Need help diagnosing / fixing problem with neck pickup in HSS type guitar

[krm27]

I'm trying to learn about DIY guitar repair, so I'm tackling an issue with one of my guitars, and I need help. It's my first attempt to fix, or actually understand, the electronics of a guitar.

The guitar is a 1985 Yamaha SE612, which is a fat-strat style with a 5-way selector switch, a volume knob, a tone knob, and a push-push switch on the tone knob which coil splits the bridge humbucker.

Since I got this guitar a couple years ago it's had the same issue. Basically, the neck pickup has very low volume/output. So if I plug it into an amp and run through the 5-way switch, I get normal volume/output from position 1 (bridge only) whether in humbucker or coil split mode. Same for position 4 (bridge & middle). Position 3 also seems to have normal volume/output (middle only). Position 2 (which I think is middle & neck) is noticeable quieter, like half as loud as the middle alone. So there's a problem there with the reduction in volume/output. Position 5 is even worse, like 1/2 as loud as position 4, maybe even quieter than that. However, it does have SOME output that I can hear if I crank the amp.

I don't know much about pickup electronics, but my gut tells me this problem might be easier to diagnose/fix if the neck was completely silent. I've been doing google searching and cannot find anyone talking about this same kind of problem with super-low volume in just the neck pickup.

Anyone have some thoughts on this? I have a digital multimeter, though I have never used it. I could figure out how to read the output on the neck pickup if that would help diagnose the issue.

Ken

 

[GuitarDoc]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

(I think you got position #2, and pos. #4 mixed up).

Have you tried moving the neck pup closer to the strings?

 

[firebirdguy72]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

+1 on the pickup height. Also if that doesn't help what I'd do is check the connections at the switch and pot to make sure you're getting a good connection to both. I'd also check the DC ressistance while you're at it. If there is a considerable difference in the ressistance than there could be a short in the coil. Something like 4k in the neck versus 6k in the middle means there is probably a short and the pickup either needs replaced or rewound... replaced being the better option because than you can put an SD in it and then really rock!

 

[Funkfingers]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

What type of selector switch does the guitar have?

I would expect either the ol' YM-50 (looks like a CRL only with the poles on the "wrong" sides!) or a generic eight-contacts-in-line type. In either case, these do tend to wear out more quickly than American switches.

Refresh the solder joints at the switch and on the baseplate of the offending pickup. Try electro-lubricant on the switch contacts.

EDIT - It is possible that the neck pickup has shed one of its underslung bar magnets.

 

[swissmountain]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

Unless you buried the neck pickup compared to the others (which can be easily corrected by setting the pickup to a appropriate height) and the problem does not go away after reflowing the solder connections either the pickup itself or the selector switch is at fault. Swap the connections on the switch for the bridge and neck pickups. If the fault stays with the switch position, it's the switch - replace it. If the fault moves with the pickup, it's the pickup - replace it or have it repaired/rewound.

 

[krm27]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

I am probably counting the switch positions backwards, with bridge as 1 and neck as 5, it just always made more sense to me since I read from right to left, but regardless I spelled out what pickup combos I meant by which position #'s I was using.

I figured out how to use my multimeter this morning from YouTube videos to check both dc resistance and alternating voltage output. Here's the data I got:

1. Resistance / Ohms:

Neck: 5.74
Middle: 5.71
Bridge: 10.59 (humbucker mode) / 5.41 (split coil mode)

That all seems okay to my uneducated eye.

2. Alternating voltage / output when strumming unplugged:

Neck: Up to 0.3 milliwatts
Middle: Up to around 50 milliwatts
Bridge: Up to around 75 milliwatts

FYI, I also checked alternating voltage on the 2 & 4 positions.

To avoid confusion, I'll omit position numbers and just use names: In the bridge-middle combo position I got around 60 milliwatts which seems in line with the rest. In the middle-neck combo position I got the same as for the neck alone -- 0.3 or so milliwatts, or nearly nada.

This surprised me a bit because while this middle-neck combo position is significantly quieter than it should be, it's still noticeable louder than the neck alone. I will say that I may not be perfect at reading alternative voltage and there was a lot of jumping around of the reading, and it may have jumped up higher than 10 milliwatts a few times when I was reading this position. Maybe higher voltage is coming through sporadically? I don't know.

As a total electronics noob, I'm guessing these readings tell me that (1) the pickup is healthy, (2) the problem is the wiring between pickup and output jack, and (3) maybe some way the neck pup is wired is "bleeding" the voltage to ground or something and when the neck-middle pickups are joined this results in a further partial bleed from the middle as well?

Any more advice on where to go next? Should I be looking at grounding or other wiring issues? What kind of "wrong" wiring set up leads to a diminished -- but not totally absent -- voltage output? Are my guesses valid or am I off base?

Ken

 

[firebirdguy72]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

I am probably counting the switch positions backwards, with bridge as 1 and neck as 5, it just always made more sense to me since I read from right to left, but regardless I spelled out what pickup combos I meant by which position #'s I was using.

I figured out how to use my multimeter this morning from YouTube videos to check both dc resistance and alternating voltage output. Here's the data I got:

1. Resistance / Ohms:

Neck: 5.74
Middle: 5.71
Bridge: 10.59 (humbucker mode) / 5.41 (split coil mode)

That all seems okay to my uneducated eye.

2. Alternating voltage / output when strumming unplugged:

Neck: Up to 0.3 milliwatts
Middle: Up to around 50 milliwatts
Bridge: Up to around 75 milliwatts

FYI, I also checked alternating voltage on the 2 & 4 positions.

To avoid confusion, I'll omit position numbers and just use names: In the bridge-middle combo position I got around 60 milliwatts which seems in line with the rest. In the middle-neck combo position I got the same as for the neck alone -- 0.3 or so milliwatts, or nearly nada.

This surprised me a bit because while this middle-neck combo position is significantly quieter than it should be, it's still noticeable louder than the neck alone. I will say that I may not be perfect at reading alternative voltage and there was a lot of jumping around of the reading, and it may have jumped up higher than 10 milliwatts a few times when I was reading this position. Maybe higher voltage is coming through sporadically? I don't know.

As a total electronics noob, I'm guessing these readings tell me that (1) the pickup is healthy, (2) the problem is the wiring between pickup and output jack, and (3) maybe some way the neck pup is wired is "bleeding" the voltage to ground or something and when the neck-middle pickups are joined this results in a further partial bleed from the middle as well?

Any more advice on where to go next? Should I be looking at grounding or other wiring issues? What kind of "wrong" wiring set up leads to a diminished -- but not totally absent -- voltage output? Are my guesses valid or am I off base?

Ken

The pickup is fine... it doesn't sound like anything is wired wrong because you have the correct options for pickups in the correct switch positions so it sounds to me like it's just a bad connection at the switch or the switch is just worn out in that position. I'd reflow the solder on the neck position on the switch just like these guys said and see if that cures it.

 

[krm27]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

firebirdguy: Thanks, I'll start with that.

This raises a new thought/question: Could the switch solder joints be okay, but the actually choice of where to solder the wires was wrong? Because I see the back of the switch has 8 "nodes" in a row and the pickup wires go to the first four of them and the other four are empty. It makes me wonder if maybe the placement is wrong rather than the quality of soldering. Is there a place to see how a 5-way switch that has an 8-in-a-row set up on back should be wired for this type of HSS guitar? Note, I found a wiring diagram for this type of guitar, but it shows the switch as having two rows of four "notes" rather than one row of eight "nodes" so it does not tell me how the 8-in-a-row style of switch should be wired for HSS.

Ken

 

[firebirdguy72]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

firebirdguy: Thanks, I'll start with that.

This raises a new thought/question: Could the switch solder joints be okay, but the actually choice of where to solder the wires was wrong? Because I see the back of the switch has 8 "nodes" in a row and the pickup wires go to the first four of them and the other four are empty. It makes me wonder if maybe the placement is wrong rather than the quality of soldering. Is there a place to see how a 5-way switch that has an 8-in-a-row set up on back should be wired for this type of HSS guitar? Note, I found a wiring diagram for this type of guitar, but it shows the switch as having two rows of four "notes" rather than one row of eight "nodes" so it does not tell me how the 8-in-a-row style of switch should be wired for HSS.

Ken

The wiring on the switch should be correct, otherwise you would not have all the correct pickup combos... Like Bridge only, bridge+middle, middle, middle+neck, neck... If it weren't wired correctly you wouldn't have all the correct combos. And from what I have read you do.

 

[Funkfingers]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

The circuitry of your guitar only requires one pole (set of four contacts) to function.

If the problem is damage or wear to the innards of the selector switch, you might get away with simply relocating the four cables to the unused half of the switch.

Visualise the switch terminals (left to right) numbered 1 through 8.

1 - 3 are the pickup terminals.
4 and 5 are the outputs for each half of the switch.
6 - 8 are another set of terminal where the pickups could be connected.

The terminals are functionally interchangeable in the following pairs;
1 and 6
2 and 7
3 and 8
4 and 5.

 

[krm27]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

Is there a way to use my multimeter to more precisely isolate where the connection is failing, like using the continuity function? Or is there a way to use the continuity function to test if the 5-way switch is damaged/worn?

Ken

 

[firebirdguy72]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

It will be failing right where the pickup lead wire is connected to the switch. Just follow it to the switch, reflow the solder and see if that does it... If you redo the connection and it still does not work than the switch is worn out in that position. Then you could put some di-electric grease inside and see if that helps. If not a new 8 row style switch is only a few bucks. Unless you want to upgrade to a CLR switch like a real fender. That's a bit more but imo worth it.

 

[krm27]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

So, before I dive in de-soldering or soldering anything, I'm trying to get an understanding of the wiring in general so I understand this stuff better. I tracked the various wires that I see in the main cavity (behind the pots) but it's still rather confusing because I can't seem to get the wiring to match up to any of the HSS+coil split diagrams that I've found online. Yet it seems to work, in that the coil split switch works and the switch seems to work but for the low output in the positions that use the neck pup.

Anyway, if anyone has time/inclination to sort through this and maybe explain what's going on here, here's what I got:

wires from HSS pups:
- 5 black-sheathed wires or sets of wires
-- 1 - to back of volume pot (ground?)
-- 2 - to back of volume pot (ground?)
-- 3 - splits into 2 white wires
--- a - back of volume pot (ground?)
--- b - 5-way switch position 1
-- 4 - splits into 2 white wires
--- a - back of volume pot (ground?)
--- b - 5-way switch position 2
-- 5 - splits into 3 wires (bare, red and white)
--- bare - to ground on side of tone pot (ground?)
--- red - turn white & connects to 5-way switch position 3
--- white - to tone pot push-pull prongs (6 prongs in 2 rows of 3, with this wire connected to middle left prong)
- 1 bare ground wire
- to back of volume pot (ground?)

From Volume Pot positions 1 - 3
(numbering 1 to 3 from left to right when looking at it from BACK, which is opposite of some sources online I've seen, but you know what I mean):

- 1 (in) - two white wires come off it
-- a - switch position 4
-- b - splits
--- i - back of volume pot (ground?)
--- ii - splits in 2
---- A - tone pot position 2
---- B - side of tone pot (ground?)
- 2 (out) - splits in two
-- a - back of volume pot (ground?)
-- b - input jack
- 3 (ground) soldered to side of volume pot

From Tone Pot positions 1 - 3
(again counting from left to right looking from BACK)

- 1 - nothing
- 2 - split into 2 wires
-- a - side of tone pot (ground?)
-- b - splits again into two wires
--- i - back of volume pot (ground?)
--- ii - volume pot position 1
- 3 - soldered to one leg of capacitor

From capacitor
- one leg soldered onto tone position 3
- one leg soldered to side of tone pot (ground?)

From push-pull prongs
- one wire on middle left prong (mentioned above, presumably from humbucker)
- the two middle prongs are soldered together
- lower left prong wired to ground

Now, I've tried to find diagrams for HSS with coil split that would "match" up to what I'm seeing, but I have not been successful. If anyone can link to that, I'd be much obliged.

I find some diagrams of 8-prong 5-way switches that show connections to more than 4 prongs and that confuses me, like prong 4 is connected to prong 5, but that's not happening on my guitar. I don't see a diagram of HSS using only the first 4 prongs like is happening here. Also, the fact that my push-pull middle prongs are soldered together does not match any push-pull wiring diagrams I've found. In general, it seems to me that there are a LOT of wires going to ground, I'm wondering if any of this is redundant.

Oh, of the 5 black wires coming from the pups, I cannot easily tell from visual inspection which is coming from which pups (though I can deduce it from what they are hooked to, I suppose) because I'd have to remove the strings & pups to "see" that and I'm trying to avoid that. So I have not said in the above summary which black wire comes from neck, middle or humbucker, but I don't think that's needed at this stage (could be wrong?)

Ken

 

[krm27]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

Oh, in case I did not mention, the switch is VLX-53 (8-in-line contacts).

Ken

 

[krm27]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

Since a picture is worth 1000 words, I have attempted to illustrate the connections that I see. Now, I have not taken the pups out and therefore, from the back cavity, I cannot tell visually which wires come from which pups. However, I assume the wire that branches off to the coil split switch must come from the humbucker, and I've made some other "deductions" and have come up with my best guess on this. See attachment. I'd love to hear any input on this. Wire colors made up by me to make it easier to read, all the wires in the guitar are black, white or red. Note, based on the wires to switches, I think I'm showing the 5-way switch upside down and this was wires up using positions 5-8 of the VLX-53 switch.

 

[Funkfingers]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

In your drawing, read the selector switch contact numbers from left to right. You are using 1 through 4.

The switch is crud. A direct replacement will eventually fail in exactly the same way.

Either buy an American eight contact switch and follow an American schematic diagram or get ambitious, buy a Superswitch and get more sounds out of your guitar.

 

[krm27]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

Well, the diagrams I've found on these 5-way switches for HSS set up seems to indicate that the bridge humbucker goes to 1st position, middle to 2nd position and neck to 3rd position. However, the one thing I'm pretty sure of is that my bridge humbucker is going to what I have diagrammed as the 3rd position (because it comes from same set of wires that go to the coil split). So I wondered how this could be right.

Then I recalled some one above said that you could wire to the 5th through 8th connectors instead of the 1st through 4th, but you'd have to realize how these match up to the 1st through 4th, so in these 8-in-a-row switches, positions 3 and 8 are the same, positions 2 and 7 are the same, and positions 1 and 6 are the same, and 4 and 5 are the same. Or something like this:

Fender 2-row set up:
1--0
3--1
5--3
0--5

Import 8-row set up
1 - 3 - 5 - 0 - - 0 - 1 - 3 - 5

This got me thinking I might be looking at the 5-way switch backwards/upside down, maybe it already IS wired to the 5th through 8th positions rather than the 1st through 4th. I checked how this would work out, and it turns out it would be "right" in that the bridge would be going to the 6th position which is equivalent to the 1st position, which is what the diagrams say the bridge should go to. So I'm starting to believe this is wired to positions 5 through 8 and I was looking at the switch backwards. If that's no the case, and this is wired to positions 1 through 4, can some one tell me how the humbucker can be going to the 3rd position when all the diagrams I've read show it going to the 1st? Is there an article or thread I can read or a youtube video I can watch to get a better handle on this specific issue?

Lastly, I've read elsewhere that there are reliability issues with this VLX53 switch and I would not mind trading it out. The main issue is me not wanting to having to drill / route the body of the guitar. I think I have plenty of space already in terms of depth for any replacement switch (or even superswitch, which I read takes 1.5" depth and I have maybe 1/4" more than that). However, I'm not sure the opening for the switch itself or the screw holes for mounting it are standard among the different switches. I wonder, too, if some of the non-fender "super" switches might be better, as I've read some negative reviews on Fender's reliability and I know there are other makers of similar type switches. And maybe out of all the options there's at least one that will fit my current mounting specs (?) Anyone know how VLX53 mounting specs compare to the current crop of 5-way switches and super switches on the market?

Ken

 

[krm27]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

BUMP / UPDATE

So I changed out the 5-way switch, since the feedback seemed to suggest that was the most likely culprit of the problem. To restate the initial problem, my neck pickup has very low output, like 1/4 the bridge (maybe less, but still SOME output if I crank volume). The resistance measurement for neck pickup with multimeter is normal, 5.3 or so, so the pickup seems okay.

If I had intermittent sound, I might think I had a bad solder joint or something.
If I had no sound at all, I might think I had a short or a disconnected / broken wire.
I am at a loss as to what might be causing this low output, or what to try next to diagnose or fix it.

Hypothetically, if I take the whole pickup out of the guitar and have it sitting on my desk, is there any way to test it to make sure it's fully functional without actually putting it into a guitar? Note, I do get the "clacking" sound when I touch the pole pieces with a screwdriver while selecting that pickup, it passes that test and the resistance measurement test.

I'm considering de-soldering and re-soldering everything. However, if I cannot rule out bad wiring, then I might need to get some guitar wire and learn how to replace old guitar wire with new, as part of the fix. It would be a pain if I de-solder and resolder every connection and have the same problem and THEN have to try replacing the wires themselves.

Ken

 

[cardinal]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

So the problem wasn't the switch? That would have been my first guess. That or the neck pickup isn't grounded well (try reflowing all of the solder connections where the neck pickup is grounded).

If you're getting sensible resistance measurements from the pickup, it should be working. If it was shorting, the resistance reading would be strange.

You could try to measure the resistance reading you get at the output jack with everything wired up. See if it's giving you something strange in positions 4 or 5.

 

[Swyse]

Re: Need help diagnosing / fixing problem with neck pickup in HSS type guitar

What if the magnet is demagnetized from something? Wouldn't that cause his very low output? I've heard of people leaning guitars against amps and the angle causing only the neck pickup to be affected by the speaker magnets. I would try hooking the neck pickup directly to an output jack and seeing if it is then much louder, taking the other electronics out of the equation. If its not I would think the magnets need looked at.