Ampeg G15 Pilot Light

[Ryan22]

I recently had my 66 Gemini II serviced by a recommended tech. When I picked it up from the shop he informed me that the pilot light only works when standby is off and doesn’t operate solely by the on/off switch as it did before. An “anomaly” he called it. He modified the power section so the bias isn’t affected by standby and the polarity function is bypassed. I have been redoing all his work throughout the rest of the amp (He had changed some values to brighten it up). Now that the values match the schematic I’m happy with the sound but I can’t seem to figure out how to wire the switches so the pilot light works with the on/off switch. I will add some photos. I’d appreciate some guidance.

[Ryan22]

Photos added:

[Latole]

A so-called technician who can't connect a pilot light the right way!  That's pretty amazing, isn't it?

It seems obvious to me that the person who recommended him to you didn't know a thing about it. What else?

Look at this schematic ;

[sluckey]

I've cropped the schematic to show only what's necessary to show how the pilot light should be wired. It may seem a bit confusing at first but it's really straight forward. Should be easy to wire it correctly.

[HotBluePlates]

A so-called technician who can't connect a pilot light the right way!  That's pretty amazing, isn't it?

It seems the tech thought he was doing a "Good Thing" by removing the line filter (aka "Death Cap") and polarity-reverse functions, and simply decided on his own way to connect the switch.

A different alternative would have been to leave the switch as it is, and simply replace the existing cap with a Class Y cap.  The YouTube techs don't seem to emphasize that option...

[PRR]

Even better if Ampeg hadn't been so darn "clever".

[Ryan22]

I suppose I will leave it as is for now. Thank you for the suggestions. Can someone explain the benefits of bias not being affected by standby? I’m afraid if I follow the schematic I will revert back to the opposite. There’s just something satisfying about that little red light coming on with the on/off switch. While I’m capable of testing and swapping parts without dying.. understanding the circuitry is still beyond me. I was hoping it would be as simple as moving a wire or two

[sluckey]

Can someone explain the benefits of bias not being affected by standby? I’m afraid if I follow the schematic I will revert back to the opposite.

It's best practice to have the bias voltage present even when the amp is in standby mode. Having said that, I bought a Gemini II brand new in 1968 and played it regularly for about 10 years. I used the standby switch for every break between sets. Never had any issues and the amp had the original tubes in it when I sold it. My advice is to simply wire it back to original and don't fret about the bias.

I was hoping it would be as simple as moving a wire or two

It probably is. But without knowing exactly what was changed there's no way to give you a road map of exactly what to do, other than to say wire it according to the original schematic.

[Ryan22]

I will take your advice and move back to the original wiring while the cab is disassembled and awaiting speaker bolts for the baffle. That class Y cap does seem like a pretty good choice in that case. Do I replace the death cap with the same value Y cap per the schematic or will it need to be different?

[sluckey]

Do I replace the death cap with the same value Y cap per the schematic or will it need to be different?

Yes. Use a .05 or .047. The .047 may be easier to find.

[mresistor]

Y2  lead length is 30mm    https://www.mouser.com/ProductDetail/KEMET/PME271Y547MR30?qs=ffqAhwBssBtNZAzmaEJJtg%3D%3D