Technics SU-V50 schematics wanted

[ZuMbAiU]

Hi guys.Now I have one Technics SU-V50 amplifier-Class Aa:

An externally hosted image should be here but it was not working when we last tested it.

I havent the Power Supply for this amp in the case and any simple parts.I want to restore this amp.The case and the PCB are like new, but I can`t find any schematics with Mr.Google.I know that I`am too snoopy in my last posts but this amp is honoured to be working for me.
Thanks

 

[ZuMbAiU]

Guys ,I can`t find any info for this amp.I have a dead PS without any info,working preamp,corrections,but the chip for the amp is missing.
I must find any schematics or info ,because I think that I can use it with any DIY amp.

I know that this model have any Technics analogous models.I can work and with the schematics for any other.

 

[Mayank]

Zumbaiu:

Go to Schematics For Free site:

http://www.schematicsforfree.com/archive/dir/Audio/Products/Amplifiers-Integrated

I saw three Technics amplifiers listed there which are from the same SU-V series as the one for your amplifier - SU-V2 (older), SU-662 and SU-V620 (newer).

Perhaps these would help you in your quest.

Good Luck
Mayank

 

[ZuMbAiU]

Mayank thanks for the link,but the archives are damaged-I can`t extract this files
If anyone can help me will be great.I want only any Info for the PS,how I can use the correction,Ins and the pre-amp with any other diy amp.
May be anyone can help with any info for this amp or no?For me this amp with this case like new isn`t dead

 

[Leolabs]

try this Japanese site: http://amp8.com/index.htm

 

[ZuMbAiU]

Thanks Leolabs!
Now will be great if anyone can understand this beautiful Japanese site,because I can`t find any Technics model here.

 

[Leolabs]

Click on the link below"NEC".

 

[ZuMbAiU]

Leolabs on the main page I can`t find any link for NEC.On the list amp page I find Onkyo below NEC.Where is this link

 

[Leolabs]

then try this http://amp8.com/tr-amp/amp/amp.htm

 

[Ian Finch]

Mighty Old Thread but a mighty old request too:
Well, I've followed a few dead end leads on similar era Super AA Technics amps and none posted seem to bear any similarity in engineering to the SUV50.

Unlike many others in the SUV super AA class series amps, this is a standard 2.5 U domestic 50 Watter model with a 1-board budget construction and apparently Darlington output stage modules. Heat pipes are an interesting feature too.

If you do have schematic access please post or PM me also for an Email address.
I would be sincerely grateful as this little feller is an interesting performer with imaging particularly. It's a shame to have it no longer operating properly.
Should you have the inclination, comments would be welcome too.

 

[east electronics]

i got suv 40 and suv 60 if this is any help to you ... e mail me if you like to have them

 

[Ian Finch]

Thank you once again, Sakis.
It is helpful guys like you that make this Forum absolutely the best.

 

[poolz50]

Sorry to bump a old thread but...

I am also trying to repair a SU-V50 AA amp.

A house move drop mean all the connectors on the back got snapped off. I replaced this with some new studs in a new mounting plate but now it won't engage, there is no click. I am worried I have turned it on without a load over the speaker connectors whilst making this repair.

So - did anyone get the complete schematics?

Would really appreciate them if so.

Best wishes

Dan

 

[Ian Finch]

So - did anyone get the complete schematics?

Well, I didn't but solid state amplifiers don't need a load to keep them stable - that's a bit of advice for the "toobs" fans.

As you're having a problem, are you sure you didn't actually short the connectors and try to use it in that condition? Unfortunately, this is not an easy design or series of designs to understand, let alone troubleshoot so don't hold your breath in hope of a simple 1-2-3 step fix unless you have simply gotten the output rewiring mixed up.

Note that there is an auto-sensing 4/8 ohm load switching controller involved in the SUV50 and that must be working correctly (IIRC) to enable correct power-up. The power-up delay is not the usual output relay though, its a delay on applying power to the current dumping amplifiers - after and only if the class A amplifier is stabilized. If that is not occurring, you may have caused more serious problems and this could be beyond the abilities and parts resources of most DIYs.

This is not a class AB amp. It's a close cousin of class S or Aubrey Sandman's feed-forward error correcting design from around 1979, hence the somewhat complex and delicate arrangement to get stable class A operation before connecting the class B power amplifiers. Quad 405,306,606 etc series of amplifiers have a similar basic operating principle but Technics' is a much more sophisticated and complex approach - later versions were simplified by using proprietary ICs and power modules - mostly unobtanium now.

 

[poolz50]

Well, I didn't but solid state amplifiers don't need a load to keep them stable - that's a bit of advice for the "toobs" fans.

As you're having a problem, are you sure you didn't actually short the connectors and try to use it in that condition? Unfortunately, this is not an easy design or series of designs to understand, let alone troubleshoot so don't hold your breath in hope of a simple 1-2-3 step fix unless you have simply gotten the output rewiring mixed up.

Note that there is an auto-sensing 4/8 ohm load switching controller involved in the SUV50 and that must be working correctly (IIRC) to enable correct power-up. The power-up delay is not the usual output relay though, its a delay on applying power to the current dumping amplifiers - after and only if the class A amplifier is stabilized. If that is not occurring, you may have caused more serious problems and this could be beyond the abilities and parts resources of most DIYs.

This is not a class AB amp. It's a close cousin of class S or Aubrey Sandman's feed-forward error correcting design from around 1979, hence the somewhat complex and delicate arrangement to get stable class A operation before connecting the class B power amplifiers. Quad 405,306,606 etc series of amplifiers have a similar basic operating principle but Technics' is a much more sophisticated and complex approach - later versions were simplified by using proprietary ICs and power modules - mostly unobtanium now.

Hi Ian,

Thanks for the reply. I am pretty sure I did not make any mistakes like wrong re-wiring. In reality the de-bugging was a little more complex. The system worked for a while, then stopped. I opened it up and noticed that it jumped back to life when wiggling one of the components. That turned out to be a brittle solder bond, a repair of which bought it back to life again.

Then, for ages it kept dropping a channel. It was strange as it seemed to change which channel it was dropping, even if I switched to the remote ring.

All in all I got a bit annoyed and shelved it until now. I want to have one last attempt but now it wont even click on at all!

I don't suppose you have a couple of obvious voltage checks I could do. I saw in another thread you (I think) recommended checking certain pins.

I appreciate you don't want to get involved in a complex remote-fix so I understand if not.

all the best

dan

 

[poolz50]

Dear Ian,

After some investigation it appears the current drive LED comes on ( I assume its happy) but the relay fails to click. a light tap on it makes it click and the unit comes back on! So - I think the relay is past its best.

The next problem to solve is that the RHS channel is dead. That could be my wiring for sure- I don't think the relay controls the channels independently.

For you - I found the service manual, which is in my drop box:

https://www.dropbox.com/sh/eoglkw2ao4x4i2y/AADlNiZvdTZlbLpKq0BmW9hLa?dl=0


Thanks

Dan