Power cord conversion

[bsco]

Question......when replacing the 2 prong power cord with a 3 prong one on an old Kustom Bass amp.....can I just cut out the death cap, and replace the cord and connect the live and neutral to the original connections and ground the Green wire to the chassis????.....The power switch is the type that is center off and either right or left positions on...and depending on which position it is in, that is the side that our death cap is connected to.......Does this switch also need to be replaced???
Cheers

[Chuck H]

The two way power switch is a polarity switch. After removing the death cap you REALLY don't want the option. You don't need to replace the switch, just one selection off center won't do anything and the other will actually turn the amp on. Make sure the hot lead is the one that goes through the switch and the mains fuse. The neutral would be wired direct to the PT. Green AC cord lead bolted to the chassis. Ideally with the addition of some anti oxide grease and a tooth washer.

[Tom Phillips]

...The power switch is the type that is center off and either right or left positions on...and depending on which position it is in, that is the side that our death cap is connected to.......Does this switch also need to be replaced?...

My old Kustom schematics show that once the "death cap" is removed there is no path to ground for either side of the power line for either ON position of the power switch. In that case, all the ON-OFF-ON power switch would be doing is selecting the phase of the power applied to the power transformer primary. Therefore, I don't see any issue with leaving the power switch stock when you do your power cord conversion with "death cap" removal.

This all assumes that the circuit is stock. If you will tell us the model number of the old Kustom amp then we can check the exact schematic for final verification.

[bsco]

My old Kustom schematics show that once the "death cap" is removed there is no path to ground for either side of the power line for either ON position of the power switch. In that case, all the ON-OFF-ON power switch would be doing is selecting the phase of the power applied to the power transformer primary. Therefore, I don't see any issue with leaving the power switch stock when you do your power cord conversion with "death cap" removal.

This all assumes that the circuit is stock. If you will tell us the model number of the old Kustom amp then we can check the exact schematic for final verification.

Thanks Tom..The model on the rear plate is a name......CHARGER.......hope this helps....
Cheers

[Axtman]

This may help.

[Tom Phillips]

I found some information that indicates that the Kustom Charger used the PC5033 power amp. Copy attached. The power amp drawing includes the power supply but the one I found does not show a death cap at all. In addition it shows a box labeled TB1 to depict the ON-OFF switch so we can't see the wiring details. Go figure?
There may be other versions of the drawing. You could check for the PC number actually used in your amp. It would be interesting to know. Otherwise, I would just buzz out the wiring and verify that the output connections from the power switch are direct to the PT primary and nowhere else. Would be interesting to post pictures if you can.
PC5033 Power Amp.pdf

[bsco]

This may help.

This one only has the one switch.....it does not have the power and ground switch separate...But I will copy what you attached as it will come in handy for doing the Fender style set-up....
Cheers

[bsco]

I found some information that indicates that the Kustom Charger used the PC5033 power amp. Copy attached. The power amp drawing includes the power supply but the one I found does not show a death cap at all. In addition it shows a box labeled TB1 to depict the ON-OFF switch so we can't see the wiring details. Go figure?
There may be other versions of the drawing. You could check for the PC number actually used in your amp. It would be interesting to know. Otherwise, I would just buzz out the wiring and verify that the output connections from the power switch are direct to the PT primary and nowhere else. Would be interesting to post pictures if you can.
[ATTACH]50377[/ATTACH]

Ok. I'll check it out and get back to you......
Cheers

[Randall]

"Green AC cord lead bolted to the chassis. Ideally with the addition of some anti oxide grease and a tooth washer."

I used to do it that way, but now I solder the green wire directly to the chassis. That way you do not stand a chance of losing your safety ground if your nut comes loose.

[eschertron]

I don't believe solder (solder only? not soldered eyelet, soldered to a bolt, soldered to the chassis?) is accepted practice. But I don't believe very much...

[nosaj]

"Green AC cord lead bolted to the chassis. Ideally with the addition of some anti oxide grease and a tooth washer."

I used to do it that way, but now I solder the green wire directly to the chassis. That way you do not stand a chance of losing your safety ground if your nut comes loose.

Easier practice I use is to drop some nail polish on the threads and nuts( locks the nut but will easily break with a little twist., i use a specific color I also use it for call backs to see if the polish has been broken.

nosaj

[Justin Thomas]

I put in a dedicated bolt with a locking terminal, put a nut on it, put another nut on top of that, then solder the nuts to the bolt...
Overkill? Probably, but I can't cover the lawsuits.

*** No, I will not drill a hole in your vintage amp. This is only for the ones I build or that already have been drilled.

Justin

[nevetslab]

My UL standards are tucked away in storage, but as I recall, the AC mains grounding wire is fitted with a round crimp lug, and mounted to a dedicated chassis grounding screw, which is masked during plating or painting. An EXT Tooth lock washer at the bottom next to the chassis, the grounding wire lug, a flat washer and then the locking nut (keps nut or hex nut with an Ext Tooth washer). I think they also allow Pem Stud in place of the grounding screw. NOTHING else is attached to this grounding screw.

[SoulFetish]

I don't believe solder (solder only? not soldered eyelet, soldered to a bolt, soldered to the chassis?) is accepted practice. But I don't believe very much...

The last version of the UL safety regulations concerning "commercial audio visual equipment" considered soldering an acceptable way to bond the chassis to the earthed conductor, however, they required that the green(yellow-green in Europe/Britain) wire have have it's own dedicated, additional strain relief to keep the wire from vibrating or moving. This is a wise practice anyways because a proper solder connection is a very reliable mechanical and electrical connection. The weakness of a solder connection is at the junction of where the wire and solder meet. Any movement in the wire causes stress at this point and there is risk of breaking. Risks increase overtime as oxide builds up on the conductors and wire insulation becomes more brittle.

[SoulFetish]

*** No, I will not drill a hole in your vintage amp.
Justin

Oh, I will.