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sansui8080

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sansui8080

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I have a snasui8080DB, when I turn it on the red protector light keeps flashing red, It will not go to green. It worked before I put it away that was two years ago. Then tried to hook it up today and that happened. What could it be? Everything else comes on it lights up and all the needles move. It wont put any sound out through the speakers or headphones. Can anyone help me I dont want to trash it because I know its a good reciever. IT looks dirty on the inside from setting could that be why? My husband has had it for years and wants it to work. Kim
 
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Hi Kim,
Dust and dirt probably wouldn't cause the problem you are describing. It needs to be looked at by a electronics technician. What part of the world are you in? It might be an easy fix for someone who knows what they're doing. Maybe we have a member close to you that can help, or point you to someone who can. We've got ALOT of Sansui fans here.
Welcome to AK :)
 
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Welcome to AudioKarma. It's always good to hear from a Sansui owner. The flashing red light indicates the unit is in protection mode. What that usually means is there is too much DC voltage present on the speaker outputs. There are a number of things that can cause this. Some more difficult and expensive to fix than others.

It is sometimes caused by fusible resistors Sansui used on the driver. These resistors fatigue over time. When the unit is stored for a long time and then turned on, there is a power surge caused by the filter caps charging. This can cause these weak resistors to fail. It is a symptom of old age. The good news is, if this is the cause, it is relatively easy to fix. Are either you or your husband handy? If not, there are several good techs here that can provide professional help. If the overall condition is good it is definitely worth fixing.

- Pete
 
Yes its in good condition we love it. We are in Saginaw, Michigan. And husband is real handy with things but needs direction into doing it right does not want to make it worse. Any help would be appreciated. Thanks Kim
 
Is this an 8080 or 8080DB? They use very different driver boards so the checks will be a little different. He will also need a volt ohmmeter to check the values of the resistors.

- Pete
 
Welcome

Kim - welcome to AudioKarma and also to the [Exclusively Sansui] forum.

It is especially nice to have another lady vintage audio fanatic join our ranks! Helps keep all these guys spiffed up and on their best behavior. :thmbsp:

Welcome!

Paul
 
Here's a possible problem you could look into if you just wanted to try a hit and miss approach. This is the problem I was having, and I did what CDFixer suggested without actually checking anything else first. I got lucky and it solved the problem.
This circuit board comes out by removing 2 philips screws on the back of the metal bracket, then pulling up with a little "wiggling". The board plugs in to the big board under it. Here's some picks to help show you exactly which 2 resistors he's talking about. Note that the ones you will have will be blue-ish. The 2 in the pictures were changed temporarily to see if it made a difference.
If you're daring, you can try this repair, or maybe have someone with some soldering skills do it for you. Only 50 cents for the parts, might be worth a shot.

http://audiokarma.org/forums/showthread.php?t=35732&highlight=8080db
 
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kcollens, great pictures. When you look at the board, all the "blueish" resistors are the fuseable type. Almost any of them can put the unit into protection if they have drifted out of range. You should check all of them. Depending on their location on the board, they should be are one of these values:
4.7 Ohm
10 Ohm
150 Ohm
180 Ohm
The colored stripes on the resistor are the color code that will give you the resistor value. Radio shack has these values and the package has the decoder for the color codes.

The board is divided into left and right channel which are basically mirror images of each other. Like kcollens pictures show, the resistor for the other channel is in the same position on the opposite side of the board. Often one of the two will be close and the other will be way off. So you can use one for a reference. Always match the color code before replacing a resistor.

Checking/replacing these resistors is where I start with these units. I haven't found one of these boards that all the fuse resistors were still at their original values. If it is still in protection after getting the resistors sorted out, then you need to check the DC offset at the protection relay. It has to be done at the protection relay because there will be no signal to the speaker terminals if it is in protection mode. See EchoWars' sticky on DC offset in the vintage forum. This test is the make or break on the condition of the amp section and will help determine the condition of the major components.

- Pete
 
thanks everyone for all your help. I will try that first. someone told me they can fix it for 100.00 so if i dont get it going then i will get it fixed. kim
 
protection relay

If it is still in protection after getting the resistors sorted out, then you need to check the DC offset at the protection relay. It has to be done at the protection relay because there will be no signal to the speaker terminals if it is in protection mode. See EchoWars' sticky on DC offset in the vintage forum. This test is the make or break on the condition of the amp section and will help determine the condition of the major components.
WHERE IS THE PROTECTION RELAY AT? AND DO YOU HAVE ANY PICTURES TO SHOW ME WHERE IT IS AT? Thanks KIM :banana:
 
The protection relay is the only relay in the unit. You can access by taking off the bottom cover. When you take the wooden case off, tip the unit on it's side, transformer side down. Then you can take the bottom cover off and have access to both the top and the bottom. There will be a blue and a grey wire, (among others) going to and from the relay. One pair will go to the speaker output terminals or the speaker switch, I forget which, the other will go to the power supply board and pass though to the output transistors. The blue and grey wires from the power supply board to the relay are the output signals for the speakers. Measure the DC offset voltage between each of these wires and the black terminal of the speaker connection. Anything more than about 300 mV will put it into protecton. It should be 0v +/- 10mv.

- Pete
 
ok the resistors are not the problem in this case then what do I check next? Then we checked the DC offset at the protection relay and now what? I am so lost on this one I just want it to work. I called a few shops here they want an arm and a leg to fix it. Any more suggestions? Please. KIM
 
When you checked the DC offset at the protection relay, what did it measure? This is kind of like taking the unit's temperature. The reading is important.

- Pete
 
ok I checked the relay And was not sure if it was the relay is it a clear plastic box? if it is husband said it read 230mv. He wants to make sure it was the right thing. KIM
 
sansui8080 said:
ok I checked the relay And was not sure if it was the relay is it a clear plastic box? if it is husband said it read 230mv. He wants to make sure it was the right thing. KIM
Click to expand...
Yes, the relay has a clear plastic cover. 230mv is pretty high. It should be 0v +/- 15 mv. It might be high enough to put it into protection. The good news is, with that reading, the outputs don't apear to be blown. That's a good thing. You need to measure the other chanel too.

DC offset is adjusted by turning a trimmer potentiometer. They are located on the driver board. This is the board that is mounted verically and held down by a black steel bracked. If you look down on it from the top, there are four holes in the bracket. There is a trimmer pot behind each of these holes. The inner two adjust the DC offset. The inner one on the left is for the left channel, the inner one on the right is for the right channel. Use a little screwdriver and turn it a tiny amount. They are very touchy, a little movement will give you a big change in the voltage reading. Adjust them untill you get 0v +/-15mv.

- Pete
 
230mV is not enough to trigger the protection. Usually takes well over a volt.

If the offset is low on both channels (under a volt), then the relay driver transistor is probably weak. Certainly the voltage supply needs to be checked, and the relay coil wrung out, but still the likely cause is a driver transistor for the relay, or bad offset due to a blown channel.

Advice: Let a professional fix it.
 
ok I have another question now we have borrowed a multi meter but our friend who checked the resistors and the relay said he was wrong in all of his readings his battery went dead so I have one now and will do it myself but not sure where to put the meter on for measuring the resistors and the relay here is a pic of the meter please tell me where to set it at. KIM
 
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