# MRC AG990 Power G 10 Amp intermittent power problem



## lincoln pin (Feb 24, 2009)

I have a MRC AG990 Power G 10 Amp power pack that appears to be putting out intermittent power, output any ideas as to what this could be. Before I pack up this big heavy power supply and ship it back to MRC I was wondering if anyone has heard of this or offer up any advice. The symptoms; While running a train on 15 foot long indoor loop with two power drops the engine suddenly stuttered and stopped, if I gave it more power the engine would start, run for a while then stop. This would happen in forward or reverse. I cleaned the track and checked the connections. Everything looked good. Changed engine, same problem, I have another power pack (older MRC) I put that on the same loop. Original engine and others run fine no issues. I don't have a meter at this location so I will have to get one and see if I can reproduce this. Any ideas? Thanks 
Mike


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## NavyTech (Aug 2, 2008)

If you open up the power pack and clean the top of the big coil inside. Check the swiper on top that the spring tension is good. If it needs more down ward pressure the it can be adjusted by the 3 screws on the shaft


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## krs (Feb 29, 2008)

Posted By NavyTech on 02 May 2010 06:22 AM 
If you open up the power pack and clean the top of the big coil inside. Check the swiper on top that the spring tension is good. If it needs more down ward pressure the it can be adjusted by the 3 screws on the shaft


Just make sure you unplug the unit from the wall outlet first - don't just turn it off using the unit's on/off switch


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## Polaris1 (Jan 22, 2010)

I own the same MRC 10 amp G unit..... but have seldom used it because my track has yet to be laid. Just got 2 15 AMP Bridgewerks too = $$$$. 
My understanding of the MRC 10amp G is that it rectifies (inverts) half the sine wave...... and generates a humpy DC voltage...... How much it smooths out the DC voltage to a RMS DC voltage value..... I do not know. I'm guessing (adding FUD) that some engines may further smooth out or process the DC voltage wave better than others...... I really don't think I helped your cause........ But others may respond with better knowledge... Dennis from GBay


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## Greg Elmassian (Jan 3, 2008)

You could add a big filter capacitor to smooth out the DC, but the "humps" help slow starting a bit. I don't know of any analog train that requires filtered DC, and of course there are large scale trains that can run on AC, so those of course don't care about humps. 

Navytech, I have never opened my Power G, but you have, is there anything else inside other than the transformer, the full wave bridge rectifier, and switches and circuit breakers? 

Regards, Greg


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