Signal KH-3 operational

This weekend I focused my spare time in getting one of the installed signals operational. I decided to do the simpler of the two KH-3. So using the same setup as my test LEDs I soldered extension leads from the signal wires to the MRC 4-way accessory decoder Acc # 16. I then turned on the system and activated Acc 16 to ON which should have turned the Green aspect on. No go. Huh? Select 16 and turn OFF which should turn on the Red aspect. No go. Double huh! A bit of head scratching then happened. It was then time to go inside, so that was it for Saturday.

Further thinking during the evening came up with possible problems like "had I inadvertently reprogrammed the MRC decoder?", "had I buggered up the LEDs?", "is there an issue with the supplied LEDs in the Eckon kit (1000ohm) versus the supplied resistors with the MRC decoder (300ohm)?", "was it a soldering problem?", etc. Too much thinking over a few glasses of red in the evening meant no answers were forthcoming!

Sunday morning arrived and with some spare time after breakfast and before waking the neighbours up with the whipper snipper and mower, I went the shed to see if I could answer some of the above. I progressed through the list and ruled out most. What was going on? I reread the Eckon wiring instructions and the MRC manual. Nothing was obvious. I put my test LEDs on to the decoder outputs and they tested OK. Hummmm. Time to think a bit more while taming the lawn.

I had intended to go to the RMCQ (my club) Buy and Sell but a small family emergency entailed after the yard work and just before lunch. Son number One had misplaced a Lego Man he was going to use in a class project. This character was in a powerpoint presentation and thus couldn't easily be replaced. We searched all over the house for nearly an hour. Everywhere was given at least two searches by myself and the missus on separate occasions in case one of us missed it. We were on the verge of conceding defeat when Son number Two all of a sudden whilst in Son number One's bedroom found the lego man. What! So an indepth chat with a 2.5 year old entailed as to where did he find it. He finally pointed out a lego liferaft model with one of its sides down and it was apparently in there. We thanked young Matt with curious looks. Lachlan was adamant he hadn't placed it in there. I strongly suspect Matt had put it in there earlier this morning. So by the time we had done this, had lunch, and tried putting Matt down for a nap (and succeeding in putting myself to snoozeland as well!), I had missed the opportunity in getting down to the club. By all accounts it went quite well.

However the nap must have reinvigorated the brain cells as I quickly commandeered the laptop the missus was pottering around on to check something on LEDs on Wikipedia. Mainly the electronic symbol and usual orientation of the positive and negative terminals. Making a note of this, and following a coffee, I went to the shed again to check the documentation. EUREKA! I thought something was wrong. The MRC's common is positive whereas as per the Eckon wiring instructions I had the common as negative and resisted. The polarity on the Eckon LEDs was reversed and thus potentially not working. So I rewired to how MRC likes them presented, turned on the system, selected Acc 16 ON and bingo, Green came on.

Oh wow, what a lesson to note. Lord knows why the Eckon LEDs are wired like this. But now that I know, I can wire the remaining signals the same way.

Here is a small video of KH-3.

Not sure what this week will bring. I know I have to paint Lachlan's shop pavement before we can place it on his layout. Maybe the other signal which has a junction feather. Let's see.