I got this with shorted outputs, shorted power supply transistors.
I replaced the outputs and power supply transistors, including the HIP4080.
The amp voltage is being dragged down, heavy load on PS. Like there is a short. hard to explain.
I removed the HIP4080 and tried again, same thing. I checked the power supply drivers and they are ok.
Also appears to be a hack in the TL494 circuit, 2 1kohm resistors and a cut trace to a 10 ohm resistor.
any ideas? Also what value are the resistors supposed to be at R213/R214 etc... I have 10K
I replaced the outputs and power supply transistors, including the HIP4080.
The amp voltage is being dragged down, heavy load on PS. Like there is a short. hard to explain.
I removed the HIP4080 and tried again, same thing. I checked the power supply drivers and they are ok.
Also appears to be a hack in the TL494 circuit, 2 1kohm resistors and a cut trace to a 10 ohm resistor.
any ideas? Also what value are the resistors supposed to be at R213/R214 etc... I have 10K
10k is correct for 212/214.
I have only seen a couple of these but in both amps, the brown filter caps started failing, one by one. Some failed in each group. When I last tried to find rail caps, I couldn't find any that fit with the same value. That may have changed.
I have only seen a couple of these but in both amps, the brown filter caps started failing, one by one. Some failed in each group. When I last tried to find rail caps, I couldn't find any that fit with the same value. That may have changed.
Yea, I had noticed that with the rail capacitors. But I checked all those caps and they appear to be ok.
Turns out the TL494 was defective, Once I changed that out it was fine. Funny thing is, The TL494 was bad, but the driver transistors were good. Figure that out.
Anyway, TL494 was fixed and it was fine.
Turns out the TL494 was defective, Once I changed that out it was fine. Funny thing is, The TL494 was bad, but the driver transistors were good. Figure that out.
Anyway, TL494 was fixed and it was fine.
If you're going to sell it, I'd suggest that you run it a full day up to and into clipping to make sure that it's going to be reliable.
No, its not for selling. Its a repair. Also, I replaced the outputs with 3415s, which is what I keep on-hand.
Since its a HIP4080 based system, instead of a self-oscillating loop like the MTX, it should be ok?
Since its a HIP4080 based system, instead of a self-oscillating loop like the MTX, it should be ok?
- Status
- Not open for further replies.