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Search: Posts Made By: redwire
Forum: General Electronics Technical Discussion Yesterday, 03:12 PM
Replies: 13
Views: 165
Posted By redwire
Re: Motor run capacitor physical size vs voltage rating & measurements?

It's more of a resonant (tank) circuit between the run capacitor and the motor's stator windings inductance - which changes with load (slip). I think the goal is 120 phase-shift at nominal load.
...
Forum: General Electronics Technical Discussion Yesterday, 02:42 PM
Replies: 13
Views: 165
Posted By redwire
Re: Motor run capacitor physical size vs voltage rating & measurements?

Open-circuit run cap- must have tripped the internal pressure switch.
The cap running voltage depends on the motor's load, so at no load I believe you are seeing worst case 363VAC.
I don't see a...
Forum: General Electronics Technical Discussion 09-19-2020, 11:14 PM
Replies: 22
Views: 712
Posted By redwire
Re: Help identify a Zener?

Try a TV remote pointed at the receiver, sometimes the pulse pattern will fool them for a bit.
Forum: General Electronics Technical Discussion 09-19-2020, 01:40 PM
Replies: 22
Views: 712
Posted By redwire
Re: Help identify a Zener?

The emitter does not care so much about it's operating voltage, the IC is good to 36V. The receiver module is a 5V part though so a zener there would be needed.

Since these (emitter, detector,...
Forum: General Electronics Technical Discussion 09-18-2020, 08:34 PM
Replies: 22
Views: 712
Posted By redwire
Re: Help identify a Zener?

Here is my schematic for older very similar 14LG472, yours is 14LG479. Same basic circuit as the other. The diode is not a zener but is a 1N4002 in series with power to the board.
Very hard to kill...
Forum: General Electronics Technical Discussion 09-18-2020, 01:42 PM
Replies: 19
Views: 514
Posted By redwire
Re: Secondary out 32 volts AC getting 146 volts DC do not understand

Euro standards for machines have redundant safety controls.
A pic of the pcb backside would make it easy to figure out, I can draw a schematic.

This thing will arc and kill any relay you use to...
Forum: General Electronics Technical Discussion 09-18-2020, 01:29 PM
Replies: 22
Views: 712
Posted By redwire
Re: Help identify a Zener?

Post pics of the board. I did schematics for a couple generations of Liftmaster/Chamberlain/Sears garage door sensors. It's a 150Hz pulse train of 38kHz bursts from an LM2903.
It's usually the IR...
Forum: General Electronics Technical Discussion 09-14-2020, 11:06 PM
Replies: 46
Views: 619
Posted By redwire
Re: Spectra S1+ Breast pump - No suction

so that's where the water went! Glad it's fixed, we don't want any starving babies ;)
Forum: General Electronics Technical Discussion 09-14-2020, 02:57 PM
Replies: 46
Views: 619
Posted By redwire
Re: Spectra S1+ Breast pump - No suction

I would tap a 1k resistor between GND and Q9-C which should drop Q7 gate voltage so it turns on.
R30 is to slow down the mosfet switching a little bit. It could be 200R.
Forum: General Electronics Technical Discussion 09-14-2020, 02:08 PM
Replies: 46
Views: 619
Posted By redwire
Re: Spectra S1+ Breast pump - No suction

This is how the circuit looks to me. To turn on the pump motor, Q9-C should go to ground. You could try tap a 1k resistor to GND and see if the mosfet Q7 turns on.
Forum: General Electronics Technical Discussion 09-13-2020, 09:33 PM
Replies: 46
Views: 619
Posted By redwire
Re: Spectra S1+ Breast pump - No suction

These parts would have resistors inside:
Q9, Q12 SOT-23 marking NF, NPN digital transistor KRC106S or DRC2124X
Q11 SOT-23 marking PF, PNP digital transistor KRA106S

Q8 SOT-23 marking AO7?...
Forum: General Electronics Technical Discussion 09-11-2020, 01:47 PM
Replies: 29
Views: 351
Posted By redwire
Re: Remote pump control ideas.

I have:
1. Used private radios with yagi antennas at each end. Like 900MHz band.MDS TransNET (https://www.gegridsolutions.com/communications/catalog/transnet.htm)
Only works if you have a clear...
Forum: Troubleshooting Audio Equipment 09-06-2020, 12:41 PM
Replies: 49
Views: 909
Posted By redwire
Re: Strange malfunctioning LED audio peak level meter problem

Be careful as any shorts on the LEDs/wiring is stressful to the COB chip on the module.
Forum: General Electronics Technical Discussion 09-06-2020, 12:39 PM
Replies: 167
Views: 5,823
Posted By redwire
Re: Running a microcontroller in car - power supply aspects

You can use a resistor to lower the coil voltage from 12V to 5V. Like 47R and dissipating ~1.5W, regardless if a resistor or vreg or zener etc. the heat is made by something.
A relay coil is mostly...
Forum: General Electronics Technical Discussion 09-05-2020, 03:02 PM
Replies: 167
Views: 5,823
Posted By redwire
Re: Running a microcontroller in car - power supply aspects

How many ohms are the 5V relay coils? It looks like 1-4 of them could be on at once, worst case. A big 6V zener?
Forum: General Electronics Technical Discussion 09-04-2020, 09:08 PM
Replies: 19
Views: 514
Posted By redwire
Re: Secondary out 32 volts AC getting 146 volts DC do not understand

It's definitely a machine-safety system. They use relay logic for AND and OR, including the foot pedal.
Safety relays- so one set of stuck contacts does not prevent any others from moving, unlike...
Forum: Troubleshooting Audio Equipment 09-04-2020, 01:06 AM
Replies: 22
Views: 600
Posted By redwire
Re: Pioneer VSX-1123 Receiver - weird voltage problem

It's normal to have small AC leakage current from a two-prong powered stereo or TV, DVD player, laptop brick, wall wart, phone charger etc. You'll commonly measure around 60VAC with a multimeter...
Forum: General Electronics Technical Discussion 09-04-2020, 12:56 AM
Replies: 19
Views: 514
Posted By redwire
Re: Secondary out 32 volts AC getting 146 volts DC do not understand

If a terminal is not used from the bridge rectifier, it might be a bipolar solenoid drive? So +ve 1/2 wave DC pulls it in, and -ve 1/2 wave DC pushes it out. Instead of simply solenoid on or off....
Forum: General Electronics Technical Discussion 09-03-2020, 10:18 PM
Replies: 19
Views: 514
Posted By redwire
Re: Secondary out 32 volts AC getting 146 volts DC do not understand

I think you might be reading stray voltage due to leakage currents. Does your multimeter have LoZ capability? Or put a 20k resistor across the leads so the multimeter is not so sensitive.

I was...
Forum: Troubleshooting Audio Equipment 08-30-2020, 11:04 PM
Replies: 29
Views: 970
Posted By redwire
Re: Car radio stopped working

The hassle with another make of radio is the wiring harness- you have to figure out the car's wiring and then make an adapter. I soldered onto the car's wiring because the radio plugs/connectors are...
Forum: Troubleshooting Audio Equipment 08-30-2020, 05:47 PM
Replies: 15
Views: 380
Posted By redwire
Re: No headphone output from electronic drum kit, which capacitors to replace?

It's what I would do as a quick test- with the unit powered up, just touch the multimeter's probe to either pin 2 or pin 6 and listen for the click/hum buzz in the headphones. Looking for signs of...
Forum: General Electronics Technical Discussion 08-30-2020, 05:01 PM
Replies: 6
Views: 226
Posted By redwire
Re: I am looking for computer fan 2 pin cables

What kind of connector are you talking about? 12V fans? The small ones do not support big conductors like 18ga- which is not needed unless a really long length.
Standard fan connectors are Molex...
Forum: Troubleshooting Audio Equipment 08-30-2020, 04:55 PM
Replies: 15
Views: 380
Posted By redwire
Re: No headphone output from electronic drum kit, which capacitors to replace?

Voltages on U18 TDA1308 (https://www.nxp.com/docs/en/data-sheet/TDA1308.pdf) look fine, single 5V supply so 1/2 that on all ins and outs.
Q6 and the other might be muting transistors which also get...
Forum: General Electronics Technical Discussion 08-23-2020, 02:06 PM
Replies: 11
Views: 509
Posted By redwire
Re: tackling lithium battery degradation

Wile E. Coyote already tried the extension cord approach. ACME seems to make them too short though.
Forum: General Electronics Technical Discussion 08-22-2020, 05:37 PM
Replies: 32
Views: 671
Posted By redwire
Re: Back to Back Transformers

The squiggle at zero-cross which is making your multimeter read double-frequency, I think is from the power meter's internal power supply (capacitive-dropper). If you disconnect the meter's power it...
Showing results 1 to 25 of 500

 
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