[HELP] Not sure where to post this but this seems like a good start - Linear encoder repair

[Dan Boy]

I have a linear encoder that I bought from China.  It worked great till I got it soaked with coolant and bang, the read head now does not read.  Anyone know where I can get this repaired as the vendor is giving me the cold shoulder.

Cheers, Dan.

[Ron Chandler]

I have never seen one of these up close, but I have manufactured some parts that resemble the damaged junk.
Just a guess, but the parts marked with "2700" are probably surface mount resistors. Check with a ohmmeter for a value of 2700 ohms.

The array to the left looks like the bases of IRLEDs (infra-red light-emitting diodes), or the matching phototransistors. Under a microscope, you should be able to see where a small chip (about .010" sq) was mounted with conductive epoxy. The other pad is where a fine wire attached to the top of the chip. It was probably originally encased in plastic. This kind of damage usually occurs when the device sees an over voltage, like when current limiting resistors are shorted like with a liquid, (coffee, Coke, tea).

If you have a friend who is a "ham" (amateur radio operator), he may be able to help you work the problem. If you are near Newcastle, there used to be some engineers at Honeywell who might help.

[EdK]

Those marked 2700 are indeed resistors. The other parts must be the detectors of some sort. If you were in the USA I'd say to send it to me and I'd do what I could to fix it. The resistors are a no-brainers. The other parts would need to be seen close up to figure out exactly what they are.

Ed

[Vinny]

I was trying to figure out if the "other parts" were even there.

[EdK]

(06-19-2015, 06:14 PM)Vinny Wrote: I was trying to figure out if the "other parts" were even there.

Yea, not enough information to give an informed opinion.

Ed

[Dan Boy]

Is there any additional info I can give here that might help?

[EdK]

How about a picture of the edge showing the side view of the parts circled in red? Clearer pictures that are in focus would help also.

Ed

[Ron Chandler]

I'm guessing that the package looked like this:

http://www.mouser.com/ds/2/143/PT91-21C-...-48049.pdf

This pdf describes a gull-wing surface-mount phototransistor. Such devices are available from Mouser, Digi-Key, maybe even Radio Shack.

[Dan Boy]

I hope these pics are better. Its real hard to get any closer in focus the thing is so damn small and I don't have any specialist photo equipment.

Ill check the resistors with my multi meter.

Thanks, Dan.

[Vinny]

So there is something there. While you have your ohmmeter out, check the 5 clear things. Then swap the leads around and check them again.