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Re: AC 50/2 Head driving me MENTAL!!!

10/6/2005 8:48 AM
R.G.	Re: AC 50/2 Head driving me MENTAL!!! You might be able to tell whether it's an internal pinhole with the inductive transformer checker schematic I have at GEO (http://www.geofex.com) in the tube amp technology section. This uses a 6V battery and an NE2 neon bulb hooked to one winding. You load up the winding with DC from the battery then open the switch. If there's a short, the short eats the inductive kickback. If there's no short, the inductive kickback blinks the neon light. All the windings have to be open circuit for this to work, of course. In your case, I'd try hooking the 6V/neon to the output winding. That would guarantee enough voltage to arc the pinhole in the primary. I'm not sure that the resistance ratio on the output windings is a good measure of the condition of the windings other than open/not open. The windings may be internally of different gauge wires and may be series/paralleled in unexpected ways. Even truly centertapped windings (like a primary is supposed to be) will vary in resistance with the length of the wires, which varies with where in the window the wire is wound.

10/6/2005 8:48 AM

R.G.

Re: AC 50/2 Head driving me MENTAL!!!

You might be able to tell whether it's an internal pinhole with the inductive transformer checker schematic I have at GEO (http://www.geofex.com) in the tube amp technology section. This uses a 6V battery and an NE2 neon bulb hooked to one winding. You load up the winding with DC from the battery then open the switch. If there's a short, the short eats the inductive kickback. If there's no short, the inductive kickback blinks the neon light. All the windings have to be open circuit for this to work, of course.

In your case, I'd try hooking the 6V/neon to the output winding. That would guarantee enough voltage to arc the pinhole in the primary.

I'm not sure that the resistance ratio on the output windings is a good measure of the condition of the windings other than open/not open. The windings may be internally of different gauge wires and may be series/paralleled in unexpected ways. Even truly centertapped windings (like a primary is supposed to be) will vary in resistance with the length of the wires, which varies with where in the window the wire is wound.

Replies:

Daniel MR Keen, you are a genius. I will d... -- 10/6/2005 12:29 PM