Burnt filament virtual tap resistors

[mozz]

I may have a jack like that, let me dig through some boxes.

[pdf64]

…
Jack sockets incorporating DPDT switches are used in many Fender amps of the past 3 decades, so may be available as spares, and could be used to replace the input sockets of this design.
…

https://guitarelectronics.com/fender...attery-switch/

[Randall]

The problem I am having with post #11 as well as the jack above is the isolated part. A normal guitar cable is going to ground out the sleeve when plugged in, which of course is how we wire up a battery switch in an active guitar or a pedal.

If anyone thinks I am incorrect about this, could you draw out what you mean?

Missing Enzo right now, he would set me straight.

[mozz]

Found one if you want it. Probably out of a piece of test equipment. It's switchcraft brand. Opps, i see no tip switch, let me search some other boxes in the shed.

[Randall]

Appreciate it mozz, close, but that's not it. Needs to have a tip switch as well. Switchcraft still makes the one you have it's a 13E.

[dai h.]

put your forefinger together with your thumb. That is the switch contacts touching each other without a plug in the jack. When the plug is inserted, it pushes against the plastic part in your picture (also the same in the pic above) and lifts the contact. Since the metal jack is pushing against the plastic, it's not "electrically touching". On the jack pdf64 posted (link), after the jack pushes up and opens that contact, it touches another contact (there are two of them in that case--it's just a DPDT). Just stare at it for a while and think about it. I am sure you'll get it. The only I can think of at the moment (using the switching jack in pdf64's link) is a John Suhr tube effects loop. Basically like a pedal footswitch bypass built into the jack. Think of a seesaw. (I hope that didn't confuse you even more, lol...)

[Randall]

dai h., I understand how the jack works, I am not confused about that. Maybe what I am not getting across is the original jack has a normally closed tip switch like a normal Switchcraft 12A. It also has an isolated plastic tabbed normally closed switch that is also operated by the tip. Both are closed with no plug inserted Both are open with a plug inserted. However they are isolated from each other as well as from ground. With a tip/ring switching set up, wouldn't the ring get shorted to ground using a regular two conductor guitar plug.

I'm sure it would, so this is my issue.

[g1]

The problem I am having with post #11 as well as the jack above is the isolated part. A normal guitar cable is going to ground out the sleeve when plugged in, which of course is how we wire up a battery switch in an active guitar or a pedal.

You mean the ring. A mono (TS) plug into a stereo (TRS) jack grounds the ring to the sleeve.
Neither of the jacks on the Fender schematic have a ring terminal.

The one pdf64 linked has a ring, but you don't have to use it. You can still use the isolated switches in the jack.
Pins 2 and 6 in the picture look like they might connect to ring or tip but they do not, they are insulated. Just a poor drawing. They would be like the terminals with the plastic nub on the picture you posted.

[Randall]

You are right, I did mean ring, not sleeve.

So are you stating that with a plug inserted, pin 2 does not make electrical contact with pin 8, and pin 4 does not make electrical contact with pin 6? And if so, how do you know this? I'm not being snarky, I'm just asking, because I don't know.. It would be a good solution if so.

[g1]

So are you stating that with a plug inserted, pin 2 does not make electrical contact with pin 8, and pin 4 does not make electrical contact with pin 6? And if so, how do you know this?

Correct. I know this from the description: "Internal DPDT switch is isolated from the stereo jack connections".
It would be better drawn with a couple rectangular 'bars' like in the fender schematic, which indicates an actuator that is not electrically connected.

[Randall]

Bravo! Thanks guys, I think you cracked this case.

Personally, I think these Rivera amps are largely over engineered. Just because you can, doesn't mean you should.

[dai h.]

yeah the drawing and the isolated part can be confusing. I would make a general suggestion (to anyone) to stare at the jack while working a plug in and out (wow, ripe for a sex joke..lol). A spring contact leaves common and one side normally closed, but insertion of the jack works against the spring and lifts it up (and open) and forces it to touch the other contact. The little plastic things (insulators--these are smaller in the boxed type) get you the switch actuation with isolation. It think you'll see the same sort of switch in a patch bay.

If the original doesn't work, have you tried cleaning the contacts (cleaner, or maybe emery paper (being gentle and careful enough to damage any plating))?

[Randall]

dai h., I think we all know how the jacks work. That isn't the issue. The issue is one of the original jacks isn't there. The issue is sourcing one to do what the circuit is drawn for. The original part is no longer available. Hence, my question. But, a few of the guys here pointed me to a improvised solution.

[dai h.]

ahh, I see it (was replaced with a non-stock one) now, sorry about that.