I set up a 6' length of track today and installed the analog DC 0-5 Amp meter on one of the power wires from the MRC 2500 power pack. I first tried a couple of older Athearn BB GP18 and GP30 locos. They both stalled (actually wheels slipped) at about .75-1.0 amps. I then put the offending P2K PA on and it stalled at .75 to 1.1 amps depending on how much throttle I gave it. At full power it was drawing the 1.1 amps with the wheels spinning. I didn't get it to short out or do anything close to that. I put it back on my DCC layout and after running it for about 10 feet it shorted (shut down) the system and when I lowered the throttle to speed step 5-10 it ran just fine and the system was back in running order. I am suspecting some other electrical issue with the motor or DC light board. I am thinking of installing the NCE D13SR decoder and removing the light board completely. I don't see any other mechanical problems with the engine.
-Bob
Life is what happens while you are making other plans!
Randy,
I have 2 of the Harbor Freight meters (just got one free last week!). Also have a more expensive one and the analog meter which I think I will use (have had it for a couple of years and never put it on my control panel).
Analog meters are much better at catching quick spikes - until you get to some really expensive digital meters. However, if there was a massive 3 amp spike on starting, then you should be able to get about that continuous if you hold the flywheels of the motor and stall it for a brief time, long enough to register on most any digital meter. If it's hitting 3 amps stalled, that's definitely a problem.
Most low cost digital meters only go up to 200mA, but they usually have a seperate inport that is good for 5 or 10 amps, just not nearly as accurate - but close enough for model railroad work. The cheapy Harbor Freight ones that you can get for $2, or sometimes even free with coupon, are perfectly fine for this sort of thing. If you have a harbor Frieght near you, stock up - it's cheaper to buy a new meter than it is to replace the batteries when they go dead! I have 3 or 4 of them around the house and in my car.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I have a few VOM's and they are all digital, so I could try one of them. I guess I really should make a 3' DC test track and run all new locos on it with the old power pack, just to make sure they ran OK before converting to DCC. I appreciate all your help. I have a busy schedule this weekend and most likely won't get to this until next week, but I will post my findings. Thanks again,
farrellaaI took a closer look at the PA model and realized it has the 8 pin NMRA socket for a decoder, so I would assume that it is a later run.
Even checking it normally isn't necessarily going to reveal all the problems. One of the ones I had (with an 8 pin) tested fine with a normal load test. Two decoders later I did more some more in depth measuring discovered that it had a "spike" of about 3 amps on start up, then fell back to 300ma. The spike was so quick I could not see it with the meter I was using 20 year old Radio Shack. I had to us a meter that measured over time and kept a "max" reading for the time period. Today's digital meters might be better at catching that.
farrellaa I do have a regular DC power pack (MRC 2500) and will try it with a 3' length of track. I had planned to remove the pc board and hard wire the decoder (NCE). The PA doesn't have the Mars light, just a single headlight (which I will replace with an LED). I have several of the P2K E units and they all run great with DCC. I have a DC 0-5amp meter that I could wire in to the DC test setup to see what it is drawing, just never have used one of the meters before. -Bob
I do have a regular DC power pack (MRC 2500) and will try it with a 3' length of track. I had planned to remove the pc board and hard wire the decoder (NCE). The PA doesn't have the Mars light, just a single headlight (which I will replace with an LED). I have several of the P2K E units and they all run great with DCC. I have a DC 0-5amp meter that I could wire in to the DC test setup to see what it is drawing, just never have used one of the meters before.
To use your meter to test the current draw, set the meter to the 5 amp scale. Connect one lead of your powerpack to one rail and the other lead from your powerpack to the meter. Connect the other lead of your meter to the last rail of your test track. You want the current flowing through the meter, not across it.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Couldn;t agree more. On the one PA I did, I didn;t remove the board, but I disconnected all the wires and soldered them tot he decoder leads. That way if the owner ever wanted to switch it back, just cut off the decoder wires and clip them back on the factory board. In any event, it was completely bypassed. Besides, just about every decoder you can buy does a better mars light effect than that silly dual filament bulb and overly complex circuit - though the one I did was a prototype that didn't have the Mars light.
My SOP is to remove or bypass any factory lighting boards. More often than not, they cause more trouble when adding a decoder than they're worth. Unless there isn't room, I always use decoders with 9 pin plugs on them, so if someone would ever want to change the loco back to DC only, they can unplug the decoder and stick on someone's leftover 9 pin dummy plug, or get new ones - Digitrax sells them.
The first run of the PA's had the 8-pin plug as well, so that's not a tell-tale sign either.
You could probably do a product search based on the roadname / number of the unit you have to determine when it was released. That would tell you if it was one of the first releases or not.
There is no visual difference between the high amp motor and the replacement either - had something to do with the internal windings. Definitely determine this either by researching your engine or doing a meter test on the current draw before adding a decoder.
When you do add you decoder - scrap that entire circuit board on the rear of the chassis and hardwire it in place. All that additional circuitry is actually detrimental to how well the decoder can function.
Definitely check the current draw - if it IS one of the bad motors, it will fry pretty much any HO scale decoder made, since most have a peak current of 2 amps and steady state limit of 1.5 amps, and the problem motors draw well over 2 amps.
It could also be a bad motor - shorted winding type of thing.
Do you have a way to test it with an actual DC power pack? Especially if yours is a version with the dual filament Mars light simulator, the circuit could do wierd things when trying to use address 00. Even the Bachmann 44-tonner I have won;t run on address 00 properly, it constantly shorts - I installed a decoder and it runs fine, so something in the design of the bachmann circuit board appears like a short. On a regular old power pack it was fine.
I took a closer look at the PA model and realized it has the 8 pin NMRA socket for a decoder, so I would assume that it is a later run. I haven't had time to go any deeper into the engine, like cleaning both truck gear boxes and putting new lube in. I am pretty sure that it is the PA causing the problem so I will work on it when I get the time. Also will add decoder once it is running OK.
Mark R.The first run of Proto PA's had the high amp motor as well. Life Like sent me free replacements at the time.
farrellaa How do I tell if it has the high amp motor?
How do I tell if it has the high amp motor?
By measuring its current draw when running with an ammeter.. A reading over 500 ma is a lot. An ammeter is a very useful tool when testing and tuning engines. The better they run the less current they draw. The reading will normally drop as an engine is broken in, lubed, etc. If current draw increases, something is wrong.
Martin Myers
The P2K PA is new to me, and it was NIB, never opened, but may be an older run. I did notice one of the worm shafts was very tight and I had to loosen it with some alcohol when I first put it on the tracks; but it has been run over the layout for several minutes (10 minutes, back and forth over a 30 foot run of track). I thought it was OK now, but still plan to open the gear boxes and clean and relube them. How do I tell if it has the high amp motor?
rrinker Are either one older production units? Even if they are new to you. There was an early run of E units that had crazy current draws, enough to exceed the 2.5 amps of the Zephyr all by itself. --Randy
Are either one older production units? Even if they are new to you. There was an early run of E units that had crazy current draws, enough to exceed the 2.5 amps of the Zephyr all by itself.
The first run of Proto PA's had the high amp motor as well. Life Like sent me free replacements at the time.
Bob,
You should be able to draw up to the Zephyr's current limit which is 2.5 amps. Actually it will be a little lower4. One of those engines is drawing a lot of current or it might have a capacitor in it that will pull higher current to charge the cap.
I have been running a new P2K PA on my layout using the 00 address on the Digitrax Zephyr DCC system. Today I placed a DC F2A on the track with the PA still on the track and the system shut down until I removed the second loco. I have done this in the past without this problem, only running two locos for a minute or less. Am I overloading the system or is it just because I am using the 00 address for more than one loco at a time? I don't intend to do this on any regular basis, I was just to lazy to go remove the other engine before testing the second one. All my engines are DCC now with the exception of a few that I don't plan to keep. Just curious about this? (also, I have about 10 sound/DCC engines on the layout all the time and never had a problem with not enough power(amperage) to run them.