Hello all,
I will be ordering the PCBs tomorrow. I have pm from couple members. I will order some extra in case any members need it.
Regards,
Subbu
I will be ordering the PCBs tomorrow. I have pm from couple members. I will order some extra in case any members need it.
Regards,
Subbu
I finished assembling the board and gave it a test with the jumper set to 2 sec delay. When I plug it in with the switch off I get a reading of a bit more than 20VAC on the output. Everything else tests out, I flick the switch and can watch the volts rise to ~117 then at 2 sec the relay clicks and it is stable. The housekeeping 5VDC is always on, led on and off 5VDC outputs as it should. This is all with no load.
Question, is the 20VAC reading in the off position a concern.
Question, is the 20VAC reading in the off position a concern.
First verify that you've correctly soldered in the jumpers for your AC mains voltage. In the US that is "P8" and "P9", see the schematic attached to post #1 of this thread. Then:
Find yourself a 1/4 watt resistor whose value is 75K or greater. 100K is fine.
Insert it into the Euroblok connector's bottom two holes, the ones labeled "P1D" and "P1N". Tighten the screws in those two positions so the resistor leads are firmly connected in circuit.
Now repeat the experiment you report in #64. How many AC volts does your meter report, (a) across the resistor, when probing the screw heads of "P1D" and "P1N" ; (b) when probing the screw heads of the other 117V output, namely pins "P2D" and "P2N".
Finally, try it one more time using a 5 watt "Night Light" as a load. Something like this
Find yourself a 1/4 watt resistor whose value is 75K or greater. 100K is fine.
Insert it into the Euroblok connector's bottom two holes, the ones labeled "P1D" and "P1N". Tighten the screws in those two positions so the resistor leads are firmly connected in circuit.
Now repeat the experiment you report in #64. How many AC volts does your meter report, (a) across the resistor, when probing the screw heads of "P1D" and "P1N" ; (b) when probing the screw heads of the other 117V output, namely pins "P2D" and "P2N".
Finally, try it one more time using a 5 watt "Night Light" as a load. Something like this
> I get a reading of a bit more than 20VAC on the output.
I wired a house-light switch and found 55VAC on the "dead/off" wire. Using my electronics-tech (10Meg) meter. Using an old needle-meter I saw hardly any voltage.
Modern HIGH impedance meters are prone to show "phantom voltage" from stray capacitance. If you put a finger across the circuit (DON'T!!) it goes away-- not enough real power to light a fire-fly.
Of course you might have a real leak, which might be fatal, so Mark is suggesting resistor or lamp instead of a finger.
For-electrICIAN meters are often, or optionally, lower impedance to reduce phantoms.
I wired a house-light switch and found 55VAC on the "dead/off" wire. Using my electronics-tech (10Meg) meter. Using an old needle-meter I saw hardly any voltage.
Modern HIGH impedance meters are prone to show "phantom voltage" from stray capacitance. If you put a finger across the circuit (DON'T!!) it goes away-- not enough real power to light a fire-fly.
Of course you might have a real leak, which might be fatal, so Mark is suggesting resistor or lamp instead of a finger.
For-electrICIAN meters are often, or optionally, lower impedance to reduce phantoms.
Congratulations upon your PCB Ordering success! It's fulfilling, it's fun, and it's not terribly difficult! Yay.
Use a Mega328 component tester from eBay to double and triple check every component's value before you stuff it. If you don't own one, buy one. Or use a DMM but it won't give great readings on capacitors.
I recommend stuffing and soldering by component height: shortest and squatty-est first, tallest last. Use common sense, think before acting. So: 115V/230V jumpers first, horizontal mount resistors and inductor and diode second. IC sockets & optocoupler third, ceramic caps fourth. Pin headers fifth, TO-92 transistors sixth. Vertical mount resistors seventh. And so on and so on.
Lay the TO-220 triac upon the PCB to see exactly where its leads need to be bent. Bend them and temporarily stuff the triac (without heatsink). Check whether the mounting hole lines up. If not, adjust the bends or do them over. When all is good, assemble bolt + PCB + heatsink + insulator pad + triac + shoulder washer ("bushing") + locknut/star_washer + nut and tighten. THEN solder and trim the triac leads. I used a Phillips pan head bolt and inserted it up through the PCB from the bottom side. This minimizes the amount of material that pokes down below the board. You can use any length bolt you want: the excess pokes up above the board and doesn't threaten a short to chassis.
Use a Mega328 component tester from eBay to double and triple check every component's value before you stuff it. If you don't own one, buy one. Or use a DMM but it won't give great readings on capacitors.
I recommend stuffing and soldering by component height: shortest and squatty-est first, tallest last. Use common sense, think before acting. So: 115V/230V jumpers first, horizontal mount resistors and inductor and diode second. IC sockets & optocoupler third, ceramic caps fourth. Pin headers fifth, TO-92 transistors sixth. Vertical mount resistors seventh. And so on and so on.
Lay the TO-220 triac upon the PCB to see exactly where its leads need to be bent. Bend them and temporarily stuff the triac (without heatsink). Check whether the mounting hole lines up. If not, adjust the bends or do them over. When all is good, assemble bolt + PCB + heatsink + insulator pad + triac + shoulder washer ("bushing") + locknut/star_washer + nut and tighten. THEN solder and trim the triac leads. I used a Phillips pan head bolt and inserted it up through the PCB from the bottom side. This minimizes the amount of material that pokes down below the board. You can use any length bolt you want: the excess pokes up above the board and doesn't threaten a short to chassis.
I was a bit curious so decided to see what would happen if I tried smaller values of resistors on the output. Worked my way down to ~95 ohm. Same result, 0VAC reading. Apparently doesn't take much to drain away the "phantom voltage" with the switch in the off position. Interesting.
Have a look at the schematic attached to post #1. Do you see the snubber composed of C3 and R7? Maybe they conduct a teeny tiny miniscule but nonzero current at 60 Hz.
PCBs ordered on Tuesday and will update once I receive them from the board house. PCBs are 2 oz Copper with ENIG. I will send a pm to the members shown interest with Paypal details.
I have ordered 10 extra, in case some other members need them. Interested members please pm me.
Cost per PCB will be $4.00 + shipping 4 - 5 to US domestic First class package service.
Cheers!
Subbu
I have ordered 10 extra, in case some other members need them. Interested members please pm me.
Cost per PCB will be $4.00 + shipping 4 - 5 to US domestic First class package service.
Cheers!
Subbu
I'm sure different builders will have different opinions about what is "best".
Possibilities might include:
- Two PCBs and two separate on/off switches, would work beautifully
- Two PCBs and one double pole switch (with separate contacts for Left and for Right), would also work
- One PCB and one on/off switch would also work, and take up a lot less floor space in your chassis
The illuminated anti-vandal switch that I used (photo and part number in post #16 above) was a double pole switch, and it would be a good choice for the 2nd possibility in this list. Mouser.com offers 334 different double pole illuminated Anti-Vandal switches, so there are plenty to choose from
https://mou.sr/2BhKcpb
ACHTUNG! CAUTION! BEWARE! One arrangement to avoid is "two PCBs and one single pole switch" because this creates a dangerous sneak-path between the +5V terminals of the two AC-to-DC modules. To make this concept work safely and reliably you'll need to hire a seasoned & experienced design consultant (not me!) and figure out all of the worst case situations. IMHO it would be far cheaper and quicker to just buy a double pole switch.
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switches and boards
I win! 3 good choices.
I got the switches from post #16 so the Achtung option won't be looked at.
With my lack of experience, I wasn't sure the board could handle 2 trafo's.
Got the first board stuffed. I think it went well but won't know for sure until I can test it this weekend. Maybe I should post a pic now in case I smoke the board.
It seems I'm always running out of real estate so the 1 and 1 option will probably be 1st choice although I could vertically mount them in same space probably but doesn't seem to be a good reason to do that.
Thank you Mark for all your support and assistance with the project.
Regards,
Don
I win! 3 good choices.
I got the switches from post #16 so the Achtung option won't be looked at.
With my lack of experience, I wasn't sure the board could handle 2 trafo's.
Got the first board stuffed. I think it went well but won't know for sure until I can test it this weekend. Maybe I should post a pic now in case I smoke the board.
It seems I'm always running out of real estate so the 1 and 1 option will probably be 1st choice although I could vertically mount them in same space probably but doesn't seem to be a good reason to do that.
Thank you Mark for all your support and assistance with the project.
Regards,
Don