# MRC Throttlepack 027



## rotorhead (Sep 7, 2012)

Greetiings from Rotorhead. Flew Seakings for 20 years. Building a giant O guage pike. 12 main lines. I bought 2 MRC transformers recently on eBay that needed repair. The Throttlepack 027 had a fuse spliced into the inbound power cord. I removed the fuse and spliced the wires directly. Puts out the required AC voltage now as measured with a meter. But I want to test on the rails. Problem is that neither terminal is labeled 'common'. How do I determine which is 'common'?


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## gunrunnerjohn (Nov 10, 2010)

Welcome to the forums. 

Would a manual for the MRC Throttle Pack 027 help? 

Normally, the U terminal is common on Lionel transformers, but there are exceptions. Also, some Lionel transformers actually do that backwards and U is the high side.

Are you saying the fuse was in the 110 volt line? If so, the only issue you may have is phasing the two transformers so they are in phase. This is important if you plan on having power districts and the two outputs could ever be bridged by a lighted passenger car or locomotive.

Here's en excerpt from the manual that shows the track connections.


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## AG216 (Sep 28, 2011)

the MRC are good, but make the motor humming a little ....something that for me is annoying. I used a MRC 027 and those brakes and momentum features was quite awesome.
Andre.


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## rotorhead (Sep 7, 2012)

Thank you for your responses. But the transformer in question is a Throttlepack 027. I searched the MRC website and there is no manual/instructions published for this animal. It has only 2 terminals and neither is marked in any way. My concern is whacking the proto board on the MTH units. If I test the whistle with a Lionel 671 steam turbine, will that comfirm the common terminal?


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## gunrunnerjohn (Nov 10, 2010)

I see the difference, I don't have either. The names are very close, just not the same. 

Since there is only two terminals, there is no danger of connecting them wrong. The worst thing that can happen is the horn and bell will be reversed. Typically, the red will go to the center rail and the black to the outside rails.

Yes, testing the conventional 671 will allow you to get the polarity correct, but there's no danger in connecting it backwards as far as damage is converned.


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## drinxbydapool (Oct 31, 2021)

i have a question about the mrc 027, is it pure ac?


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## Jetguy (Mar 22, 2019)

drinxbydapool said:


> i have a question about the mrc 027, is it pure ac?


Just to make sure, we are talking about this model right? AH104

















I'm have one of these in for repair and NO, this is NOT pure AC output.
This is an electronically controlled transformer and thus has a chopped wave output.


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