Sansui 9090db Blown Fuse

[Kevin Bailey]

I've got a Sansui 9090db in pretty good condition, but both channels were coming in and out for some time (and sounded scratchy). Recently, the left channel went out altogether. I should mention that I've never attempted to service/repair a receiver. In an attempt to diagnose the problem, I cleaned the pots. A subsequent test revealed that right channel was improved, but the left channel was still out. I read some more threads on this forum and found that it might be a fuse problem, and also that the fuses need to be proper replacements or it could cause new problems. I then found that one of two fuses on one of the boards was out. The fuse is an F3A. Behind the fuse, the board says 125V7A. Perhaps foolishly, I ran out to the local Home Depot to look for a replacement and found some Bussmann 3A AGC fuses that are the same size (1/4" x 1-1/4"). The box says, "All fuses in this kit for auto, marine, or electronics applications up to 250Vac."

I'm wondering if these are proper replacement fuses. My research thus far has been less than conclusive. If I replace the fuse and the problem persists, I'll probably take it to a professional, but my hope is, of course, that this will fix it. If these aren't correct, and anyone can point me in the right direction to buy proper replacements, it'd be much appreciated.

 

[LBPete]

As long as they are fast blow, the right physical size and the right amperage rating, the 250v fuses will work fine.

Most channel drop, low volume and scratchy sound issues are caused by dirty controls. Each knob, lever and push button on the front panel has a switch or a pot behind it. The 9090DB has a lot of controls and they all need to be cleaned on this 35+ year old receiver. To do it efficiently, you need to disassemble the unit enough to get access to the controls. Then you need to get the proper cleaners inside each of them.

If it's not thoroughly cleaned, you are just chasing your tail.

- Pete

 

[Kevin Bailey]

Thanks so much, Pete!

I'm fairly certain the new fuses I purchased are fast-blow, if this can be trusted (that is, if fast-blow is the same as what they're calling "fast-acting"). The ones I purchased are nearly identical to the fuse I pulled out of the Sansui (and the others that are still in the receiver), in terms of length and appearance (they have a single wire running through them, rather than a coil). The only difference between the fuses that I can discern is that the etchings are different (original said F3A; new fuses say AGC 3A) and that the end caps are mildly convex on the original but slightly concave on the new ones.

I have to admit that I didn't clean every single control. Though I am a little encouraged by the fact that, after cleaning the pots and the selector, the right channel is now back and sounding quite good. But, if, after replacing the fuse, the left channel is still out, I'll definitely go back and give all of the controls another thorough cleaning.

Again, much appreciated!

 

[onemug]

What Pete said

Something you can try in the meantime is to exercise "all" the controls and I mean 20-40 times and see if that helps. You will still need to "properly" clean them but it may give you some temporary relief.

 

[petehall347]

f03 is 3 amps .
if the lights are on f03 is fine
can you confirm what the board id is for where the fuse came from as there are a few 7 amp fuses ?
if its number is f-2657 that is a speaker fuse and 7 amps