Vox ac15c1

[pnut5150]

Amp had no sound at all, F1 was blown(heater fuse). After I changed the fuse, J7(blue wire from OT) was arcing. I can pull that wire off and get pretty good volume from normal channel. That tube burns much brighter than the other one. Changed that el84 socket and same thing. Also I can put the brown wire(J12)on J7 and it will arc there also. What could be shorted out there? I see that J7 runs to pin 1 on that power tube there. Have swapped tubes also.

[pnut5150]

Ok, ohms is 23.38 at standby switch from transformer. Since there I a dead short as soon as standby switch Is flipped, co lx the power transformer be shorted on the HT side?

[Jazz P Bass]

What output tubes are you running?

The OT Blue & Brown should only go to the plates.
Pin 7.
Red is the B+ center tap.

[pnut5150]

El84's. I started in the wrong place on my trouble shooting.
I was assuming prob was coming from output tranny, but the HT fuse back is problem. Checked everything on schematic in that circuit, cannot find anything. BUT...the ohms reading from white wire from power tranny to standby switch had the 20+ ohms reading. Transformer appears to be open there if I am reading right. Does that seem possible?

[Audiotexan]

Don't have a c1 schem...so kind of hard to follow exactly...

Amp had no sound at all
F1 was blown(heater fuse).
...
That tube burns much brighter than the other one.
Changed that el84 socket and same thing.

No sound = check basics.
------------------------
Have mains power? (highest voltage in amp)
Have heater voltage (typically 6.3v or 12v)

F1 blowing could be a result of a shorted tube or other things.

One tube burns brighter: which one? preamp? output?
I assume you mean output, but you say 'changed the socket'.
So that doesn't necessarily mean you swapped the tubes from one socket to another. Which is was would usually be recommended before changing a tube socket.

Then you say "same thing" meaning, the same tube glows, or any tube in that same socket glows?

Could also be a simple bias adjustment being weighted more to one tube than the other if it's a 'balance' type bias adjust. Again, I can't assume anything given I don't have a schem for reference, so these are just general things. If it's not a balance adjustment style, then you could have a shorted cap, open resistor...who knows yet. Need more to go on

Not trying to be contrary, but specifics are important before we make any leaps

[mozwell]

AC15C1 sch

Pull the two power tubes out, replace the HT fuse, power up, check all power supply voltages, including heater voltages & op amp voltages
Report them here.
Recheck the HT wiring
AS Jazz P said, The OT Blue & Brown should only go to the plates. Pin 7.
Red is the B+ center tap.

[pnut5150]

I will.
The terminal where the BLue wire goes has 20+ ohms on it. Signal path all the way back to standby switch does as well. That's why I believe there is a short on the transformer. With both power tubes pulled, and the blue hooked up, the wire/terminal sparks/arcs. I can unhook that blue wire, and amp will "half" work. Does it make sense the way I am explaining it?

[pnut5150]

Oh yea I forgot to mention I did check both tubes in both sockets. Then I changed socket itself in front of the blue wire. I jumped the gun on that one. There is a dead short on that wire terminal.

[jesusfreak]

I couldn't get my original account of pnut5150 to work anymore, so I created a new one.
Anyhow, I fixed this booger. J7 (goes to pin 7 of V4) was shorted somewhere in the the circuit, I obtained a schematic and decided it must be in the board itself, So I lifted Pin 7 of V4 tube socket and jumped the OT blue wire directly to it. Thanks for all the advice

[Chuck H]

I've had some trouble with site functions also. Glad you got it worked out y ANY means.

On a strictly semantic note... I've always referred to an unintended connection between two circuits as a "short". Because this is how I learned the term, and most commonly see it used, I do not refer to breaks in connectivity as shorts, I refer to them as faults. I know the terms have been commonly swapped before, but I feel it's important that we here are all consistent if we wish to communicate effectively. Any opinions to the contrary are now being accepted.

[Enzo]

Agree, a short is an unintended connection. IN fact, it makes the circuit shorter than it would have been for current. An open is an open.

A loose connection is a short to a truck driver on his trailer lights, not to us.


One might suggest you short two wires together. One would never suggest to break two wires apart and call that shorting them.

[The Dude]

Agreed.

Short = connection
Open = no connection

[pnut5150]

The reason I used the term "short", was because when I connected the blue wire from the OT, the terminal(j7)seemed "grounded", it would arc. So did I use that term correctly? I hope this does not sound sarcastic. I just want to make sure I use correct terminology next time. Thanks guys for your help

[Chuck H]

The reason I used the term "short", was because when I connected the blue wire from the OT, the terminal(j7)seemed "grounded", it would arc. So did I use that term correctly? I hope this does not sound sarcastic. I just want to make sure I use correct terminology next time. Thanks guys for your help

That's cool. I wasn't trying to be a correction douche either. The way that post read I just interpreted it mean that there was no connection, not an incorrect connection. I figured if that was the case it would be ok to clarify terms for future reference.

[pnut5150]

That's cool. I wasn't trying to be a correction douche either. The way that post read I just interpreted it mean that there was no connection, not an incorrect connection. I figured if that was the case it would be ok to clarify terms for future reference.

I should have said it was open..right? I'm learning, I like being corrected..so I don't sound like an idiot when I post! Lol