Help identifying part - Page 1
Forum section: electronics / beginners

author: subcosin
author_rank: Newbie
timestamp: June 26, 2022, 11:03:43 am
content: Hi all,This is my first post so please be light with me, I have a Swann DVR that stopped working, upon closer inspection, I found a component that had perished and the outer shell of it had crumbled away.I tried to find schematics but had no joy.Does anyone know what this part is/was?Thanks

author: gamalot
author_rank: Super Contributor
timestamp: June 26, 2022, 11:06:04 am
content: Like a 32.768kHz crystal.

author: subcosin
author_rank: Newbie
timestamp: June 26, 2022, 11:13:22 am
content: Thanks, what makes you sure its that frequency?

author: Ian.M
author_rank: Super Contributor
timestamp: June 26, 2022, 11:16:56 am
content: Its *Probably* a 32.768kHz crystal, as very few things except low frequency time-keeping crystals are ever in that particular type and size of package, and 32.768kHz is by far the commonest time-keeping crystal frequency.However as long as the crystal's metal can is still intact, any breakdown of any coating on it or corrosion of the outside of the can is very unlikely to stop it working as the can is hermetically sealed to protect the tuning fork crystal inside it.I see green powdery residue nearby on the PCB so odds are you've got one or more broken tracks or vias due to corrosion.

author: gamalot
author_rank: Super Contributor
timestamp: June 26, 2022, 11:17:52 am
content: Quote from: subcosin on June 26, 2022, 11:13:22 amBecause the crystals I've seen in this package are all 32.768KHz.

author: Ian.M
author_rank: Super Contributor
timestamp: June 26, 2022, 11:21:51 am
content: You can also get 100KHz crystals in that package, e.g:https://uk.farnell.com/citizen-finedevice/cfv206-100-000kazf-ub/crystal-100khz-cyl/dp/1457087but they aren't particularly common.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: June 26, 2022, 11:39:23 am
content: There is no shell or outer coating on that part the material is the brownglue that was holding the part in place which does account for the corrosionor at least some of it.The surface mount capacitors may also be causing some corrosion.Both should be checked and reglued/replaced.Jeff

author: gamalot
author_rank: Super Contributor
timestamp: June 26, 2022, 11:45:55 am
content: Quote from: Ian.M on June 26, 2022, 11:21:51 amYes, there are 32, 32.768, 50, 75, 100KHz and maybe others that can be found in catalogs, but the most likely one we see should be 32.768KHz.

author: mariush
author_rank: Super Contributor
timestamp: June 26, 2022, 11:46:10 am
content: Devices need a oscillator or crystal to keep track of time. 32768 Hz or 32.768 kHz is a very common frequency used for such purpose in clocks and chipsets to keep track of time - 32768 is a very "computer friendly" frequency, as it's divisible by 2 (it's 215so a computer can determine 1 second has passed just by counting the ticks from the crystal with a simple circuit)In your picture you see right under a oscillator that's working 24 Mhz - that's probably used by the sound card or network chip, or for chipset for the internal sata controller or whatever that partRight under it there's another one, probably equally high frequency... so that leaves you with the most probably purpose

author: wraper
author_rank: Unknown
timestamp: June 26, 2022, 11:49:25 am
content: As said other than 32.768kHz clock crystals do exist in this package but it's not a common thing. Considering there is another 24Mhz crystal nearby, most likely it should be 32.768kHz clock crystal connected to the same chip. Also there is a socket for a CR2032 or similar battery nearby, which confirms it should be for clock.