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Yamaha B-1 Quickie

clinic-audio said:
I have restored more than 12 B2 and one only with 2 bad cap on the 4
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more than 12 B-2s here too and at lease 7 had leaky caps.

Photos I posted are from the last one I restored. That B-2 looked to have had very minor use, yet one of the caps leaked. I am convinced that there is nothing more damaging to the B-2 than to keep it in a tight space while in operation. The PSU already gets very little ventilation as is.....
 
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Vint Age said:
:yikes: that's big! Really, 60%?

By now I've restored 7 of these and none so far have had a leaky main cap. With those odds I'm going to buy a lottery ticket right now! ;)
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if you recall, EW's feedback was similar to mine and he had his fair share of B-2 restorations..just say'n you are really lucky indeed
 
rottalpha said:
if you recall, EW's feedback was similar to mine and he had his fair share of B-2 restorations..just say'n you are really lucky indeed
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I don't recall his stating a 60% failure rate on these but please prove me wrong. :)

I do recall this advice though from EW from back in the day ...
EchoWars said:
If it were reasonably easy to replace the caps, I'd do it, but Yamaha buried these things deep (plus the solder tab-to-PC board mounting will be a battle for the novice). Unless the big caps are leaking, I'd leave them alone.
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:thumbsup:
 
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Vint Age said:
I don't recall his stating a 60% failure rate on these but please prove me wrong. :)

I do recall this advice though from EW from back in the day ...


:thumbsup:
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If my memory serves me correctly, there is another response EW provided on this topic and I might have to dig for it....nonetheless, he did replace the main caps on his B2 rebuilds and he states that in numerous posts...am hoping he comes back one day so we can chat some more.

That said, everyone is entitled to do as they please with their B-2. I do not need to prove anything....I worked on a decent sample size of B-2 units for which I collect various data. As such, In the case of the PSU main cans I have empirical evidence supporting the "must replace soon" rater than "replace only if the originals are leaking". If the caps are not leaking today, they will leak soon. At 40+years old and living their lives in an "oven" the original caps are on borrowed time.
 
rottalpha said:
If my memory serves me correctly, there is another response EW provided on this topic and I might have to dig for it....
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No need to dig. I wasn't saying that EW didn't change them if he was suspicious of them or when people asked him to and don't get me wrong, I'm not suggesting that it's a bad idea to replace them if there's any doubt. I always offered that as an option when I restored 1, but to my thinking, to say that 60% WILL fail and if the caps are not leaking today, they will leak soon based on your bad luck likely causes undue distress to B-2 owners based on my good luck. ;)
...am hoping he comes back one day so we can chat some more.
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Me and lots of others too. EW If you're reading this, we miss you! :)
 
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Vint Age said:
No need to dig. I wasn't saying that EW didn't change them if he was suspicious of them or when people asked him to and don't get me wrong, I'm not suggesting that it's a bad idea to replace them if there's any doubt. I always offered that as an option when I restored 1, but to my thinking, to say that 60% WILL fail and if the caps are not leaking today, they will leak soon based on your bad luck likely causes undue distress to B-2 owners based on my good luck. ;)

Me and lots of others too. EW If you're reading this, we miss you! :)
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~60% is not bad luck...it is a statistic based on a decent sample size...good, bad...lucky or not...it is what it is. B-2 owners can do as they please, I shared my opinion based on my data.
Not all amps and PSU caps are created equal, but the Yamaha B-2 PSU design creates an environment that exposes those caps to higher than typical temperature. The fact that some capacitors are still OK after 40+ years of use, it is a testament to their quality....but by now they are on borrowed time.

I am not sure what you mean by suspect...you need to pull them out of the board every time to inspect. When they just start to leak, they can still test OK, so if you test them still soldered to the board it is possible to miss an imminent problem.

I do plan to go through a few pulled sets and see if there are any that are in better shape than others and try to reform them for possible non-vfet use.
 
Hi Guys!
Would appreciate if you fine folks could point the right place for getting them internal speaker switch connectors for the B2.
On Speaker A set, all is well. The audio is pristine & awesome.

On Speaker B set, the right speaker is slightly lower on high frequency treble. I swapped my speaker sets & the result is the same. I remember on one of the threads, Patrice had shared a pic of B2 original speaker switches (transformed from oxidised to pristine state of shiny contacts) on this daredevil dude - Nashou66's thread on B2 restoration.

My question is - Should I dismantle & clean these switches & put them back or buy a set if available?

Thanks guys!
 
Hello aarmath

Buying a new one ?? I don't think that you will find any new .
To get the better result would be cleaning all these switches , this is a long process , but you will not need to buy anything if you are very carefull
 
clinic-audio said:
Hello aarmath

Buying a new one ?? I don't think that you will find any new .
To get the better result would be cleaning all these switches , this is a long process , but you will not need to buy anything if you are very carefull
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Thanks for replying Patrice, appreciate it mate.
Now, I know a chap who excels at servicing Yamaha gear BUT although hes well aware of VFETs, hes not worked on them.
Ergo, for this speaker switch cleaning process, could I lean on him for dismantling the Yamaha only till access to the switches?

Please let me know your thoughts.

Warm regards mate :-)
 
aarmath said:
Thanks for replying Patrice, appreciate it mate.
Now, I know a chap who excels at servicing Yamaha gear BUT although hes well aware of VFETs, hes not worked on them.
Ergo, for this speaker switch cleaning process, could I lean on him for dismantling the Yamaha only till access to the switches?

Please let me know your thoughts.

Warm regards mate :)
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Yamaha used Alps selector switches, customized for this application. That said, the selector assembly can be serviced by someone that has done work on pots and switches of Japanese equipment. Make sure he does not use abrasive materials to clean the contacts.
 
rottalpha said:
Yamaha used Alps selector switches, customized for this application. That said, the selector assembly can be serviced by someone that has done work on pots and switches of Japanese equipment. Make sure he does not use abrasive materials to clean the contacts.
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Thanks a ton RottAlpha!
I will keep this in mind and ask the chap on this. He's a straightforward guy & will only acquiesce if he can do it. When you say to not use abrasive materials, I can use denaturated alcohol, yes?

Warm Regards,
Aaron
 
aarmath said:
Thanks a ton RottAlpha!
I will keep this in mind and ask the chap on this. He's a straightforward guy & will only acquiesce if he can do it. When you say to not use abrasive materials, I can use denaturated alcohol, yes?

Warm Regards,
Aaron
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no problem with alcohol, just don't use sandpaper or something similar or you will destroy the silver plating on those contacts.
 
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