Re: Technics SU-9070 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th February 2006, 07:42 PM   #1
diyAudio Member
 
Join Date: Sep 2005
Default Re: Technics SU-9070

Hello all,

I am in a bit of a pinch and was looking for some advice... I have a rack of beloved Technics equipment from the late 70's and early 80's... One of the pieces is an SU-9070 stereo preamplifier.

The volume and balance pots are trashed... Scratchy, breaking contact, etc. I've tried my best to clean them and breathe some new life into them... Unfortunately, they seem to be too far gone to actually be salvaged.

The pots are actually a gang of about 6 or so all linked together.

I'm looking for two things:

1) Does anyone have any advice on what route I should
go in order to repair this preamp?

2) Does anyone have a schematic of this piece of equipment?
I am ordering the service manual, but I'd like to start ASAP.

Thanks,
Brad
  Reply With Quote
Old 10th February 2006, 07:57 PM   #2
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
A few weeks ago I had an old Pioneer amp with very scratchy pots.
Spraying them wasnít too satisfying and the amp was very dirty inside.
I decided to give it a thorough cleaning and as our member Janneman ones suggested I put the amp (top and bottom plate off) in the dishwasher and let the machine do itís job.
After keeping it warm on the radiator for two days to make sure it was completely dry, I repaired the one broken channel and had a listen.
No scratchy pots anymore and a nice looking amp, inside and outside.
Howís that for a Diy solution while waiting for the schematic?

/Hugo
  Reply With Quote
Old 14th February 2006, 08:10 PM   #3
diyAudio Member
 
Join Date: Sep 2005
Lol that sounds like more than I am willing to do. Haha. Then again, I have tossed electronics into the bathtub and scrubbed em... Guess there isn't much of a difference between the two.

Thanks,
Brad
  Reply With Quote
Old 14th February 2006, 08:20 PM   #4
dimitri is offline dimitri  United States
diyAudio Member
 
dimitri's Avatar
 
Join Date: Oct 2002
Location: retired
Send a message via ICQ to dimitri
Quote:
I put the amp (top and bottom plate off) in the dishwasher and let the machine do itís job.
What kind of detergent did you use?
  Reply With Quote
Old 14th February 2006, 08:46 PM   #5
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
Sun 3 in 1.
Good for the sound as well.

On a more serious note, I wouldn't do that trick with cd players or gear with displays or monitors and the like.
But these old robust amps can take it with amazing results.
It's the second one I washed, the first one is playing every day for more than a year and the second one for a few weeks now.
Keep in mind that it should be completely dry before plugging in the mains, hence why I left it standing on the radiator for two days.

/Hugo
  Reply With Quote
Old 14th February 2006, 08:52 PM   #6
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Hugo,
You always did like your amps to sound clean. Arrrrgh Sorry.

This treatment would end the life of a CD unless you got very, very lucky. How was the front end alignment after you were done?

-Chris
  Reply With Quote
Old 14th February 2006, 09:00 PM   #7
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
The first was a power amp and the second one an integrated.
No receiver. But I bet the old gear front ends don't care.
I'll report next time I'll 'threat' a receiver.

/Hugo
  Reply With Quote
Old 14th February 2006, 09:05 PM   #8
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Hugo,
I was woried about the ......................... trimmer caps. You know, the water seeps in and never leaves. Then there are the IF coils on older sets. The wire is so thin it might go away by itself.

-Chris
  Reply With Quote
Old 14th February 2006, 09:13 PM   #9
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
You could be right. Unfortunately I don't have an old tuner at hand to try....wait, an old Rotel is collecting dust on one of the shelves.
But it's clean. One of these days, I'll give it a try, I like the challenge.

/Hugo
  Reply With Quote
Old 14th February 2006, 10:58 PM   #10
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Hugo,
Should be interesting. I am not going to try that one. An amp, maybe.

Cheers!
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
SU-9070 help ?? bobrown14 Solid State 5 20th August 2013 12:59 PM
Technics SU-V2X zega55 Chip Amps 5 5th January 2008 01:54 AM
Technics SL-5 pinkmouse Analogue Source 22 5th July 2006 10:59 AM
Technics SA-600 ZigDaPig Solid State 0 16th August 2005 01:33 PM
technics sl-23 ironfinger43 Analogue Source 0 29th May 2004 05:44 AM


New To Site? Need Help?

All times are GMT. The time now is 05:16 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2