#1
Picked up a vk100 for cheap knowing it wasn't working. I was hoping it was just a cracked soldier joint on the input jack, however I wasn't lucky.
You can plug into the return of the FX loop and get sound, so the power amp is working. I went over all suspicious soldier points and attempted to clean the input jacks. I also replaced all preamp tubes with known working ones. Still no sound. If you put it on the dirty channel with all pots maxed you can ever so slightly hear the guitar.

I have tried every combination of words I could on google and didn't find anything that would help, so sorry if I missed something and am double posting.

I don't know where to go from here!
Thanks for any suggestions!!
Last edited by aschaetz at Jan 29, 2017,
#2
Did you clean the tube sockets with electrical contact cleaner?

Check the FX send - maybe it is shorted and it is acting like a cable is inserted.

Does running a cable in the loop change things?
Guitars:
Jackson Kelly KE3 - MIJ (Distortion/Jazz)
Jackson DKMGT Dinky (EMG 81/85)
ESP E-II Eclipse Custom (JB/'59)
ESP LTD EC-1001FR (EMG 81/60)
Fender MIM Strat

Amps:
Mesa/Boogie Dual Rectifier Roadster 212
Laney IronHeart IRT-Studio
Peavey Vypyr 30
Peavey ReValver Amp Sims
TOOOO many T.C. Electronic Pedals. . .
#3
metalmingee
Great thinking on the fx send. I will look into that and will try cleaning the sockets. Jumping the fx loop doesn't make anything happen either.
#4
aschaetz
Does the VK have a tube driven loop?

I'm also assuming you tried both input jacks.

Did you clean the FX jacks too?
Guitars:
Jackson Kelly KE3 - MIJ (Distortion/Jazz)
Jackson DKMGT Dinky (EMG 81/85)
ESP E-II Eclipse Custom (JB/'59)
ESP LTD EC-1001FR (EMG 81/60)
Fender MIM Strat

Amps:
Mesa/Boogie Dual Rectifier Roadster 212
Laney IronHeart IRT-Studio
Peavey Vypyr 30
Peavey ReValver Amp Sims
TOOOO many T.C. Electronic Pedals. . .
#5
metalmingee
I have no idea on if the loop is tube driven.

I did indeed try both jacks.

I'm about to pick up some contact cleaner so I can legitimately clean the input/fx loop jacks and tube sockets. All I did beforehand was plug and unplug multiple times hoping it would somewhat clean the jacks.
#6
aschaetz
Ah, quality contact cleaner is your friend! I use DeXoit D5 and couldn't be happier. I picked up a can years ago and use it on a ton of stuff around the house and cars besides guitar stuff.

When you get some, spray the cable and tube pins then insert into the sockets a few times. The tube sockets should feel nice and smooth when you are finished.
Guitars:
Jackson Kelly KE3 - MIJ (Distortion/Jazz)
Jackson DKMGT Dinky (EMG 81/85)
ESP E-II Eclipse Custom (JB/'59)
ESP LTD EC-1001FR (EMG 81/60)
Fender MIM Strat

Amps:
Mesa/Boogie Dual Rectifier Roadster 212
Laney IronHeart IRT-Studio
Peavey Vypyr 30
Peavey ReValver Amp Sims
TOOOO many T.C. Electronic Pedals. . .
#7
metalmingee
Ok we are kinda getting somewhere- I cleaned all that I could and the barely audible sound on the dirty channel has gotten noticeably louder (it could just be me though) however still nowhere close to what it should be. Nothing audible on the clean channel though. I also didn't see anything visibly shorted out on the fx loop send.

Going to try more cleaning and see if it gets any louder.
#8
Not sure if this will help, but this is the noise I'm getting out of it on the gain channel. Then I plug into the fx loop return. All pots maxed except volume at 50%

#10
did you replace the preamp tubes? may be something that simple. also did you check all the fuses?

the VK's loop isn't tube driven for the record.
#12
Quote by aschaetz
monwobobbo
I replaced the preamp tubes with known working ones.
All fuses were checked both visually and w/multi meter


even the internal fuses?

have you looked at the board? tube sockets, etc?
WTLT 2014 GG&A

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#13
trashedlostfdup
Correct- even the internal ones.

I've looked at the board and went over all of the soldier joints that looked suspicious. I keep going back hoping I missed something. I also went over all transformer connections with electronics cleaner.
#14
maybe a bad transformer? that is about all i got. lol.

edit: have you swapped the PI?
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#16
Quote by aschaetz
That's what I think it might be coming down to.
Can you define "PI"?

phase inverter.

its a 12AX7, that is usually assumed to be a preamp tube (as it is a 12AX7), but it serves in the power amp.

i didn't mean to split hairs, you probably considered it as a preamp tube, but if you were getting really technical i just wanted to make sure that it was swapped too and didn't get overlooked.

if thats not it, the last thing is the transformer.
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#17
phase inverter and its solid state on the VK would be in between the preamp and power amp section on the mother board. I'm thinking mother board issue at this point which may not be something you'll see. time to take it to an amp tech me thinks
#18
monwobobbotrashedlostfdup

Ohhhh ok. That was replaced too- I was calling it a preamp tube.

Not what I'm wanting to hear about an amp tech, but it is starting to look like something I can't fix! Hopefully I'll see something I missed.
I appreciate all of the responses!
#19
Quote by monwobobbo
phase inverter and its solid state on the VK would be in between the preamp and power amp section on the mother board. I'm thinking mother board issue at this point which may not be something you'll see. time to take it to an amp tech me thinks


i knew that. i currently have my VK torn apart. too busy to do much to it though.
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#20
Quote by trashedlostfdup
i knew that. i currently have my VK torn apart. too busy to do much to it though.


oops I'm thinking of the rectifier so you're right. either way the OP needs to take it to a tech as it is likely to be a motherboard issue
#21
Quote by monwobobbo
oops I'm thinking of the rectifier so you're right. either way the OP needs to take it to a tech as it is likely to be a motherboard issue


ok. i was right then... lol.i didn't think there were any all tube amps with SS PI's. but ya never know. lol.
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/