4PDT switch confusion

[alex89d]

Dear members of this amazing forum,
i've been lurking around for a bit now and have decided to go for the ultimate mod (10.1 in Daves PDF) on my Tribute L-2500. But it seems that I'm making some mistakes. First I bought this switch: https://www.allparts.com/products/ep-4363-4-pole-on-on-on-4pdt-mini-switch which behaves differently from the one described by Dave. The middle position switches not

Code: Select all


1 --  2     3
4     5 --  6
7 --  8     9
10    11 -- 12

but

Code: Select all


1 --  2     3
4     5 --  6
7     8 --  9
10 -- 11    12

So already I tried to modify the connections accordingly, but I get unexpected behavior. I barely can tell a difference between two of the states and on one state I loose one pickup. What is a good way to measure the correct selection? If I tap the pole pieces, I get some signal-pop everytime because of the common ground in the Tributes. I do have a multimeter but I am a noob and cannot make sense of the circuit.

Now I tried to back up and first try mod #7. But, again, I can't tell apart two of the three settings on the 4PDT. I seem to have a short somewhere or maybe the color coding of the coils is wrong?

I do not have the C1/C2 caps, should I just ignore them?


Thank you in advance!
Alex

[Ken Baker]

Dear members of this amazing forum,

Look at you! Trying to butter us up!

First I bought this switch: https://www.allparts.com/products/ep-4363-4-pole-on-on-on-4pdt-mini-switch which behaves differently from the one described by Dave.

Without a pinout and shunt chart from the manufacturer, you would have to VERY carefully test. Not just for functionality, but also to make it's working as it should. Not fun.

Instead, give this post a read. You'll find pinouts and shunt positions for the recommended switch, a C&K Components model 7411SYZQE.

Now I tried to back up and first try mod #7. But, again, I can't tell apart two of the three settings on the 4PDT. I seem to have a short somewhere or maybe the color coding of the coils is wrong?

If the switch you have uses the "normal" shunts positions like the C&K and it's healthy, you'll probably need to recheck your wiring. The single coils mods from Dave all assume USA wiring. With the Tribute soapbars made in Fullerton, the color coding from the pickups should be correct. If your bass has a blue wire, just ground it.

I do not have the C1/C2 caps, should I just ignore them?

As I recall, those are the OMG caps. Yes, ignore them.

Ken...

[alex89d]

Dear Ken,
It switches like I drew in my post, but here is the official sheet: https://octopart.com/ff629a59-a70d-4208-ab36-fc8c1b4261fc

Is I switch the connections on the bottom two rows, it should be equivalent or am I missing something?

Which resistance measurements on the coils should I get so I can confirm my bass is fine?

In Dave schematics, he connects one of the “series loops” after the C1/C2 caps to PU select and one to ground. In your drawing, the jumpers on the coil selector are not connected elsewhere but to close the loop for series mode. Is that maybe the source of my shorts?


Edit: 1. yes I should have ignored the connections following the C1/C2.
2. my switch was not switching like on the manufacturers details, even after double checking the markings. It was exactly mirrored. Now it works like intended!

Thanks,
Alex

[daveplaysbass]

Hello Alex,

Here's a few thoughts. First, let's verify that the switch you bought has 3 distinct "on" states. If that switch is good, this will work in the end. In state 1 everything goes to the "left". State 3 everything goes to the "right". State 2 half of the switches are going left and half are going right. It looks like from your original post, State 2 has the 3rd and 4th rows switched from my original schematic which shouldn't be a big deal as long as we switch up the schematic accordingly. Make sure this is absolutely the case. And make sure that everything is on-on-on. Some switches may throw in opens or be momentary. BTW the link you had for the datasheet didn't work for me.

After that I would verify that when you removed the caps from the schematic that everything was removed and connected appropriately. I know you didn't have the caps in there but you had to remove them from my original schematic. I have redrawn a schematic below that removes the caps and switches the position of the third and fourth switches.

The next thing I would do is make sure that both of the pup green wires (neck and bridge) are grounded. In fact you should check all of the ground connections in your wiring to make sure they are all good. It is easy when doing rework to forget grounds. Electrons need a path out and a path back. Some folks aren't familiar with the ground symbols used in schematics. The ground symbol makes it easier to read rather than connecting everything to a ground point in the drawing. Be sure that every ground symbol is connected to ground in your bass. I usually use the backs of the pots as my ground points which is the way things come from the factory.

Also, after verifying all the wiring against the diagram below, try things one pup at a time? Does the neck give you three distinct state? And then the bridge? Parallel and SC can be similar if you are not playing loud. You probably get some SC noise though when going from parallel to SC when soloing a pup.

If you continue to have issues, we probably will want to go thru the ground connection checklist which is in the Supermod document. All of the pots need to be connected to each other. Battery ground. Jack ground. Pup cavity ground. 4-way switch ground. Volume pot grounds. Treble pot ground. etc. And detailed pictures of the 4-way switch, pots, etc, may be in order.

https://drive.google.com/file/d/1TlVRN7q0mmacBDIoxm20M5zIp0rPv6oi/view?usp=drive_link

[Ken Baker]

Thanks, Dave!

[alex89d]

Just to give this thread a happy ending for future reference:

Everything works. The instructions are excellent, once you are able to read them properly.

Regarding my switch, I had to simply switched the rows of the switch around. Another helpful resource was Ken‘s drawing, because then it finally dawned on me that I should not ground the series jumpers if I don‘t use the OMG caps.

@Dave: I couldn’t open your google drive link. But thank you for your thoughts!