Huge struggle installing 7-string pickups

[mholden020]

Hi everyone,

I'm trying to install a Pegasus/Sentient pickup set in a 7-string guitar and I'm having a very, very hard time getting a strong signal from the guitar. Last night I wired it up following the schematic on the SD website and it produced almost no sound at all (extremely faint, but it did make some noise), thought I might have wired the switch up wrong so I took that out and tried again only to get the same result. I've tested the pots and they're good, I tested the pickups with the "screwdriver to the poles" method and they made a sound but both have the same weak signal so I'm confident it's a wiring issue.

Today I've taken everything out of the guitar...again...and removed all the solder to start from scratch, but there are two things that have sent me for a loop:

- First, if I had the guitar plugged in and I poked the wire going from the input jack "hot" tab to the volume potentiometer's middle pole the guitar produced a massive hum. I found that I didn't actually have to touch this wire at all, just having my finger near it triggered the hum. That specific wire's in the garbage now and I've cleaned off both terminals to re-do it but nothing's reconnected at the moment.

- Second, the 3-position blade switch I'm installing does not match the SD schematic and I'm really having a hard time figuring out how to adapt the schematic to what I have. I've attached images below of my switch and the schematic, and the problem is that my switch's tabs are backwards. I've installed pickups on two other guitars and one had a blade switch so this isn't completely new territory, but I simply cannot make sense of how my tabs correlate to the schematic. I've looked at the switch and moved the blade to see what's connected at each setting, doing this resulted in my wiring the switch up backwards (Selecting NECK activated BRIDGE) but also had a weak sound. Swapping the pickup leads fixed that, but the sound was still weak and I'm not sure if I've wired the "bridges" correctly since I don't know which tab is which.

I'm in the process of checking the connections on the red/white wire pairings as well as the green/bare wire pairings, but I don't know what else to check. I'm at a complete loss here...

Thanks,
Matt

[AlexR]

On that type of 3 way you are attaching the pickups to the common lug.....the one that is always in contact with the slider. Those pics unfortunately do nothing to help here.

Try firstly wiring your pickup(s) directly to the jack. If it/they are both actually working 100% still, then try doing it/them into the volume pot -> Jack and re-test. Once you know both of those components are working then I think you are down to the switch wiring.

[mholden020]

On that type of 3 way you are attaching the pickups to the common lug.....the one that is always in contact with the slider. Those pics unfortunately do nothing to help here.

Try firstly wiring your pickup(s) directly to the jack. If it/they are both actually working 100% still, then try doing it/them into the volume pot -> Jack and re-test. Once you know both of those components are working then I think you are down to the switch wiring.

Even though the pictures didn't help, what you said helped me immensely so thank you so much!

Tested both pickups wired to the output jack and they both have pretty good output levels so I'll keep pushing on.

[mholden020]

Wired up again and the output is still extremely weak. It's slightly louder than it was but it's still not enough of a signal to do anything with...the sound from the pickups themselves is quieter than the hissing and humming. I'm at a total loss, I have double-checked the wiring over and over and it's just as the schematic shows, but it just doesn't work.

I've emailed SD's support for help but here's where it is right now:

- The switch is wired correctly and all connections are good. It's selecting the pickups as expected, no noise or issues when jiggling any of those wires.
- Both potentiometers read the correct resistance (500k) and they're wired as shown in the diagram, they control the volume and tone as expected for what can be heard.
- Both pickups are working, I tested this via the suggestion above but I feel I might need to point out that the sound was very scratchy when I did this.

The only thing I can find that is weird is the input jack's "hot" wire will start humming if I touch it, and wiggling it around will cause loud popping and hissing but I cannot for the life of me figure out why this is happening. I've replaced this wire three times and cannot get rid of this problem.

[AlexR]

Pots will die if you overheat them (especially during attaching grounds to casing) - so if your switch is indeed wired correctly it really leaves only one possible option. Did you try wiring a pickup via the pot to the jack after trying just to the jack as I suggested??

[GuitarDoc]

A couple good, clear pics of your wiring which show every wire and connection/solder joint could go a long way to helping us figure out the problem.

[mholden020]

Pots will die if you overheat them (especially during attaching grounds to casing) - so if your switch is indeed wired correctly it really leaves only one possible option. Did you try wiring a pickup via the pot to the jack after trying just to the jack as I suggested??

I did this late Saturday night (Bridge -> Pot -> Jack) and it produced no sound at all, so I removed the pot and went straight into the jack and it worked. Both pots on a multimeter produced very erratic readings so I purchased two new ones yesterday from the local store. These new pots show a value through the entire range while the other pots did not show a value at either extreme, even when the guitar was new and before I'd even plugged in the soldering iron.

[AlexR]

So you are still getting bad sound even with the new pots then?? Doublecheck that you still have good readings for the pot from input to output lugs at 10 (as in it should be no resistance.

Similarly with your multimeter set it to ohms (fairly low reading for continuity) and see what the readings are from the lug the pickups attach to on the switch through to both the volume pot 'input' lug and also the jack when the volume is set to 10. This should really be less than 1ohm, and nominally 0 ohms. Cycle through the switch positions and check all pickup selections in every position.