Picked up a Sansui 7000

I have the quick start for my 2000A it is actually a laminated large sheet. Larger than 11x17. I think I scanned it at work and uploaded it. I'm sure the 7000 is different however.
 
All the information in the "quick start" card is also in the owner's manual.

- Pete
 
So some bad news I guess... The honeymoon was short lived.

Yesterday the 7000 started acting up. I had it cranking pretty good. It started to get crackly and then quiet. Turned it off and let it sit for a bit. Then it worked fine.

Today have been listening to it for a couple hours at mild to moderate volume and now same problem. The volume is reduced, although no loss of frequency range but with intermittent mild crackling. The volume will rise back up and fluctuate around with some crackling. I've already deoxit-ed all of the knobs. What are the chances it needs it again or am I looking at a component problem?

BTW, this happens in all modes, FM, AM, Aux, etc. Same to left and right channels. When I turn the power off, sound lingers for a few seconds, which I think is normal for a relay-less unit. When its really cranky it'll offer a loud crackle.
 
So some bad news I guess... The honeymoon was short lived.

Yesterday the 7000 started acting up. I had it cranking pretty good. It started to get crackly and then quiet. Turned it off and let it sit for a bit. Then it worked fine.

Today have been listening to it for a couple hours at mild to moderate volume and now same problem. The volume is reduced, although no loss of frequency range but with intermittent mild crackling. The volume will rise back up and fluctuate around with some crackling. I've already deoxit-ed all of the knobs. What are the chances it needs it again or am I looking at a component problem?

BTW, this happens in all modes, FM, AM, Aux, etc. Same to left and right channels. When I turn the power off, sound lingers for a few seconds, which I think is normal for a relay-less unit. When its really cranky it'll offer a loud crackle.

Racer2086, did you ever get anywhere with diagnosing the problem? I just picked up one of these myself.

DW
 
image.jpeg I really enjoyed my Sansui 7000 which I received for free. I had a tech go through it and clean and lube everything and sounded great for 6 months. One day the left channel went quiet. Mine was the same tons of warm sounding power. I was thinking of selling it and let some else repair it but decided to hold on to it and have it restored in the next few years.
 
AKDATABASE................ www.akdatabase.org/AKVIEW .........type it as written or you won't get in.

Check the parts list and the board schematics for 2sc458's on any board. They should all be replaced. These can cause the channel drop out's when they heat up and when cool down be ok. At least for a while until they say "F it, I QUIT!" Then it's permanent until you replace them with ksc1845's.
 
Racer2086, did you ever get anywhere with diagnosing the problem? I just picked up one of these myself.

DW

I've been so darn busy didn't even look into it. Not to mention it has never happened again. So it's not a hugely pressing issue. Unit sounds great with tons of power.

Thanks for the post above about the transistors. Great info there.
 
Just wanted to update this thread (what a year and a half later?). I have replaced all the bulbs and restored the wood case. I used my preferred method of restoration on the wood, which I've used on a number of real wood speakers and I think it turned out great. Clean with Murphy's Oil Soap, rub Watco rejuvenating oil on with #0000 steel wool, let soak according to instructions and wipe excess, then after 72hrs finish with Howard Feed n Wax. Here are some pics:

20180415_190834.jpg 20180415_190840.jpg 20180415_190904.jpg

As good as it looks now, it still has issues with both channels crackling and sometimes going way down in volume. I was driving it yesterday and everything was great for the first 10-15 minutes. Then it started intermittently getting static in both channels.

Racer2086, did you ever get anywhere with diagnosing the problem? I just picked up one of these myself.

DW

No I didn't, but someone on here mentioned replacing known bad transistors, which may be a good start. I'm thinking of hitting the volume control once more with deoxit, in case that is simply the problem. But if I can remember right, it wasn't easy to get to it...
 
Don't know if it will help you, but I'm in the midst of repairing and restoring two Sansui solid state 7000 units right now in this thread: http://www.audiokarma.org/forums/in...d-state-7000-repair-recap-and-restore.807427/

I'll review my BOM tonight and point out any "known to go noisy or bad" transistors. I don't recall any off the top of head and I'll check the real spreadsheet tonight.

There are plenty of electrolytic caps in the 7000 and it has capacitor-coupled output, so that's an area to consider, too.
 
someone on here mentioned replacing known bad transistors, which may be a good start.

Looking at my list (could be incomplete) of transistors in the Sansui solid state 7000:

Driver (two of them) TR801 2SC711 (E or F)
Driver (two of them) TR802 2SC817R (F)
Driver (two of them) TR803 2SC627 (3)
Driver (two of them) TR804 2SC984 C
Driver (two of them) TR805 2SC680 (B)
Driver (two of them) TR806 2SA566 (B)
On bridge 2SC627
(outputs) TR807-TR810 2SC1116 (R, O or Y)
Power and Protection Block TR010,TR011 2SD223 (O, Y, G)
Power and Protection Block TR901,TR902 2SC711 (E, F)
Power and Protection Block TR903 2SA628 (E, F)
Tone board TR020 2SD223
Tone board TR501-TR504,TR601,TR602,TR605,TR606,TR701,TR702,TR703,TR704,TR705,TR706,TR707,TR708 2SC871
Tone board TR603,TR604 XA 495C


the only one that stands out as a "known to go bad" or "known to start producing noise" are the sixteen 2SC871 transistors on the tone board. You can replace those with KSC1845F or BC550C. You may also need to check which tone board you have. There are more than one version of the tone board in the Sansui 7000 as per this thread: http://www.audiokarma.org/forums/index.php?threads/sansui-7000-a-tale-of-two-bothers.369638/
 
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Oh my so much good info. Thank you. I also bookmarked the two links.

whoa! Just looked at the first page of your restoration thread. Wow can't wait to read through that after work. Also the tone board thread is great. I think I have the larger board, but will have to double check.

I'm the guy that likes leaving things original if they are working good. I know plenty would disagree with that due to the improvement in sound from new components, but there are a ton of components in there that I would rather not have to replace. I may start with the transistors on the tone board and hopefully that will do it because this thing sounds pretty good as it is, minus the crackle.
 
I'm the guy that likes leaving things original if they are working good. I know plenty would disagree with that due to the improvement in sound from new components, but there are a ton of components in there that I would rather not have to replace. I may start with the transistors on the tone board and hopefully that will do it because this thing sounds pretty good as it is, minus the crackle.

Totally understand. Everyone has to do what they are comfortable with or their own version of what is best.

In the BOM parts lists I share you'll see a "recap-only" list and an "everything" list. Happy to help people reduce their research workload regardless of how they want to approach their own gear.
 
[QUOTE = "dlucy, post: 11529055, member: 159882"] Не знаю, поможет ли это вам, но я сейчас нахожусь в процессе восстановления и восстановления двух твердотельных модулей Sansui 7000 прямо сейчас в этой теме: http: //www.audiokarma.org/forums/index.php?threads/sansui-solid-state-7000-repair-recap-and-restore.807427/

Сегодня вечером я проверю свою спецификацию и укажу на любые «известные как шумные или плохие» транзисторы. Я не припоминаю ничего из головы, и сегодня вечером проверю настоящую электронную таблицу.

В 7000 есть много электролитических колпачков, и у него есть конденсаторный выход, так что это тоже область, которую нужно учитывать. [/ QUOTE]
You have golden hands!
 
I am wondering if this is the right place to ask and if anyone can help me diagnose a problem with a Sansui 7000.

The problem - Right channel doesn't play at all. Left channel sounds crappy. If I go straight into the Main inputs using a pre-amp from something else, Both channels work and sound great! So I started debugging what could be the problem. From what I can tell, the issue has to lie in the Tone/Pre-Amp board "1316". I tested with a transistor tester all of the transistors on the board ( yes still on the board, but just trying to find the problem) and all test out as NPN devices. I did not pay particular attention to any of the gain etc. information. There was one that came up with a strange Diagram, maybe a Darlington transistor. I tested all of the larger Dielectric Caps (yes still on board) and they were within some reasonable comparison to their stated values.

I also noticed that one of the diagrams on the Service Manual had Voltages listed, so I checked them, and they were all over the place. Many were not even close!

I checked all of the Variable Resistors (POTS) for the Bass, Treble, Volume, Balance, and everything was within range.

Question - Am I barking up the wrong tree? Could the problem lie elsewhere? The sound does not change (Right channel gone) no matter what selection I choose (Aux, FM, AM, etc..) nor does it change with any button pressed.

Sorry for the long post. and possibly wrong location to post...

I have an order ready to purchase new Transistors and Caps (thanks to Doug's information and the Service Manuals), but I would like to have a culprit in hand before going forward and replacing parts.

Thanks in advance... Andy = Newbie, Luker, and relatively inexperienced guy...
 
It's probably best you start a new thread rather than tacking onto this old one. The first place always to start is to clean all the controls. Almost any of the knobs, buttons and switches on the front panel can cause the symptoms you describe if they are dirty. Your 7000 will be 50 years old next year so odds are the controls are dirty.

- Pete
 
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