hot rod amp input 1 replace switchcraft jack

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dub-setter

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hey..
i wanted to replace the first input on my hot rod deluxe
with a switchcraft shorting jack with isolation washers.
i soldered the jack as in this sheet:


but it will stay silent when i plug in a cable or guitar.
note that i kept the green groundwire goin from pcb to ground.

im not sure now how to wire it correctly (wich lug of the jack goes to
ground/tip, where i wire the "jumper cable" from lug to lug ?

note that i only want to replace input one, not both.
i found a video too, but does this function also if i only
replace input one?
in the video the guy uses different locations of where the cables are connected to the pcb holes,
then in the sheet above ...
????




63mm-mono-jack-with-switch-switchcraft-12a.jpg

in this video i hardly can see the wiring of the jack as well..
 
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Norton

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did you take pics of your before situation? I'd say just use a mono jack.

There's really No benefit to using some sort of "fancy" input jack to your amp. any noise or other issues are going to be inside the amp... not at the input point. and almost half a tube amp is noise filtering so there are ample points to make those improvements if you need them.
 

dub-setter

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hey,
i ordered this jack
as it was recommended in other forums as an replacement for the hot rod deluxe..
the plastic input jack fender used are soldered directly to the board and
are known to fail from time to time.

in the sheet above i attached you can read about the
original jack and the mounting points on the pcb.

but i have the feeling in that sheet the wiring shown must be somehow wrong,
as theres no signal now after i replaced the jack.
 

dub-setter

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i was thinking this could be working....
(plus ground wire on pcb and isolation washers)

????

switchcraft-12a-wire.jpg
 

Mark Seven

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hey..
i wanted to replace the first input on my hot rod deluxe
with a switchcraft shorting jack with isolation washers.
i soldered the jack as in this sheet:


but it will stay silent when i plug in a cable or guitar.
note that i kept the green groundwire goin from pcb to ground.

im not sure now how to wire it correctly (wich lug of the jack goes to
ground/tip, where i wire the "jumper cable" from lug to lug ?

note that i only want to replace input one, not both.
i found a video too, but does this function also if i only
replace input one?
in the video the guy uses different locations of where the cables are connected to the pcb holes,
then in the sheet above ...
????




View attachment 57049

in this video i hardly can see the wiring of the jack as well..

You know, that's interesting because I wanted to replace the fitzbot in my Oleo Circuit Beam but ran into a problem when I found that the smear end of the rack tip would not align with the lap coil. Since that didn't work, I ended up taking the prozon off a 1943 Audiovox and bolted it into my Flux Capacitor and now everything is copacetic.
 

Norton

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Do you have a multimeter with a continuity setting? I'm asking because the ground lug should be easy to locate, that's the lug that is visibly connected to the center of the jack shaft (when looking from behind the outward face of the jack).

The other two lugs should be connected to the hot signal wire. Again... you CAN put TRS jacks into mono circuits, but unless you're using the switching capacity of the switch there's no benefit to doing this.

The jack itself (circuit board mount vs. standard wire) etc. can be a thing... esp in high stress areas. but you're not going to hear any audible difference.

Hope you get it wired up and working!!!!
:cheers: 🤘
 

dub-setter

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hey..
i did some wiring today like in my last picture...
(lf i understood correctly from the video with the two inputs)

but when i turned on the amp
i heard a bad hum on input one (the one i replaced)
and the first (bigger ) cap (+47 uf) on the board exploded !!! :shock:
fuse was blown too,
but noo smell or burned cables/tubes.


luckily nothing had happened to me,
but i will now just order a regular fender replace ment plastic jack with new washers/nut.
(same that was in there before , with 4 lugs mounted on the pcb)


its just too dangerous following bad pictures or videos
if u dont know exactly about electric paths..

don t know now what made the cap exploding
( it was modded last year with a better cap as the cheap fender
caps, brand -new, and yes it was installed correctly)

maybe the wiring in the video was only for if u replace both jacks together.
but im done with replacing the jack with switchcraft for now.

the wiring in the sheet above also did nt worked,
as i wired it the same way like in the sheet. (1 st attempt)

its a bit of a let down i cannot find a right information about wiring a shorting
jack simply on that board, which should nt be much of a problem , normally.

i must also mention that english is not my mother language, which make it a bit harder as well.
 
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Norton

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Can you take it to an amp repair tech ? it's not going to work with an exploded cap. that's for sure.

But the repair will be the cheaper now than if anything else goes wrong.

Sorry you're having this trouble.
 

dub-setter

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hey..
i ordered another cap (same +47 uf) from tubeamp doctor..
(with the input jack, fuses and washers)
no probs in soldering in a new cap.

(the mods were done all acurate by
an expert, i was in contact before about the mods in this amp,
some easy ones i did also myself)

but i was wondering, what made it explode...
could it been a short with the wired jack??

anyway,
i hope i didnt blow anything else..
but there was no smell or burned parts so far...

if i replaced the jack and the cap,
and theres still something goin on/not working
i will contact a tech.
 
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Norton

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short wired jack could cause all sorts of strangeness. I'd expect the cap is the only thing damaged. Maybe a fuse.
 

dub-setter

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hey,

maybe the input/lug somehow was touching the pcb , when i was installing it.
or the wiring in the video was only for replacing two jacks at once...(input one+two)
who knows..?


fuse was blown as well, as i mentioned above.

anyway i will solder in the cap and the new input
over the weekend..
thanx so far...
 

dub-setter

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hey..
i did solder in the new cap and the replacement input.
but unfortunately the amp now won´t even turn on.
(no red lamp and the tubes stay cold..)

since there was no smell or burned cables
my guess now is something/component/resistor fried on the pcb,
or the power or output transformer died. (without smell)

i replaced the fuse as well, and it didn t blow up again after switching the amp on.
could that be a hint to somewhere/what..???
(no power at all in the circuit)

also i didnt know that there are two transformers in there:
an out put transformer and a power transformer (power supply)

???

anyway time for the tech now.. i will
upgrade you if i get any news.

a pity, that a change of an input pot can lead into serious problems...
but theres always something to learn.
 
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Norton

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Oh man... sorry to hear that. This is no longer something you can fix by yourself, or diagnose over forum posts.

It would seem pretty unlikely that you fried the power (input) transformer... usually in order for that to go bad you get some pretty heavy smoke.

Good call for a trip to the amp tech. Odds are it's an easy fix with a few resistors. 🤞 🤞 🤞

good luck!
 

Les’s Nemisis

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Yeah, sad news. Likely just another component or two fried, but you need detailed electronic knowledge to fix it at this point.
 

dub-setter

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thanx...

yap,
as there was no smoke (beside the one from the exploded cap, which was more like a small white cloud)
and no smell,
i hope ist just a smaller resistor in the power circuit.
but on the other hand, theres no "juice " comin in at all...

i will keep u updated,
though it will take a while with contacing the tech plus the repair.
 
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dub-setter

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short update...
tech was busy with other gear/amps..
(good techs are always "too busy"..:)

but will have a closer inspection soon.
 

dub-setter

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another update..
the amp didnt turn on because of (another ) blown fuse.
(its a slow blow i guess my first replace was a fast blow)

so all safe with the transformer / or tubes.

but the blown capacitor did hit some connections on the reverb pot,
so the reverb wasnt working, therefore the tech had to look closer to the board (detach it),
suspected the reverb chip was blown, so the charge is not low,
because of the amount of time he worked on the amp was altogether +/- 3 hours.
he also found by accident a loose connection of the speaker, which
could cause more trouble, so at the end it was good that he looked closer at the board.

puhh..
im glad the tramsformer is still okay,
but i will think twice next time im workin on a tube amp. ;)
 

Norton

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it's gonna be good to fire that amp back up!

good to hear it's a fixable thing that's on its way back home! 🤘
 


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