Photos of early 1970s Guild S-100 w/ Phase Switch Wiring (or schematic)

cobascis

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I'm looking for a high resolution photo of under the control panel on an early 1970s Guild S-100 with Phase Switch. I'm following a schematic and having some issues. The previous owner copper-taped the cavity and is grounding everything to that. How was the original grounded? I found a picture without a phase switch wired.

Additionally, I'm wiring the HB-1s with two wires coming off of the terminals (hot and ground). The bridge pickup I've grounded to the bridge. I'm replacing the output jack and both capacitors. A photo of the back of one of these as wired would also be nice.
 

cobascis

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Excellent! Thank you. I was poking around your website but didn't think to check if the 90s ones were the same. Good to know re: the shielding. Hopefully I'll get it back and running tonight!


I don't have '70s, but I do have '90s and they should be pretty much the same: http://www.gad.net/Blog/2018/03/13/1994-guild-s-100-polara/

BTW it was common for Guild to shield the cavities on solid-bodies during that time, so it may be original.
 

cobascis

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I had been using this diagram, which seems to be slightly different. (Dif cap values, a few other differences in where wires go). Does anyone know functional differences between these two?

s100.pdf

Guild-S100-1994-Wiring.jpg
 

GAD

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I would not put 200k pots on humbuckers. I can also tell you that the S100 that I took my drawing from sounds freaking amazing. So there's that. :encouragement:
 

fronobulax

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Excellent! Thank you. I was poking around your website but didn't think to check if the 90s ones were the same. Good to know re: the shielding. Hopefully I'll get it back and running tonight!

1971 JS II bass. Not quite applicable but does show what the factory shielding looked like.

DmP8Ad3KZb1Bbz7zuDjma-Bn7TsPBqrPJyJl1Vp4-FHSZNv7T6_c2eYfRL3uO-yQmGrvmStjhy3E2bb8SrBUtGkx1qCo8n7N_KmwuBiy9d1iz-rdY-KeCSHDJQm4_f9GOt8dic_Rzl5PLP01uy7Hn5t8tbbPYurSeN13YSuK78Es-Q2B9VTFkzCKP3ANlHxkCzlhGo3A34YjDL5d3g84EF2bLv7n8EBef2NOjmKBgpTwN7RHOO0W5jLoFrLf03ctD9bgUWNWNwoJI5Wl9ZriJoA2dvEtIWLmi3tpV9lSQms-eBxP18anHD2BL2sEtgFvZL2SxEHiUGe6yYjpR5TPeBhAOkDPQBX3uzgLi6adEIFuxLrzeWoBTdQBh0bkKIBb349nfj3O7jvCo9ZVq9CJxeBQpsVs3D_hS2vD-_GLch5UWXpGXggDe0L0_WSgUkL5gpheZvpeg_9bDZ5qXgtVasrCAOLsolIjwxCyl_ShNajJUN0oWJb5VHDPSFqSUaFX0SAMLwoatClUbNmdasAHe1QLPft1Z_irkFedQmcjLjjHkIuHUs-JsBOcWOIJxB7OLBpEbWxQt3Z3k2cZzA36FHovZde0c4f4BCy4yXBz5_5jxGMJpdetCprA0N1uJgjpJ-hIWWIg36rjedBlqYVpJVH6gDye-17czUdtmmjisew=w2048-h1536-no
 

Nuuska

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1971 JS II bass. Not quite applicable but does show what the factory shielding looked like.

DmP8Ad3KZb1Bbz7zuDjma-Bn7TsPBqrPJyJl1Vp4-FHSZNv7T6_c2eYfRL3uO-yQmGrvmStjhy3E2bb8SrBUtGkx1qCo8n7N_KmwuBiy9d1iz-rdY-KeCSHDJQm4_f9GOt8dic_Rzl5PLP01uy7Hn5t8tbbPYurSeN13YSuK78Es-Q2B9VTFkzCKP3ANlHxkCzlhGo3A34YjDL5d3g84EF2bLv7n8EBef2NOjmKBgpTwN7RHOO0W5jLoFrLf03ctD9bgUWNWNwoJI5Wl9ZriJoA2dvEtIWLmi3tpV9lSQms-eBxP18anHD2BL2sEtgFvZL2SxEHiUGe6yYjpR5TPeBhAOkDPQBX3uzgLi6adEIFuxLrzeWoBTdQBh0bkKIBb349nfj3O7jvCo9ZVq9CJxeBQpsVs3D_hS2vD-_GLch5UWXpGXggDe0L0_WSgUkL5gpheZvpeg_9bDZ5qXgtVasrCAOLsolIjwxCyl_ShNajJUN0oWJb5VHDPSFqSUaFX0SAMLwoatClUbNmdasAHe1QLPft1Z_irkFedQmcjLjjHkIuHUs-JsBOcWOIJxB7OLBpEbWxQt3Z3k2cZzA36FHovZde0c4f4BCy4yXBz5_5jxGMJpdetCprA0N1uJgjpJ-hIWWIg36rjedBlqYVpJVH6gDye-17czUdtmmjisew=w2048-h1536-no

With all respect - over here it looks like a big empty place with small "do not drive this way" traffic-sign . . .

p.s. whta´s the correct name for that sign?
 

kakerlak

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With all respect - over here it looks like a big empty place with small "do not drive this way" traffic-sign . . .

p.s. whta´s the correct name for that sign?

That's weird, b/c it showed up for me this morning, but not anymore.
 

fronobulax

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My bad. The image is hosted in Google Photos and there are many ways to share them "wrong". I thought I had shared this before and had the permissions correct. Stand by.

Rehosted on WordPress.

2007_11-074.jpg
 

DThomasC

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Frono, that's an interesting photo. There are a few things that I wouldn't expect, though I have not looked under the skirt of a '71 JS II Bass, so I guess I wouldn't really know what to expect.

For one thing, the ground wire with red insulation doesn't look like it came from the factory. I won't draw any conclusions from that alone, but it indicates that someone has been in there with a soldering iron. There's also a 150k resistor in series with the bridge pickup. Maybe that was standard on JS II Basses? I don't know, but I'd be surprised if they would put one on a guitar as it would cut all the top end, which was a thing guitarists were chasing at the time.

I'm not sure whats going on around the mini switch, but the 220k resistor and capacitor suggest that it it's not the same simple phase switch that was found on Guild guitars of the 70's.

Anyway, thanks for the photo! I love stuff like this.
 

fronobulax

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Frono, that's an interesting photo. There are a few things that I wouldn't expect, though I have not looked under the skirt of a '71 JS II Bass, so I guess I wouldn't really know what to expect.

For one thing, the ground wire with red insulation doesn't look like it came from the factory. I won't draw any conclusions from that alone, but it indicates that someone has been in there with a soldering iron. There's also a 150k resistor in series with the bridge pickup. Maybe that was standard on JS II Basses? I don't know, but I'd be surprised if they would put one on a guitar as it would cut all the top end, which was a thing guitarists were chasing at the time.

I'm not sure whats going on around the mini switch, but the 220k resistor and capacitor suggest that it it's not the same simple phase switch that was found on Guild guitars of the 70's.

Anyway, thanks for the photo! I love stuff like this.

The serial number dates the bass to 1971. I bought it new in early 1972. If anyone was in there with a soldering iron after I bought it, it was not me and was not done with my knowledge :) I'm pretty confident that the wiring is original. We could say "that's Guild". The 1970 JS IIs has pickups that were not Guild humbuckers so it is plausible that Guild learned some lessons with the change and one was that the "old" wiring did not work was well as it should and the red wire was a bandaid applied at the factory.

In the bass the mini-toggle was described as a "Deep/Hard" switch. It only effected the neck PU and in one position it cut most of the treble out of the sound, although it sounded like a bass boost. So it is definitely not the guitar's phase switch and that is an error that sellers of JS basses often make in their descriptions.

The bridge resistor seems to be common on basses to cut the top end.

Nose around in the Bass section. There is a long thread where I incorrectly analyzed the circuit and Zelja politely corrected me. There is also one about taking the Deep/Hard switch out of the circuit. My recollection is that it makes the PU hotter and brighter. Both threads could be several years old which is why I'm not looking for them now.

Also note the absence of a label on the back of the cavity cover. It was not there when I bought it and Hans has said he has seen other solid body electrics from the same period with missing labels.
 
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cobascis

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After wiring the the schematic I posted (the 70s one), I'm getting a strong buzz that is louder than the guitar signal. I have checked with my multimeter and everything is grounded. Notably, the sound doesn't change when I touch the grounded components. I've double and triple checked the schematic.

Next step if I cant figure it out is rewiring it to match the GAD '94 schematic, undoing a lot of soldering work. I replaced both caps, input jack, and majority of wires. How can the buzz be happening if everything is grounded ? Maybe I'm sending the signal to ground somehow? I've wired quite a few guitars and haven't had such a baffling issue as this. I can take pics if that would help troubleshoot...

Also, I have what I think is two HB-1 bridge pickups (wide terminals with ground in middle). On the neck pickup, I jumped the black wire terminal to the middle ground, and then grounded that, to make it act like the typical neck pickup where the black wire is on the grounded terminal.

On the bridge, I added a third wire to the middle grounded terminal, and grounded that. The black wire goes to the phase switch.
 

cobascis

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Also, my S-100 had the same exact red wires like Fronobulax's bass connected the pot casings.
 

GAD

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After wiring the the schematic I posted (the 70s one), I'm getting a strong buzz that is louder than the guitar signal. I have checked with my multimeter and everything is grounded. Notably, the sound doesn't change when I touch the grounded components. I've double and triple checked the schematic.

Next step if I cant figure it out is rewiring it to match the GAD '94 schematic, undoing a lot of soldering work. I replaced both caps, input jack, and majority of wires. How can the buzz be happening if everything is grounded ? Maybe I'm sending the signal to ground somehow? I've wired quite a few guitars and haven't had such a baffling issue as this. I can take pics if that would help troubleshoot...

Also, I have what I think is two HB-1 bridge pickups (wide terminals with ground in middle). On the neck pickup, I jumped the black wire terminal to the middle ground, and then grounded that, to make it act like the typical neck pickup where the black wire is on the grounded terminal.

On the bridge, I added a third wire to the middle grounded terminal, and grounded that. The black wire goes to the phase switch.

Pics would help.
 

DThomasC

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Also, my S-100 had the same exact red wires like Fronobulax's bass connected the pot casings.

That's Guild! :untroubled: Seriously, that's Guild. The other three pots are connected with bare wire, just like every other Guild I've seen from the 70's up through the early 80's at least. I can imagine somebody in production putting together harnesses, "should all four pots be connected together?", "I don't know, just do what it says on the written procedure." Blame an engineer for this one; they're the one's that write the procedures. What puzzles me most is why the person that reworked all of those harnesses didn't use bare wire too.

Anyway, I don't know for sure the cause of the buzz, but it's bound to be either a simple wiring mistake - GAD's schematic should result in a noise free instrument - or a cold solder joint. Sometimes it's difficult to get solder to flow on those old pots, so look over every joint carefully and reflow any that are questionable.
 

DThomasC

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The serial number dates the bass to 1971. I bought it new in early 1972. If anyone was in there with a soldering iron after I bought it, it was not me and was not done with my knowledge :) I'm pretty confident that the wiring is original. We could say "that's Guild". The 1970 JS IIs has pickups that were not Guild humbuckers so it is plausible that Guild learned some lessons with the change and one was that the "old" wiring did not work was well as it should and the red wire was a bandaid applied at the factory.

In the bass the mini-toggle was described as a "Deep/Hard" switch. It only effected the neck PU and in one position it cut most of the treble out of the sound, although it sounded like a bass boost. So it is definitely not the guitar's phase switch and that is an error that sellers of JS basses often make in their descriptions.

The bridge resistor seems to be common on basses to cut the top end.

Nose around in the Bass section. There is a long thread where I incorrectly analyzed the circuit and Zelja politely corrected me. There is also one about taking the Deep/Hard switch out of the circuit. My recollection is that it makes the PU hotter and brighter. Both threads could be several years old which is why I'm not looking for them now.

Also note the absence of a label on the back of the cavity cover. It was not there when I bought it and Hans has said he has seen other solid body electrics from the same period with missing labels.

It makes sense that basses would have different eq switches, and it makes sense that the mini switch is a high-cut circuit.

I'll have to start checking the bass section...
 

cobascis

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Thanks for the replies all. I figured it out! I was actually right in that there was no reason it should be making a buzzing sound. While I was rechecking it late last night and making sure everything was solid, I forgot I was testing it through my pedal board into my amp. Previously, I had used another guitar as a reference to make sure the buzzing wasn't a result of the bad wiring in my house. I have an old Deluxe Memory Man that is not true bypass, and when it is off it passes a noisy and weak signal. The pedal was off! But I thought it was the wiring.

Anyway, it is all set. I'll upload a picture tomorrow to show you what I did. The old schematic does work...

The HB-1s sound awesome. Almost like a fuller Fender style sound. Definitely sounds like a vintage guitar now. The vibe of the Super Distortion humbuckers didn't match the guitar IMO. Glad I replaced them. Maybe I won't sell it now. Just need to track down some silver covers, but it looks good as is.

Any tips for filling the body hole left by a second switch? My old SG deluxe has little plastic caps that fit in the pickgaurd holes. I might try to find some of them.
 
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