Good job. I wouldn't worry about the difference between output's. The diff could be wire length as Fred noted in a post.
Good job. I wouldn't worry about the difference between output's. The diff could be wire length as Fred noted in a post.
Nice work, hope it solves all your problems, nice to see the old iron saved if possible.Well, I found the stub too small to coil it around the tiny 1mm that was there. What I did though was to use paint stripper and then soldering flux to clean the connection on that 1mm. That seemed to clean it pretty well. I tinned it and took 4 strands from some 18awg speaker wire and soldered it on to the stub. I tied the strands back to the center-tap and was able to at least wrap that around the center-tap connection. After that I used some liquid electrical tape and started putting it back together after letting it dry for an hour.
Here's some pics. I've got the coil all wrapped up. I'm going to repaint the bells before final assembly though.
View attachment 929006 View attachment 929007 View attachment 929008 View attachment 929009 View attachment 929010
Great find Tim. I am now inspired to dig in to the couple of dead transformers I have around.
How does it sound?
If mama will allow it, bake 'em in the oven @ 200*F for a few hours (upside down). Kill Two Gremlins in one transformer. Bake off any moisture inside, and Bake the paint HARD! Just make sure the vent fan is running on HIGH!
Good job. I wouldn't worry about the difference between output's. The diff could be wire length as Fred noted in a post.
So, I found some time tonight to play it again. Before powering it up I flipped the plug on it. Suddenly it is working right. I wonder if the plug polarity can have that big an impact? In looking at the schematic the primary of the PT is not grounded anywhere, so I'm unsure why that has an impact. Could I have an accidental ground on the primary side? I can certainly trace it out. I don't think so, but if anyone thinks that is a concern I'll certainly do that.
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It would be quick to check for a ground on the primary side but also check the location of the death cap. There is also capacitance between transformer windings and reversing the plug would put the opposite end of the winding at ground potential. This can also sometimes be observed when measuring leakage.
The standard leakage test is to disconnect all external connections (speakers are isolated from any outside ground connection, so can be left connected), then connect a 1500 ohm resistor and 0.15 µF capacitor in parallel between the chassis and earth ground. Measure voltage across the RC combination. Leakage should be no more than 0.35 volts for any combination of plug orientation and power on or off.
As an additional experiment, disconnect the RC network and measure voltage chassis to earth with a digital meter (high input impedance). You may find close to 100 V for some combinations. This is a very low current path from capacitive coupling in the unit and is the cause for the light tingling that one may feel when lightly touching the unit.
Thanks Fred. That's a pretty easy check. I'll stop and get the parts from the local store. So I should measure from chassis to the house ground in a 3-prong outlet?