Hi Greg

I don't have the 7686 decoder but I read a number of complains about its implementation and memory problems
On my 7286 TT I have installed a DSD2010 decoder made by DigitalBahn. It is sophisticated and IMO the most powerful one.
It allows
- up to 3 rail sensors on the bridge to detect locos position
- 2 speed control of rotation
- optical sensor for TT position (no more klac klac noise when reaching a track
- it can drive 4 signals, cabin lighting, flashlight, sound all digital controlled.

It is made of 2 decoders: one under the bridge ("Bühne")and one outside ("Grube")
It is sold as a kit with all SMCs (Surface mounted components) already wired). The cost is 135€
The manuals can be downloaded here:
- user's manual https://digital-bahn.de/shopping...sd2010_anleitung_1v7.pdf
- installation manual https://digital-bahn.de/shopping...010_einbau_anleitung.pdf
- all other documentations (wiring instruction, test protocol, etc https://www.digital-bahn.de/bau_ds2010/dsd2010_doku.htm

The configuration and diagnostic software can be download (no charge) here https://www.digital-bahn.de/bau_ds2010/exe/dsd2010_070.exe
The changes to be made to the TT are:
- the removal of the electromagnetic latch / solenoid
- the addition of the opto-sensor for the bridge rotation
- the wiring of signals (optional)
- the plugging of a SUSI sound module (optional)

This is an excellent product (the best IMO) BUT
- the instructions are in German
- the wiring of the bridge is delicate
- the decoder connection to the PC is using an RS232 link so if your PC doesn't have one you need a USB/RS232 converter

You may see the result here in automatic operation using Rocrail


So in short it is an ambitious project that is worth the while.
Cheers

Jean

I use the LDT TT-DEC-G decoder for mine and am very happy with it.

Thanks fellas for the advice. I ordered LDT TT-DEC and it arrived today. All I need is a quiet few hours with no interruptions and I'll give it a go.

Regards
Greg

My turntable also has awful running characteristics. I always assume due to long period of no use coupled with the horrible little Fleishman motor that was used. To make things worse I have found that now that I have landscaped in the edges, the bridge can no longer be removed to be serviced. So yes, getting that sucker to run smoothly should be your next step.

Hi Joachim,

The first thing to check is make sure the centre rail spring contacts have movement.

If the bridge is jamming in a couple of positions only it is very likely that the track is too tight on those stub connections. This can be caused by having the hole too tight around the turntable or pushing the track up to the stub which in turn pushes the segment towards the centre of the turntable and the drive mechanism jams or the centre rail spring contacts jam. Expansion and contract of the layout timber will also cause this problem.

Glad you got it going! Yes you have to program the positions. It was that programming that I found would be lost over time.

The switch to delay getting power is only for when you need to program the TT decoder.

Normal operation does not require the powering up to be delayed.