Help save a Marshall Valvestate 8080

[3hree6ixty]

A few months ago while scouring the Salvation Army thriftstore for guitars and amps, i came across really beat-up Marshall VS 8080. when i tested it at the shop, all i could hear were hisses and pops coming from the 1x12 combo. i paid the cashier the $80 price tag (it was a steal, no matter the state of the amp. It's a marshall for crying out loud!) and happily lugged it home to toa payoh from changi.

i spent the whole week after that taking it apart and resoldering old/broken connections, cleaning the pots and checking the sole tube for damages. it plays great now and the ECC83 pre-amp really packs a lot in the boost setting, even though it's missing a few knobs and the cab skin is torn in places.(might reskin it later)

the only problem is, while playing, i noticed that it goes softer or even refuses to make a sound unless i wiggle the cable in the socket. there's nothing wrong with my cables. so i'm beginning to suspect if it's the input jack that's causing the drop in sound. and if so how do i rectify it? i have no formal training in electronics and everything i know is self-taught. so if possible, stick with layman terms unless neccessary..

thanks...

 

[widdly]

Just resolder the input socket pcb pads. Most likely the solder around socket has cracked. If you reheat it then it will flow into the little cracks.

If that doesn't fix try replacing the socket with a new one. It might be that the socket is mangled inside.

If that doesn't work then check the pcb traces leading to the socket for any cracks and layer some solder over the broken tracks. The PCB is probably conformal coated which will need to be scrapped off if you want to repare broken tracks.

 

[3hree6ixty]

thanks. hmm.. any idea where to get the socket? i dont see it being sold anywhere and it looks different. then again, the only sockets that i've worked with are guitar output jacks and audio ports on a computer...

 

[zenesh]

Are the sockets box type with 6 soldering legs?

I might be able to help you with those.

Hopefully it is just the input jack.

When there is no sound, you wiggle the jack then it is fine? So you do stop playing to wiggle the jack yeah?

You can find the schematics here

http://www.drtube.com/marshall.htm

 

[widdly]

thanks. hmm.. any idea where to get the socket? i dont see it being sold anywhere and it looks different. then again, the only sockets that i've worked with are guitar output jacks and audio ports on a computer...

Sim Lim Tower has a bunch of different sorts if you hunt around. Looking at this schematic http://www.drtube.com/schematics/marshall/8080-pre.gif it looks like a switching jack that switches the input to earth when nothing is plugged in. Its probably like the ones 3hree6ixty described.

 

[3hree6ixty]

Are the sockets box type with 6 soldering legs?

I might be able to help you with those.

Hopefully it is just the input jack.

When there is no sound, you wiggle the jack then it is fine? So you do stop playing to wiggle the jack yeah?

You can find the schematics here

http://www.drtube.com/marshall.htm

i really cant read schematics. but from what u say , that it's the one with the 6 soldering legs, yes it is...

 

[charles]

hey there. does the salvation army have a connection to valvestate 8020-8080 series or what. i got my vs 8020 from the salvation army located bukit timah! haha. pretty awesome amp. and i think its ur input jack. just change it. even if its not the input jack its not expensive.

 

[PatheinRaindropMoe]

salvation army dont have anything to do with marshall or guitar in general.

but they have this service(from their website)

Salvation army thrift store

"The Red Shield Industries (RSI) Family Thrift Stores are a social enterprise as well as a serving ministry. The Salvation Army receives donations-in-kind from the public and companies. In turn, RSI resells them at affordable costs through its network of Family Thrift Stores. The income generated supports Salvation Army social and community programmes."

 

[3hree6ixty]

probably Charles here was just lucky someone donated the amp to the thrift-store. my dad works for the salvation army thrift store. i should know.

 

[zenesh]

Haha lucky guys. I worship at the salvation army church in Bishan and these stuff never make it to our worship inventory.


I should have some extra 6 pin input boxes. Do pm me if you want them 360..

I got them from the states when i was changing a fender amp some time back.

Regards