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New to me "Sansui 8" -need help

M

Majoryyz

Active Member
I bought off the bay a model 8 serial number: 222C1C975 in which it has 2 problems at first glance. First is the volume on the right side is way low, even with headphones. I knew this before buying it but thought maybe the controls need a good cleaning/lub. All lights work, speaker relay is quick to click, so that's good. The second problem is the dial string slips, what can I do about that? All in all for $42 plus S/H I think the reciever is in really good shape, the wood top has a few scratches but in fine shape. I'll invest some time and cash to get this Sansui up and running. If she sounds as good as I've read about 8's she'll be a keeper.
Btw, I have read about the Saucer shaped transistors which I can see from the top, how bad are these and do I need to start to make a list on replacing these along with all the caps? I really like to first get it up and running on both channels first. Thanks for all your help.
 
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The tuner string will probably be obvious when you open it up, if not the service manual typically will show the correct routing for it.
Yes, those flying saucer transistors will require replacement, the experts can tell you all about the details.
Get the book, clean the controls, check the fuses and get back to us.
 
The string isn't broke but slips here and there. from what I can determin it's good and tight. Is there a spray to make it tackier so it won't slip?
 
Checking the 4 fuses on the bottom side, found 1 fuse bad, this one was on the bottom toward the center-2 stacked near the back the other 2 near the center. What side of the channels do these fuses cover, right channel??
 
Looking at the service manual, it shows 5A 100-127V and 3A 220-250V, what I pulled out were 2 5A-250V, one bad the rear side fuses we're a mixed set of 5A-32V and 5A-250V. Should all 4 be the same 5A-250V?
 
Noborigama said:
I'm no expert but a little wax on the tuner string may solve the problem.
Click to expand...

Noborigama is correct, but use beeswax.
Put whatever fuses in that the manual says, for V operation.
Does the string look black at the flywheel shaft where it's probably slipping?
If so somebody may have spilled oil on it.
You can attempt cleaning it with Q tips and alcohol.
Restringing is a task I personally suck at, therefore I hate it. I don't have the patience it requires....:thumbsdn:
 
Replaced all 4 fuses with 5A-250v and when I turn the reciever on, none blew in the right channel where I found the blown fuse. So that's good. Removed the preamp/poweramp jumpers to see if any difference in the headphones which I believe won't change since the headphones are in the front preamp-headphone amp section. So my next step will be to remove the front face to have access to clean and lub all control pots & switches, and see if that makes a change. If that doesn't clear up the right channel, where do I need to go next, what board and what I need to test etc.?
 
Before jumping into boards, clean all the controls. That solves the majority of channel drop problems. As far as the slipping tuner string, the Eight has a very complex string routing. Don't disturb it. It's a real nightmare to restring. Before gunking up the string with bees wax, try lubricating all the string pulleys to make sure they are all moving freely.

Also, post the serial number in the Sansui database thread so it can be recorded. Now for the important question. Does it have a speaker relay?

- Pete
 
To clean the switches and controls, inject the cleaner into any opening you can find in the control. The pushbutton switches can be cleaned from the front, after you remove the front panel. If you look where the shaft goes into the control, on the body of the control there is a small cover where the ratchet is. You can inject the cleaner there. Also you can inject the cleaner into the body of the switch, where the shaft goes in. Sometimes you have to remove the front panel and then remove the boards to get to the controls. I haven't done one of these in years so I can't recall what has to come apart.
Another thing to check, if cleaning the controls doesn't fix it, tap on the speaker relay and see if the channel pops back in. If so, replace the relay.
 
Majoryyz said:
Looking at the service manual, it shows 5A 100-127V and 3A 220-250V, what I pulled out were 2 5A-250V, one bad the rear side fuses we're a mixed set of 5A-32V and 5A-250V. Should all 4 be the same 5A-250V?
Click to expand...
F001 - F006 all 5A Quick Acting Fuses. F007 (Primary) Slow blow 5A.
If you replace quick acting fuses with regular standard fuses you will not get the protection. Model Eight doesn't have a relay. For protection Eight uses QA Fuses and a Power Limiter A QA fuse at 2.7 times the value will blow withing 50ms and a fast type at 600ms.
A quick acting fuse blow immediately when current exceed the value. Just a tip :thmbsp:
 
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Where can I get quick acting fuses? Also I cleaned all the controls and switches which didn't have any static/noise in them anyway, with no change on the right channel. Which leads me to believe with 1 fuse found blown on the bottom set for the R channel is saying there was too much DC voltage going to the output amp from either the power supply or the right channel amplifier board, which is why it blew and why the right channel is weak with headphones. I've yet to run any speakers. The DC offset is L 38.1mv and the R 18.2mv. I don't know what it should be as yet, but maybe someone here can shed light to the DC offset and the other question/theory I have, what to look for next.
 
You can get the fuses from Radio Shack, or Mouser Electronics.
The offset should be as close to 0VDC as you can get, usually + / - 5mV. Those readings indicate that the output stages are at least working well enough to not blow the fuse. Someone may have shorted the speaker wires and blew the fuse.
Someone on AK said that some later Model 8's do have speaker relays, and I believe the one I used to own did have one. It may have been an 8 Deluxe, I don't recall.
 
dr*audio said:
You can get the fuses from Radio Shack, or Mouser Electronics.
The offset should be as close to 0VDC as you can get, usually + / - 5mV. Those readings indicate that the output stages are at least working well enough to not blow the fuse. Someone may have shorted the speaker wires and blew the fuse.
Someone on AK said that some later Model 8's do have speaker relays, and I believe the one I used to own did have one. It may have been an 8 Deluxe, I don't recall.
Click to expand...

When i turn it on it's about 2 secs. before you hear a click and then sound. Knowing what my Pioneer's and Marantz's recievers relays look like, I haven't seen one in this reciever. What would be my next step to find he problem on the right channel??
BTW I have the service manual for the "8" but it doesn't explain the steps to correct the DC voltage, anyone?
 
If you have the service manual in pdf form, can you post it somewhere for download? I don't have it and I need to look at it to help you.
 
Ok, I have the manuals now, thanks, Stene!
To adjust the DC offset, perform the "Balance Adjustment In Main Amp Section" procedure. You should also do the current adjustment in the differential amp, and in the main amp.
The headphone output comes off the speaker outputs, through resistors. If one of the resistors was open, or the jack was dirty, you could lose a channel and the speaker outputs would be fine. Do the adjustments, and then connect speakers and see what you have.
The model Eight Deluxe has a board #F-1475, and the speaker relay is located on this board, so look for that board, yours may have it. If a channel is still out, tap on the relay.
 
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