42-RP2 help needed - Printable Version

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42-RP2 help needed - Chris Drumma - 11-30-2005

I bought one off e-bay and need some help placing some loose wires and figuring out what the person did.

1. I need to know what and where to get a crystal cartridge and needle for this.
2. The crystal cartridge wires where do they connect to the chassis? I have the schematic but can't figure it out.
3. The phono motor wires one is connected to the tone arm plunger assembly. Where does the other one go?
4. The previous owner connect a small plug to the chassis. I am assuming to to plug into a speaker. One of the wires is connected to the chassis, the other one is connected to pin 5 of the 6A7 tube.

If any one has one of these and could help out or send some pictures I would appreciate it.
thanks
Chris

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- Chuck Schwark - 11-30-2005

Chris, here are some answers:

1. See LINKS either here on Ron's site or mine for pickup replacements and/or repairs.

2. The one pickup connection probably ties to chassis possibly near the junction of resistor 11 and cap 13 or the 6A7 socket grid pin. Schematic does not show if this is a shielded cable - I assume it might be. If so, shield should run almost to the tube's grid pin for max hum shielding, since this is a high impedance pickup.

3. The junction of cap #6 and the other side of the AC line cord which is also one side of the power transformer primary. See schematic.

4. That jack is probably for an improvised "external audio input" to the oscillator instead of the phono pickup. Not factory original. This is not a radio that can use a speaker for any reason. It is a simple one-tube oscillator circuit (6A7) for transmitting.

Pin 5 is the grid and anything else tied here could induce hum, depending on lead dress.

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