Tuesday, November 12, 2019

fixed SynScan key pad

Had a go at Elaine and Tony's SynScan hand controller. They reported significant problems with the 3 button on the keypad.

After fixing my digital multi-meter, I started by testing the main control cable. All good. Good continuity and no apparent shorts.

DB 9 male
RJ 45 male
1 = 7
4 = 4
5 = 1
6 = 6
8 = 8
9 = 5

The pin-out agreed with diagrams I found on the interwebs.

I did not stress-test the cable. Considered that would take a bit of doing... So I decided to open up the hand paddle. I was not expecting to find anything.

Surprise number 1 was the broken bit of glue flopping around. Jammed down by the connectors. Removed.

Surprise #2 big label on the board.

inside of SynScan hand controller


Surprise #3 was the daughter board for the jacks separate from the main board. This would allow for flexure and forces that would not find their ways to the main board. Smart. Not going cheap.

Surprise #4. No detachable plug for the power leads to the back-light. What the hey? Now that was cheap. Lack of foresight.

Detached the header connectors from the daughter board and removed the small PCB. This allowed the main board to flip up. Removed the rubber button monolithic sheet.

inside of rubber button sheet

It seemed A-OK. Clean. No debris. Completely fine. Noted two conductive pads per button. Redundancy. Right-handers and south-paws?

Then I turned my attention to the contact pads on the "top" side of the main board. Oh ho! Surprise #5.

main board with contact pads under buttons

Corrosion. Well, that's a strong word. Discoloration, debris, stuff on some of the contact pads. The worst? The number 3 key! How about that. Water intrusion.

Rigorously cleaned all the contact points with isopropyl alcohol. Buttoned everything up. Connected the control to a HEQ 5 Pro mount. Booted up: version 4.37.03. Got myself to the Longitude and Latitude screens and entered 3 digits everywhere. Tested every other key. Positive and immediate responses. All good!

Phoned Tony and relayed the good news. He was very happy. He said they are expensive.


We came up with a great idea. An astronomy tip for those encountered dew. At the end of an observing session or imaging run, disconnect the hand controller, and (like a wet phone) throw it in a sealed container with rice (or a few silicone desiccant packs). You might assume water got it so don't let it sit for a long time without getting the moisture out as fast as possible.

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