how to mount full-can crystal oscillator on soldered breadboard - Page 1
Forum section: electronics / beginners

author: jdutky
author_rank: Regular Contributor
timestamp: October 29, 2020, 04:04:16 am
content: I'm laying out a small single board computer on a soldered proto-board and I'm going to socket all the chips, partly because I expect this to be a throw-away design (I'm just learning about digital electronics, so I'm building something relatively simple, and I'd like to reuse most of the chips in the project I'm working my way up to), and partly because I expect to be doing a fair amount of rework on this board as I discover my mistakes; I want to be able to remove the chips while I'm re-soldering stuff so I don't damage anything with excessive heat.My question is how to mount the full-can crystal oscillator that I'm using to drive the clock. The pins are about twice as long as the pins on a normal DIP, so if I try to mount it in a 14-pin DIP socket it rides pretty high. Is there another kind of socket I should be using? Should I cut the pins down in length so that it sits snuggly in the DIP socket? Should I just not worry about it and solder it directly to the proto-board?Inquiring minds want to know.

author: oPossum
author_rank: Super Contributor
timestamp: October 29, 2020, 05:17:27 am
content: Yea, just trim the leads a bit if you want it to sit flush. Machined pin sockets will have better grip than stamped. You can get sockets for oscillator modules, but that really isn't necessary.https://www.mouser.com/ProductDetail/Aries-Electronics/1108800?qs=WZRMhwwaLl%2FwPZzvk3pU8Q%3D%3D

author: Ian.M
author_rank: Super Contributor
timestamp: October 29, 2020, 05:47:06 am
content: Be careful trimming the leads as mechanical shock from cutting them has a small risk of damaging the crystal or disturbing its contacts. I would suggest holding the lead firmly with needle nose pliers between the can and where you want to cut to dampen the shock wave when you cut.

author: jdutky
author_rank: Regular Contributor
timestamp: October 29, 2020, 06:15:12 am
content: Quote from: oPossum on October 29, 2020, 05:17:27 amQuote from: Ian.M on October 29, 2020, 05:47:06 amI saw the oscillator specific sockets, and I would prefer machined sockets, but I've got stamped sockets (14, 16, and 20 pins) coming out my ears, and I'm going to use them before buying more. Not that sockets, even machined ones, are particularly expensive, but my wife is becoming suspicious of my hobby's balance sheet, so I must economize.Thanks for the advice, especially the warning about heedlessly cutting the oscillator leads. I will be careful.

author: magic
author_rank: Super Contributor
timestamp: October 29, 2020, 07:56:08 am
content: Frankly, I have sometimes dropped crystals or crystal-carrying boards on the bench or floor and they still workI use three segments of a SIL socket for that. And trim the leads, they are way too long for either socketing or soldering.

author: Ian.M
author_rank: Super Contributor
timestamp: October 29, 2020, 08:09:55 am
content: Some side cutters are vicious, and are capable of sending a cut lead end right across the room at high velocity. The shockwave going the other way up the lead can be stronger than you would normally get dropping the crystal, either on its own or mounted on a board on any surface softer than ceramic tile. Its rare to see damage from it, but it only takes a moment to minimize the risk as I described above.

author: magic
author_rank: Super Contributor
timestamp: October 29, 2020, 08:22:14 am
content: Hmm, I use simple front cutters which basically pinch the wire between two jaws. Never had problems with high speed ejection of anything

author: greenpossum
author_rank: Frequent Contributor
timestamp: October 29, 2020, 08:42:35 am
content: I use crystal oscillators with pre-cut pins, i.e. salvaged from boards.

author: jdutky
author_rank: Regular Contributor
timestamp: October 29, 2020, 01:27:40 pm
content: Quote from: greenpossum on October 29, 2020, 08:42:35 amA bunch of the oscillators I have in my parts bin are salvaged or from grab bags. Many still have their full length pins. Some have pins that were clearly manufactured to be shorter and sturdier than is otherwise common. If I could get more of those I would in a heartbeat.The part of the left has much shorter and sturdier leads than is normal. The part on the right is chosen to be representative for purposes of comparison.

author: oPossum
author_rank: Super Contributor
timestamp: October 29, 2020, 02:27:35 pm
content: The xtal on the left was made to be used with a socket. They where common before PLL synthesis became practical and replaced banks of socketed crystals in multichannel radios.

author: chris_leyson
author_rank: Super Contributor
timestamp: October 29, 2020, 02:34:47 pm
content: If you want to mount leaded HC49 or similar style crystals vertically, like the one on the right, don't use plated holes with pads on the top of the PCB. There is a chance that solder will wick through the hole and short one or both of the pins to the metal can.