Customer somehow inadvertently and accidentally moved the voltage selector switch from 220 to 110V, plugged in to hear a fair crack and now dead! Fuse had blown – after putting a temporary fuse in, brought up power slowly, could hear some loud intermittent cracks I expect coming from a partially shorted capacitor (which took the […]
Ampeg PF500 accidental blowup Read More »
Customer states problem started a couple of weeks previously with a crackling sound, thought it was one of their speakers at first but now got a burning smell when plugged it in so turned it off right away. Found R115 burned up – part of zobel network: Removed in order to clean up – it
Ampeg PF500 crackling/burning smell Read More »
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 »
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 »
