Sanusi 8080 light problem, need help

Hi replaced the blown fuse (F3) but still, no lights at all!
Any other ideas? (just refreshing - I tapped with a screw on one of the fuse lamps housing and than the lights went off)
 
If I understand you HAD lights then you "tapped" a fuse lamp housing and the lights went off... is that correct?
 
Do you understand how a conventional filament light bulb works ? ( not trying to be rude here, just trying to see what you know ) ... Do you understand how a series circuit functions?
 
Do you understand how a series circuit functions?

The Sui fuse lamp boards aren't usually a series hookup. Each bulb has a direct power feed with common ground.

~ ~ ~

Have you tried tapping the back of the fuse light circuit board? Try pressing down on each fuse clip with an insulated tool. The solder breaks where the clips are attached to the traces because of all the hot/cold cycles over time. It's standard practice to just reflow and refresh ALL the clip connections once any dial light issues come up.

Normally, it's just random flickering, or a lamp will light or not, depending on whether the board is hot or cold. I can see losing the whole array though, if the main power feed develops a cold joint.

So, IF you have a good fuse, and IF you have power past that fuse, that's the first place I'd look.

PS ... Sui also tends to pull power from that same board for other dial lamps. I've had a couple quads that lost either the 2 or 4 lamp because of a cold connection there.
 
In an 8080 ( DB ) the lamps are in series with the switch, going back to the power supply ( 6.4vac ) … The 8080 ( DB ) doesn't have a series string O lights, but with out detailed information about exactly which lamp went out hard to advise… I would venture a guess the TAP caused the filament to break. Every fuse style holder could benefit from a cleaning & every connection could use a re flow. I'll mark up a print.. BRB
 

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This is an 8080DB right? If so, the dial lights should be on whenever the power is on.

Are all the lights out or just the dial lights? Are the power meter lights on? If any light other then the FM stereo light is on, the power supply is OK and you have a circuit problem. If ALL the lights are out (except the FM Stereo light), you have a power supply problem.

The lighting system is AC voltage. Set your voltmeter to AC voltage and check the voltage between each of the terminals of fuse 03 and chassis ground. If you have voltage on one side but not the other, the fuse is bad. If you have voltage on both sides, your problem is down stream.

The x0x0 series is famous for bad solder joints on the fuse lamp holders. Bad solder joints will give you the symptom of the lights going on or off when tapping them. Put your AC voltmeter across the lamp holder and see if the voltage fluctuates when you tap it.

- Pete
 
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