Friday, 1 January 2010

Finally got the turntable working

After many attempts at getting power to the track, I finally stripped the whole thing down this week. I put a lot into making sure that everything was right. I threw the Walthers track base away by cutting it out from the two sides of the deck. I then made a new deck out of 30 thou styrene so that I could lay some standard track down. The previous attempt at laying individual rails using superglue was rubbish. At least this way I know that the track is going to stay in alignment.

After putting it all back together again, I still found that I couldn't get power to the track properly and decided that the brass fingers pressing against the two brass collars on the pivot just didn't have enough pressure. I discussed with a friend (Dan) the option of just 'sledgehammering' it by using direct wire connections into a connector block. That way, every session, I could unwind the wires. He suggested using some springs as they do in slot cars. I didn't fancy the work so what I did was to solder a wire from each finger around the collar so that the finger couldn't lose contact.

At last I have something that works - not every time, but if it fails, it seems I just have to do one more round trip and it all sorts itself out.

Don't forget that the whole layout is DCC, so the turning motion is controlled by a DCC chip addressed at 99. I have set the CV for maximum speed right down so the fastest speed you see here is with the controller full on. This also gives me tremendous slow speed control - I can move it by about 1/16th of an inch very easily. I do have a DCC booster that can control the polarity change as the turntable turns automatically but I don't have a suitable cable. Hence, I have resorted to a DPDT switch which I flip with every turn. Fortunately the DCC controller overload protection is excellent so no damage occurs if I get this bit wrong. I will get it controlled properly but I need to get a cable, which is proving difficult at the moment.

Here is the exciting video.


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