That's just it, i do have the barrier strip istalled, but internally the ground wire going from the barrier strip to the ground speaker wire has been cut, and to my dismay i just soldered it back, POOF ! my ground path in the output board of my mixer is now vaporized, what the hell ? could it be that the previous owner cut that ground wire because of a problem ? or is there a ground difference between the power amp and home appliances ? they both use grounded pin wires !
Thanks...
Thanks...
Oh Man!,
There is something seriously wrong there!
The chassis ground should be at the same potential as everything else unless your house wiring is bad. It's now time to examine everything carefully and assume nothing. That means check your outlet wiring and the internal wiring. Unplug and measure the resistance to the line cord from ground, both sides. I wonder if a transformer leak / short to core has occured. The amplifier would then be unsafe to sell.
I'm glad you didn't get a shock or worse!
-Chris
There is something seriously wrong there!
The chassis ground should be at the same potential as everything else unless your house wiring is bad. It's now time to examine everything carefully and assume nothing. That means check your outlet wiring and the internal wiring. Unplug and measure the resistance to the line cord from ground, both sides. I wonder if a transformer leak / short to core has occured. The amplifier would then be unsafe to sell.
I'm glad you didn't get a shock or worse!
-Chris
well i checked the amp, i see no short, but i did notice one thing, i remember a while back that i needed to have a ground lift for some of my items when i used my pm1200 also, i remember that when i plugged my laptop to the amp or even to my house amp (el cheapo yamaha) i would get the famous 60hz hum even the image on my tv would get the 60hz roll, could it be the same issue for my mixer ? btw i had an old laptop lying around i connected it direct to the carver running on batt worked fine, as soon as i plugged on the 3 pron batt charger, the poor sucker died right there, same phenomena the ground path connecting to the 1/8 jack totally burnt off, there goes a good old toshiba 386 !!!, so i think i'll just put the amp back as it was, i've talked to a few of my friends who also dj's and they told me that they have a lot of issues with the power amps they use concerning grounds, they have mismatches of crown's, qsc's, bgw's and they told me horror stories of some amps still having the chassis to output barrier still on and having fire coming out of the torro coils as soon as they plugged them in on the same mixer, funny how household technology and disco don't quite work the same....or am i just talking non sense ?, if it were'nt true why would the enginers put those lifts there in the first place ? Please correct me if i am wrong...I checked my mains in the house, i just get a steady 244 ac when i connect my tester to the hot wire and the ground !!!!!!!
JUST KIDDING......
JUST KIDDING......
Hi pjaneiro,
The ground lift is for reducing the level of hum, not for preventing sparks and smoke.
You must have a serious wiring fault in your home AC electrical outlets.
Buy an outlet tester. Test each and every outlet that you use. I am worried about open grounds and / or hot and common mixed up. The other possibility is that your mag coil is shorted to the frame and chassis. Either way, there is no way that amount of current should ever flow between grounds. I don't think there is a member here that would disagree.
So don't cover the problem up, FIX IT!
The only difference between commercial and home wiring is the quality of the work. The outlets ought to be wired the same way.
-Chris
The ground lift is for reducing the level of hum, not for preventing sparks and smoke.
You must have a serious wiring fault in your home AC electrical outlets.
Buy an outlet tester. Test each and every outlet that you use. I am worried about open grounds and / or hot and common mixed up. The other possibility is that your mag coil is shorted to the frame and chassis. Either way, there is no way that amount of current should ever flow between grounds. I don't think there is a member here that would disagree.
So don't cover the problem up, FIX IT!
The only difference between commercial and home wiring is the quality of the work. The outlets ought to be wired the same way.
-Chris
Well i just did something better than that , i just installed myself a new braker and a new 3 pin wire to it, same results, i am also using a powerbar/noise suppressor from monster, all lights indicate clean power with good grounds, i've checked for a short in the amp all is good, excuse me for my ignorance but why is the negative prons on my amp connected to the chassis anyways ? i am still trying to figure out that one, i thought sound was sent in AC form ? i've just checked with my home amps (nad / yamaha and my good old trusty dynaco, nope no ground connected to chassis there....even for fun i checked my car amps, only one actually has a neg speaker post to chassis, and yes i checked the positive side also, as i know some car amps invert signal for bridge 🙂
please enlighten me, i find this fascinating, Oh yeah, another stupidity, since i reconnected the neg speaker back to chassis, the squeel is gone !!!
please enlighten me, i find this fascinating, Oh yeah, another stupidity, since i reconnected the neg speaker back to chassis, the squeel is gone !!!
pjaneiro said:
The PM-1.5 fan actually is a DC fan. The DC voltage supplied to the fan is increased as the load on the amplifier increases. If you try driving the amp into a dummy load, you'll hear the fan speed increase as the power demand on the amp in increased.
Hi pjaneiro,
Please use caps and punctuation properly. Your post is hard to read.
If you are referring to the AC ground pin, it's connected to the chassis for your safety. Should anything short to the chassis to make it live, the ground connection directs the current to the AC return rather than through your body. It's actually a law and a requirement for UL and CSA approval.
If you are talking about the black (or common) speaker connections, you will be able to measure continuity to the chassis ground. There is no speaker AB switch to interrupt that connection. The speaker return must not travel through the chassis or RCA ground.
-Chris
Please use caps and punctuation properly. Your post is hard to read.
prons??
If you are referring to the AC ground pin, it's connected to the chassis for your safety. Should anything short to the chassis to make it live, the ground connection directs the current to the AC return rather than through your body. It's actually a law and a requirement for UL and CSA approval.
If you are talking about the black (or common) speaker connections, you will be able to measure continuity to the chassis ground. There is no speaker AB switch to interrupt that connection. The speaker return must not travel through the chassis or RCA ground.
The Carver M400 did that too. Other Carver amps did as well, but I can not remember which ones did that.
-Chris
Would it be possible to get a copy of the service manual?
I've got one sitting on my test bench that needs some tlc...
I've got one sitting on my test bench that needs some tlc...
Hi There,
I have a PM-1.5 sitting on my desk with that "hi pitch noise" coming from the outputs.
I did some checks on the MAG COIL regulator and could observe that the noise is related to the TRIAC switching.
I have only the schematics of the PS section.
Can anybody mail me the service manual or complete schematic?
Regards
Inch-o
I have a PM-1.5 sitting on my desk with that "hi pitch noise" coming from the outputs.
I did some checks on the MAG COIL regulator and could observe that the noise is related to the TRIAC switching.
I have only the schematics of the PS section.
Can anybody mail me the service manual or complete schematic?
Regards
Inch-o
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