No power, fuse blown, found mosfet switching transistor shorted in PSU section, perhaps due to a power spike, and usually other stuff blows, but could be lucky and only be that… Mosfet (STB36NM60ND) was a pig to get out as not much space and the heatsink soldered to the board, but a combination of hot […]
Peavey Mini Max class D bass amp dead Read More »
Dishwasher was not heating up, element had continuity and relay was clicking but no power getting to element. Relay contacts worn out: Replacement Omron relay ordered and fitted Then after replacing the board back in the machine to test, discovered the ULN2003A IC had subsequently failed, so this was also replaced and everything back in
Baumatic dishwasher not heating Read More »
Intermittent crackling noise – which proved to be quite elusive… There was some aluminium shielding tape which exhibited a little noise when amp module was moved slightly, so made a better connection to that, also found a dry solder joint and replaced NE5532 op-amp. And whilst in there, gave all the sliders and pots a
Dynacord BS412 Bass Amp Read More »
Missing knob, reverb not functioning, loud pop on shutdown, volume pots very sensitive (almost full volume by quarter point). Genuine Fender replacement pots with audio taper ordered from US to replace existing linear (not sure why they were linear): and fitted: Added an arc suppression cap across switch load contacts to reduce power off pop
Fender Princeton 112 Plus repairs Read More »
Fault – preamp not detecting signal – traced signal through TL084 opamps but indicator section was a little awkward with PCBs in situ. Found contour pot had a cracked PCB: Made enquiries with Porter & Davies and as a refreshing change to most similar other enquiries, Tim Porter was extremely helpful, not only providing schematics,
Porter & Davies Bumchum Tactile Monitoring Amp Repair Read More »
Customer states that TLAudio FatTrack mixer is cutting out after a while, and wanted a valve swap for something better. Found MPSA42 getting extremely hot exceeding 100deg C and breaking down (this is part of the HV circuitry for valves), even with small heatsink attached it was still 86+ and clicking out of service: The
TLA FatTrack mixer cutting out and valve swap Read More »
This THD Univalve came in with a dead HV fuse, was replaced, serviced and tested all ok with the exception that the bias is way too hot for the installed 6L6GC valve. Measuring >110mA and red-plating on Hi-V setting. On Lo-V it was ok of course, but really needed a rebias for using on our
THD Univalve stopped working Read More »
This Linn Kairn with MM/MC came in dead, apparently “was working fine and went off”. Fuse blown so took a look at the power supply (‘Slimline’ switching version) and found a number of dead parts, including both mosfets shorted, controller and a few resistors: I wanted to check the other component values against the PSU
Linn Kairn ‘no power’ Read More »