Chris,
I was quite successful in bending the contacts on the relay. I have read in other forums where people stated the relay kicks in after about 3 seconds. Is there an acceptable time frame for this to occur? As I stated earlier mine kicks in after about 6 seconds. Have not yet been able to center the B+ adjustment pot and obtain 74 Volts. I wanted to thank you again for all your help I could not have progressed this far without it. There is one other problem I will have to deal with, calibrating the watt meters they are definately off. I am sure I dont have the equipment needed to do this the right way so I am going to have to improvise. I can use the computer to produce a 1KHZ tone is there a way to figure wattage across a dummy load of 8 ohms? Such as P=I x E. Anyway I am going to have to break from this side project (the M500) as of Sept 1st I have an empty apartment that I need to redue and this will take me several weeks. Thanks, Harry
I was quite successful in bending the contacts on the relay. I have read in other forums where people stated the relay kicks in after about 3 seconds. Is there an acceptable time frame for this to occur? As I stated earlier mine kicks in after about 6 seconds. Have not yet been able to center the B+ adjustment pot and obtain 74 Volts. I wanted to thank you again for all your help I could not have progressed this far without it. There is one other problem I will have to deal with, calibrating the watt meters they are definately off. I am sure I dont have the equipment needed to do this the right way so I am going to have to improvise. I can use the computer to produce a 1KHZ tone is there a way to figure wattage across a dummy load of 8 ohms? Such as P=I x E. Anyway I am going to have to break from this side project (the M500) as of Sept 1st I have an empty apartment that I need to redue and this will take me several weeks. Thanks, Harry
Hi Harry,
6 sec is just fine. There is no set limit and if I timed other M500's, they might be the same - or not. It does not matter really. So this may be a non-issue.
To calibrate your watt meter, simply use a low frequency signal (unless you are using an HP bench meter or Fluke 87 or equiv., then use 1 KHz) like 60 ~ 120 Hz and measure the AC output with no load. Use your power formula and figure 8 ohms. Easy as pie. 😉 So no dummy loads required.
Stricktly speaking, a low distortion oscillator should be used with a dummy load. Do one channel at a time to avoid tripping breakers with some amps. You may need a preamp to increase the level out of your computer to supply a high enough signal.
Meters. Most digital meters have terrible high frequency response. The better Fluke meters and Agilent (HP) meters should be fine. An older HP analog meter is deadly accurate too. Their response goes way up into the MHz for some. Other meters are not trust worthy at 1 KHz. They will read low.
-Chris
6 sec is just fine. There is no set limit and if I timed other M500's, they might be the same - or not. It does not matter really. So this may be a non-issue.
To calibrate your watt meter, simply use a low frequency signal (unless you are using an HP bench meter or Fluke 87 or equiv., then use 1 KHz) like 60 ~ 120 Hz and measure the AC output with no load. Use your power formula and figure 8 ohms. Easy as pie. 😉 So no dummy loads required.
Stricktly speaking, a low distortion oscillator should be used with a dummy load. Do one channel at a time to avoid tripping breakers with some amps. You may need a preamp to increase the level out of your computer to supply a high enough signal.
Meters. Most digital meters have terrible high frequency response. The better Fluke meters and Agilent (HP) meters should be fine. An older HP analog meter is deadly accurate too. Their response goes way up into the MHz for some. Other meters are not trust worthy at 1 KHz. They will read low.
-Chris
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