The lamp initially lights up due to the inrush current charging the secondary capacitors. If the capacitors remain charged, the inrush current is significantly less.
The Z44 staying cool is good. The only reason I want it to survive is so that testing can continue and you can get the parts ordered.
Did you try adjusting the bias to see if the light would get a bit brighter?
The Z44 staying cool is good. The only reason I want it to survive is so that testing can continue and you can get the parts ordered.
Did you try adjusting the bias to see if the light would get a bit brighter?
I tried but, the light isn't lit at all so I can't tell when it gets brighter. I understand your explanation on the inrush current.
Perhaps I will need a smaller bulb?
Perhaps I will need a smaller bulb?
Confirm that you have approximately ±25v from the center leg of the rectifiers to ground.
You should also see that voltage on the large 0.1 ohm resistors.
You should also see that voltage on the large 0.1 ohm resistors.
IS the power LED still lit?
Do you have positive 15v on pin 8 of the various op-amps and negative 15v on pin 4?
When you initially power the amp, does pin 14 of the LM339 go from 0v to approximately 10v (after a second or so)?
Do you have positive 15v on pin 8 of the various op-amps and negative 15v on pin 4?
When you initially power the amp, does pin 14 of the LM339 go from 0v to approximately 10v (after a second or so)?
The power LED stays lit anytime I have it hooked up. I've been removing it while I come on here so as not to overheat anything.
Do op-amps have board designations beginning with U? For example U101-A?
This might be a good point to end for the night because I will need to study up on where all of these test points are.
Ok, thank you. I'm getting pretty sleepy so I will measure them tomorrow night. Thanks a lot Perry.
The Various Op-amps are showing -10.31 on pin 4 and +11.86 on pin 8. They were all consistent.
The LM339 pin 14 is showing open.
The LM339 pin 14 is showing open.
After a second or so, it just goes to 1. Sometimes it will have a quick voltage before it goes to 1. but, it hasn't been a consistent voltage. I keep trying over and over.
Yes, I tried both meters because I didn't expect that reading. Confirmed DC voltage is set on the meter. If I leave the lead on there and remove amp power, it then will return to 0V
I'm embarrassed I didn't think of that when I saw that goofy reading. I was set on 20V and expecting around 10V
DC voltage is 24.8V
Find R122 and R276.
Before the voltage goes high on pin 14, the voltage across those resistors should be low (0v?). After the voltage goes high on pin 14, you should read approximately 10v across those resistors (both probes on the resistor). Is that what you have?
Before the voltage goes high on pin 14, the voltage across those resistors should be low (0v?). After the voltage goes high on pin 14, you should read approximately 10v across those resistors (both probes on the resistor). Is that what you have?
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