Pot replacements for Mexican precision bass deluxe series-98-99?

ellangus

Help!

My son has a Mexican precision bass deluxe series-98-99 red with gold anodised pickguard with passive pickups (1 x Jazz and 1 x Precision).

He has an issue with a crackly pot (not sure which) and has asked if I can sort it.

I have decide that the best course of action is to replace the pots as the are reasonably cheap and it would be a good place to start.

I would like to do it during the festive period, but my problem is that I can't get my hands on the instrument before Christmas so that I can see what the pots are which I would need to buy for the job.

Does anyone know which pots are in the bass - 250k or 500k, Linear or Audio-taper.

I THINK it currently has 2 vol + 1 master tone.

Pic attached of the bass

Thanks all.

https://imgur.com/ei8mltF

ICBM

Try some contact cleaner first before spending time and money replacing what are probably perfectly good parts.

ellangus

Blimey @ICBM that was quick!

Probably wise thing to do - in the event of it needing replacements though - do you know which parts are needed?

Cheers

ICBM

ellangus said:

Blimey @ICBM that was quick!

Probably wise thing to do - in the event of it needing replacements though - do you know which parts are n@ ;

I live to serve .

Not sure - traditionally Fender always used 250K Log, but I'm fairly sure that some earlier Mexican ones used 500K - I can't remember about this series. It actually won't make a huge difference, surprisingly.

ellangus

Excellent - I knew I could rely on you ;-) Thanks

Funkfingers

ellangus said:

anodised pickguard

These can create noise problems, in and of themselves. Check everything for reliable connections to ground.

ellangus said:

Does anyone know which pots are in the bass - 250k or 500k, Linear or Audio-taper.

Traditionally, all pots are audio taper 250k. Hopefully, the stock pots in your son's instrument have the same size threaded shaft diameter as the intended replacements. Otherwise, you will be enlarging the holes in the aluminium.

ICBM said:

I'm fairly sure that some earlier Mexican ones used 500K - I can't remember about this series. It actually won't make a huge difference, surprisingly.

I cannot remember either.

Much depends on how cheap 'n' nasty the stock pickups are. i.e. Stud polepieces and underslung ceramic bar magnets instead of "proper" alnico rod magnet sections. 

ellangus said:

2 vol + 1 master tone.

Correct ... but the proposed component upgrade would be an opportunity to reconfigure to Volume, Balance, Tone, if desired.

In recent weeks, @Bridgehouse has been raving about East onboard active electronics systems. Not inexpensive but far more affordable than a USA Fender instrument.

ellangus said:

... a good place to start.

Dangerous talk. Costs money.

If you are minded to eventually upgrading more than just the controls and output jack socket, consider that the EMG-GZR PJ pickup outfit includes the pots, jack socket and all interconnection cables. 

The Quick Connect solderless system means that, in the longer term, it would be a doddle to add an EMG-TBC or -VMC active EQ accessory.

ellangus

Funkfingers said:

ellangus said:

anodised pickguard

These can create noise problems, in and of themselves. Check everything for reliable connections to ground.

ellangus said:

Does anyone know which pots are in the bass - 250k or 500k, Linear or Audio-taper.

Traditionally, all pots are audio taper 250k. Hopefully, the stock pots in your son's instrument have the same size threaded shaft diameter as the intended replacements. Otherwise, you will be enlarging the holes in the aluminium.

ICBM said:

I'm fairly sure that some earlier Mexican ones used 500K - I can't remember about this series. It actually won't make a huge difference, surprisingly.

I cannot remember either.

Much depends on how cheap 'n' nasty the stock pickups are. i.e. Stud polepieces and underslung ceramic bar magnets instead of "proper" alnico rod magnet sections. 

ellangus said:

2 vol + 1 master tone.

Correct ... but the proposed component upgrade would be an opportunity to reconfigure to Volume, Balance, Tone, if desired.

In recent weeks, @Bridgehouse has been raving about East onboard active electronics systems. Not inexpensive but far more affordable than a USA Fender instrument.

ellangus said:

... a good place to start.

Dangerous talk. Costs money.

If you are minded to eventually upgrading more than just the controls and output jack socket, consider that the EMG-GZR PJ pickup outfit includes the pots, jack socket and all interconnection cables. 

The Quick Connect solderless system means that, in the longer term, it would be a doddle to add an EMG-TBC or -VMC active EQ accessory.

Thanks for that lot Mr Fingers - much appreciated

spark

always I have seen 250K installed,  but I'm not sure if the volume pot is linear or Log, I think it will be Log just because is how "works" our ears.

prowla

I'd use 250k log.

CTS are generally acknowledged as one of the better brands and Switchcraft for jack sockets.

ICBM

spark said:

always I have seen 250K installed,  but I'm not sure if the volume pot is linear or Log, I think it will be Log just because is how "works" our ears.

For general music, yes. But for a guitar volume control, linear can actually work better - the normal setting is full up, and Log drops the volume very rapidly as you turn down, usually too much so unless you’re using it to clean up an overdriven sound. (Which you probably aren’t with a bass.)

ellangus

OK, thanks for all the advice from everyone, finally got the bass and able to take a look.
It might just be a loose connection but I may need a 250k mini pot with a solid shaft, that's what's in there at the moment due to the tight space. The two volume pots are full size but it's the master tone which is at fault and it's right at the bottom of the scratchplate (where the jack socket usually is).

Does anybody know where I can get one - I've had a look at the usual places but they all seem to be split shaft.

Thanks in advance

Funkfingers

ellangus said:

I may need a 250k mini pot

There should be space in the control cavity for a regular CTS pot. You just have to be careful about the positioning of its three terminal lugs. i.e. Facing towards the two volume pots and, possibly, with the lugs flat rather than bent through ninety degrees.

ICBM

If it’s the tone pot it will just need cleaning, or at an outside possibility has a bad solder joint on it - the signal path doesn’t actually go ‘through’ the pot, and it never normally gets enough use to wear the track - the crackle will almost certainly be caused by dust from *lack* of use.

ellangus

ICBM said:

If it’s the tone pot it will just need cleaning, or at an outside possibility has a bad solder joint on it - the signal path doesn’t actually go ‘through’ the pot, and it never normally gets enough use to wear the track - the crackle will almost certainly be caused by dust from *lack* of use.

Thanks,
I'll clean and re-solder first as I think you may be right as it occasionally needs a 'tap' go get it to work. Given that they only cost a few quid, I was going to try and get a pot just in case so that I could fix it over Christmas should it need replacing, if not, it's always there as a spare.

ellangus

Funkfingers said:

ellangus said:

I may need a 250k mini pot

There should be space in the control cavity for a regular CTS pot. You just have to careful about the positioning of its three terminal lugs. i.e. Facing towards the two volume pots and, possibly, with the lugs flat rather than bent through ninety degrees.

Thanks for that.
When I took a look at it under the plate it did look very tight already, I'm guessing that's why Fender use the mini pot on that control only (The other two are full size).

Funkfingers

ellangus said:
Fender use the mini pot on that control only.

The tone pot connections need to clear the barrel jack contacts and fastening nut. 

ellangus

Funkfingers said:

ellangus said:
Fender use the mini pot on that control only.

The tone pot connections need to clear the barrel jack contacts and fastening nut. 

The jack socket is on the edge of the body on this bass. See pic. https://imgur.com/ei8mltF

ICBM

ellangus said:

I'll clean and re-solder first as I think you may be right as it occasionally needs a 'tap' go get it to work. Given that they only cost a few quid, I was going to try and get a pot just in case so that I could fix it over Christmas should it need replacing, if not, it's always there as a spare.

It's also worth using a pair of narrow-nose pliers to squeeze the rivets which hold the two terminals at the outer ends of the track board - occasionally these get a little loose and stop making a good contact with the board. It doesn't seem to often affect the middle one because the track is metallised rather than carbon normally.

ellangus

ICBM said:

ellangus said:

I'll clean and re-solder first as I think you may be right as it occasionally needs a 'tap' go get it to work. Given that they only cost a few quid, I was going to try and get a pot just in case so that I could fix it over Christmas should it need replacing, if not, it's always there as a spare.

It's also worth using a pair of narrow-nose pliers to squeeze the rivets which hold the two terminals at the outer ends of the track board - occasionally these get a little loose and stop making a good contact with the board. It doesn't seem to often affect the middle one because the track is metallised rather than carbon normally.

Will do - Excellent advice, thanks for that