I have a Potter PFC-5002 that I had acquired from a fellow collector after I managed to damage my MS-4. Unfortunately, the NAC power seems to be acting up. I was trying to diagnose an issue with a Simplex sync module. As I was metering the circuit, I noticed some very high current spikes that managed to blow out my meter unfortunately. (And yes, I know Simplex devices do not like FWR current. I will not be attaching another Simplex device to this power source)
I haven’t had any actual devices die out on me, but since my multimeter blew, I simply do not think it’s a good idea to put another device on the circuit. That meter has been very reliable for a long time for both AC and DC applications. I’m wondering if it’s time to get a new panel, which I have been trying to do, I’m just having trouble justifying the few hundred dollars that will be.
From what i know, FWR power is subject to damage a lot easier than DC or AC power. The internal transformer feeding to the NACs is probably malfunctioning and putting the input voltage out in short spikes. It is most likely that your panel needs to be trashed. If it blew out .your meter, Its got to be an extremely high voltage. If you are looking for a new reliable panel, I suggest an Edwards EFS1004RD 10 zone panel. They’re about $200 to $300 on eBay which is pretty good since the retail price is over $800. I wouldn’t risk trying to fix or diagnose the problem with your panel. Sorry this happened.
With your meter, were you measuring for current or voltage? Multimeters have a high internal resistance when measuring voltage, but a very low internal resistance when measuring current which makes it easy to blow a fuse in the meter, or even the meter itself. Before you confirm your meter is blown, check for any blown fuses. If I ran in to a similar problem, I would check the voltage output on the NACs. Unlike the voltage, I wouldn’t measure the current between + and - , that function is used for measuring the amount of current a circuit is using. Measuring voltage requires a live circuit, which means extreme care. Make sure you KNOW what you are doing before you try to troubleshoot things like this.
I have always used autos, both at home and in the field. Maybe the spike was enough to fry something in the meter. I never used a manual, would a spike out of the range damage your meter or does it have some protection against that sort of thing.
It looks like this panel does put out FWR on NACs. You can try checking the secondary AC voltage on the transformer once you have a meter with proper fuses. If that’s out of whack, then that will almost certainly be passed through to the NACs. Replacing the transformer would be a lot cheaper than replacing the whole panel.
You should disconnect the devices from the panel and put the EOL back at the panel and check voltage. Then remove one leg of the resistor and check voltage again. This way you will see the circuit voltage change from a proper EOL circuit and an open circuit. This will allow you to see if the supervisory circuit is working for the NAC. This will also let you know the panel is functioning. If that all checks good, then, leave the resistor leg off and set your panel into alarm. Check voltage. At this point you should be seeing full voltage from the NAC. Now, you can move your red lead over to the ampere port on your meter. Observing polarity place one lead on the empty terminal at the panel and the other lead on the open leg of the resistor. You should see a small amount of current on your meter. The amount of current will be dependent of the resistor size and voltage.
As far as buying a new meter. If you are on a tight budget then go for a small digital meter from one of the big box stores. You can also check pawn shops. But, always make sure the meter works at the pawn shop. If you over amped your meter there is a fuse inside that will blow. Make sure you check that before buying another meter. I would also look for an analog meter(they are cheap). Being able to use an analog meter properly will teach you to better use a digital meter. Especially the autorangers.
