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μWatch
03-02-2019, 12:16 AM
Post: #12
RE: μWatch
Success!!
I’ve adapted an old 5v DC power supply, removed the battery compartment all together and sent the 5v directly to the +ve and -ve connections on the main UWatch PCB. The new LCD sprung into life as soon as I pressed the Mode button and after displaying an (old) date, went to the Setup screen.
I’m assembling the watch on a flat breadboard and will spend tomorrow tidying all the new cables and connections neatly so I can use it as a desktop (albeit with a tiny 16 x 2 screen and a minute keyboard!).

I’m also thinking of powering it with 5v from a standard USB cable from a standard power pack I’ve already got UNLESS anyone thinks that might not be a good idea?
Should I be using a cable with a ferrite ‘choke’ on it or doesn’t it make any difference - I’ve always used ‘choke’ USB cables in my recording studio, especially when powering external audio interfaces, I was told they stop/reduce RFI & EMI interference which can appear as ‘noise’ on a digital audio recording (although the majority of my 18 track Recording Studio is based on ProTools with a DIGI 002 FireWire Audio Interface - although I also still use analogue Reel to Reel occasionally as well). I don’t know if or how RFI/EMI interference would affect a calculator though?
Using a rechargeable USB pack and an USB cable would make the Desktop μWatch portable and negate the need to have an AC 5v DC Power Supply plugged into the mains.
I think I’ve been lucky here as my whole repair has been based on just Logic (the LCD screen needed at least 4.7v DC so I went ahead changing the power supply to 5v, not having enough EE knowledge to know if that would cause other issues - some might say I used guesswork!) and I could have ended up ‘frying the whole thing?
I bought the right size of LCD screen replacement, not having checked that it had the same voltage requirements as the original (3.3v) - instead the new LCD needed 4.7v to 5.3v; I’m assuming that the μWatch was actually running under the old in parallel 2 x CR2032 3v batteries but that there wasn’t enough voltage to actually power output to the LCD? The other huge advantage (for me) was that the new LCD came with its 16 pin ribbon cable already attached to the LCD - all I had to do was to put the other end into the female slot on the μWatch and lock it into place as in no way would I have been able to solder the bare 16 pins of the ribbon cable to the LCD.

This has been a good hands on project (eventually!) for me. I’m trying to improve my EE knowledge with a combination of paid and free online courses.
So having completed the repair (I’m very grateful for everyone both on the Museum Forum and via email who offered advice as to how to proceed) I’m now contemplating a couple of things:-
(1) Is it possible to drive a bigger screen (preferably by piggy backing to the existing LCD so as not to have to remove - a bit like the dual screen setup I have on My Windows Recording Studio PC.
(2) what are the two male connectors on both edges of the μWatch circuit board? I think both are 5(6?) pin and are they UART serial connections (and/or IR?) - but for what purpose?
(3) Can either/both serial ports connect the μWatch to external accessories like printer, PC or storage device like tape recorder or minidisc to load and save programs?
(4) Can a larger keyboard be attached?

Thanks
Dennis

Denny Tuckerman
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Messages In This Thread
μWatch - Leviset - 02-16-2019, 05:12 PM
RE: μWatch - BobVA - 02-17-2019, 02:24 PM
RE: μWatch - Leviset - 02-19-2019, 03:39 PM
RE: μWatch - Robert VM - 02-21-2019, 11:27 PM
RE: μWatch - Leviset - 02-22-2019, 03:48 PM
RE: μWatch - mpark - 02-22-2019, 09:00 PM
RE: μWatch - BobVA - 02-23-2019, 01:07 AM
RE: μWatch - Leviset - 02-28-2019, 12:00 AM
RE: μWatch - ijabbott - 02-28-2019, 12:35 AM
RE: μWatch - Leviset - 02-28-2019, 02:58 PM
RE: μWatch - teenix - 02-28-2019, 09:37 PM
RE: μWatch - Leviset - 03-02-2019 12:16 AM
RE: μWatch - grsbanks - 03-02-2019, 11:41 AM



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