Uncle Paul's B-2 Rehab

[Mr. Yamaha]

Well, I hope to be as good a student - so far just a white belt, and it's kind of dingy at that...

How is everybody cleaning their chassis? Seems like every B-2 thread is full of as new looking hardware.

Yeah, remember, I have never overhauled an amp before, let alone a B-2

I have no experience with a dirty chassis, as mine was completely clean. Some small dust particles were removed with compressed air and the transformers were made dust free with a damp cloth.

 

[clinic-audio]

A really dirty chassis is easy to clean as a new !









now the cleaned one







nice no ?

 

[Mr. Yamaha]

Maybe it helps when you tell Uncle Paul how you cleaned it?

 

[Vint Age]

nice no ?

Nice yes!

 

[Uncle Paul]

A really dirty chassis is easy to clean as a new !

View attachment 892934


View attachment 892935

View attachment 892936


now the cleaned one

View attachment 892937

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nice no ?

Beautiful! What cleaners did you use? I don't want to damage the galvanized finish and if possible make it look like it just came out of the factory.

 

[clinic-audio]

this is not with a cleaner , this is chemical bath and after re-galvanized .
It is brand new

 

[Uncle Paul]

this is not with a cleaner , this is chemical bath and after re-galvanized .
It is brand new

Beeeuuuutifuuuulllll....

Hmmmmmm......

If I can't shine mine up I might give this a try:

After dipping in muriatic acid to remove the old finish.

 

[Oilmaster]

this is not with a cleaner , this is chemical bath and after re-galvanized .
It is brand new

So why do you say "now the cleaned one" then ?

When posting your results, why do you always show off but give no information/methods etc?

And BTW, this is somebody's else thread about his B-2 project, in which you again put massive results of yourself.
Why don't you start your own threads instead?
Hijacking is the word.

 

[Mr. Yamaha]

So why do you say "now the cleaned one" then ?

When posting your results, why do you always show off but give no information/methods etc?

 

[belgianbrain]

You guys are too irritable.

Everyone go have a good Trappist and come back. I will too, just for kicks.

 

[rottalpha]

If yo

Beeeuuuutifuuuulllll....

Hmmmmmm......

If I can't shine mine up I might give this a try:

After dipping in muriatic acid to remove the old finish.

If you have access to an ultrasonic cleaner that is large enough, you might not need to mess with acids

 

[Uncle Paul]

If yo

If you have access to an ultrasonic cleaner that is large enough, you might not need to mess with acids

I don't have access to a cleaner that large. If I go that route I can get an inexpensive Sterilite box at home depot that has a 2" clearance, then line with 6 mil polyethylene sheeting - I have some tacky glue that can hold it to the sides, but will also let me pull it away when needed. Then change out each sheet as I move through each step - remove plating, neutralize the acid and dispose, plate with Zinc using a car battery hooked up to a charger for the current, dispose of salt bath, swap liners again and dip in chromate solution then air dry.

 

[Mr. Yamaha]

Is your chassis rusty or just dirty?

 

[Uncle Paul]

Is your chassis rusty or just dirty?

It looks a lot like the "before" chassis posted by @clinic-audio. I can get it clean, but only the areas covered by the transformers look new. I could probably live with it, but am kind of intrigued by making it look "factory fresh". Obviously, I'll have to experiment on some galvanized metal before doing the chassis - IF I decide to go that route. Since I have another B-2 as well as an M-4 to rehab the cost of the chemicals per chassis won't be too bad.

Still pondering... I'm both anal and binary about things - I'm either all the way "on" and examining everything in minute detail, or I'm "off". A B-2 is worth being "on". I even removed the old solder flux from under the bridge rectifiers left over from when they were made - something nobody will ever see but that I know would be there.

On another note the parts I ordered from Mouser are arriving today, so I can finish out the PSB and ECB

 

[Uncle Paul]

The snubber caps for the diodes would across each diode (hence 8 pieces), between the leg of the diode and the pin of the heat sink next to it.
These would do.

While you are on it, better replace those old C251 polyester caps by decent polyprop caps; same as proposed for the rectifier snubber caps (so 10 caps in total)

Would these caps also work as replacements for C201 - C204, C217 & C218? I'd like to replace with polypropylene as in @Mr. Yamaha 's thread. Unfortunately the only 0.01uF/630V purpose pp capacitors that I can find in stock have the square plastic covers that are out of place in appearance:


From what I can find the difference between microwave (like the Panasonic ECW's) and general purpose capacitors from what I can find is that microwave capacitors have higher tolerances:

"Microwave capacitors are used as tuning elements, or as components in simple or complex filter structures. Used as a tuning element, a high tolerance is often required on a low capacitance value. Used as a DC block or bypass, usually all that you will care about is a that your RF signal sees a low impedance."​

https://www.microwaves101.com/encyclopedias/capacitors#background

Am I missing something?

 

[Oilmaster]

The issue with those boxed capacitors is:
1) the very short legs
2) the small pitch (distance between legs)
Which makes them hard to fit in, and often results in clumsy works.
So I think you won't be able to do a nice job by using those.

And, IMHO, aesthetically they don't belong in a vintage Japanese amp, but that's your decision.

 

[Uncle Paul]

The issue with those boxed capacitors is:
1) the very short legs
2) the small pitch (distance between legs)
Which makes them hard to fit in, and often results in clumsy works.
So I think you won't be able to do a nice job by using those.

And, IMHO, aesthetically they don't belong in a vintage Japanese amp, but that's your decision.

We are on the same page here regarding aesthetics and proper fit. Would the Panasonic ECW-F6103JL work for these caps - it's the same one you recommended for the diode snubbers and C251/C252?

Thank you so much for all the valuable input you have given so far.

 

[Oilmaster]

yep, the same.

 

[belgianbrain]

Would these caps also work as replacements for C201 - C204, C217 & C218? I'd like to replace with polypropylene as in @Mr. Yamaha 's thread. Unfortunately the only 0.01uF/630V purpose pp capacitors that I can find in stock have the square plastic covers that are out of place in appearance:

Why do think you need 630V?

I think the highest DC voltage in this amp is +/- 85VDC.

There is a wealth of choice of 0.01uF polyproylene caps, and nearly all will take 100V. Panasonic, Wima, the list goes on...

 

[Uncle Paul]

Why do think you need 630V?

I think the highest DC voltage in this amp is +/- 85VDC.

There is a wealth of choice of 0.01uF polyproylene caps, and nearly all will take 100V. Panasonic, Wima, the list goes on...

Whenever possible I meet or exceed the original part. In this case the originals are 0.01 uF/630 V mylars and I would like to replace with polypropylene. Looking at all general purpose 0.01 uF PP caps that have 10mm lead spacing there are still few non "WIMA style" caps that I can purchase singly.

Looking more closely at the power circuit (which I should have done before I asked), these are all used as diode snubbers so I am going to go with the same ones here that @Oilmaster had recommended for the Electrolytic Capacitor board.