[Nick Danger]

Mica Caps polarity?

Tech question: Do I need to figue out polarity of mica caps to install them?