SVT-2Pro Troubleshooting

[csholtmeier]

A got a line on getting a 2Pro insanely cheap. I'm told by the seller the power switch is broken or the wiring to the switch is faulty.

What's the best way to check this out to make sure it's not DOA otherwise?

 

[JGR]

The wire connectors on the inside of the switch are press-on types so you could easily just pop them off and carefully clip them together to "hotwire" the switch, with say an alligator clip (WITH THE AMP UNPLUGGED!!). then plug it in and see if it lights up!

if it is indeed only the switch, it's a quick and easy repair.

JR

 

[csholtmeier]

I was hoping I something like that was possible.

How does that work in relation to the standby switch? Will hotwiring the power switch be like turning on both switches at the same time, not letting the amp warm up?

 

[ChenNuts44]

What I would do is disconnect the supply wires from the switch and verify the voltages present with a multimeter. Should be ~6.3VDC (AC voltage is often used as well for the filament supply) for the power switch and a few hundred VDC for the standby switch. To verify the switch's operation, you can either do a simple continuity test or reconnect the supply to the switch while disconnecting the switch's "output" from the rest of the amplifier and re-verify the voltages present after passing through the switch in each position. If everything looks ok, your problem is elsewhere.

Edit: Probably worth mentioning that the power switch will be a multi-pole switch with one pole passing the AC from the wall to the power supply and the another passing the transformed and rectified DC to the amplifier. In order to do the testing of the supply voltages without involving a switch, you'll have to temporarily connect the AC wires to the supply. This simply involves taking the wires connected to the pole the AC passes through and tying them together. This would be like "hotwiring" the switch as previously suggested, only it isolates the supply from the rest of the amplifier. Should be obvious which wires are which.

 

[Jerrold Tiers]

"Hotwiring" past the switch will work.......

But, in my experience, "switch is broken" often is "seller code" for "I sure as S$$$ don't want anyone to turn this on until I have the money and am way gone from here".

Sometimes it only means " it didn't turn on", because the seller knows nothing..... the switch is the only visible item so if it doesn't turn on, that must be the problem......

Unless the switch actually feels weird, or is in pieces, I'd check very carefully before applying power. Even then.... I'd still want to check inside.....

Switches are so easy to replace that you have to wonder why a person would take a bunch less for something when a $10 ($2 ??) switch would fix it.....

Implication is that he knows very well that isn't the problem...... and wants it gone.

 

[BassIan]

"Hotwiring" past the switch will work.......

But, in my experience, "switch is broken" often is "seller code" for "I sure as S$$$ don't want anyone to turn this on until I have the money and am way gone from here".

Sometimes it only means " it didn't turn on", because the seller knows nothing..... the switch is the only visible item so if it doesn't turn on, that must be the problem......

Unless the switch actually feels weird, or is in pieces, I'd check very carefully before applying power. Even then.... I'd still want to check inside.....

Switches are so easy to replace that you have to wonder why a person would take a bunch less for something when a $10 ($2 ??) switch would fix it.....

Implication is that he knows very well that isn't the problem...... and wants it gone.

Definitely a big +1 here. Be careful!

 

[JGR]

Definitely a big +1 here. Be careful!

+3

That's an expensive amp to part with over something as trivial as a power switch. I'm gonna vote for a bad power or output trannie. Buyer beware - if it sound too good to be true, it probably is.

JR