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Yamaha B-3 V-fet restoration

Vint Age said:
What speakers you're driving with your B-3's? If they spend a lot of time working below 4 ohms I'm thinking the B-3 won't be happy ...
Click to expand...
Aloha
Thank you guys for assistance and well good to know Mr.Oilmaster is one of the V-Fet Experts here in AK i will contact him asap as it says he is living in the Netherlands which is close to Hamburg so no problems
Well always use 8ohm JBL speakers with the B-3s never use other load all my speakers are 8ohm except the JBL L-90 which never use with B-3
Ok stay safe and enjoy the weekend I'll keep you informed about how it continues
Cheers
:beerchug:
 
Thanks for the kind words and likes gents, but I am in the middle of changing job and housing, the entire electronics workshop and parts packed up in a storage facility. No time for the next half year :(.
 
rottalpha said:
Obviously not a Sansui connoisseur...so thanks for the education. I was actually thinking of SANSUI AU-07 Anniversary, when I was referring to 907ltd and BJTs ...need to get up on my Sansui game :)

I like that old school sound ;) How is the 2102 comparing to 2103 and 2105?

I am sure the OP does not mind a minor Sansui spicing to the Yamaha conversation :D
Click to expand...
I been eying all those Sansui eye candy for years. And has never been the right time...
One day soon. I like the looks of AU-9500 :) As for the sound have yet to properly experience them in my setup but from what I hear bass is great. on the tweeter side V-fet rule :rockon:
 
Aloha
good News Heinz the old Mastertechnician found the protection mode problem with the spare Yamaha B-3
Its was the ground wire from the inside RCA connector plug
In disassembled status when testing protection switch release so all ok
Assembled status didnt release as discribed before
The conector plugs with the ground wire was defective so it was actually easy solve problem after find out whats wrong
Heinz couldn't find a spare part so he told he soldering the connection and all works fine im very happy about the spare B-3 is fully in action now and its time to enjoy the Music in Btl Modus
Thanks all V-Fet Aficionados give a hand to solve the problem
Cheers
:beerchug:
16021062255116749363350335040600.jpg

The plug with cable on the right the one with lousy connection :naughty:
16021134670096461775086984000948.jpg
Disassembled the plug myself and thinking about how easy it is to refit the plug and connectors but this things take time so Heinz decided to cut of the weir and soldering well i call it the freelance way to solve this tiny problem cause already he invested 4-8hr work into find out the major problem for the unreleased protector switch well today i was Short I in time to talk with him about the case and show him the disassembled plug
Know this typ of Job eats workforce cleaning 40 years old plug, connectors and switches etc. In nowertimes its actually unpayable here in Germany
Good thing is Heinz,s workshop is just 2,5km away from my house
Cheers and good night
:beerchug:
 
Last edited:
Wally1955 said:
Aloha
good News Heinz the old Mastertechnician found the protection mode problem with the spare Yamaha B-3
Its was the ground wire from the inside RCA connector plug
In disassembled status when testing protection switch release so all ok
Assembled status didnt release as discribed before
The conector plugs with the ground wire was defective so it was actually easy solve problem after find out whats wrong
Heinz couldn't find a spare part so he told he soldering the connection and all works fine im very happy about the spare B-3 is fully in action now and its time to enjoy the Music in Btl Modus
Thanks all V-Fet Aficionados give a hand to solve the problem
Cheers
:beerchug:
View attachment 2000786

The plug with cable on the right the one with lousy connection :naughty:
View attachment 2000906
Disassembled the plug myself and thinking about how easy it is to refit the plug and connectors but this things take time so Heinz decided to cut of the weir and soldering well i call it the freelance way to solve this tiny problem cause already he invested 4-8hr work into find out the major problem for the unreleased protector switch well today i was Short I in time to talk with him about the case and show him the disassembled plug
Know this typ of Job eats workforce cleaning 40 years old plug, connectors and switches etc. In nowertimes its actually unpayable here in Germany
Good thing is Heinz,s workshop is just 2,5km away from my house
Cheers and good night
:beerchug:
Click to expand...


did you look at my prior post on reccomandations for the B-3...look at the first line item ;)

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
these are a few things that come to my mind:
  • look for a viable solution for the wire to board connectors. Original ones are a disaster waiting to happen
  • I would replace all zeners
  • I would replace all resistors in the PSU with metal film low noise, low PPM
  • All caps in the PSU replace with long life, 105deg panny or similar...not audio caps. When applicable, use low inductance ...( I think the light green one is supposed to be a specific type...I suspect low Z) Unfortunately Yamaha calls out the capacitor series rather than low Z or something relevant to the characteristics of the capacitor and not the series and MFG. I could not find the datasheet for those caps.
  • no need to change the dual-diodes in the Yamahas....replace only if paranoia kicks in
  • rectifier(s): soft recovery might make a difference...the fast switching part in a low frequency application will not make a difference, yes, snub with PP
  • possibly main caps (tested mine and are border line)
  • coupling caps.....replace with something more appropriate (e,g, Mundorf, Jensen, etc)
  • cleaning of the rear switches and the step attenuators if necessary
  • replace the relay driver if you did not do it already
I am sure I am missing a few things but this is a good start.

good luck!

edit:
  • replace the trim pots if you did not do it already
  • check your fusible resistors and make sure they have not drifted
 
rottalpha said:
did you look at my prior post on reccomandations for the B-3...look at the first line item ;)

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
these are a few things that come to my mind:
  • look for a viable solution for the wire to board connectors. Original ones are a disaster waiting to happen
  • I would replace all zeners
  • I would replace all resistors in the PSU with metal film low noise, low PPM
  • All caps in the PSU replace with long life, 105deg panny or similar...not audio caps. When applicable, use low inductance ...( I think the light green one is supposed to be a specific type...I suspect low Z) Unfortunately Yamaha calls out the capacitor series rather than low Z or something relevant to the characteristics of the capacitor and not the series and MFG. I could not find the datasheet for those caps.
  • no need to change the dual-diodes in the Yamahas....replace only if paranoia kicks in
  • rectifier(s): soft recovery might make a difference...the fast switching part in a low frequency application will not make a difference, yes, snub with PP
  • possibly main caps (tested mine and are border line)
  • coupling caps.....replace with something more appropriate (e,g, Mundorf, Jensen, etc)
  • cleaning of the rear switches and the step attenuators if necessary
  • replace the relay driver if you did not do it already
I am sure I am missing a few things but this is a good start.

good luck!

edit:
  • replace the trim pots if you did not do it already
  • check your fusible resistors and make sure they have not drifted
Click to expand...
All very true Rottalpha but what can i do if Heinz not reading your post i told him to read the AK Expert V-fet Forum
Mostly ppl not following the rules
Thank you Rottalpha anyways
 
Wally1955 said:
All very true Rottalpha but what can i do if Heinz not reading your post i told him to read the AK Expert V-fet Forum
Mostly ppl not following the rules
Thank you Rottalpha anyways
Click to expand...
By the way all the B-3 working fine now and hope it will last
Time to enjoy and relax
Cheers :beerchug:

IMG_20200902_101224.jpg
Very good results paired with Sony TAE-8450
IMG_20201114_214813.jpg
 
hmm shall we replace the custom made capacitor ?

And does anyone know the rating of the transformer ? I want to convert it from 110v to 220v
 
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