Technics SA-206 stereo receiver from 1982

[Porque223]

Anybody have a link to a schematic? The Web is leading me on a wild goose chase.

The output intermittently disappears but the signal strength meter says the RF works.
If the problem is in the huge hybrid IC output stage this thing is probably not getting fixed.
But, since both channels go it might still be a power supply problem.

We just use it to boost the treble range from the TV sound so speech doesn't sound so indistinct.

I have a much better set with schematics in the basement but the left channel sound on that one gets ratty after a half hour. Spending more time chasing that problem might now be the thing to do.

 

[ChrisFrost]

Out of idle curiosity I found a manual for that receiver. Took about 30 seconds. It wasn't difficult It's 24 bucks. Here's a
link Yep, someone actually went to the trouble of preserving or reproducing a real paper manual. Pretty impressive for a 30+ year old product. More impressive still when you consider that the service department of an electrical retailer will have been given only one copy, so it's not like these things were in wide supply.

Having played this game too many times in the past to recount, the conversation goes something like this...

"What's that? You found that too. But you don't want to pay $24.... Why, is the equipment not worth that to you?"

"Oh, you think you should be able to download it for free.... because it's the internet. Yeah, well good luck with that."

"Tell you what, seeing as you don't seem to value the work involved in supporting your old receiver then why don't you buy a copy, scan it in high res, assemble a pdf version, then host it on the web for others to download free."

"What's that you say? It's a lot of work... and you'd be $24 out of pocket.... well Duh! So why do you think you're entitled to it for free?"


Time for a pragmatic approach: Old Technics + hours spent trawling the web + parts + vague bits of advice on repairing it + no guarantee of success for what would sell on Ebay in working condition for $20 if you're lucky... versus.... An hour with Craig's list/Ebay + $30~$50 for something far more modern that actually works.

If you're going to spend hours resurrecting something from the grave then make sure it's actually worth it.

 

[Porque223]

Out of idle curiosity I found a manual for that receiver. Took about 30 seconds. It wasn't difficult It's 24 bucks. Here's a
link Yep, someone actually went to the trouble of preserving or reproducing a real paper manual. Pretty impressive for a 30+ year old product. More impressive still when you consider that the service department of an electrical retailer will have been given only one copy, so it's not like these things were in wide supply.

Having played this game too many times in the past to recount, the conversation goes something like this...

"What's that? You found that too. But you don't want to pay $24.... Why, is the equipment not worth that to you?"

"Oh, you think you should be able to download it for free.... because it's the internet. Yeah, well good luck with that."

"Tell you what, seeing as you don't seem to value the work involved in supporting your old receiver then why don't you buy a copy, scan it in high res, assemble a pdf version, then host it on the web for others to download free."

"What's that you say? It's a lot of work... and you'd be $24 out of pocket.... well Duh! So why do you think you're entitled to it for free?"


Time for a pragmatic approach: Old Technics + hours spent trawling the web + parts + vague bits of advice on repairing it + no guarantee of success for what would sell on Ebay in working condition for $20 if you're lucky... versus.... An hour with Craig's list/Ebay + $30~$50 for something far more modern that actually works.

If you're going to spend hours resurrecting something from the grave then make sure it's actually worth it.

I hope I don't get sucked into that outcome.
Having bought this book
http://www.amazon.com/Making-Decisions-Edition-Dennis-Lindley/dp/0471908088
from one of your guys, I should be able to crank out a decision tree with likelihoods, plug in my utility function and pop up with a numerical answer on the way forward but that may take me longer than getting one of these receivers to work (I have about a week before something needs to be making audio with boosted treble).

Maybe I should start work on my backup circuit, three resistors summing both TV sound channels into the working side of the better receiver.

BTW, I found a suitable amp for $18 but it runs on 12vdc, 3A, which supply I don't have.

Maybe the real question I should ask myself is if I'd want to do this work even if someone paid me not to resurrect these pieces of history. My wife might pay me a substantial sum to trash these things and clear space in the basement so I'm not going to ask her.

 

[ChrisFrost]

I think you're making a simple situation in to something very very complicated.

 

[dhutch]

I think you're making a simple situation in to something very very complicated.

Indeed

 

[Porque223]

Part of that happens because I'm a cheapskate.

 

[ChrisFrost]

There's nothing wrong with being frugal. But there comes a point when it's just not worth the cost, or the time, or the uncertainty of embarking on a rescue mission like this. The rest of us don't need a book or decision tree or any of that rubbish to recognise that, for this amp, that time is now.

As for the amp that requires a 12v power supply..... are you mad? I spent a few minutes looking through Craig's list. I chose L.A. as a random selection. On the first page of Receivers came up with half a dozen between $25 and $50 that would suit your needs.

There's undoubtedly something nice about the build of some vintage gear; the weight of the switches and dials is kind of reassuring. However, inside you have components that don't stand the test of time quite as well. Capacitors is a major one. They dry out and go faulty. Replacing two large Rubicons can cost you $50+ with no guarantee that something else in the chain isn't going to fall over after.

Sell the faulty amps on Ebay as spares or repairs. Recoup some money. Buy something that works and forget silly ideas of 12v amps.

 

[daxi]

BTW, I found a suitable amp for $18 but it runs on 12vdc, 3A, which supply I don't have.

Take a look at CB power supplies on ebay, a decent secondhand 3amp power supply is only a few $'s. The newer CB power supplies are often noisy & less well built, than the old ones.

 

[Porque223]

I've gotten two more-or-less independent suggestions to use contact cleaner for this device.
This symptom doesn't fit with my experience as to dirty pots
but
I don't fix radios for a living and it's quick and it's cheap and can possibly save me hours.

In any case, I'll take voltage readings on that huge SIP IC, for the next time.

Thanks, folks. . .

BTW, it worked and I am going out and get drunk!

 

[ericmark]

I still have a 13.2 volt power supply my son made years ago using a 16 volt Gents alarm transformer and a voltage regulator chip which used an old spring to measure the current to operate the fold back shutting the supply down if there was an overload.

About 12 inches square and 24 inches long to get rid of the heat and after all that supplies 5A.

I look at a laptop power supply which will give same output and just 8 x 2 x 1 inch in size. However connect to a single side band transmitter and my sons old PSU works far better.

But I look at my old Brother MFC-465CN printer, fax, scanner and realise likely just one component has failed the device which measures ambulant temperature and did do a quick look for info as to where it is situated but failed to easy find the info and really not worth the time and effort to reverse engineer to find it. Forked out £80 on new printer. Lost fax capability but not used that 19th century invention in years.

It would seem we now live where repair is a thing of the past. But in the days of valves they would maybe last a couple of years before failing and to change was to simply un-plug and insert a new one. Today although IC holders are made in the main it's solder suckers and with surface mount even they are not good enough.

With old stuff even when you locate the fault getting the replacement part is a problem. Years ago every TV shop stocked parts, slowly they went leaving Tandy (Radio Shack) as the only outlet. Then this was replaced with Maplin. Yes Fanell and Radio Spares still trade but not on the high street.

Don't know what it is like in US but in UK DIY electronics is not easy. Hong Kong when I lived there was great everything you could want all in one street but UK I would need to travel at least 50 miles to get anything.

I once a year visit the local radio rally and one has to stock up with all you need for the year.

Last time I changed a valve was 1990 it was a 27MHz RF welding machine using 7kW I was temped to try using one for a CB amp but never did. Air cooled with Aluminium case not the glass we think of.

But I am afraid I would cheat. I did it with one old ladies radio. I grafted a transistor radio into the old chassis and told her I had used new type valves and she needed a 9v battery now not a 64 volt one. She stopped me in street latter to sing the praises of the old valves much better than new transistors and said how she had not had to charge the accumulator once since we repaired it. Temped but never told her.

So think it's time for the bin/trash and buy new!

 

[Sam Gangee]

one component has failed the device which measures ambulant temperature

I get hot when walking. Maybe I need one of those devices.

ambulant |ˌambjʊl(&#601nt|
adjective Medicine
(of a patient) able to walk around; not confined to bed.
• (of treatment) not confining a patient to bed.
ORIGIN early 17th cent.: from Latin ambulant- ‘walking,’ from ambulare.

 

[Porque223]

I get hot when walking. /quote]
It's the women you see while walking.

 

[plugwash]

Don't know what it is like in US but in UK DIY electronics is not easy. Hong Kong when I lived there was great everything you could want all in one street but UK I would need to travel at least 50 miles to get anything.

Though recently CPC have started offering free delivery no matter how small the order. So if you want a couple of reasonablly common components you can get them (usually next day) without paying through the nose.

 

[ChrisFrost]

This is only my opinion based on my personal experiences and observations but I don't think access to parts is the problem. Yes, those useful little shops that stocked electrical parts have disappeared. But then again the range of components has increased; so would a little family-run repair business stock a similarly wide range. Probably not. However, the nature of retail is changing so Ebay and mail order is becoming easier and filling that gap.

What I see as more of an issue is the skills gap. There's a lot of information on the web that encourages people to have a go. Yet many don't posses even basic skills such as soldering. There's almost an "app" expectation that repairing something is as simple as a couple of clicks of the remote or changing a fuse. The idea that one has to learn a skill seems an alien concept. I think this also extends to an expectation that all answers are on the web and that all information is free.

 

[Sam Gangee]

You are correct, in my case. I do encourage people to "have a go". I suppose I simply can't conceive how ignorant some people are.