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bitrex <user@example.net>: Aug 15 01:38AM -0400 On 8/11/2020 3:38 PM, legg wrote: > exposed, they're easier to replace anyways.   > V13 is just digital.   > RL   Still no luck on figuring out this one. :( Tested the current op amp output with respect to the logic board ground, which is the output positive terminal, to avoid doing large voltage divisions to feed the 3.3V uP at the higher voltage settings I'm guessing. Output looks okay, and the constant current mode works correctly, it regulates down the output voltage if the load goes over the current set point. so the "ADJ" pin to the power board, transistor "V12" must be outputting signal OK. so the current sense amp from the shunt and DAC and all that must be able to enter closed-loop operation.   Still, the output indicator always reads 0 mA when in CV mode. Ugh. Where does the current sense amp voltage actually enter the PIC via an ADC? Can't find it anywhere. Maybe there's a processor fault or something, unfortunately.

legg <legg@nospam.magma.ca>: Aug 15 11:00AM -0400 >Where does the current sense amp voltage actually enter the PIC via an >ADC? Can't find it anywhere. Maybe there's a processor fault or >something, unfortunately.   DAC input current sense pin is VIS (pin19); so C22 short, R30 open, or contact trace problems.   ?   RL

"ohg...@gmail.com" <ohger1s@gmail.com>: Aug 14 10:51AM -0700 On Friday, August 14, 2020 at 12:14:12 PM UTC-4, Mike Coon wrote: > small daughter board (which I have seen on some variety of tablet > recently) which can be purchased cheaply and easily replaced.   > Mike.   If you don't have SMD experience, then changing that connector will be problematic. Most people can learn this with time, patience, and donor equipment to experiment on. I used to do these with a fine tip solder iron but now do them with hot air. You need a lot of heat so it can be done as quickly as possible. Also, bright light, magnification, and flux will improve the process.

Mike Coon <gravity@mjcoon.plus.com>: Aug 14 09:52PM +0100 In article <378cdc0a-08e3-417a-a16a-5e4f4c2bfcd8n@googlegroups.com>, ohger1s@gmail.com says... > > recently) which can be purchased cheaply and easily replaced.   > > Mike.   > If you don't have SMD experience, then changing that connector will be problematic. Most people can learn this with time, patience, and donor equipment to experiment on. I used to do these with a fine tip solder iron but now do them with hot air. You need a lot of heat so it can be done as quickly as possible. Also, bright light, magnification, and flux will improve the process.   Part of the problem that I foresaw is that the connector has to be firmly fixed mechanically to withstand the forces of insertion and withdrawal, possibly clumsily. Merely soldering may not be adequate!   Mike.

Bennett <bjprice@cal.berkeley.edu>: Aug 14 01:57PM -0700 > because sourcing everything is difficult in the pandemic. (Unless you tell me > Target or PC Richard have them, which they almost certainly don't. I haven't > seen a Radio Shack in several years.)   The surface mount connectors are available on Amazon. Those I've seen have solderable mounting taps to provide mechanical support.   But as others have noted, replacing this part is quite difficult unless you have the appropriate equipment - a soldering iron is not enough.

"jfeng@my-deja.com" <jfeng@my-deja.com>: Aug 14 02:44PM -0700 On Friday, August 14, 2020 at 1:52:08 PM UTC-7, Mike Coon wrote: > firmly fixed mechanically to withstand the forces of insertion and > withdrawal, possibly clumsily. Merely soldering may not be adequate!   > Mike.   I decided that the micro USB connector looked too fragile to tolerate more than a few hundred insertions. My solution was to get a magnetic USB charging cable which almost completely eliminates the strain on the connector. The one disadvantage is that these do not provide any of the data connections, only ground and power.

etpm@whidbey.com: Aug 14 04:02PM -0700 On Fri, 14 Aug 2020 14:44:03 -0700 (PDT), "jfeng@my-deja.com" >> withdrawal, possibly clumsily. Merely soldering may not be adequate!   >> Mike.   >I decided that the micro USB connector looked too fragile to tolerate more than a few hundred insertions. My solution was to get a magnetic USB charging cable which almost completely eliminates the strain on the connector. The one disadvantage is that these do not provide any of the data connections, only ground and power. I got a couple of those and really like them. Not only do they remove much of the strain they also just snap on and rotate to boot. So no twisted cables. Though the ones I use do prevent data transfer I rarely transfer data from my tablets through USB. I mostly use wireless or a micro SD card. Eric

Ralph Mowery <rmowery28146@earthlink.net>: Aug 14 08:00PM -0400 In article <VO6dneQjNtlXZ6vCnZ2dnUU7-e3NnZ2d@giganews.com>, bjprice@cal.berkeley.edu says... > have solderable mounting taps to provide mechanical support.   > But as others have noted, replacing this part is quite difficult unless > you have the appropriate equipment - a soldering iron is not enough.   Much of the time the hot air is the way to go. For the hobbiest you can get a hot air and soldering iron station for about $ 75 or less.   Go to you tube and look at how to do it. Not too bad after getting some old circuit boards and practicing. Sometimes the Kapton tape use as a heat resistance and shield will be a big help to keep the hot air from melting out too much stuff.

etpm@whidbey.com: Aug 14 03:32PM -0700 On Fri, 14 Aug 2020 05:00:41 -0700 (PDT), "pfjw@aol.com"   >But, to answer your question directly, yes, hot-running is a symptom of a failed cap - as is slow starting and poor load handling.   >Peter Wieck >Melrose Park, PA Yeah, I'm betting that the cap is as old as the motor. I'll take your advice and replace it. I don't understand how the current can be different if there are only two wires feeding the motor. What am I missing? Thanks, Eric

Michael Terrell <terrell.michael.a@gmail.com>: Aug 14 04:06PM -0700 > advice and replace it. I don't understand how the current can be > different if there are only two wires feeding the motor. What am I > missing?   If the capacitor's value is wrong, it doesn't provide the proper phase shift. That causes the motor to require more power to do the same work.

Ralph Mowery <rmowery28146@earthlink.net>: Aug 14 07:56PM -0400 In article <sm3ejf9e1rqjfl8pmgp4tbr9r1s0htnteq@4ax.com>, etpm@whidbey.com says... > missing? > Thanks, > Eric   Not likely, but if one of the windings is shorted to ground or the capacitor is leaking to ground the current could be different.

etpm@whidbey.com: Aug 14 10:21AM -0700 On Fri, 14 Aug 2020 07:41:20 -0700 (PDT), "pfjw@aol.com"   >I also think that putting the pressure switch next to the well-head is a good idea. The tank really does not care where it is in the system.   >Peter Wieck >Melrose Park, PA Water well pressure switches should always be placed as close to the pressure tank as possible. Within 1 foot is best. Nearly 300 feet away at the well head would be a bad idea. Eric

"pfjw@aol.com" <peterwieck33@gmail.com>: Aug 14 10:56AM -0700 > Water well pressure switches should always be placed as close to the > pressure tank as possible. Within 1 foot is best. Nearly 300 feet away > at the well head would be a bad idea.   That posits a conventional pressure switch. If I understand correctly, your well is some distance from your house, and the tank is some distance from your well - by your description, some 300 feet. You also state that the pressure switch is 100% mechanical in action, and capable of switching the 240 Volts to the pump. You intend to re-purpose that switch to activate a contactor switching pump power from the house - because there is an emergency generator at the house. So, being a bear of little brain, I am trying to understand how you intend to do this:   a) Take power from the line at the pump and send it to the Pressure Switch, then back to the contactor to activate it. Makes sense if you have a ground and a neutral in the run between the pressure switch and the pump and the same to the well-head from the house - 240V 4-wire (hot/hot/neutral/ground) allowing you to use 120V as the coil voltage. This makes all voltage to the pump and its controls originate at the house. If carefully managed, and all the conductors are the correct gauge, this will even meet codes. However, you need to verify that the pressure switch is properly rated (most are).   b) Use the existing power from the shed to activate the coil - problematic as you have two different power-sources in the same panel - able to be managed, but code compliance, again, is problematic. And, if the power goes out, so does the well as there is no power to run the coil.   I sent you to an industrial pressure switch sophisticated enough to account for the lag due to the distance from the tank. As the tank is (apparently) doing its job as far as house-pressure is concerned, it can continue to serve with a distant pressure switch if that switch can be programmed to include the lag. This keeps all your controls in one place, served by one source, with fewer failure opportunities. All good when a critical function is being covered.   We have a similar set-up here for the diesel fire-pumps and generators scattered across 1,200,000 square feet of building covering a city-block. There is a Veeder-Root tank monitor system some 80 feet away from the three x 1,000 gallon underground tanks under the sidewalk outside. This device monitors tank levels, fuel temperature, moisture content and so forth. There are three (3) local pumps on a lead-lag system that feed the day-tanks located at each fire pump and/or generator (total of seven (7)). These are activated as-needed (1/2/3, then 2/3/1, then 3/1/2) as needed - any two can keep up with all seven locations if needed. But, the float-switches in the day-tanks are as much as one flat block and 23 floors away from the USTs and pumps. And, all of these things "talk" to the Veeder-Root, which prints out a status once-per-day, and also a report every time a fill-pump is activated. Point being that the controls are nowhere near the tanks.     Peter Wieck Melrose Park, PA

etpm@whidbey.com: Aug 14 03:58PM -0700 On Fri, 14 Aug 2020 10:56:02 -0700 (PDT), "pfjw@aol.com"   >We have a similar set-up here for the diesel fire-pumps and generators scattered across 1,200,000 square feet of building covering a city-block. There is a Veeder-Root tank monitor system some 80 feet away from the three x 1,000 gallon underground tanks under the sidewalk outside. This device monitors tank levels, fuel temperature, moisture content and so forth. There are three (3) local pumps on a lead-lag system that feed the day-tanks located at each fire pump and/or generator (total of seven (7)). These are activated as-needed (1/2/3, then 2/3/1, then 3/1/2) as needed - any two can keep up with all seven locations if needed. But, the float-switches in the day-tanks are as much as one flat block and 23 floors away from the USTs and pumps. And, all of these things "talk" to the Veeder-Root, which prints out a status once-per-day, and also a report every time a fill-pump is activated. Point being that the controls are nowhere near the tanks.   >Peter Wieck >Melrose Park, PA The pressure switch at the tank is the typical snap action type found on every well and air compressor I have seen. Even though I have 4 wires coming from the shop and going to the well I will only be using two of them. I have found several 240 volt coil motor start contactors that are suitable for switching power to the well. The power from the house will power both the contactor coil and and the well pump. The ground and neutral from the shop will not be used because code says the only ground and neutral for the pump house must come from a single source. So the generator sub panel is connected to the main panel ground and no other. The box at the well head will still have a floating ground and floating neutral, just like the gen. sub panel, but instead of getting the neutral and ground from the shop will now get them from the house. Is there any reason that a 120 volt coil contactor should be used instead of a 240 volt coil? Since I did run 4 wires from the house as I did from the shop I could use a 120 volt coil by using the neutral, but I don't see the point. There is no reason to relocate the pressure switch as near as I can tell. The current pressure switch is inexpensive, reliable, and available 7 days a week even here on the island. Besides, I already have an extra new one sitting on the shelf. And I already have wires in the ground going to the switch, so why not use them? They will just be switching less current. And from what I can tell, the snap action type of action used in these switches is so the contacts always make good contact because they slam together. They even slam right through spiders and beetles. I dunno why the bugs like to hang out on the switch contacts. Mebbe it's done on a dare. Thanks, Eric

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