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[scimitarjohn]

I have never seen a Fleet AM set and I can't remember if the NE5044 is a fixed frame time.
  There is no rule stating frame length. It can be ~15msec or less for old sets with few channels. Old sets could centre the channel pulses on 1.3ms then +/- whatever.
    If you had your old Tx to hand you can pick up its timing in a second by wrapping a few turns round the aerial and crank  up the scope gain.

  Great idea thanks, the bad news, the PCB was so heavily corroded I've had to use a brass brush to follow tracks (death or glory) and seems the coin fell on death, no pulse train from the encoder.  The pulse output was iffy anyway, I think a lost cause.

[HMS Invisible]

 I think a short between tracks on 10 and 11 would make the output a sawtooth.
 If it was me, I'd take the chip out it's socket, home in on 10,11 tracks @ experiment on test boards with super crack ultra and Rust-Go. This aerosol from euro car parts opens rusted nuts where WD40 is a penetrative lubricant only.
Rust-Go is a chelating agent dip like USA's Evaporust. It eats oxide in minutes where white wine vinegar converts red rust to magnetite over a day or more. Unfiltered, possibly useless, info from an internet search suggests bicarb & toothbrush.
 The cost of either product I mentioned is not justified by long-shot attempt unless you service 2nd hand bikes too.

.

[scimitarjohn]

  I've checked at the encoder leg and the board, the encoder appears dead.  Come to the conclusion that as the pcb is so badly corroded I'd never want to trust in the TX anyway so decided to bale out.  I have an alternative route in mind to save the old Fleet mechanicals, if I can make it work I'll let you know.  Many thanks for your help, been most interesting and informative.   Regards John

[HMS Invisible]

If you go back to it one day , serial out is open collector. A pull up resistor connecting to pin 16 (Vcc) takes it high.
  It is possible to damage one i/o of a chip but I think, on probability, a fault is elsewhere unless it's been subjected to reverse polarity, in which case, other outputs like pin 15 (Vreg) and Vc mux would not reflect the datasheet traces.
NE5044 is programmable in that it limits number of channels to <7 if an input channel's voltage is set below that of pin 12(range.) So if a pot is turned, or moisture on the board,  takes pin 12 high the output pulses stop.

[scimitarjohn]

  Thought this might be of interest to you, it's from the service manual that came with the AM set.
         Regards  John

[scimitarjohn]

If you go back to it one day , serial out is open collector. A pull up resistor connecting to pin 16 (Vcc) takes it high.
  It is possible to damage one i/o of a chip but I think, on probability, a fault is elsewhere unless it's been subjected to reverse polarity, in which case, other outputs like pin 15 (Vreg) and Vc mux would not reflect the datasheet traces.
NE5044 is programmable in that it limits number of channels to <7 if an input channel's voltage is set below that of pin 12(range.) So if a pot is turned, or moisture on the board,  takes pin 12 high the output pulses stop.

  Well I did go back but with a bit of lateral thinking.  A cheap Flysky set (about £30), pcb fitted fine, see photo, joysticks another matter!  Digifleet uses 80deg of a 300deg 5k pot but Skyfly uses a 5k 80deg pot, so had to adapt Digifleet to accept Flysky pots, turned out to be tricky, it not only has to work but be reliable eh, but got there in the end.

[roycv]

Back in 1965 I bought a 'Derek Olley' bang bang rc set, just switches and actuators.  Back then if there was an electric motor in the actuator I think it was called a servo.
For its day it was great all the other radios had mechanical reeds to decode the signal, my one had an electronic equivalent operating at 1400 cycles (we never had Hertz in those days)!  That was the start the 4 frequencies ascended from there so did not interfere with the mechanical decoders.
Also proof against electric motor RF.  I ran this set up without fault for a few years until Acoms introduced cheap proportional radio.

When eventually the 40Mhtz band arrived I bought a Fleet 4 ch. set and it worked very well and still does.  Mr. Olley was supplying a lot of 35Mhtz equipment then and the 'Plainsman' sets on 40 Mhtz were the same sets with a 40Mhtz crystal installed.

I have been challenged on this!  But when I look at the bottom of the 2 sets I have there is a sticker declaiming it is 35 Mhtz.  It was a great pity that he did not stick to accepted conventions and have standard servo wire connectors both in type and in the wiring order.  Also his charger connection was an oddity.
Having met the man and complaining that his short aerial did not have the range that he claimed, he refused to replace it and as again the aerial had a bespoke screw thread I was forced to buy another telescopic aerial. 

I also had an argument with him about the very expensive sail winch he sold me which hunted the whole time, I still have it and it still hunts!  He would not have it and said it was the traffic going past his shop and insisted that if I used rechargeable batteries the fault would go away.
A bit of a mixed blessing all round.  I still use his transmitters a copy of the Futaba M series in polished aluminium but not the receivers.  The multi choice model set ups in each of the 2 trannies I have are each different and I have to refer to the instructions for any adjustment.

During my innocent phase with him I recommended buying his equipment to a friend and he had some trouble very early on, like the first week of use.  The receiver had got wet I told friend to make sure it was switched off and battery removed and dried out.  Unfortunately he did not, and when he went to see what could be done at the shop he refused to repair it and forced friend to purchase another rx.

In today's market he would soon come to grief with service like that.  Maybe others saw a different side to him but I never bought anything else from him.    I heard somewhere you can only use his crystals in the Fleet Tx's, I use Futaba with no problem.
Bit of a rant, never put it all together before but all happened to me and the friend I mentioned.  Water under the bridge now and very happy with the Futaba Hitec and other equipment I use.

The best 27Mhtz FM receiver I ever saw was the the one Micron used to sell both made, and in kits, I made up the kits they are excellent, but not many people use 27 FM!  I have a few crystals and carry on carrying on!
Regards
Roy

[dodgy geezer]

I have a Micron PL-7D that I must get to work sometime. Did you have any experience with Flught Link?

[roycv]

I have a Micron TX sounds the same quite a long build but switched it on and it worked no problem.  Got a fault on it at the moment but have left it.   It had all sorts of extras and they all worked.
Roy

[HMS Invisible]

Text capture, by phone, of page1, paragraph 6 of the Digifleet Custom III brochure.

Radio control equipment is only as good as the service it gets, and it gets the finest available from the manufacturer at the Fleet Servicentre. A full spares inventory is carried to enable the Digifleet owner to purchase replacement parts down to the smallest screw or gear. In addition, service manuals can be supplied to registered owners at £2.50 per copy for FM systems and £1.50 per copy for AM system

 I have 15 pages of documentation with the 1984 Custom III helicopter set so that's why I didn't spot it before.
However the six page operating system guide is marked 20p, the same as my central Edinburgh to Pilton works bus fare & the Glasgow Herald or Scotsman newspaper. Bus & paper are now £2 so if price inflation was uniform the £2.50 FM diagram would set you back £25 if you could get one now.
 Two things I can tell from a look at the AM circuit is 2s lipo is ideal on its own and external wiring on AM & FM is the same and common to other sets that used a 2.1mm dc jack and additional diode in case of polarity reversal.


Now PostIMG generates a BB code for a thumbnail but replying is blocked but I can't even upload a 1.1MB photo via Attachments

trying again... Works at the second attempt.
The drill is cntrl "c" the message body, use postimg button & cntrl "c" again to catch the image code after a successful upload. Keep the whole copy in your clipboard until the post is allowed.
Pure speculation that IT pros might comment on is if postIMG and the forum must handshake on checking the image for obscenity & the process times out. Just a wild guess

[scimitarjohn]

  Most 'IT pros' I dealt with would have a job changing your screen saver!  Pretty sure my service manual came with the set but if not I dread to think of the hours I'd have to work for that £2.50 back in the day.

[roycv]

Another memory has surfaced!  I used to do my own repairs and bought several Fleet servo electronic kits to replace the electronic kits in older servos, they all worked fine and there were no problems.  At the time the government decreed that there should be a circuit diagram of the electronics in all items, radios etc, that was when we had more discreet components in use.
I noted that the electronics chip in the kit had the description scraped away, there is a notch in the chip to orientate it in the circuit and I am prettty sure the components in the circuit were not identified either.  I knew which chip he was using and anyone else could have worked it out from the component placement.

Make what you will of it but it seemed a bit 'cheap' to me.
Maybe around that time Acoms brought out an esc with a full speed over ride.  Back then there was a 0.7 volt drop across the power transistor (OC29 or OC 35 etc,) and if you were using 10 amps (I never did) then there was a significant power loss in heat and hence the large heat sinks at the time.
I had an idea how to make a circuit that did an over ride but wondered how Acoms did it.  I borrowed one and traced the circuit out for my own benefit.  It was a straight copy of a published circuit I had also found.

If anyone wonders what I mean, you take a sample of the output current which is via a resistor in the emmitter / gate circuit of a transistor with a relay as its load.  When the current hits the maximum it is enough to trigger the transistor to call the relay which then switches the battery direct to the electric motor, so eliminating the esc and power losses from the operation.  I know it seems a bit cheap on my part but the equivalent cost then was more like £100+ for an ESC.

The first esc I made was the Pompey esc published in one of the magazines.  This had the motor across the bar in the H with 4 power transistors at the corners of the H, so the total voltage drop was double the above at 1.4 volts and with 10 amps flowing that is 14 watts of heat that could be going to the motor!

I do not know how it is done now as I have tiny esc's that take 10 amps with no heat problems at all.  I stopped my electronics when the surface mount technology came in!
Everything is so cheap now there is no incentive to diy your electronics.
Roy

 

[scimitarjohn]

I know what you mean, it's a cost benefit thing but I still play, my last was variable voltage/current power supply for the Lions etc. My first set all valve, non het outfit, 27 Tx with twin triode for variable mark space, relayed output on the Rx to drive a leadscrew rudder positioner. All homemade, still have the Rx ! how I wish I'd have kept the whole thing.  When I'd saved up enough for the Digifleet, I'm not even sure esc's were available, were they? anyway built my own using the Ferranti SRC419 chip with a bank 2N3055s on a big copper heat sink to drive. Still use it in a Sea Viper I built when I was about 12.

[Circlip]

Now that looks like a hairykits Sea Hornet?


  Regards Ian.

[scimitarjohn]

  I'm afraid it was over 60 years ago Ian so only remember the name as someone on here told me a while ago. It ran with single channel radio and a 6v lantern battery for the motor so a very leisurely pace, perhaps a good thing with no speed control?  I played on a lovely pond at Blackheath, no boating there now thanks to the killjoys.