    
Monk
Junior Member
Username: Monk
Post Number: 31
Registered: 2-2002
| | Posted on Thursday, June 11, 2015 - 2:02 am: | 
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At least one of your tubes is shorted.
The tubes don't get high voltage until the amp is keyed that is why the choke doesn't blow when you turn on the amplifier. When you key up the choke is acting like a fuse. I suspect the fuse in line is bigger than factory specs.
You can check for plate to grid shorts with your ohm meter. Clip one lead to the top of the tube and use the other lead to check the 9 pins on the bottom of the tube one at a time. There should be no continuity on any of the pins to top. You must have the tubes removed from the amp to test them. If you are lucky the short will be cold, the tube not heated up. If not you will have to put a small fuse (5 amp) in the line input and remove the plate cap from one tube at a time and then key up to see if you have picked the shorted tube. Have as many fuses as tubes. Sometimes it is the first tube you check, sometimes the last.
You must have the amp unplugged from the wall before removing the cover. Do not touch anything on the underside of the amp. D&A amplifiers did not come with capacitor bleeder resistors!
Hope this helps
Monk |
