1980 F-100 Neck Pup Sounding Thin/Low/Crappy

[s_danilo]

Hi there!

Just purchased a very clean and (seemingly) all original F-100. It has barely seen any action to say the very least...

Don't know if you've come across this "issue", but when I change from the bridge to the neck pickup, I sense a noticeable drop in volume and the sound becomes very thin (not in a good way, unfortunately). This happens only with both coils engaged.

With coil-splitting engaged, there is no volume loss and both pups seem calibrated.

I really did not want to mess with the wiring, as it seems all original and "untouched".

Thank you!!
SD | 1980 F100 S2

[Craig]

Hi there!

Just purchased a very clean and (seemingly) all original F-100. It has barely seen any action to say the very least...

Don't know if you've come across this "issue", but when I change from the bridge to the neck pickup, I sense a noticeable drop in volume and the sound becomes very thin (not in a good way, unfortunately). This happens only with both coils engaged.

With coil-splitting engaged, there is no volume loss and both pups seem calibrated.

I really did not want to mess with the wiring, as it seems all original and "untouched".

Thank you!!
SD | 1980 F100 S2

See these F-100 instruction sheets in our Gallery: Album: F-100 and F-100E Instructions.
Which version model do you have?

[s_danilo]

See these F-100 instruction sheets in our Gallery: Album: F-100 and F-100E Instructions.
Which version model do you have?

Thanks for the quick reply, Craig!
I have a 1980 F-100 Series II (just included the serial G003101 to the database). No active circuitry.

I had already seen those instructions here at this website... At first I thought the phase switch was inverted, but I don't believe so...
The "problem" occurs with the guitar is on "humbucking" + "in-phase": the rhythm pup sounds much lower than the lead pup.
It is the kind of side effect I was expecting to get when switching from humbucking to single. I'm starting to believe my rhythm pickup is only connected as single at all times. Maybe a loose connection?

Thanks again!
SD

[Craig]

See these F-100 instruction sheets in our Gallery: Album: F-100 and F-100E Instructions.
Which version model do you have?

Thanks for the quick reply, Craig!
I have a 1980 F-100 Series II (just included the serial G003101 to the database). No active circuitry.

I had already seen those instructions here at this website... At first I thought the phase switch was inverted, but I don't believe so...
The "problem" occurs with the guitar is on "humbucking" + "in-phase": the rhythm pup sounds much lower than the lead pup.
It is the kind of side effect I was expecting to get when switching from humbucking to single. I'm starting to believe my rhythm pickup is only connected as single at all times. Maybe a loose connection?

Thanks again!
SD

Check out this post [if you have not already ] : Test driving an F100 for a few weeks..

My F-100 is at our other home in Paso Robles, so I can't check mine out to give any any feedback. Perhaps, other members will be
able to help.

[s_danilo]

Check out this post [if you have not already ] : Test driving an F100 for a few weeks..

My F-100 is at our other home in Paso Robles, so I can't check mine out to give any any feedback. Perhaps, other members will be
able to help.

@Craig, thanks for the thread. I really appreciate your help here. :0)
The thread describes a very similar situation to mine. Will work on string action vs. pole pieces height asap.
I really hope that solves, because the control cavity is immaculate. Don't wanna mess with that... I also had to spray some Deoxit, but I guess this is pretty common when you have a 40-year old guitar, right?

BTW, my pots date from Dec 79. I have not seen the neck pocket yet, but since I have flat pole-pieces, I would bet my guitar is a 1980.

[john o]

Hi SD, the problem you describe sounds abnormal to me. I have an '81 F100, there is no significant volume loss when switching to the neck p'up with phase switch and coil splitter both off, nor is there any sig volume loss with coil splitter on. The eq of the p'ups changes with coil splitter on and there is something in the circuit that increases the bass frequencies a bit with this, but again, no sig volume loss. There is very mild output reduction with the phase switch on compared to off, and of course the sound you get with phase switch on is same no matter which setting of the pickup selector toggle.
I am electrically challenged so I can't explain your problem, but it may be worth checking out with a tech who is in the know.

[Danley]

My '83 F100 is the fattest, thickest sounding guitar I own (and is most fat in the neck position.) Does the guitar hum-cancel when the neck is selected? Can you measure the DC resistance at the jack with a multimeter when you select the neck pickup? Sounds like something is wrong.

[s_danilo]

Hi guys!

Following your suggestions, today I messed with the pups height and 80% of the volume-loss is gone! \0/
Since the F-100 gives us a huge amount of flexibility (polepieces + pickup heights) I'm assuming it will take me a looong time to fine-tune it to the tone I'm searching for, but I'm really releaved to have achieved such "quick results". Cannot forget to thank Craig, John and Danley for the attention dedicated to this post!

While studying my F-100, I learned a few things that I will post below for the sake of information/curiosity and in case of any future research on similar matters.

(1) Switches seem to be working as they should (tested all combinations)
(2) SINGLE MODE >> the coils closer to the bridge were ON, while the coils closer to the NUT were muffled (*not completely off)
(3) OUT OF PHASE >> the OUTER coils were ON, while the INNER coils were muffled (*not completely off)
(4) BRIDGE Resistance >> 7.36K (does not matter if single or humbucking is selected... I bet this is related to the *not completely off feature)
(5) NECK Resistance >> 289K (crazy, I know! I'm assuming this is related to the PTB wiring + reading from the output jack)

Thanks again!!
SD

[Danley]

Hi guys!

Following your suggestions, today I messed with the pups height and 80% of the volume-loss is gone! \0/
Since the F-100 gives us a huge amount of flexibility (polepieces + pickup heights) I'm assuming it will take me a looong time to fine-tune it to the tone I'm searching for, but I'm really releaved to have achieved such "quick results". Cannot forget to thank Craig, John and Danley for the attention dedicated to this post!

While studying my F-100, I learned a few things that I will post below for the sake of information/curiosity and in case of any future research on similar matters.

(1) Switches seem to be working as they should (tested all combinations)
(2) SINGLE MODE >> the coils closer to the bridge were ON, while the coils closer to the NUT were muffled (*not completely off)
(3) OUT OF PHASE >> the OUTER coils were ON, while the INNER coils were muffled (*not completely off)
(4) BRIDGE Resistance >> 7.36K (does not matter if single or humbucking is selected... I bet this is related to the *not completely off feature)
(5) NECK Resistance >> 289K (crazy, I know! I'm assuming this is related to the PTB wiring + reading from the output jack)

Thanks again!!
SD

Cool; I'll have to check the measurements on mine again but they probably will be different anyway since the '83s/newer F100s were wired different (tone works on the bridge pickup.) MFDs pretty much need to be close to the strings

[john o]

the DCR measurements on my F100 p'ups are 7.26 neck, 7.46 bridge

pic