| Author | Message | ||
| Joe |
I've dusted offand put new tubes in my Music Man RP 112-100 (board date) 11-24-78 and the reverb is dead and the sound is lacking in bass and volume. Because of bad connections, I've wired the footswitches and reverb RCA in/out jacks directly to the board (I have all the old parts and it can be restored). Still no reverb or change. When I adjusted/checked the bias it was 25 mv on the 3.9Ohm and 10 mv on the other. This can't be good. Are there there a test point or a component layout? Can I get a custom tune-up kit with Caps and transistors from someone/somewhere out there? I'm looking to fix this myself ASAP. I have electronic experience. Any ideas? Thanks for your time. | ||
| TERRY |
JOE, YOU DON'T NEED A FOOTSWITCH FOR THE REVERB AND PHASER TO WORK ON A MUSICMAN AMP. ON A FENDER AMP...YOU DO. IF YOU HAVE IT WIRED DIRECT, THEN YOU MAY HAVE IT TURNED OFF INSTEAD OF ON. TAKE YOUR OHM METER AND CHECK THE REVERB TANK. IT SHOULD HAVE A STAMP ON TOP #8FB21B. THE INPUT SHOULD READ 1475 OHM. THE OUTPUT SHOULD READ 2250 OHM. IF YOU DO NOT GET A READING, THEN THE TANK IS BAD. IF YOU ARE NOT GETTING 25MV ON BOTH OF THE 3.9 OHM RESISTORS, THEN THE JE1692 POWER TRANSISTORS ARE BAD. YOU SHOULD REPLACE THEM WITH 2N6488. IF YOU NEED PARTS, E-MAIL ME. TERRY. |
Tue, 03/25/2014 - 09:56
#1