20K dual Variable Resistor - centre indent - Resources?

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sheeny
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20K dual Variable Resistor - centre indent - Resources?

Post by sheeny » 04 Mar 2018, 11:25

Hi there,

Can anyone point me in the right direction to source the following?

CTS 280S1109 (20K dual variable resistor - PCB Mount long) Body assembly approx 15mm

I'm replacing a faulty blend pot in a Fender Jazz Bass Elite 2016

Images: https://1drv.ms/f/s!AmWlm0pa7YtDqwJJJ81a16B03Zuu

Very difficult to find.

Thanks in advance.
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by bassbass » 04 Mar 2018, 12:10

What taper is it? If MN, then a 25K will work fine, and these are easy to find.

If linear, then these are also easy to find without the centre click. 25K or 22K would work fine.

(I have a feeling I might have a B20K with click though, I'll have a look...)

If it's A/C, then that'll be harder to find. Try bartolini maybe? I seem to recall seeing A/C blend pots in their twin-buffer (iow active blend) stuff... Again, 25K or 22K will work fine.

As for the right-angled lugs, well For this you'd need a genuine fender part I'd say. And this will give you a nice quality CTS pot, so if not too $$, then worth it I'd say.

For regular pots, you can still mount them on a board like this, with wire extensions, (or possibly flying leads.) But find a tech with PCB experience. The old will need to be removed gracefully, and the new needs to be mounted at the right height.

If you get one with a 6mm splined shaft, that's also not the end of the world. Use an adapter sleeve for your 1/4 knob...
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sheeny
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by sheeny » 04 Mar 2018, 13:05

Thanks for the heads up. Just about to determine the taper atm.

Also, I need a centre click.

Cheers, Sheeny
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by bassbass » 04 Mar 2018, 19:54

OK, cool, well I have 3 or 4 B25K dual gangs with centre clicks...
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by bassbass » 05 Mar 2018, 10:20

PS:


BTW, is it actually busted, or just scratchy? Perhaps it just needs a squirt of contact cleaner...

Oh, and what about Fender Australia for a genuine part?...
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by sheeny » 05 Mar 2018, 10:54

I'll try Fender Australia for sure!

I've contacted CTS direct as well.

It's a lot more than scratchy, it is failing readings on one of the two pots on the assembly.

One is fine, the other goes to ground.
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by bassbass » 05 Mar 2018, 11:09

Cool. Well good luck mate. Happy to post one to ya if you can't otherwise work it out. They've been kicking around in my parts bins for years. They tested ok, though. They are just Alpha type ones, but would work fine as long as they are installed by someone with good soldering experience...
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by sheeny » 05 Mar 2018, 11:13

Thanks very much Rob, I really appreciate it!!

I'll definitely let you know either way how I go sourcing genuine.

I've never had so much trouble finding a part in my life!! LOL
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by bassbass » 05 Mar 2018, 11:16

PS: when pots fail in active preamps, I always test that they don't have DC across them. If there's another prob in the pre, say a bad cap, and the pot is between two different DC voltages, it will crackle when rotated and have a fairly short life. With multimeter set to VDC and the black probe to earth, both sides of the pot should read the same voltage. Usually zero V, but it may be 1/2 of the battery voltage, depending on the pre design...
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by sheeny » 06 Mar 2018, 08:11

Well I just received a response from an official fender genuine parts supplier form the states....

"Hello again John,

Fender have informed me that they do not sell the pot you are looking for without purchasing the control PCB. The control PCB is on backorder until March 30th, here is the part/ordering information. Let me know if you have any additional questions.

Fender Part#: 7708254000 PCB,CONTROL W/ HARDWARE AM ELITE J BASS 2016

$183.99 ea"


USD too, and that's not shipping from a freight forwarder in the US included either, because they don't directly ship internationally....What a bargain eh? all for a $2.50 part, if that? :(

I'll PM you Rob, and we can chat.
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by bassbass » 06 Mar 2018, 23:30

Ouch. But that's the way of the world I'm afraid, with surface mount boards.

So is it actually a dual gang linear pot?

FWIW, EMG have used a 25K dual gang linear blend pot for their active pickups for well over 20 years. But in recent years it comes on a little pcb which you'd have to desolder to make work with your board. They are quality Alps pots, but desoldering this would probably stress the pot a fair bit. Plus they are really expensive these days: https://www.ebay.com.au/itm/EMG-Blend-B ... xy83JRHMJa Plus getting hard to find as EMG now sell little active twin-buffer blend controls. (I'm not sure they even list this on their site anymore.)

FWIW, when you go to remove your dead pot, don't bother trying to desolder it all intact. You are better off cutting the legs, then desoldering each individually. You are much less likely to damage the board this way. You'll also need too use a desolder pump to clear the holes.
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by sheeny » 07 Mar 2018, 07:29

So, I've had correspondence from a Fender Tech in USA now, it's actually a 250K pot (apologies from novice the electronics enthusiast!). I retested the pot again, and now it's working fine???. Yes, I did cut and remove as recommended, and re-installed successfully. However, it all now points most likely to a PCB issue - way outta my league.

Unfortunately, I'm going to have to bite the bullet on this one and order a replacement. :(
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by bassbass » 07 Mar 2018, 08:39

Hey mate, no sweat. Good luck with the repair.
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by sheeny » 07 Mar 2018, 08:40

Thanks for your very informative input Rob!! Much appreciated :)
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Re: 20K dual Variable Resistor - centre indent - Resources?

Post by sheeny » 20 Mar 2018, 08:09

So anyway....a little further down the track now....

I have a further (and related) question for the tech heads. My Fender Jazz Elite 2016 obviously has a faulty pcb mounted blend pot. While I'm waiting for my backordered replacement pcb (should be here in about three weeks) , I thought I'd have a play with the original one....It was now clear from emails received that Fender or CTS (pot manufacturer) refuse to sell me the single component. I've subsequently been in touch with Fender service (USA - Australia won't ever reply to any emails) and they actually suggested a replacement pot which I have now fastidiously mounted on the pcb (nice job if I do say so myself. Now I get a full bridge pickup signal full turn one way (counterclockwise), a full neck pickup signal the other way (clockwise), however at centre detent I have zero signal? Any clues?
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