BillGriffiths100 wrote:I concur. To hard ATM, hence the request for a schematic. Life's priority's are keeping them on the shelf
Seriously your chance of getting a hens tooth (
http://beeradvocate.com/beer/profile/203/878 ) is more likely than a schematic, get the tx's apart and trace the wires to the circuit board give them a wiggle and a pull. Your problem is not likely to be on the board and a circuit diagram would only show the pot central wire going more or less directly to the single encoder chip NE5044 or equivalent found on these tx's so you wouldn't really be any the wiser. Failure of this type is nearly always a wire fracture, a faulty pot would give an intermittent jerky failure.
You can find information on the chip from:
http://www.datasheetarchive.com/NE5044-datasheet.html
I originally purchased 2 of these models, 1 to learn how to fly a larger coaxial model, the 2nd for parts when (not if) I trashed the 1st. Both out-of-the-box gave odd differing intermittent problems. I should have sent them back but unfortunately at the time I had put them on a shelf due to not having any time (or a location really) for play, let alone fault finding.
Eventually I MADE some time to play. By the time I worked out it wasn't me causing the problems there was no warranty left... 90 days if memory serves. So they became my white elephants. I disassembled both transmitters to look for
'the usual suspects' that normally cause these types of faults. broken wires from cold joints, connector miss alignments etc. I found nothing obvious and yet again, out of spare time, they went back on the shelf. Now that I was out of pocket for these 2 originals, I thought it best to make a few phone calls to the local electronics shops that had sold them and get a few more returned faulty models for a few bucks, cash in hand. These items for more spares in the hope they'd see me thru.
Sooooooo now it's time to fish, or cut bait.
I dissembled all of the transmitters, as after a process of elimination by changing crystals, it appeared that all the receivers were working, at least on the bench. I found that ALL of the transmitters were in the same condition... nothing obvious, no loose or cold joints. Eventually I came to the conclusion that (most likely) there had been a
dump of factory-rejects of this item into the country, due to the large number of returned items with nothing obviously wrong or easy to fix.
So that's where I am now. I'd not gone to the trouble of serious fault finding to date. Now I have some time (well soon
).
Thanks for the tips Bill and the link to the "Programmable seven-channel RC encoder". I've downloaded the specs and tho the RCs are only 4ch, a quick glance at page 1 shows it will 'do' "3 to 7 channels" so it's a good place to start... if they're very common they may well be the one used, if not thanks to your direction I should be able to track down similar. I'll drag my old CRO out of storage and hopefully (if it's still working) I'll be able to make something work out of the pile of spares.
Also thanks for mentioning the pots, I wouldn't have thought to meter them, as I've never had one fail on me touch wood... the vast majority of my electronics experience has been on Mil-spec or high-end commercial equipment.
cheers...
PS: Thanks for the link to the Hens Tooth... I'll try to get one to contrast my Round-Tuit, and display with my resin-mounted Rocking-Horse Poo.