Technical, Techniques, Hints, and Tips > Radio Equipment
Old Micron data request...
dodgy geezer:
I picked up what I thought was an old Micron combo the other day, and found that it was a part-finished kit. The RF board and the encoder board look fairly complete, but I would like to check them before I put power through.
The problem is that they look to be very early examples. The encoder board, for instance, does not have a 4017 IC chip. I have circuit diagrams for later Microns, but nothing that early. If anyone has a circuit diagram for a Micron encoder board without a 4017 chip, or an RF board with no Toko inductors, I would appreciate a copy....
HMS Invisible:
Some descent photos will suffice. I'm familiar enough with that era of radio.
All the emitters of npn transistors are tied to 0volt and you don't have to worry so much about exceeding a voltage limit.
dodgy geezer:
OK - if you want to have a go!
What turned up was a Micron receiver (looks like 27mHz AM, though no crystals), a Tx box assembled with sticks and unsoldered, an aerial which looks like a commercial radio receiver one (no Micron centre load), two PC boards populated and soldered apart from a few components which were threaded through and the wires bent back, and a box of oddments including a transformer, several resistors and a diode (parts for a charger?)
The RF board has +, - and signal wires attached, also an aerial-out lead (unscreened - later Microns were screened) pictures below. It has one PCB hole unpopulated. There are two copper sections on the board which look as if they are intended to take a wire connection.
The encoder board has no wires attached. It is populated with 4 'half-shot' transistors for four channels (no 4017 chip), with space for a further 3 channels. There is some electronics at one end that I do not recognise. I can work out the + and - lans, and the norcim site has a similar example encoder which I might be able to infer the stick pot connections from (though there are no obvious points on the lans to fix a wire...). There is one unpopulated hole in the electronics at one end, covered by a link.
I was planning to power up the RF board, connect to an aerial and see if I get any radiation. Then I was going to wireup/power up the encoder and poke around with a scope until I found a stream of pulses. And then connect the two... But I could really do with a circuit diagram to see if there are any missing/incorrect components...
HMS Invisible:
The extent of what I hoped to point out is what you seem to already understand.
As well as the half-shot transistors there is an astable timer. A recent thread about restoring a Digifleet transmitter showed one using inverting logic gates.
The ring circuit is completed with a fixed or variable frame, and the output to the rf board will be obvious if you sketch one stage. Without referring to an old Tx or diagram, I think that will be npn collector 4 to 7.
I'll look out an old set & search for the relevant thread about NiCds.
I could further add, which you may have guessed, that the polyester capacitors are the stable timing caps.
HMS Invisible:
https://www.modelboatmayhem.co.uk/forum/index.php/topic,70532.msg764983.html#msg764983
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