On Fri, 2 Jul 2021 04:58:02 +0000 (UTC), DecadentLinuxUserNumeroUno@decadence.org wrote:>John Larkin <jlarkin@highland_atwork_technology.com> wrote in >news:fqqncg50hpi43anlhmglts2db61n3gh8is@4ax.com: > >snip > >> We have a similar issue now. We will sell a general-purpose relay >> module as part of a modular test system, and we are concerned that >> once a relay is used to switch power, it may not be good for >> signals any more. >> >> That may be urban legend. It would be awkward to test. > > > High freq relays with SMA I/O ports are supposed to address small >signal long term reliability.But they are absurdly expensive and don't mount on PC boards. There are surface-mount RF relays. The Fujitsu FTR-B3GA relays are pretty good up to 3 GHz. https://www.dropbox.com/s/se162xpw86hpmzs/DSC06884.JPG?raw=1
Wetting current
Started by ●June 17, 2021
Reply by ●July 2, 20212021-07-02
Reply by ●July 2, 20212021-07-02
Clifford Heath <no.spam@please.net> wrote in news:168deb1da11cc477$1$1356503$70dd7a6b@news.thecubenet.com:> On 2/7/21 3:33 pm, DecadentLinuxUserNumeroUno@decadence.org wrote: >> Clifford Heath <no.spam@please.net> wrote in >> news:168b11ac909b0362$1$2193376$28dd226e@news.thecubenet.com: >>>> Well it's not 1930 anymore and the applications for reed >>>> switches are few and far in between. The wiki article even >>>> mentioned reed switches being used as sensors in old brushless >>>> motors. Awful. >>> >>> Bosch are still using reed switches to make their dishwashers >>> unreliable >>> >>> So much for "German engineering" >>> >>> CH >>> >> >> Pretty goddamned good piece of gear anyway. > > 50% rate of intermittent or total failure in a $1600 appliance > because of a badly installed $0.01 part does not constitute a > "goddamned good piece of gear". >The one my boss had has lasted for years. The one he has in his new house is still running as well.
Reply by ●July 2, 20212021-07-02
John Walliker <jrwalliker@gmail.com> wrote in news:678ed96f-d6f0-4573-8ed3-5089a2b45b96n@googlegroups.com:> On Friday, 2 July 2021 at 05:58:09 UTC+1, > DecadentLinux...@decadence.org wrote: > >> The old reed switch operated pinball machines were a joy to work >> on because the contacts had to be 'burnished' individually >> because they used the cheap contact materials back then that >> would rub off if you cleaned them wrong. A poor reed switch was >> always the first thing one would search for when working on a >> faulty machine (that contained several dozen). And they switched >> higher currents and voltages then than today's modern pinballs, >> so the contacts could go bad pretty quickly. Especially since >> their closure usually involved the firing of a solenoid making >> for back EMF current and arcs at the contacts, etc. > > I thought that reed switch contacts were always sealed in a glass > tube, so how were these pinball machine reed switches constructed? > John >Open air designs throughout the cabinet of the machine. They get actuated by the pinball hitting a bumper that has a lever or rod behind it that depresses the reeds together.
Reply by ●July 2, 20212021-07-02
On 02/07/2021 10:55, John Walliker wrote:> On Friday, 2 July 2021 at 05:58:09 UTC+1, DecadentLinux...@decadence.org wrote: > >> The old reed switch operated pinball machines were a joy to work on >> because the contacts had to be 'burnished' individually because they >> used the cheap contact materials back then that would rub off if you >> cleaned them wrong. A poor reed switch was always the first thing >> one would search for when working on a faulty machine (that contained >> several dozen). And they switched higher currents and voltages then >> than today's modern pinballs, so the contacts could go bad pretty >> quickly. Especially since their closure usually involved the firing >> of a solenoid making for back EMF current and arcs at the contacts, >> etc. > > I thought that reed switch contacts were always sealed in a glass tube, > so how were these pinball machine reed switches constructed? > John >They're not 'reed switches' as we know them today, but that's what some people called them before 'reed switches' were as we know them today. They're a bit like ordinary relay contacts, but without the coil and operated by physical movement or impact. -- Cheers Clive (former amusement arcade technician)
Reply by ●July 2, 20212021-07-02
On 3/07/2021 4:07 am, DecadentLinuxUserNumeroUno@decadence.org wrote:> Clifford Heath <no.spam@please.net> wrote in > news:168deb1da11cc477$1$1356503$70dd7a6b@news.thecubenet.com: > >> On 2/7/21 3:33 pm, DecadentLinuxUserNumeroUno@decadence.org wrote: >>> Clifford Heath <no.spam@please.net> wrote in >>> news:168b11ac909b0362$1$2193376$28dd226e@news.thecubenet.com: >>>>> Well it's not 1930 anymore and the applications for reed >>>>> switches are few and far in between. The wiki article even >>>>> mentioned reed switches being used as sensors in old brushless >>>>> motors. Awful. >>>> >>>> Bosch are still using reed switches to make their dishwashers >>>> unreliable >>>> >>>> So much for "German engineering" >>>> >>>> CH >>>> >>> >>> Pretty goddamned good piece of gear anyway. >> >> 50% rate of intermittent or total failure in a $1600 appliance >> because of a badly installed $0.01 part does not constitute a >> "goddamned good piece of gear". >> > > The one my boss had has lasted for years. The one he has in his new > house is still running as well. >We have had 10 years so far out of ours.
Reply by ●July 2, 20212021-07-02
On 2021-07-02, DecadentLinuxUserNumeroUno@decadence.org <DecadentLinuxUserNumeroUno@decadence.org> wrote:> John Walliker <jrwalliker@gmail.com> wrote in > news:678ed96f-d6f0-4573-8ed3-5089a2b45b96n@googlegroups.com: > >> On Friday, 2 July 2021 at 05:58:09 UTC+1, >> DecadentLinux...@decadence.org wrote: >> >>> The old reed switch operated pinball machines were a joy to work >>> on because the contacts had to be 'burnished' individually >>> because they used the cheap contact materials back then that >>> would rub off if you cleaned them wrong. A poor reed switch was >>> always the first thing one would search for when working on a >>> faulty machine (that contained several dozen). And they switched >>> higher currents and voltages then than today's modern pinballs, >>> so the contacts could go bad pretty quickly. Especially since >>> their closure usually involved the firing of a solenoid making >>> for back EMF current and arcs at the contacts, etc. >> >> I thought that reed switch contacts were always sealed in a glass >> tube, so how were these pinball machine reed switches constructed? >> John >> > > Open air designs throughout the cabinet of the machine. They get > actuated by the pinball hitting a bumper that has a lever or rod behind > it that depresses the reeds together.I'd call those leaf switches. -- Jasen.
Reply by ●July 2, 20212021-07-02
On 3/7/21 8:49 am, Rheilly Phoull wrote:> On 3/07/2021 4:07 am, DecadentLinuxUserNumeroUno@decadence.org wrote: >> Clifford Heath <no.spam@please.net> wrote in >> news:168deb1da11cc477$1$1356503$70dd7a6b@news.thecubenet.com: >> >>> On 2/7/21 3:33 pm, DecadentLinuxUserNumeroUno@decadence.org wrote: >>>> Clifford Heath <no.spam@please.net> wrote in >>>> news:168b11ac909b0362$1$2193376$28dd226e@news.thecubenet.com: >>>>>> Well it's not 1930 anymore and the applications for reed >>>>>> switches are few and far in between. The wiki article even >>>>>> mentioned reed switches being used as sensors in old brushless >>>>>> motors. Awful. >>>>> >>>>> Bosch are still using reed switches to make their dishwashers >>>>> unreliable >>>>> >>>>> So much for "German engineering" >>>>> >>>>> CH >>>>> >>>> >>>> Pretty goddamned good piece of gear anyway. >>> >>> 50% rate of intermittent or total failure in a $1600 appliance >>> because of a badly installed $0.01 part does not constitute a >>> "goddamned good piece of gear". >>> >> >> The one my boss had has lasted for years. The one he has in his new >> house is still running as well. >> > We have had 10 years so far out of ours.The problem I'm referring to is the models with a water flow sensor containing a reed switch to detect the rotor moving. The reed switches are soldered on to a rigid PCB with no provision for thermal expansion, so depending on the ambient temperature at the time it was soldered, a temperature excursion or/combined-with a slight shock cracks the glass at one end, and the reed becomes unreliable. It might be always on, always off, or might work normally. It might work at some ambient temperature and not at others. It will probably pass factory QA, under the same climate conditions where it was manufactured, but become unreliable as soon as the machine is put on a truck or a boat. The effect of intermittently reporting water flow problems is very hard for service techs to diagnose. In our case the dishwasher is in a rental and we live in another city, so I wasn't there to chase it down myself - but it caused us dramas multiple times with tenants complaining about flakey behaviour. There are many reports online of the same kind of failure, and no clear "here's what's wrong, here's how to fix it" - so I know this is not just a one-off issue with our unit. All for not soldering the damn thing down with a tiny allowance for thermal expansion. Now that I've fixed it, I'm sure the washer will be good for ten years. But this was just to point out that 99% good reliable engineering is still 1% unreliable, and that can spoil the whole party. Clifford Heath
Reply by ●July 5, 20212021-07-05
On 02/07/2021 4:55 am, John Walliker wrote:> On Friday, 2 July 2021 at 05:58:09 UTC+1, DecadentLinux...@decadence.org wrote: > >> The old reed switch operated pinball machines were a joy to work on >> because the contacts had to be 'burnished' individually because they >> used the cheap contact materials back then that would rub off if you >> cleaned them wrong. A poor reed switch was always the first thing >> one would search for when working on a faulty machine (that contained >> several dozen). And they switched higher currents and voltages then >> than today's modern pinballs, so the contacts could go bad pretty >> quickly. Especially since their closure usually involved the firing >> of a solenoid making for back EMF current and arcs at the contacts, >> etc. > > I thought that reed switch contacts were always sealed in a glass tube, > so how were these pinball machine reed switches constructed? > John >I worked on pinballs until ca 1977 and I never saw a reed switch in one. Jukeboxes had a maybe a few.
Reply by ●July 5, 20212021-07-05
gray_wolf <gray_wolf@howling_mad.com> wrote in news:iQzEI.104771$Hy1.31481@fx43.iad:> On 02/07/2021 4:55 am, John Walliker wrote: >> On Friday, 2 July 2021 at 05:58:09 UTC+1, >> DecadentLinux...@decadence.org wrote: >> >>> The old reed switch operated pinball machines were a joy to work >>> on because the contacts had to be 'burnished' individually >>> because they used the cheap contact materials back then that >>> would rub off if you cleaned them wrong. A poor reed switch was >>> always the first thing one would search for when working on a >>> faulty machine (that contained several dozen). And they switched >>> higher currents and voltages then than today's modern pinballs, >>> so the contacts could go bad pretty quickly. Especially since >>> their closure usually involved the firing of a solenoid making >>> for back EMF current and arcs at the contacts, etc. >> >> I thought that reed switch contacts were always sealed in a glass >> tube, so how were these pinball machine reed switches >> constructed? John >> > > I worked on pinballs until ca 1977 and I never saw a reed switch > in one. Jukeboxes had a maybe a few. >What do you call them then? The early pinballs had several open contacts in them. Hell the left and right flipper actuator switches were (and still are) open contact devices.
Reply by ●July 6, 20212021-07-06
On Fri, 18 Jun 2021 09:18:19 -0700 (PDT), John Walliker <jrwalliker@gmail.com> wrote:>Pickering make a wide range of reed relays and provide a lot of advice on how to choose and use them. > >www.pickeringrelay.com > >JohnYikes. The rep says prices on the surface-mount parts is "$73.96 - $8.28, depending on the quantity and the part number."
