As mentioned, the secondary of the OT has one side grounded, the primary has one side connected to the main filter cap. When you test for continuity, your meter will attempt to charge the filter cap and while this is happening it may well look like a short to the meter. Depending on what meter you have it may not have enough "oomph" to ever charge the cap to a point where it no longer looks like a short. If you really want to test your OT you should absolutely desolder its connections and test it out of circuit. It really is much more likely that you have one or more wiring mistakes than a faulty OT imho. I would start by looking at the input and output jacks, if they are the shorting type it is very easy to get wrong, and either one wired incorrectly will result in no sound from the amp...
I tried an experiment to test this theory. I hooked up my DMM across a 10uF electrolytic cap as this is the closest value I have to the 16uF in the schematic at this node of the power supply. This is simulating the theory you proposed above. Not once did it show even close to a short. I put the meter on all scales to test every one from 200 ohms up to 20 meg. The only setting that even got a reading was on the 2 Meg setting. It started at 1.6 Meg and started to move up as the cap charged.
I agree in principle that if all else is checked, remove the connections, but why do that if it won't help? Just more work.
What do you make of post #23?
I agree in principle that if all else is checked, remove the connections, but why do that if it won't help? Just more work.
What do you make of post #23?
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I like the way you think, man! No more work than is necessary. 🙂 I have also never read a direct short with a DMM across a GOOD filter capacitor- if you read a short, the cap is bad- if it's grounded (most filter caps are) you're gonna let out the magic smoke- I just fixed a Gretcsh 6160 with this issue! Lol. I think that just for the heck of it, and because I could use the practice (i guess that's a good excuse lol) I'll take the OT leads out of circuit and test between windings again. Just to be absolutely sure. Thanks to everybody for showing interest in showing a tube n00b like me the ropes. By the way- my Analog EET professor has agreed to help me troubleshoot it in person- although I did have intentions of trying to figure it out on my own... Oh well. Win some lose some 🙂 But I will see what he has to say about it- he gets back from vacation in like a week.
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