MRC Pure Power Dual Transformer Issue

These transformers have an internal fuse- in your case two fuses. Its possible that you blew the fuse before the c.b. tripped. 

If the screws holding the transformer casing are not of a common type, you may have to send it back to mrc for fuse replacement.

@prrhorseshoecurve posted:

These transformers have an internal fuse- in your case two fuses. Its possible that you blew the fuse before the c.b. tripped. 

If the screws holding the transformer casing are not of a common type, you may have to send it back to mrc for fuse replacement.

Wonderful. I'll peak at the underside and see what kind they are. Btw, I should've mentioned. I use both DCS and legacy. 

I don't remember any fuses in the AH601.  The fact that power returns when you hit the direction key "the right way" suggests something has gone wrong that's not a fuse internally.  You'll have to open it up and look, they're actually a very simple transformer.

Got her open. What should I be looking for? 

Following with interest, as I have one where one side is completely dead.  Hoping for a simple fix.  Thanks in advance.

@Mallard4468 posted:

Following with interest, as I have one where one side is completely dead.  Hoping for a simple fix.  Thanks in advance.

Is it the same issue I'm having? Or something different? 

Remove the boards with the diodes and yellow plastic strips on the left side. Flip it over and check all three copper tabs very carefully where they are soldered to the board. Look for failed solder joints and broken contacts. This is a known issue with these transformers. I have the PP Dual and the PP. Both of mine have had this failure and replacing the tabs on one and resoldering a tab on the other took care of the issue. MRC has the tabs in stock. If you want to fix it yourself, contact them and they will send the tabs to you. I got three tabs for about fifteen bucks. I only replaced the tab that broke instead of all of them as they suggested. No point in replacing parts that haven't failed yet. They will fail later and you'll have some spares. If you don't press them too hard, which is difficult because they are stiff and don't have the familiar 'click' when they are pressed, then the chances of them failing are greatly reduced.

What he said.

@Trainlover9943 posted:

Is it the same issue I'm having? Or something different? 

Similar, but possibly with a slight difference.  As far as I remember, one side of mine is completely dead - don't get anything by pressing the reverse button.  But I also don't know that I tried that.  Other side works perfectly.

Mallard, advise for you is the same I gave to TrainLover. I am almost certain you have a failed contact.

@Mike D posted:

Remove the boards with the diodes and yellow plastic strips on the left side. Flip it over and check all three copper tabs very carefully where they are soldered to the board. Look for failed solder joints and broken contacts. This is a known issue with these transformers. I have the PP Dual and the PP. Both of mine have had this failure and replacing the tabs on one and resoldering a tab on the other took care of the issue. MRC has the tabs in stock. If you want to fix it yourself, contact them and they will send the tabs to you. I got three tabs for about fifteen bucks. I only replaced the tab that broke instead of all of them as they suggested. No point in replacing parts that haven't failed yet. They will fail later and you'll have some spares. If you don't press them too hard, which is difficult because they are stiff and don't have the familiar 'click' when they are pressed, then the chances of them failing are greatly reduced.

 

I took it off and didn't notice anything wrong. Of course I may not have been looking hard enough. 

Okay, sorry. You have to remove the yellow plastic bar. I think it has four screws in it. the traces are on the other side of the board. the picture you have is of the bottom of that board. BE CAREFUL when removing the plastic bar. There are three springs in there that keep the tabs in place. It is not bad, but if you aren't used to working on this kind of stuff it can be a PITA.

When I looked more closely at the first picture, it looks like the contact on the right is detached from the board.

If it is just a failed solder joint and the metal isn't actually broken, you should be able to reflow the connection and be good to go. That is how I repaired one of mine. The other one had the contact actually broken in two.

Got it off. Looks like the one for the direction key need to be resoldered as it popped off when I took the strip off. 

Fixed. Wonder how that tab got unsoldered? 

@Trainlover9943 posted:

Fixed. Wonder how that tab got unsoldered? 

Flexing or a cold solder joint from the factory.  I see a lot of that in brass locomotives, the solder joint seem to crack and lose strength with age.

I purchased one of these to replace my Z4000 which I believe needs the potentiometer replaced. I would like to get that fixed eventually. The right throttle of the MRC seems to have a similar issue as mentioned here. It worked fine at first but after multiple uses it became unreliable. Since I don't run conventional I leave it on full power and just turn it on & off with the rocker switch & power strip. So far so good. 

The throttle on these are usually almost bulletproof.  They go directly to a really large carbon wiper on the toroidal transformer coil.  I can't imagine it being a high failure item.