Ok, I attached some speakers, turned the bias back down and the voltage on the center leg of the diodes, inductors, and at the outputs is still +40, -27 volts. Do I need to feed the input with a signal and output a decent amount of power to measure or should just attaching the speaker load have been enough?
I was wondering if you ever got a chance to measure the inductance value of a good output inductor on a 500/5?
My 'good' LCR meter is giving me unreliable readings. I ordered a new one. It will be here Wednesday or so.
I tried testing with a signal generator but the reference inductor that I was using was giving me high readings. It was either mis-marked or I was making a mistake somewhere.
I tried testing with a signal generator but the reference inductor that I was using was giving me high readings. It was either mis-marked or I was making a mistake somewhere.
Do you know if the operation frequency on the 500/5 is around the 58khz you mentioned for the 500/1?
I've never compared the two. If the capacitor connected between pin 6 of the 555 timer and ground is the same value for both amps, I'd expect them to oscillate at the same frequency.
Perry, I was wondering if you could confirm the valve of resistor R813 on the 500/5. In this amp it appears to have been very hot and burned most of the color marking bands off. It faintly looks like 2 orange, a black and a gold band. I believe it might be a 33 Ohm resistor.
Do you happen to know the value of the large resistors right behind the output capacitors? Mine are a bit defaced from the exploding capacitors so I'm unable to read them. However from your picture and what I can see on mine I'm guessing they are 5 watt resistors.
5 ohm 5 watt. The following link is a zipped file of photos of that area.
http://www.bcae1.com/temp/jl500slash5.zip
http://www.bcae1.com/temp/jl500slash5.zip
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Is there any reason performance wise why the resistors could not be axial mount instead of radial? I'm not finding many options on future or digikey for replacements similar in size to those.
Didn't look through mousers inventory yet but looking at that part number it looks pretty close. I'll take some measurements when I get home and see how it would fit. Thanks
Ok, its been a while but I've finally collected all the parts I think I need to get the amp back up and running. I've swapped everything out and powered it up. 4 channels all seem to work just as expected, sub channel also appears to be alive. I'm going to run it on the bench for a while to monitor its condition. Do you have any ideas of what would cause the output capacitors and inductors to melt down but leave the outputs and power supply section in working condition?
It could be that a winding shorted on the inductor first. That would have caused overheating and could have produced too much of a load for the capacitors (from the high frequency carrier passing through the inductor). Of course, this is a guess.
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