Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tdvt on January 25, 2024, 10:41:03 am
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Working on a Gibson Crestline Falcon for my son, it seems to have a PT ground wire I am not seeing on the schematic, or a few other Gibson schematics I looked at.
The PT Sec CT & heater CT are connected to the 5Y3 socket.
The amp works, so there isn't an issue, just wondering what it is..?
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:laugh:
the more you work on Gibson, the more undocumented features you'll find. they had a lax Lunch policy :icon_biggrin:
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:laugh:
the more you work on Gibson, the more undocumented features you'll find. they had a lax Lunch policy :icon_biggrin:
Apparently...
The trem wasn't working & wasn't wired quite how it was drawn, but still looked mostly original. All good now.
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The extra wire going to ground is a shield it is shown on the schematic as a dashed line going to ground in the pt core..
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The extra wire going to ground is a shield it is shown on the schematic as a dashed line going to ground in the pt core..
Yup..
There it is...blind as a bat.
Thanks
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Working on a Gibson Crestline Falcon for my son, it seems to have a PT ground wire I am not seeing on the schematic, or a few other Gibson schematics I looked at.
The PT Sec CT & heater CT are connected to the 5Y3 socket.
https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga19rvt.pdf
The amp works, so there isn't an issue, just wondering what it is..?
This schematic clearly shows a PT shield connection to ground. But the schematic nor your pic show those CTs connected to the 5Y3 socket. In fact the schematic shows that the CTs are not connected together.
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This schematic clearly shows a PT shield connection to ground. But the schematic nor your pic show those CTs connected to the 5Y3 socket. In fact the schematic shows that the CTs are not connected together.
You are correct on all counts..
Those CTs run to the adjacent 6V6 socket.
V6/P1 was used as a multi-ground point for; the Sec CT, 2 of the filter cap grounds, the power tube bypass cap ground & a ground wire to the trem "depth" pot shell.
Heater CT goes to V6/P8
V5 does not even have a Pin 1.
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V5 does not even have a Pin 1.
Well that's a first and would make Leo proud. them Kalamozoo boys wuz real cost savers
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them Kalamozoo boys wuz real cost savers
OR
they had a lax Lunch policy
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Wrapping this one up, converted/adapted it to radial caps while I was working in there, as the installed caps were only gooped in place & had come loose.
Made a small turret cap board for the new ones & fit 4 higher rated caps in the area that had previously been home to just 2.
Board is held in place by an OT screw through it & also some adhesive. No extra holes, etc.
Checking voltages I was surprised to see somewhat of a color-code for the wiring; plates, cathodes, etc.. who'd have guessed?