Sansui 350A need advice

[Hayes]

Hello people. I was installing a new speaker selector switch on my 350a the other day and the good news is that it was a successful venture. The bad news... I noticed a dial light out and decided to replace it and another weak one with 2 LEDs (8V) that I got for another project and didn't use, the light string is 6.3V. Anyway, everything lit up except the bulb at the far right which was a 6.3V. So I went to pop that bulb out and pulled a rookie move and didn't cut the power. My screwdriver hit the end of the fuse bulb and BAM... all lights out. There is still continuity on the light string but no power. Traced the 3 white wires from lights under to the circuit boards. attached images show where they terminate. Wire #1 has continuity. Wires 2 and 3 do not. Wire 4/5 is a jumper,white colored and also has no continuity. Outputs and speakers function. This was the first receiver that I bought back in the 70's so it's a sentimental favorite. Any help would be appreciated and keep in mind that I am a tinkerer, not a tech in any way. See pics. Thanks. View attachment 1466483 View attachment 1466483 View attachment 1466483 View attachment 1466483 View attachment 1466483 View attachment 1466483

 

[skippy124]

HI,

There is a "wired in" fuse in the supply for the lamps, it will be either 1.5A or 3A depending on the power supply version in your particular unit. I have circled the fuse in one of your photos - see below.



This is what a wire ended fuse looks like



Hope this helps

Cheers

John

 

[Hayes]

Hey John, Yes I see that fuse now. It has continuity but no juice when powered on. Will check into it more tomorrow. It's bedtime for me. Thanks.

 

[skippy124]

Hi,

I was guessing that the fuse I circled is the lamp protection fuse. There should be two green wires coming out of the secondary side of the transformer - these are the lamp supply wires (according to the schematic). There should be approx 5.7VAC on these wires.

Cheers

John

 

[Watthour]

I have a 350, but not a 350A, so not much help here.

Mine doesn't even have a fuse for the lamp circuit. Yours should have a 3A fuse protecting it. Skippy has you covered.

HOWEVER, be aware that the circuit also has a rectifier and filter cap for the 7½VDC used elsewhere in the unit, so adding LEDs instead of incandescent lamps may affect that, and not be as straightforward as you may believe.

 

[Hayes]

Hello again. Yes John, that lamp fuse that you pointed out was bad. It's weird but I still felt like I was getting continuity there but after cutting off the plastic cover you could see it is blown. And Watthour... it is a 3A fuse. Will order a couple of them and some new incandescent fuse bulbs to be safe in relation to that rectifier and filter cap which is Greek to me as is the schematic that I downloaded from before. Keep this thread tagged and I will let you know how it turns out. Thanks again.

 

[Hayes]

well, I dug up an old fuse holder from a parted out car tape deck. Two alligator clips later. Bingo!!! Lights(see pic). Is there a reason to just not go ahead and solder that rig in? I know I'm not the first one to do this? And would there be any reason not to switch to LED lights? I have appreciated the help so far.

 

[Xpress_hess]

Newbie here - I have had the exact issue happen with my Sansui 1000x. lights went out after a I accidentally knocked the fuse bulb behind the tuning meter. Can someone here help me identify the correct fuse? I think it is the one circled (bottom of the unit) but similar to Hayes - I seemingly get continuity to it. any help is appreciated. The unit still functions great but, no lights is no fun.

This happened when I was trying to figure out how to modify the lights so that the dial lights are always on.... if anyone has any good info. on that too. It would be very helpful!