Running again.
My Trinity Tramp smoked a bit & quit working a couple days ago.
I had installed a 7581 and was sounding great. Cranked to the max.
Had the correct bias setting on my switches. Ran about 10 minutes, cut out, sparks in the tube slight smoke, then died.
Blew the main fuse. I replaced it, put in an EL34, switched the bias & load switch to the correct positions. Tubes glowed, but no signal.
Traced it down to a 100ohm, 5watt resistor. DC voltage before the resistor, nothing after.
Replaced with a 10watt. Now it’s singing again.
Attachment:
357D6D72-69E3-4E73-903D-718FEC74B69C.jpeg [ 301 KiB | Viewed 8015 times ]
Attachment:
06E98107-0B1C-49D9-B266-F7F8DB7F9F12.jpeg [ 252.38 KiB | Viewed 8015 times ]
I put the 7581 back in, was working again. When I adjusted the VRM above 5, it would start to cut out. Checked the voltages, was in spec, increasing properly till I hit 5 on the dial, then voltage dropped to 31VDC & cut out. Shut it down right away.
So now I don’t know if it was a failure of the brand new tube that caused the 100ohm - 5watt resistor to go, or if the resistor failed, & caused the tube to go.
With the new 100ohm - 10watt resistor in, I cant feel it heat up when cranked.
At least its working again now with the EL34 or KT88.
Scott