Hi, i’m trying to repair my Bass amplifier. I shorted cable blew the outputs. I tried and failed a long time ago to replace them and then let it sit for years and now I am working on it again. I think I’ve succeeded this time but I have to replace a circuit protection fuse first before I know . The power supply board in the amp is putting out 76 V and about 16 V. The 16 V seems to be going through a 12 V regulator to power the chips on the amplifier board. The 76 V for the Mosfets is currently blocked by the aforementioned mentioned blown fuse.
The amplifier board has three ics- ti074 op amp, 556 timer and hip4080 mosfet driver. I found a couple of blown transistors and when I replaced them red green status LED switched to a flickering green for about 15 seconds before going off completely so I think I need to replace the HIP 4080. The 556 is still alive and outputting a triangle wave. The 074 op amp doesn’t appear to be doing anything but the highest voltage I redone any of its pins is about 1.3 V.
there’s a Molex connector to supply power to the preamp board and to feed its signal to I’m assuming the op before it goes to the HIP 4080. I don’t read anything on those pins.
The company that made these amplifiers went out of business and don’t seem interested in sharing their schematics with the public so it’s just me and my limited hobbyist knowledge (and equipment) and YouTube university.
The amplifier board has three ics- ti074 op amp, 556 timer and hip4080 mosfet driver. I found a couple of blown transistors and when I replaced them red green status LED switched to a flickering green for about 15 seconds before going off completely so I think I need to replace the HIP 4080. The 556 is still alive and outputting a triangle wave. The 074 op amp doesn’t appear to be doing anything but the highest voltage I redone any of its pins is about 1.3 V.
there’s a Molex connector to supply power to the preamp board and to feed its signal to I’m assuming the op before it goes to the HIP 4080. I don’t read anything on those pins.
The company that made these amplifiers went out of business and don’t seem interested in sharing their schematics with the public so it’s just me and my limited hobbyist knowledge (and equipment) and YouTube university.
