It is currently Mon Mar 16, 2020 8:27 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 22 posts ]  Go to page 1, 2  Next
Go to page 1, 2  Next
Author Message
Post subject: Frontman 212R potentiometers
Posted: Fri Nov 03, 2017 7:01 am
Offline
Hobbyist
Hobbyist

Joined: Fri Nov 03, 2017 6:52 am
Posts: 11
Hi everyone!
So I own a 10 years old Frontman 212R, all the pots are shattered so they need to be replaced.
These are snap-in pots like this one:

http://musicpartsguru.com/closeup.asp?s ... 5&offset=2

Well, I ordered some regular pots (not snap in) and thought I could build the extra connections with some wiring. The thing is that these pots conduct between the shell and the shaft while the original ones they're isolated. So that means that, unlike the original, the replacements pots will be electrically connected to the chassis.

I take it that's a big problem, right?


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Frontman 212R potentiometers
Posted: Mon Nov 06, 2017 1:57 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14045
Location: Province de Québec, Canada
dazz. wrote:


I take it that's a big problem, right?


No.

Do you try to clean pots with high quality contact cleaner like Deoxit brand ?


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Mon Nov 06, 2017 2:32 pm
Offline
Hobbyist
Hobbyist

Joined: Fri Nov 03, 2017 6:52 am
Posts: 11
stratele52 wrote:
dazz. wrote:


I take it that's a big problem, right?


No.

Do you try to clean pots with high quality contact cleaner like Deoxit brand ?


I got some contact cleaner but it's crap. It instantly ruins pots. This one http://www.3enuno.es/dynamic-LIMPIADOR% ... 9&pid=1062

But the original pots were shattered anyway so even if I had a good contact cleaner it would make no sense to use it. By shattered I mean the shafts snapped in two while I was removing the knobs in 7 out of 10 pots! Most of those were impossible to turn.

That's why I decided to go with cheap generic pots I got for 10€ from china (And I have enough to change them all 3 times). The original ones were crap anyway and those cost $4 each plus shipping. No thanks

BTW, I checked again and the shaft in the original pots are indeed electrically connected to the bracket. Good to know that wouldn't have been an issue anyway,

thanks stratele!


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Mon Nov 06, 2017 3:00 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14045
Location: Province de Québec, Canada
:)


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Mon Nov 06, 2017 3:08 pm
Offline
Hobbyist
Hobbyist

Joined: Fri Nov 03, 2017 6:52 am
Posts: 11
stratele52 wrote:
:)


Just for the sake of reassurance, may I ask if my "ghetto" approach (bend some wire to form a 4 legged bracket, solder that to cheap generic chinese pots, put those in) makes sense here please?

Mercy!


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Mon Nov 06, 2017 3:20 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14045
Location: Province de Québec, Canada
I can't tell without seeing the amp circuit and pot


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Mon Nov 06, 2017 3:37 pm
Offline
Hobbyist
Hobbyist

Joined: Fri Nov 03, 2017 6:52 am
Posts: 11
stratele52 wrote:
I can't tell without seeing the amp circuit and pot


Here's the amp's schematics

https://mega.nz/#!79oTGCRC!oiPrcDMbJ1DG ... wQNgOW56O8

The pots are "snap-ins" like this one, but with split shafts

http://musicpartsguru.com/closeup.asp?s ... 5&offset=2

The values and tapers are:

CLEAN CHANNEL

Volume 1: B50K
Treble: B50K
Mid: 15A 5K
Bass: 15 50K

DRIVE CHANNEL

Drive: 30C 100K
Volume: B100K
Treble: 30C 100K
Mid: B50K
Bass: 30C 250K

REVERB: B50K

The replacement pots I got are these:

https://www.aliexpress.com/item/5pcs-st ... 0.0.c6YfVi

http://www.ebay.es/itm/2-x-50K-OHM-Loga ... 2749.l2649

http://www.ebay.es/itm/2-x-200K-OHM-C20 ... 2749.l2649

http://www.ebay.es/itm/2-x-5K-OHM-Logar ... 2749.l2649

http://www.ebay.es/itm/2-x-100K-OHM-C10 ... 2749.l2649


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Mon Nov 06, 2017 3:42 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14045
Location: Province de Québec, Canada
I don't talk about shematic but picture of the board.

Pots must grounded to the amp ground, with or without leg.


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Tue Nov 07, 2017 7:52 am
Offline
Hobbyist
Hobbyist

Joined: Fri Nov 03, 2017 6:52 am
Posts: 11
stratele52 wrote:
I don't talk about shematic but picture of the board.

Pots must grounded to the amp ground, with or without leg.


Oh, I see. So I guess I need to check all pots for connectivity to GND once mounted.
We'll see how that goes! Thanks again


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Tue Nov 07, 2017 7:58 am
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14045
Location: Province de Québec, Canada
dazz. wrote:

Oh, I see. So I guess I need to check all pots for connectivity to GND once mounted.
We'll see how that goes! Thanks again


If no reading from pot body to ground, you may had some wire. I guess amp faceplate is at ground and you won't need anything.


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Tue Nov 07, 2017 9:16 am
Offline
Hobbyist
Hobbyist

Joined: Fri Nov 03, 2017 6:52 am
Posts: 11
stratele52 wrote:
dazz. wrote:

Oh, I see. So I guess I need to check all pots for connectivity to GND once mounted.
We'll see how that goes! Thanks again


If no reading from pot body to ground, you may had some wire. I guess amp faceplate is at ground and you won't need anything.


Looks like the coating in the faceplate is not conductive, so the pots are not connected to the chassis through the retaining nut & washer. The chassis is definitely grounded (green wire from chassis to center pole of the AC plug)


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Thu Nov 23, 2017 9:37 am
Offline
Hobbyist
Hobbyist

Joined: Fri Nov 03, 2017 6:52 am
Posts: 11
stratele52 wrote:
If no reading from pot body to ground, you may had some wire. I guess amp faceplate is at ground and you won't need anything.


Just dropping by to say thanks again, stratele. The pots arrived today, and everything went smoothly. Can't believe I didn't botch it, LOL

212R Ready to rock again!


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Thu Nov 23, 2017 3:45 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14045
Location: Province de Québec, Canada
:)


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Fri Aug 30, 2019 6:35 am
Offline
Hobbyist
Hobbyist

Joined: Fri Aug 30, 2019 6:20 am
Posts: 7
Quote:
Just dropping by to say thanks again, stratele. The pots arrived today, and everything went smoothly. Can't believe I didn't botch it, LOL



212R Ready to rock again![/quote]

Hi dazz,

I also need to replace my pots and am thinking of using the list of substitute parts you provided.

Does everything work correctly? Did it all fit properly? Was it strictly just solder the new pots in and no jumper wires?

Any insight you can give me would be appreciated.

Hopefully you see this after 2 years.

Thanks,

Mark


Top
Profile
Post subject: Re: Frontman 212R potentiometers
Posted: Tue Sep 03, 2019 5:24 am
Offline
Hobbyist
Hobbyist

Joined: Fri Nov 03, 2017 6:52 am
Posts: 11
Mark4P wrote:

Hi dazz,

I also need to replace my pots and am thinking of using the list of substitute parts you provided.

Does everything work correctly? Did it all fit properly? Was it strictly just solder the new pots in and no jumper wires?

Any insight you can give me would be appreciated.

Hopefully you see this after 2 years.

Thanks,

Mark


Hi Mark. I ended up selling the amp after a few months. Everything seemed alright, but if I was doing it again I would get Alpha pots. They're quite inexpensive and very good quality.

You can get them here:

Linear: https://www.taydaelectronics.com/potent ... inear.html
Log: https://www.taydaelectronics.com/potent ... thmic.html
Anti-log: https://www.taydaelectronics.com/potent ... verse.html

I don't think snap-in pots are strictly needed. These should be a good fit, just make sure they're tightly screwed to the chasis to avoid stressing the solder joints when they're loose. No jumpers required either.

Good luck!


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 22 posts ]  Go to page 1, 2  Next
Go to page 1, 2  Next

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: