lately I have had a few repairs come my way that have me baffled because I can attribute them to I-D-10-T errors I dont get it or maybe I've been really lucky ,I dont know #1 Yorkville Bassmaster 800 this unit has a switchable/ and blendable ( to the main signal) tube or SS preamp separate inputs for Active and Passive pickups quasi parametric EQ , it requires a STANDARD 12AX7 ( higher grade tube) L&M sent this amp back to Yorkville for servicing prior to me getting it , they found no fault at all and returned it , unsatisfied the customer brings the amp back to L&M again a nice amp, cant find a service manual for it but I found the owners manual, it runs really well and quiet , but loud, as a bass amp should , so after 7-8 days if trying to find the fault, the customer claims is there, which was, that there is a difference in the level of the two inputs and wants them equalized, I dont see it. One input for passive and one for active pickups. so after hours of reading and watching Youtube videos on this amp , I find it .......page 2 of the owners manual....do not use both inputs at once , or more specifically ...Not intended to run both inputs at once. I called the customer he states " I was hoping they had an other amp so I could get a new one" #2 Next was the Peavey 5150 II just retubed with mesa 6l6's and JJ 12AX7s gorgeous amp but the service rep fpr peavey could not explain why the amp would work for 10 min then crap out ( the subject of one of my last posts ) solution I burned the tubes in for 48 hours and now it works like a charm #3 today I got a DITTO mic looper issue was the light would come on but no output after finding the correct power supply for it 12 volt 2 amp negative tip I plug it in to the fishman SA220 I am working on as well, I plug in a 58 clone mic, press and release the loop button (the red light comes on) "testing , one two three " press / release the loop button again the LED goes green, turn up the loop level and bingo I have my sweet voice comming back at me as wonderfull as ever bestowing my counting prowess that would make the count from sesame street proud . I'm almost ashamed to charge for this stuff except for the tube issue with the 5150 II , the Peavey service guy should have caught that. well thats my weird rant for the day.