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Hey Phil,
Tnx for documenting all that VT-71/73 info on your site. Nice set and a great picture It's helped me in trying to get this one going.
It's funny that the folks I've talked to with these little Motorolas most have more that one. I've got three, two VT-73's one has a TS-4J the other is unmarked but it has the square HV cage and no fine tuning. Both of these don't have the copper plated chaiss. Maybe earlier models than the copper ones? The set on the bench is a VT-71 with a copper plated TS-4J chaiss. All three are not working and I need one more 7JP4 to complete all of the sets.
I'm at a little bit of a loss even on how to troubleshoot this B+ problem because it's a matter of balance between the top tube with 250v and the bottom tubewith 125v. If the top tube isn't drawing enough current then the botton tube dosen't get enough or if the bottom tube is drawing too much then it loads the circuit and causes the voltage to drop. Pardon, it's my hair . It's smoldering again.
I guess I could measure the current from the top to the bottom tubes and see if it comes out equal.
Terry
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