MRC Model 260 Power Supply

[Anonymous]

Hello. I had been using three small used power supplies for my three main track loops and finally purchased three MRC Model 260 power supplies with the momentum feature, on line. I am disapplointed with how they work and am wondering if something is wrong. With the old power supplies I just turned up the power and the trains always ran. When the momentum feature is turned off, the new runs may run about the same but I do not like the way the momentum feature works.

If I turn the power high enough the trains usually move. However, if I don't turn the power high enough the trains either do not move at all of else start to move slightly and then stop. What is especially bad is that if the trains do not move, then they will not move at all even if I turn the power to maximum or even if I turn off the momentum feature. The only way to get the trains moving again is to give them a very slight push and then they go. I have changed the location of the electric feed and cleaned the track but that did not make much difference. This does not seem right and I don't think I would have purchased them if this is the way they work. I had the impression that they would be significatly better than the inexpensive used power supplies that I had been using.

I can also add that when I opened them I questioned if they were really new or if they had been returned because two were scratched and appeared to have been repainted and one was a darker shade of black than the other two.

I called the manager at the company and she said she intended to send new ones and if they were not new, then her supplier had taken advantage of her. I also called the manufacturer and the person there was no help at all. I can't expect the local store to help me since I did not purchase them there. Can someone tell me if these are normal or if there appears to be something wrong. These were my first on line purchase of model railroad equipment and I don't know if I can even return them. Any help will be appreciated.

[Anonymous]

I should have mentioned that I have N scale and use Kato Unitrack. Larry

[Anonymous]

Hi Larry,
The symptoms you describe do not sound normal. If the engines run well with a different power pack, and fail to run well with the new ones you bought, I believe the problem would be in the power pack. The momentum feature on the MRC packs works by slowly increasing the voltage up to the level selected by the knob. This allows the train to appear that it is loaded and is increasing in speed gradually. How long did you wait for the trains to reach full speed? I have an MRC "sound & power 7000" that I obtained ten or eleven years ago, and it still works like new. With momentum turned on, it takes a couple minutes to reach the selected speed. If yours is taking more than about two minutes and the trains are still not functioning, I would suspect a problem. If you have a multimeter, you can read the track voltage at the supply terminals to see what it's doing. If the voltage is increasing as it should, then the problem would be in the locomotive or the track itself. Try a different locomotive (if possible) to see if that may be the problem. Otherwise, try reading your track voltage at various locations around your layout to see if you have a bad rail joiner or other form of electrical connection. I hope these ideas at least help you to determine the source of your problem, so you can focus on where the problem lies. If you still need help after this, just ask!
-Joe

[Don Gibson]

SOUNDS LIKE you have engines that stall or your description is fauty.

A 'Momentum circuit is merely a TIME DELAY.
You turn your knob to your desired running speed and wait for the engine to start and gradually come ip to the selected speed.- somewhere around 10 -15 seconds. You
can do the same by turning the knob slowjy with the Mom. sw. off.

MRC's momentum is too slow for me, so I don't use. I suggest you do the same.

1. There should be NO difference in nunning with Momentum on, or off - except for the time delay. If an engine starts and then stops (stalls) as you describe, That could be mechanical. Clue: Is it one engine or all?

2. It would be near impossible for 3 different powr paks to exhibit starting, stopping, and stalling as you desribe.

QUOTE: "if I don't turn the power high enough the trains either do not move at all of else start to move slightly and then stop. What is especially bad is that if the trains do not move, then they will not move at all even if I turn the power to maximum "

.
I suspecr you are linking the 'stalling'- which is a mechanical freezing - and an elecrical 'charging' circuit. What disturbs me is turning up the power "to maximum" part. If this is a bind in the Engine, you could burn out the motor.

Possibility #2. You're getting a short cicuit and the power paks are shutting down. When yor train is stalled, can you get a spark across the tracks?

[cacole]

According to MRC's Web site, the Model 260 is supposed to have enough power output to operate up to 7 HO scale trains. I think the model number 260 indicates 60 Watts of power output.

Momentum is a time delay effect. When momentum is on, the power pack charges a built-in capacitor, which gradually increases the power to the track so a locomotive gradually builds up speed. When the knob is turned off, the momentum effect keeps the locomotive running for a short period of time as the capacitor discharges, thereby slowing the locomotive down gradually.

That's what momentum is designed to do.

The other symptoms you have indicate dirty track or inadequate power feeds to the track. What gauge of wire are you using between the power packs and track, and is is stranded or solid wire? Try using a larger gauge of wire, something like 18 gauge stranded speaker wire, and see if that doesn't improve things.

Make sure your track and locomotive wheels are clean, and that you have good electrical connections between track sections, especially with that portable stuff.

[cwclark]

the momentum feature is also very prototype...locomotives just don't take off at the touch of the throttle when under a load...the momentum feature is slow, yet it simulates a train pumping up the air brakes and then it slowely starts to move until it reaches the speed the power pack throttle is set for...a very prototype situation...there is nothing wrong with your power pack...that's the way it works...I have 4 tech 4 - 260 models and i think they are great!.....I try to run a prototype layout even if it means the train will not start at the flip of the throttle...I don't run my MR as if it were a race track for locomotives and the momentum feature keeps that from happening...oh well..."different strokes for different folks"...Chuck

[Virginian]

I don't know what's wrong, but suffice to say something is. I can't believe 3 MRC packs would exhibit the exact same problem, and therefore tend to think the problem is elsewhere. I definitely suspect bad electrical conductivity to the locomotives.

[willy6]

I had a simular problem when I first got my Tech 4-350 with programable memory. I could not get full throttle and sometimes only one constant speed. It ended up being operator error. After I read the operating insructions in detail, my problems went away.

[Anonymous]

Thanks for all of your repsonses. I still have some questions.

All of my locomotives seem to work the same way. I want to emphasize all work fine with the old inexpensive power supplies and all work fine with the MRC 260 with the momentum turned off. The trains stall only when I use the momentum feature. They will usually run if I start with the power turned up to 50 per cent or higher. They ususally stall only if I try to start at 40 per cent or less. If there is only a delay in getting full voltage, why won't the locomotives run when the voltage increases. They will move if I give them a light tap.

Is it still possible that the problem is in the power supplies or is it more likely that the problem is in the track, locomotives or electric cords. I do not have a voltage meter. With the momentum turned off the locomotives start and run fine even if the power is set at 20 per cent and even if I have only one feeder track in each loop. I have never had a locomotive stall with the old power supplies or with the MRC 260 with the momentum feature turned off.

I now have two feeder tracks in each loop. The problem seems more serious when the locomotives are far from the feeder track. I am using Kato electric cords. Wouldn't those be designed to be adequate.

Really looking forward to any additional comments. Thanks. Larry

[cacole]

I still suspect poor electrical wiring and track joiner contact, dirty wheels, and/or dirty track more than the power packs.

The only way you're going to find out for sure is to lay some new track in a totally separate area away from your layout, such as on a 1x6 pine board at least 8 feet long, connect an MRC power pack using good wire, use flex track instead of that sectional stuff, and see how your locomotives perform. If they run okay that way, then the problem is in your track and electrical wiring.

In my opinion, sectional track should never be used for a permanent layout because there are too many rail joints that can go bad and cause intermittent electrical contact. Flex track with soldered rail joiners is much better in that respect.