Re: AVR Scope Clock


John Clark
 

Raymond,
Yeah, everything is installed (no leftover parts, lol) and I triple checked all components before soldering to make sure I had the right ones in the right place.

It may not be quite 60 seconds per day. I didn't check it that closely. I've just noticed after a few days that I'm a couple minutes fast. I do unplug the clock board and turn off the scope at night and sometimes don't turn it on for a day or so. It would just be running on the battery during that time.

The old Bluetooth GPS is great because it hasn't been used in ages and now it, once again, it too, has a new purpose in life. Besides, if you need one they can be had for less than $20 on eBay.

John
________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Raymond Domp Frank <hewpatek@gmail.com>
Sent: Thursday, December 20, 2018 10:29 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] AVR Scope Clock

On Fri, Dec 21, 2018 at 02:19 AM, John Clark wrote:


I found the clock was running fast, somewhere around 30-60 seconds per day.
Hi John,
Nice idea to use a BT-GPS. OTOH, 30 - 60 s/day fast is a suspiciously/impossibly large deviation for the built-in quartz crystal oscillator. 350-700 ppm?? No way...
Are you sure C3 and C4 (the two caps on the quartz crystal) are in? Your 20 MHz quartz could be defective as well, though not likely.

Raymond

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