Tweet
Bought this amp about 4 years ago for my Son. Just hooked it up after it has been in storage for the last 2 years. Was working good when last played. Now it has anemic output. Very faint. No output in FX mode at all, Fan Still ruining good. CD input works correctly loud and clear. Does produce Normal hum as expected with Gain maxed. Several cords and guitars check good. Little hum when touching the input tip of a plugged in cord. Input connector appears good and solid, not broken or suffering broken solder joints at the PCB. Looks like I have to put it on the bench and check the front end. Have the schematic. Appears to have input issues. Bad Cap? Any Suggestions? Seen this? Thanks
-
-
Note: After reading similare Post here. I have tried pataching the send adn receive with no change. I'm pretty sure pots are ok as I can here the Output hum increase as the gain is increased. No pots appear to be scratchy as they are worked. Also slight pushing and flexing of the board under power does not result in intermittant sound blast. Indicating that the solderconnections are OK. I also un-plugged all circuit board connectors and plugged them back in. Everythink looks new. I am sure the output stage is good. -
Case closed. Put the amp on the bench. All power supplies good. Plugged in bare jacks to input and headphone out and connected a scope to each. With all knobs pointed up and power on. I touch the input and see the hum. Faint signal on the output. Looked at the first stage and nothing. Had signal at the input jack connection but nothing at the other end of the connecting copper trace. I noticed that the solder connection at the input jack was "Bulbous" so I figured it was cold. When trying to re-flow it with a soldering iron the doughnut spun loose! The trace was cracked and broke. So I added a small short wire on the back of the PCB between the input connector lead and the input filter choke lead. That wont ever break again.....Comment
-
Nice repair.
When all else fails, tear into it.Comment
-
Thanks JP, Appreciated. Made my Son smile when he got it back. I think I hear him playing it now. :-)Comment
Comment