Crystal ID S793 - Page 1
Forum section: electronics / repair

author: Audiorepair
author_rank: Frequent Contributor
timestamp: June 21, 2023, 02:33:05 pm
content: Not really my field, but is it possible to ID the frequency of this crystal marked S793?Its from a Radio Microphone (829 - 865 MHz, which I suspect is irrelevent as this one is driving a processor)Cheers.

author: coromonadalix
author_rank: Super Contributor
timestamp: June 21, 2023, 02:40:11 pm
content: remove the tape to show whats under it ?? youll get an idea

author: Audiorepair
author_rank: Frequent Contributor
timestamp: June 21, 2023, 02:52:06 pm
content: Quote from: coromonadalix on June 21, 2023, 02:40:11 pmDoh! Now I feel a bit foolish.Its MC68HC908GP32https://www.farnell.com/datasheets/1578711.pdfI'm still not familiar enough to guess frequency, but I'll have a go at 8MHz.Edit - From datasheet: "The PLL can generate an 8-MHz bus frequency using a 32-kHz crystal" , so its 32kHz or less then?Er, do they not mean 32MHz? You can see I'm out of my depth on this one!

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 21, 2023, 03:09:15 pm
content: "The PLL can generate an 8-MHz bus frequency using a 32-kHz crystal."32KHz (32.768 or 215Hz to be exact, divides nicely to 1 pulse per second) is a standard crystal for "quartz" time clocks, usually comes in that sort of package.

author: coromonadalix
author_rank: Super Contributor
timestamp: June 22, 2023, 10:33:52 am
content: if its a 32 ... khz crystal, they are easily found for time related clocks / ic's etc ...

author: Audiorepair
author_rank: Frequent Contributor
timestamp: June 22, 2023, 11:16:01 am
content: Quote from: coromonadalix on June 22, 2023, 10:33:52 amI don't know what it is, it sounds like the 32kHz crystal capability is designed for a clock, not a radio mic, which presumably would just want a bog standard crystal to run its reasonably basic user functions.I've been through all the crystals on Farnell and Mouser and there don't appear to be any part numbers or frequencies incorporating "793".(In this cylindrical package)

author: coromonadalix
author_rank: Super Contributor
timestamp: June 22, 2023, 12:29:26 pm
content: https://www.mouser.ca/ProductDetail/ABRACON/AB38T-32768KHZ?qs=m%2BUhWDcpCfbdp9ovMbeW3g%3D%3D&mgh=1https://www.digikey.ca/en/products/detail/yic/32.768K12.5P2/DT38/15648610?utm_adgroup=Crystals&utm_source=google&utm_medium=cpc&utm_campaign=Shopping_Product_Crystals,%20Oscillators,%20Resonators_NEW&utm_term=&productid=15648610surely in your country youll find them if needed

author: Audiorepair
author_rank: Frequent Contributor
timestamp: June 22, 2023, 01:43:03 pm
content: Quote from: coromonadalix on June 22, 2023, 12:29:26 pmI found those in Mouser, and can get them, but mine is marked 793. Those are 32.768KHz.So I figured mine isn't one of them?I didn't find any crystal frequencies ending 793.I think I found one 792.Yes, there are a few 22.5792Mhz crystals available, which led me to believe 793 is not indicating its frequency, but is a part/ ID number.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: June 22, 2023, 03:19:25 pm
content: From the datasheet:3. Choose a practical PLL (crystal) reference frequency, f RCLK, and the reference clock divider, R.Typically, the reference crystal is 32.768 kHz and R = 1.So its probably worth trying one of these even though I can't identify the frequency of the one I have, in the hope Shure have used these typical values in their application.They are very cheap.