MIMF

I have a late 70s Traynor TS-15 solid state practice amp that I bought new and passed on to my son for his college dorm. Fifteen watts, 2 - 8 inch speakers.

He tells me the on/off switch is stuck. No evidence of abuse or liquid spillage, but hey, its nearly 40 years old. I've opened it up; switch has 1/4 inch quick connect lugs, and the switch is a snap in mount. Should be a simple repair.

I measure the panel cutout dimension. The body of old switch says: 10A 125VAC, 5A 250VAC, 1/2HP 125-250VAC. I'm searching Digikey and find 13A and 16A at 125VAC for my panel cutout dimensions for a SPST rocker switch.

Is the difference in amp rating from my original switch critical for this application?

When I opened the amp, I noticed the fuse holder had one of the four spring clips is broken off (2 curved spring metal clips at each end to hold the 1/4 glass tube type fuse). The fuse is still held tight but I figure while I'm in I can replace it. I find the same fuse holder on Mouser. It has 2 wire soldered wire connections. I've wired electric guitars many times, so I figure I can handle this.

Safety question: Do I need to be concerned about discharging capacitors?

I've attached a photo (green arrow is the switch to be replaced and the red is the fuse holder). I've heard that low watt solid state amps are low risk. Also, it hasn't been turned on in months; does the capacitor discharge over time? There is distance between the capacitors (the large blue cylinders, right?) and my switch/fuse holder.

What is my risk with the planned repairs?

Thanks,

For the switch, as long as you meet or exceed the rated amps and voltage, you should have no problem. Your capacitors appear to be on the other side of the power transformer from where you would be working, but if they harbored a high voltage charge, you would want to make sure they were empty in case you accidentally brushed them. I would expect your capacitors to be low voltage in a solid state amp and thus no risk, but how can it hurt to discharge them first? Just short them out. If they were high voltage, like in an old tube circuit, you would want to make sure that whatever you used to discharge them insulated you from any current. In most power supplies, the load of the circuit discharges the capacitors after you turn the equipment off (that's what powers the circuit as you hear it fading out). I haven't worried about discharging capacitors since I worked on tvs 50 years ago and those caps were really high voltage. I would jump into that repair with no reservations.

I agree - no danger from the caps, as they are rated at 25V, and even if charged, 44v would pose no danger.

Here's the schematic if you need it.

http://www.lynx.bc.ca/~jc/790130_TS15_iss6.gif

Thanks for providing some piece of mind.