New Loco for the Stable

Saturday this week was our normal Club Meeting day.  So at about 10:30am yesterday I shot off over to the Club but first I had to call in at Horizon Hobbies at Warner.  As I turned off South Pine Road towards John's shop, I noticed that the road was closed.  Damn!  I then had to do a quick 'U' turn and head further down the road and take the next right and hope that my GPS could find John's shop via some back streets.  As it turned out the route to the shop was straight past one of the Wife's Girlfriend's house that we had previously visited, so I sort of knew where I was being taken.  Thank God for GPS's.

So I made it to Horizon Hobbies and asked if John had a Powerline Mark III 48 Class.  John produced 4894, which ran very smoothly on the test track. So it was then added to my stable of locos for a reasonable price.

I then drove over to the Club, had a few conversations, had a Club meat pie from the freezer, talked about the new HO clubroom layout (and I think we resolved a few questions), sat through a good Club meeting, had a good arvo tea and then it was time to travel home.  While at the Club I had picked up an NCE DA-SR decoder from the Club shop to install into the new 48 class. 

We really have a great setup at the Club.  Hot water urn runs all day for free tea and coffee.  The fridge is always stocked with cold softdrinks, and the freezer is stocked with various pies, sausage rolls and sometimes - iceblocks.  The Club Shop has a range of decoders, KD's, and foam inlays for our carry trays for rollingstock.

So later that night I sat down at the kitchen table and started cursing while I attempted to take the Powerline 48 Class loco apart.  Bits of step and other detail parts flew everywhere.  The Damn loco would not come apart.  However it soon did.  I took the loco down to the shed and switched the loco over to DCC mode.  I thought it was about to lift off the track like a helicopter from the rear fan assembly which is connected directly to track power.  The loco was very noisy.  It definitely was not a 'Silent Drive' decoder that was fitted.  However the loco did run very well in DCC mode.  So I made the descision then and there to remove the factory installed decoder and replace it with the NCE DA-SR decoder.  The decoders almost looked identical or so I thought. 

So I took each wire off the factory installed decoder and then soldered it directly to the NCE decoder in the identical place.  I had everything installed except the cab light and the fan as I was going to do some extra work on these.  I took it to the test track and hit forward and it ran in reverse.  I hit the headlight and nothing worked.  I changed direction and the rear headlight also did not work.  I had a theory.  So I decided to look at the factory decoder I just removed.  The motor tabs were reversed when compared to the NCE decoder.  So I switched them over.  I looked at the two tabs for the front headlights.  They were also reversed when compared to the NCE decoder.  I switched these wires over and I did the same for the rear light tabs as they were also reversed when compared to the NCE decoder.  Well the decoder was not a good copy of the NCE version.  So back to the test track.  It now ran correctly, and the front headlight worked in forward and the rear headlight and front marker lights also worked in reverse.  The rear marker lights did not work.  A closer inspection showed that I severed the wire to the rear marker lights when I pushed the decoder onto the mounts in the locos.  This was soldered back together and head shrinked.  Voila!  Just like a bought one and it did not make any noise.

A closer inspection of the cab light and the fan motor, showed that these ran from a small bridge rectifier board in the rear of the loco.  This allowed the cab light to always get DC current, as the motor for the fan to also get DC power.  But there was a couple of resistors, one about 100 Ohms and another at 300 Ohms, something else that I could not measure (it might have been another resistor - I will check again later) with a transistor attached there as well.  I measured the fan motor amp draw on my NCE Powercab system (this system is just great) and it was showing between 0.01 Amps or Zero Amps.  So I knew that this motor could be controlled direct from a decoder output.

Being not too much an electronics Guru, (we leave that to Brendan)  I just connected the cab light up to function 1 in the decoder and ran it via a 1000 Ohm resistor.  Works like a charm.  I connected the fan motor wires up to function 2 and also via a 1000 Ohm resistor.  When this was switched on, the fan did not spin.  It wanted to, but would not move.  You could touch it and it would move off and keep spinning.  So I replaced the 1000 Ohm resistor with a 680 Ohm resistor.  Still the same result.  I was wondering what the transitor is used for, when this afternoon following our running session on Cassino when Brendan mentioned that he was thinking about a transitor circuit to control the fan motor.  No doubt some smart Chinese factory engineer has done just than for Powerline. 

I think I will leave the loco for a while, while I think about how to kick the fan motor off and hopefully let it run at a slower speed.  I may re-install the small circuit board that came with the loco and have its input come via the function 2 output and use all the kit on the board provided by teh smart Chinese engineer.  If anyone has any other ideas or has already done this, please drop me a line via the blog or via email.

I can't wait until this locos joins the roster.