Sony TA-5650 - any techs out there in NSW?

[VinylAddict]

Hi all,

I acquired a SONY TA-5650 VFET amp about 12 months ago. According to the original owner, it was working and had been serviced by Sony at some stage in its life.

After some online research , I discovered the potential fragility of the vfets, so I have never powered it on.

Does anyone know a good tech with experience with vfets ? (preferably in Sydney but willing to travel in NSW)

cheers, Paul 

[Grizzly]

@vintagejapan would be good for advice, in Qld though I believe. Sony did have an official fix for the infamous diodes so if they arranged the service it's likely that the disastrous issue has been resolved.

[vintagejapan]

Thank you @Grizzly!

 

@VinylAddict, yes. I have time and can sort out your Sony. Message me if interested 

[VinylAddict]

Thanks @Grizzlymuch appreciated.

and yep, I’ll reach out @vintagejapan

One of my questions is how might I identify for myself if the diode fix has already been completed ?

i hope I’m not being culturally insensitive, but I assume all diodes basically look alike?

or should I be able to look at the board and identify clearly that the relevant diodes have been replaced?

[thejt]

@vintagejapan did a terrific job on my 5650. 

[Steever]

Tim at Tuned in Audio in Hornsby.

 

[Vencel]

On 01/11/2023 at 2:20 AM, VinylAddict said:

Thanks @Grizzlymuch appreciated.

and yep, I’ll reach out @vintagejapan

One of my questions is how might I identify for myself if the diode fix has already been completed ?

i hope I’m not being culturally insensitive, but I assume all diodes basically look alike?

or should I be able to look at the board and identify clearly that the relevant diodes have been replaced?

Hello,

 

I hope I am sending my answer still on time. The replacement of the diodes can be visually checked on the boards.

Original ones have dark (black) color and they must be replaced. The diodes are covered with some resin coating and with time and changing temperature the coating brakes and the diodes get short and this will ruin the VFETs.

Here you can find a good description of a restoration and you can also see these diodes and how they are being replaced on the photos: https://www.diyaudio.com/community/threads/sony-ta-5650-restoration-doc-it-breaths-life-at-last.311612/

[Vencel]

Despite of the replacement of those diodes I think it is worth getting it checked anyway by a tech person. I got all electrolytes replaced in mine and all settings have been set according to specifications.

On the other hand in mine the Sony recommended revisions/changes and the tweaks recommended by some members have not been done, but mine is playing excellently since 2 years, it doesn't get hot and very silent.

I did experience a big improvement in sound after getting the capacitors replaced, some of them were so much out of value that it was a miracle it was still playing.