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Dang. I did a bunch of work for a restoration of a '69 0r '70 Ampeg Jupiter B-22x, and upon the initial power up stages on my light bulb limiter, it misbehaved. I first powered it up with no tubes to tinker with the bias supply that I made from fixed to adjustable, I was curious as to why the voltages were lower than I expected, and took some time to reach the high and low adjusted levels. The bulb was not lit.
When I put in just the rectifier tube in standy, the bulb lit slightly, but when I switched out of standby the bulb lit up and it blew a 4 amp fuse. Uh, oh. I started probing around and found short paths to ground where there shouldn't be, most notably 10 ohms from rectifier pin 8 to ground. At first I suspected the PT, but when I disconnected the B+ lead, I found the 10 ohms to ground on the OT center tap, as well as 10 ohms to the lifted secondary.
So this OT is toast, but what to do now? I honestly don't really know much about spec'ing transformers, and could use a bit of guidance.
https://ampeg.com/support/files/Sche...matics%201.pdf
When I put in just the rectifier tube in standy, the bulb lit slightly, but when I switched out of standby the bulb lit up and it blew a 4 amp fuse. Uh, oh. I started probing around and found short paths to ground where there shouldn't be, most notably 10 ohms from rectifier pin 8 to ground. At first I suspected the PT, but when I disconnected the B+ lead, I found the 10 ohms to ground on the OT center tap, as well as 10 ohms to the lifted secondary.
So this OT is toast, but what to do now? I honestly don't really know much about spec'ing transformers, and could use a bit of guidance.
https://ampeg.com/support/files/Sche...matics%201.pdf
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