Help with Riviera wiring and multimeter results

Hello all. I need to finish repairs on my Epiphone Riviera before I start the builds on my GR and TLA kits which is requiring enourmous self dicipline and as I just want to get started on the new builds. Anyway, I have recently put together a wiring loom based on the Pitbull and SD Two Humbuckers to 2 Volume, 2 Tone and a 3 way Switch.. The problem is when I test the thing I'm getting no signal at the output jack. I have tried to trace back the fault and got the following results from the multimeter:

• the pickups are supplying the required resistance to both volumes pots
• Both volume pots are transferring the resistance to both tone pots
• when I check the volume pots by placing either side of the multimeter on the input and output of each pot I get the correct resistance when dialled to ten and 0 resistance when dialed to 0

My Problem is:
I'm am not getting any resistance value from the output pins from both volume pots. Therefore no resistance being provided to the switch, or the jack and therefore no sound. I have checked the diagram and wiring 3 times and sure I've got it right.

Does anybody have any idea why this is happening?????

Rodger

Are you reading off both outer pins on the pots and are the pots wide open?

Hello Tony,

I'm taking readings off the middle pin and outside pin being the output and input. When volume on 10 I get full pickup resistance, and 0 when volume on 0, which I assume is correct. I'm also taking readings from both outside pins being earth and input pins as you queried, and the same results occur which I assume is correct again.

Hey Roger Yes outside and middle and inside and outside will give you a reading, have you tried taking a reading at the Jack? and or the switch

If no go need a pic of the wiring...

this may help
Attachment 8235

Yeah thanks mate, I have that one and thats the diagram I've followed. No resistance reading at the switch or jack because none feeding out of the pot. My problem appears to be related to the fact I'm not getting any value from the output of the volume pots. This occures when the volume pot is connected to the switch or is not connected to the switch. I've disconnected one of the wires from the vol pot to the switch to test if I get a value at the output pin of the vol pot. Answer was no.

Without it on my desk i am at a loss. I wired my Baritone ages ago and went nuts on it, and couldnt get it to work, its was a shielded braided cable touching on the shielding inside, had me stumped for a couple of hours then a palm slap to the forehead, it was right in front of me.

Man that’s a similar story to mine!!! I originally had the whole thing wired in braided cable and couldn’t work out why things would work one second and then not the next. I then too had the forehead slap moment and realised the cables were moving as I moved the loom and were then shorting against each other at different spots and creating unpredictable results for me.

I have come to my senses and swapped out all hot wires with standard audio cable and left the earth wires in braided only.
I just watched a youtube clip describing how pots work and based on details of one of my earlier posts:

“I'm taking readings off the middle pin and outside pin being the output and input. When volume on 10 I get full pickup resistance, and 0 when volume on 0, which I assume is correct. I'm also taking readings from both outside pins being earth and input pins as you queried, and the same results occur which I assume is correct again”

My understanding is that the volume pot on 10, will channel all resistance through the output pin and; the volume pot on 0, rolls off the resistance through the earth rather than the output.

It appears that maybe my output pin is acting like an earth?? I shouldn’t be able to get a resistance value when metering the output and input pins should I?????

Heres a real easy look at it

https://youtu.be/zXBiWREKY3E

Rodger, is the loom currently out of the guitar? If so, please post some pictures of it so we can take a look. Often something small will standout in an image that isn't obvious in text. Ideally, set it up with the pots and switch fixed on a piece of cardboard so that everything is facing the same way, and get some close-ups of the connections on the pots and switch. Hopefully we'll spot something.

Scott

Yeah all set - up as you suggest. I'll get the photo's.

Thanks to both of you. This is killing me. I just want to get on with the new builds.

I'm trying to upload the photos. Got home and checked the multimeter again. Getting constant resistance across the outside pins. Only getting resistance from middle (wiper) to input when pot on 10. No resistance at any other point in the shaft rotation on both volume pots.

Resize the photos to no more than 1000 px on the longest side and file size less than 1MB.

Quote:

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Originally Posted by Rodger

I'm trying to upload the photos. Got home and checked the multimeter again. Getting constant resistance across the outside pins. Only getting resistance from middle (wiper) to input when pot on 10. No resistance at any other point in the shaft rotation on both volume pots.

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If that's the case, both pots are shot! What's the odds of that? A Pot is also known as a Variable Resistor. You get a variable resistance between the middle and either of the outer pins as you turn the dial. If you only get a reading when it's on 10, and across the outer pins, then the wiper (middle pin) isn't contacting until it gets to one end.

Attachment 8256Attachment 8254Attachment 8255Attachment 8257Attachment 8258

See photos above. Please let me know if you need better detail

The first thing that jumps out is you're probably getting a short between the braided ground and the hot tip/arm on the output jack:
Attachment 8259

I'm not sure, but it looks like there's something wrong/missing with the neck volume/neck tone connection. It's difficult to tell if there are some other shorted spots, but realistically, you are probably better off pulling it apart and starting over. Currently it's not really using the shielded wire to best advantage, either for wiring efficiency or actual signal shielding. Ideally, you want the shielding around a 'hot' wire to carry the ground connection between points, rather than running a separate ground like you have on the output jack etc. Once it's all apart, test each component separately to ensure they're all working individually, then rewire and reassemble.

I'm not sure if it will help, but a while ago I did a rough diagram to help a member with the braided wiring on their bass. The wiring layout is obviously different to yours, but it should give you an idea of how to use the inner core as the 'hot' signal wire with the surrounding shield/braid wire for the ground.

Thanks gents. The odds of them being shot are pretty high I'd say as there is a good chance I cooked them during the soldering process. Scott I've separated all the braided stuff away from other points and equipment to ensure it wasn't shorting and still no result. I got too clever for my own good. A mans got to know his limitations. I'll start again; test the pots out of the loom and replace if necessary. Is the grey audio cable OK to use? If so, I'd prefer to use the loose cable around the inner sheided cable as it it a beeter size for all the connections. Do you see any problem with that?

Cooked pots maybe and lots of shorts on that braided wire by the looks, i can see a few likely problems that i would investigate, read rewire.

Put some heat shrink tube on the braided cable, apply some heat from a lighter to shrink it, then check the pots, if you got them too hot they will have cooked, i always attach alligator clips to them as a heat sink, and i am only on the pots long enough to melt some solder onto them, i then solder on the tinned wires.

Give the top of the pots a sanding before you solder them.

So I pulled it all apart and re-tested the pots. As it tuns out, they're functioning just fine. Anyway, solved the problem by buying a pre-wired loom on ebay in the same set-up. Took just two minutes, one click and all for the cost of a Chiko roll and small big M. The parts aren't as good as the one I was planning but the end result will surely exceed anything I can put together. The quality will possibly match the limitations of the guitar. Now I can start on my new builds and stick to working with tools and mediums I understand.