I have definitely ruined slide switches by over-heating them while
soldering. They get a mushy feeling, very different from the crisp click
of a new switch.
John
On Fri, Jan 20, 2017 at 10:03 AM, Brian Home <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
So, as I sit here on an ice pack for the last week, I've been following
this thread with interest because I put the suspicious switch in my new MAC
Performance 75mm Skyscraper. To me, I just didn't like the feel of it. So
just last week I pulled it out and replaced it with the Featherweight Screw
switch. $5. (Featherweightaltimeters.com)
They also have a very cool magnet switch I used in my Mariah.
I tried the wire twist a long time ago on a Black Brandt Terrier two
stage and had a VERY nervous moment when I had to pull it off the pad while
the staging timer was still armed.
On Jan 20, 2017, at 8:54 AM, R Dierking <applerocketry@xxxxxxxxxxx> wrote:
I reached 310 cycles on the test switch with no symptoms of failure. I’ll
be providing some observations as a new post including checking a switch
after being overheated a bit when soldering the wires.
300 cycles doesn’t seem like much until you actually do it btw. I
personally do not have any concerns about these switches in my projects at
this point. However, all switches should be inspected for good soldering
connections and checked for resistance with no intermittent connections
before flight.
Richard Dierking
*From: *Vern Knowles <knowles.vern@xxxxxxxxx>
*Sent: *Thursday, January 19, 2017 7:06 PM
*To: *roc-chat@xxxxxxxxxxxxx
*Subject: *[roc-chat] Re: Switch Warning - Schurter 110-220
John,
The power dropout duration that electronics can survive is totally
dependent on the design of the electronics. It could range from
microseconds to seconds.
I have no idea if the problems seen with these switches are because they
are intermittent or if they fail hard and simply don’t conduct when
switched on. Might even be both.
Vern
*From:* roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@
freelists.org <roc-chat-bounce@xxxxxxxxxxxxx>] *On Behalf Of *John Coker
*Sent:* Thursday, January 19, 2017 2:46 PM
*To:* roc-chat@xxxxxxxxxxxxx
*Subject:* [roc-chat] Re: Switch Warning - Schurter 110-220
If we really wanted to test switches, what is the shortest length brownout
that would affect electronics during normal operation (i.e., make a flight
computer reset)?
I.e., if you ran a data logger to measure resistance, what sampling
frequency would be required?
John
On Thu, Jan 19, 2017 at 12:55 PM, R Dierking <applerocketry@xxxxxxxxxxx>
wrote:
I really wonder about that 300 operations number. It isn’t listed as a
MTBF. It does seem low compared to other switches. Also, keep in mind
that other types of switches (for example, household types of rocker
switches) are intended to be operated many times. So, the statistical
number of cycles before a failure would be very important. Perhaps they
just decided to put a low number of cycles for a lifetime of the switch so
people wouldn’t use them for other applications?
Here’s another important consideration: Say you are planning on using a
Microswitch to arm electronics. Chances are, you will need to create some
mechanism to do this. But, how durable and reliable will your mounting and
operation of the switch be? Would you be able to cycle it 10,000 times?
Just saying that I’ve had the little tube that guides a pull rod on a
microswitch fail when the epoxy came loose.
So, there are many considerations, and we never run out of stuff to cause
us to lose sleep. 😊
Richard Dierking
*From: *Gregory Lyzenga <lyzenga@xxxxxxxxx>
*Sent: *Thursday, January 19, 2017 12:35 PM
*To: *roc-chat@xxxxxxxxxxxxx
*Cc: *Allen Farrington <allen.farrington@xxxxxx>; Vern Knowles
<knowles.vern@xxxxxxxxx>
*Subject: *[roc-chat] Re: Switch Warning - Schurter 110-220
On Jan 19, 2017, at 12:22 PM, R Dierking <applerocketry@xxxxxxxxxxx>
wrote:
Now, I think Vern has identified the most likely cause of this problem.
The switches are ‘cooked’ prior to even being used.
You should be careful not to assume there is just one singular failure
mode. Soldering damage doesn’t seem like it would explain the
manufacturer’s small number of rated cycles. There may be more than one
factor in play.
- Greg
----------------------------------------------------------
Gregory A. Lyzenga <lyzenga@xxxxxxx>
Dept. of Physics, Harvey Mudd College (909) 621-8378
Claremont, CA 91711-5990 mobile (626) 808-5314
