NGD - Pawnshop Danelectro - with an electrical problem

[tjcurtin1]

OK - so following up on the 'surprise in the pawnshop' thread, I got to jonesing for that Dano... I had always had an attraction to them since I was a kid - the lipstick pups and all, plus the oddball looks.

http://i295.photobucket.com/albums/mm144/tjcurtin1/DanoU31.jpg (http://s295.photobucket.com/user/tjcurtin1/media/DanoU31.jpg.html)

Anyway, while it's in great cosmetic shape, it needs some work - either a pickup or switch issue. It has a 6-position selector switch, with two of the positions dead - middle alone and middle +bridge. The bridge works alone, and the neck+middle works, but doesn't sound different than the neck alone. It also has a 'blow' switch which bypasses the selector and gives you all three pups at once - in SERIES. In fact, the guitar is wired with the pups in series however they are selected. I was trying to check the pups per Voods link in Marnolds recent post about a dead pup, but I had this thought/question: if one of the pups was bad, and since the pups are wired in series, would that mean that when you selected a position that included a dead pup, that you would not get anything out? If that is true, wouldn't that mean that if the guitar works when the 'blow' switch is on (which it does), that all the pups are good, and I can rule that out as a problem, and that it must be the switch? Thanks to all you electrical wizards for help with this.

[tjcurtin1]

If it helps, here is the schematic for a two-pup Dano: The U3 does have stacked pots - one tone and one volume.

http://danguitars.com/uploads/Lipstick_pu_wiring.JPG

[duhvoodooman]

Have you opened the guitar up and looked at the wiring? I would suspect some sort of wire connection problem having to do with that middle pickup. But that's speculation, so try this first:

To confirm that the switching does indeed involve series connections between the pickups try this: Using my shortcut pickup resistance measurement, measure the resistance of the bridge and neck pickups INDIVIDUALLY. Remember to have the volume knob turned all the way up. Then measure the bridge+ neck position resistance. If it is indeed a series connection, it should be very close to the sum of the two individual resistances.

Next, throw the "blow" switch and measure that pickup combo resistance. If the middle pickup is good, then the resistance should be about half again higher than the sum of the B+N. If that all checks out, then the problem is definitely in the wiring or internally in one of the switches. But eliminate the pickup as the issue before you dive into that.

Incidentally, that diagram isn't helpful here--the two pickups selected together would be in parallel with that hookup. It's just like a standard 2-pickup Les Paul hookup.

[tjcurtin1]

Thanks, DVM - well, strange goings on here. Here is what the switch positions are supposed to be:

1. neck & bridge
2. neck
3. neck & middle
4. middle
5. middle & bridge
6. bridge
7. Toggle switch bypasses the rotary switch and turns all 3 pickups on at once in series.

I tried all positions with the guitar plugged in, while tapping the pups with a screw driver.
In positions 1, 2 & 3 I got a 'pop' from the neck pup only (there is also no change in the sound/tone of the guitar between these positions)
In positions 4 & 5, nothing from any pup
In position 6, pops from middle and bridge pups only (thinner, brighter sound with less volume)
Blow switch on: pop from neck pup only (and same sound as positions 1, 2 &3 with blow switch off)


Measuring the resistance per your method, I got
Positions 1, 2 &3: 3.49
Positions 4 & 5: 0
Position 6: 1.78
Blow switch on: 3.50
So, all the pups seem to be alive, but something is messed up. I did look inside - nothing seems to be amiss there... at least not anything obvious.

[tjcurtin1]

Some more info found online:

Because there isn´t any information on the Select-o-matic 6-way 4-pole switch, here´s how it works:


Pole 1 -- C 1 2 3 4 5 6

Pole 2 -- 1 2 3 4 5 6 C

Pole 3 -- C 1 2 3 4 5 6

Pole 4 -- 1 2 3 4 5 6 C


And this: (text of full post here; the guy who posted this changed the blow switch, tho: http://www.thegearpage.net/board/showthread.php?t=999150

http://img64.imageshack.us/img64/976/danelectro3pickupwiring.jpg

[tjcurtin1]

Update on the Dano -
I tried replacing the selector switch on a suggestion: found one, put it in, tried it before putting it all back together - bingo, working in all positions! Put it all back together, plug it in - same exact problem as before! Major puzzlement, but I decide to backtrack by loosening the controls mounting bracket. Suddenly, its working again - and then not -. I realize at last that all along it was a loose ground wire on the back of the pots where all the grounds are soldered...GRRR!

Anyways, it is a keeper - low output single coils in this funky hollow body give a cool variety of sounds. And man, when they say they are made of plywood and masonite, they aren't kidding! Kind of amazing that you can make a good-sounding guitar out of such minimalist stuff! Or even one that stays in one piece...

http://i295.photobucket.com/albums/mm144/tjcurtin1/IMG_6546.jpg (http://s295.photobucket.com/user/tjcurtin1/media/IMG_6546.jpg.html)

[Robert]

Good you fixed it! They do sound cool.


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