Quote:
Originally Posted by Electronic M
Why not touch a voltmeter to the 12V plug with the wall wart plugged in and find out the polarity yourself? I can't imagine a Ham/radio collector like you not having a DMM or VOM.
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I do have a DMM, and will use it to determine the polarity of the wall wart. However, what I was planning to do was to hard-wire the wall wart directly to the radio, bypassing the adapter jack altogether. The schematic isn't too clear on how to do that, and as I said, I don't want to destroy the audio output transformer, output transistors or both by using the wrong side of the wall wart output as ground. There was a post here in this forum quite a while ago which addressed this very issue, stating if the ground connection is made to the wrong terminal of the AC adapter jack (or the plug on the wall wart output cable is wired such that the wrong side of the circuit is grounded), the parts I mentioned will be instantly destroyed. If anyone remembers where that post is, I'd appreciate the information so I can look it up. I think the T/O 3000's AC adapter has a positive ground, but I am not sure and don't want to find out the hard way--by burning up several parts of the radio that may now be NLA, after almost 50 years.