MERG kit # 3 (USB) started

I ordered the 12VDC transformer earlier in the week, so while waiting I started on putting together the USB interface kit from MERG. Once again it was an easy assembly up to the point of needing to check for voltages, and this is where I stopped as I needed the transformer. No further work on the terraces as I had a busy week apart from checking that I had the various components for the LED lighting. 

The transformer arrived Friday. I had to get a 2.5mm DC connector to connect the transformer plug to the test bed / bus. So off to Jaycar in the morning to get this and a 6A bridge rectifier for the ammeter mentioned in the previous post. Saturday afternoon was done at the club for a few hours. Firstly a working bee on the HO layout to make a start on cutting the various straights and curves for around the helix blob. Then the monthly meeting followed, and afterwards some more cutting. Later in the arvo I spent some time in the shed getting the DC connector mounted to the test bed.

Saturday night I spent wiring up the CAN / Power bus into the test bed and into the Input and Output kit boards. To my surprise the boards where not getting 5VDC power! 12VDC was going into the Output board which would then supply 5VDC to its own electronics as well as the power input to the Input board. Nothing. I followed the instructions again to make sure everything OK, and it appears to be. I'm stumped! I'm going to have to do some research through the forums to see if this has happened before and if not make contact with a fellow MERGer to see if he has any ideas what might be happening.

Sunday afternoon I quickly did a temporary hash-up of the ammeter to the bridge rectifier and track power (3Amps max through the SB3A booster). Immediately the 'short' light came on and the ammeter was registering about 1.5Amps. I wonder if this was supposed to happen? I'll have to check with Mr Mackie.

Well this week will be spent trying to sort out the MERG kits' power supply problem and maybe install the LED lighting into the terraces so that I can continue the build.