Mode Zero

Many thanks to all those who have responded to my cry for help . Max, by "as it was" I meant that I removed the additional resistor shown in Phil's document and put the wiring between the stick and trim pots back as Simprop had intended and as it was before I started fiddling with it ie., with no resistor. Thanks too for your offer of trim pots but thankfully, after a serious "session" today, I am not going to need them . I felt the problem HAD to be either with the trim pot or with the wiring between it and the main stick pot. Access with the stick unit in situ is not good so in desperation I took the stick unit out and decided to re-wire it. (While it was all disconnected I checked the resistance of the trim pot and it is 2.5K end to end.) It was fiendishly fiddly to rewire but I got it all back together and BINGO.... It all works!!! So it looks as though the problem was indeed in the wiring between the pots.

Stuart, I have done mine somewhat differently to yours. There was corrosion on some of the module boards so I haven't used them, other than the switches and pots on the Rate/Expo board. All my other stuff is DSMX/DSM2 so I took the innards out of an Orange module and installed it in the Simprop module case.... I like to make my own antenna and disguise it in a dummy frequency pennant.....




I have used Phil's latest 7 channel encoder. I haven't used the mixers but have used the Rates and Expo facility, using the pot and switches from the old Simprop module.




Thankfully the wind has now reduced so this evening I was able to test the new Simprop by flying the "Junior" out of the field at the back !

Paul

Fascinating stuff! It was Walter Klaas who put the money up for the prize for the first successful RC helicopter - won by Dieter Schluter - that paved the way for the modern RC helicopters.

Wire wound pot tracks really shouldn't give any problems. They are generally almost indestructable. The servos in my Bonner Digimite-8 use them and still function fine 50 years on! However, they do get dirty, and need cleaning once in a while.

I would suggest using good quality switch cleaner on a cotton bud (or lighter fuel, if you can't find switch cleaner!). Be careful not to leave any cotton fluff behind! Also clean the wiper. It is often the wiper that wears, rather than the pot itself, and it may be possible to fabricate a new wiper with a bit of ingenuity.

After cleaning, the slightest smear of silicone grease will help with smoothness. Do not apply too much! The surface of the track should just be glistening slightly.

My only experience with Simprop radios was with a Digi-5, which was pretty disastrous! The pots in the servos seemed to need cleaning after every flying session (NOT wire wound!), and I had really weird range issues with it. On its second flight, it failed completely, writing off a new model. Post crash investigation revealed that the wires in the battery pack were totally unsupported - no heat shrink, not even a knot in the cable where it exited the end cap. One of the solder joints had fractured in flight, leading to the loss of control.

I sent it back and got it repaired, but I don't think it ever completed a single flight without a glitch, or worse, at some point! After about a year, I traded it for a red-box Sprengbrook and never looked back!

I did like the look of them, though. Shame the Digi-5 quality didn't match up the the appearance!

--
Pete

My binding problem is solved...... sort of . The original receiver was fairly elderly and though completely reliable with other transmitters, was DSM2 only. It did seem to bind in DSMX mode and the problem was that as soon as I switched off either the receiver or the transmitter, binding would be lost in both modes. So I have replaced the receiver in the model for a newer, DSMX/DSM2 receiver and all is well with binding being kept as it should and I have now had several flights using the SAM with no problems . I still don't know why bind was lost with the old receiver though and it still works fine with other transmitters.

Many thanks to all who contributed their thoughts.

Paul

To round off the SAM range, Simprop introduced the PCM20 in 1983 as their first PCM transmitter and here is my old flying buddy, Doug Allardyce's transmitter which he has owned from new, which still sees active service flying a Simprop Extra 230 with a ST3000 in it.
You will see that the modules were designed for different aircraft applications and Doug being a dyed-in-the wool aerobatic pilot, has the F3A module fitted to his PCM20.

Thought I would post some pics of the swansong of Harsewinkel designed transmitter, The System 90 from 1990. This was effectively the ultimate development of the SAM architecture and layout.

They were introduced to compete with the multi model memory computer Txs of the time, such as the offerings from Graupner/JR, Robbe/Futaba and Multiplex.

It was a full 10 channel set and had a matching receiver with the TOP TEN Rx. It would operate in PPM and PCM modes.

It had several novel software features, notably the variable gain switches for aileron & elevator (infinitely variable rates), 3-Level switch, similar to flight phases and a whole raft of inbuilt mixes for Aircraft and Helis.
The pics below are my old development one which I used when writing the English manuals for it, it now resides with my old buddy, Doug Allardyce in N Yorkshire, who kindly took the pics you see below.

The Top Ten and Contest servos were taken yesterday on my workbench testing out the Simprop Contest servos as used by Wolfgang Matt and Hanno Prettner back in the day and were operated by my SAM gold on 35 MHZ which was last switched on in 1989!
Enjoy!

I remember the led battery monitor shown in the pic with the servos and Rx. They were a standard addition in all my models. I always used that type. We're they manufactured by Simprop, I can't remember.

Cheers,

Shaun.

Shaun, Simprop did make them, but that particular one is a Webra one.
Great lil devices, still use them myself