Carver PM1.5 heavy current draw
Hi jle_tarzan,
The "transformer" is probably okay.
This is not the type of amplifier that non-professionals should attempt to service. Your top supply rails are + / - 125 VDC and do not discharge on their own very well.
Given the age of this amplifier, it will need a number of things looked at. If there is a good technician who really does understand Carver products, take your amp in for him to service. It doesn't take much to really hurt or kill yourself working on these amplifiers. It's also very easy to cause a great deal of expensive damage.
This is really not a good amp to service without knowing exactly how it works.
-Chris
I've got the same problems after repair of a Carver PM1.5.
I'm an expierienced engineer, able to repair al kinds of pro power amps, including the digital ones
While the amps are old, they're still in use.
At this example I replaced the dual capacitors, because there was no capacity at all anymore.
After replacing the fuse, the amp seemed to be without defects.
But when I applied an testtone of 1000Hz, the fuse blowed after a few seconds. Only one channel driven.
I live in the Netherlands and the amp is factory connected for 230 volts, so the fuse has to be 6 1/4 Amps slow blow.
I tried to measure the primary current draw and used a FLUKE 177 in series with the amp. Currentdraw with one channel driven was over 10 amps, meter reading overload.
Using a currentclampmeter, I measured over 15 amps. That reading could be faulty because this was not a true RMS meter.
I checked the triac circuit and also the firing of the triac. That seems all correct. Conducting time varies with current consumption.
I borrowed another amp, which i tought it was a good one, but there was fitted a 15 amp fuse. So this amp could have some (or the same) problem.
A third amplifier used still the original 6.25A fuse.
When i applied a 1000Hz sinewave and a dummyload of 4 ohms. Current draw was also over 10 amps with one channel driven.
Is there anyway a method of checking the transformer (magcoil), so i can exclude that part.
Greetings from Holland
Speakertech