Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Rebuild - Marantz, Sansui, Technics
Rebuild - Marantz, Sansui, Technics
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 6th February 2019, 01:36 AM   #1
thisandthat is offline thisandthat
diyAudio Member
 
Join Date: Feb 2019
Default Rebuild - Marantz, Sansui, Technics

I've got a
Marantz 2216
Sansui 7070
Technics SU-8088

I've used them all at one point in my life.

Like to bring one back to life. All of them sort of work, one channel, or some crackling, to similar degrees.

Any advice on which one is the best quality (worth while doing), easiest? Or any other factors.

Thanks

Jon
  Reply With Quote
Old 6th February 2019, 02:22 AM   #2
Sqeek is offline Sqeek  United States
diyAudio Member
 
Join Date: Nov 2018
Location: Decatur Il
HI thisandthat i would suggest the one that you can get the best schematics/service manual on first or the one with the least issues describe what equipment and experience you might have and explain what each one is doing in detail.
  Reply With Quote
Old 6th February 2019, 04:57 PM   #3
thisandthat is offline thisandthat
diyAudio Member
 
Join Date: Feb 2019
Seems like there is pretty good info on all of them

Marantz is quiet on one channel and crackly
Sansui is dead on one channel
Technics is crackly on one channel

I think cleaning the switches etc will go a long way.

I've got an ok set of tools, to work with
  Reply With Quote
Old 9th February 2019, 11:43 PM   #4
thisandthat is offline thisandthat
diyAudio Member
 
Join Date: Feb 2019
I'm going to go with the Marantz.

I thought it was the balance control, but after some testing, I don't believe it is.

Sound is pretty good (quality), but one channel is probably 25% as much power.

I think its oscilloscope time.
  Reply With Quote
Old 10th February 2019, 10:34 PM   #5
mjona is offline mjona  New Zealand
diyAudio Member
 
Join Date: Jul 2007
Location: Upper Hutt
Quote:
Originally Posted by thisandthat View Post
I'm going to go with the Marantz.

I thought it was the balance control, but after some testing, I don't believe it is.

Sound is pretty good (quality), but one channel is probably 25% as much power.

I think its oscilloscope time.
With ageing of equipment solder joints can deteriorate and you might have more resistance between circuit points. If this has happened in the feedback loop RC decoupling arm to earth the closed loop gain could be below par.

While you are on the job you should consider replacing the old RC decoupling capacitor. Quite possibly there will be others too - if some look suspect and you decide to replace them do that progressively one or two at a time - that will avoid having to work backwards to find out where if any problem arises after a full scale replacement in one step exercise.

You should not need to replace any transistors or resistors.
  Reply With Quote
Old 11th February 2019, 06:54 PM   #6
Sqeek is offline Sqeek  United States
diyAudio Member
 
Join Date: Nov 2018
Location: Decatur Il
thisandthat good luck with the cleaning i hope it is that simple of a fix
  Reply With Quote
Old 11th February 2019, 07:15 PM   #7
indianajo is offline indianajo  United States
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
I repair amps and radios without a scope. A DVM for DC voltages, and an AC analog voltmeter with 20 vac and 2 vac scales for tracing music suffices. One has to put a capacitor in series with the negative probe to keep the needle from responding to DC signals. I use a .047 uf usually. This $27 one looks useful with a 10 vac and 50 vac scales: KT8260L high accuracy analog multimeter with backlight function transistor check | eBay
No experience with that brand. I've also seen similar items in the hardware store. I have a simpson 266XLPM analog multimeter from about 1987.
You can trace music through the signal path and see where it gets unbalanced. Input coupler, source switch, volume pot, internal connector? DC power supplies off balance? Oxidized connectors, pots, switches, and dried up electrolytic caps are the usual suspects for channel imbalance.
Some pamona grabber clips are useful for getting in right on the lead of a component without shorthing things together and blowing them. Use a lot of light and possibly reading glasses if you are as old as this equipment. I have 1,2 and 3 diopters for different distances. The +3 diopters allow me to read the markings on tiny parts.
I use a pocket FM radio to produce the signal for test. Don't use a $600 cellphone, accidents can blow it up. If you tune to a rock station, the beats of the music about 3 per second show you are seeing music, not an ultrasonic oscillation. BTW you can check the frequency of a signal with the blocking cap. A signal that passes through a 390 pf cap is RF or ultrasonic, anyway. Music goes through .047 uf.
I just finished a PV-4c PA amp I bought for $48 including freight. About 10 hours and about $38 in parts. Sounds great. Goes on my TV to replace the plastic sounding Samsung flat screen audio. No $190 "sound bar" with the miracle 3" woofer for me. My Peavey 1210 speakers have dual 10" woofers.
Good Hunting.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300

Last edited by indianajo; 11th February 2019 at 07:29 PM.
  Reply With Quote

Reply


Rebuild - Marantz, Sansui, TechnicsHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Technics SP-25 rebuild JimM Analogue Source 2 16th June 2017 01:49 PM
Sansui AU-101 Rebuild: Help needed ahankinson Solid State 4 19th December 2015 01:01 PM
My first Sansui AU-111 Rebuild Bugsi Tubes / Valves 4 22nd November 2014 01:16 PM
Sansui AU-111 rebuild and need some help coolmaster Tubes / Valves 8 7th January 2013 11:31 AM
Marantz 510 - Rebuild? LHMAudio Solid State 8 22nd May 2007 03:23 PM


New To Site? Need Help?

All times are GMT. The time now is 11:31 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki