100 step rotary encoder

The ones I've seen have 2 printed concentric zero ohm tracks, in a "square wave" pattern. Each track is supplied with 5v by the pullup resistors, the wiper shorting out the tracks as it is turned, producing 2 square wave outputs.

The tracks are printed such that turning it one way makes one output lead the other, turning it backwards makes it lag the other.

It is then possible to use these as data lines to a uP port, where software determines direction of rotation and increments or decrements a counter to show how far it has been moved.

Obviously it is not possible to determine absolute position.

Gareth.

Software is quite easy - using one output to trigger an Interrupt routine on change of its state.

P0 change of state Interrupt:

If P0 = P1 then increment else decrement

end.

Gareth.

different

investigate.

or

software

And then non-volatile memory storage of the last stored position . So presumably you can turn the control when powered off and it will display the stored setting when powered on again. So there is a good chance of getting inside one to clean etc and return it to productive use .

My experience is that mostly when they go dicky you need to replace them.

You can get away with a bit of a crackly pot, but not a misbehaving Data encoder, where often they will only go one way, or jump several positions at once and be almost impossible to home in on the right spot. This pretty much renders them useless unless perfect.

Gareth.

I have on a occasion been able to substitute a cheap easily available off the shelf Alps part where the original is difficult or impossible to find. (e.g. Behringer)

Once I had to reverse the two outputs because forwards was backwards, and another time I had to add pullup resistors, since the original encoder had them onboard with a 5v supply for some reason. (These were both on FX units)

Mostly though its a question of trying to get it to physically fit and mount properly, but then you do a lot of that sort of thing so shouldn't find it a problem.

Cheers,

Gareth.

replacement

lead

it

mount

You would think something the best part of 3x2 foot would have plenty of space to fit generic componentry in.

Yes, but the Chinese make everything themselves, they are not going to have Alps or anyone else make them for them at far greater expense.

Thats why they are so cheap, that's their modus operandi.

Gareth.

Interesting that you've found that. I have had total success cleaning the ones that are fitted to hifi's, for years now. The rotating encoder rings and the wiping contacts are normally gold plated, and the intermittency issue is caused by the 'stirring treacle' grease that's used in them, migrating down the shaft and onto the contacts. When removed from the pcb, these encoders are easily stripped. A little drop of IPA on a cotton bud turns the grease to a sort of 'jelly', which is then easily picked out with tweezers. Once it's all clean, I normally retension the contacts, and add a single drop of cleaner / lubricant before reassembling. I can't recall ever having to replace one, and have done scores of them over the years. It was a favourite problem in many of the Aiwa models that were on the market a few years ago.

Arfa

These are the type typically found in Mr Cooks mixer, FX units etc.

At £2.05 for a new one I am certainly not going to bother trying to bodge a few extra months out of a knackered one! (The official parts from manufacturers (Yamaha, Roland, Korg etc) can admittedly sometimes cost up to £10 after postage/packing etc)

But that's more my policy than anything else - Do I charge the customer labour for bodging, or do I, in my opinion, do the right thing and replace the faulty part instead? If the customer finds it goes dicky again less than a year after I've charged him at least an hours labour to supposedly fix it, my reputation is going to take a hit.

With a new one, it feels all nice and new again, its easily within an hours labour plus parts, the customer is well chuffed, and it should last the same amount of time again. No brainer, IMHO.

Cheers,

Gareth.

I found a couple very common types available very cheap from Onkyo in the U.S. About $1.00 each.

I've had good success cleaning them for the most part, but I did have a very nasty re-do on a JVC stereo which had a slightly different encoder, seemed to work after cleaning, then wound up having to order the original part from JVC when the unit came back.

It was buried on a sub-board in the front panel of a tabletop stereo, so the double extra-special labor to get in there a second time probably cost me >100.00.

As cheap as they are, I generally replace them with the Onkyo parts, since most models use one of the two Onk parts I stock.

I did have a Marantz SR-18U recently which had a "special" one, and no longer available from Marantz. I cleaned it, and it worked OK, but I was kind of sweating bullets on that one...

Mark Z.

counter

display

return

them.

Data

positions

the

rings

pcb,

and

on

is

hours

same

This one has a co-axial switch for the memory change function and as far as I remember no where in that 2x3 foot panel , any space to squeeze a switch , apart from having to cut a new hole in the top pannel. So recondition of the existing or constrained to the main-dealer for supply of a direct replacement

Alps make these with switches too.

Gareth.