I’m making a copy of a device for personal use. I have checked, or so I thought, all connections, but can’t get my version to work on the b.board.
IMG_2059.zip (12.0 MB)
Components used: 12v buzzer, red led, transistorC33725, 104 cap,472cap, resistors 4.7K,270K (2), 560K, 4.7µf, ICHCF4538BE and I think a Zener diode - original has the number 45 on it and the black line. If a detailed list of my b,board connections is needed, or other info, please let me know. The function of the device is to activate an electric “sport foil sword”, which is a NC circuit, so the device should deactivate the circuit when the tip ( the momentary switch takes the place of the + & - pin connections) is depressed.
Hi @wescannon1 ,
Unfortunately I do not know enough about this circuit. However it does appear you are shorting red and black when the mom. switch is closed which would be forbidden.
Hello @wescannon1,
If you are still working on this project, could you provide a schematic, as it is very difficult to troubleshoot from a picture.
Sincerely,
Aaron
Working on a schematic of what I did and what I was able to determine of the original.
I’ll post soon.
Ryan 2724
Here’s the schematic as best I can duplicate the original board. I used multimeter continuity to test each pin on the HFC4538BE (16) and each component. I set up the breadboard the same, using the momentary push button as the Banana pins. Battery is A23 12v. The original device works perfectly when the pins are shorted to each other, as when the device is connected to the foil weapon - the tip of the foil weapon opens the circuit for this device or the scoring machine.
Let me know if you can decipher the schematic - I’m an rank amateur using KiCad.
Wes
(attachments)
Foil indicator.kicad_sch (60.1 KB)
Hello leosolgen,
Welcome to the DigiKey TechForum.
Great advise to help troubleshoot the circuit.
Also, when I looked at the picture, it doesn’t appear to be anything connected to the left pin of the blue capacitor. I hope wescannon1 will keep us posted on how it turns out.
Hi David,
One pin of the blue 472 1K capacitor is connected to Pin #1 of the HCF4538BE and the other pin is connected to Pin #11 on the HCF4538BE. This is identical to the original device.
Changes I made to the original components are:
cap 472 10K is marked on original and I used 472 1K ( I had no luck locating an identically marked capacitor, and I don’t know if this makes a difference.
cap 104 Z5F is marked on original and I used 104; same situation applies.
cap 4.7µF 35V polarized capacitor on original and I used a 50V 4.7µF
HCF4538BE is what I used on a replacement recommendation from Digikey - the original is obsolete. All pin connections were made identical to original and of course I have checked for continuity many times, but never checked the original in a “working mode” e.g. applying the 12v power, pressing the foil weapon’s tip and seeing where the power actually goes, mostly because I don’t know how to do this test or what I should be looking for - I do understand that I could compare what happens on my breadboard model to the original, i.e. where the 12 volts goes when circuit is activated, but again, I don’t know how to go about this other than measuring voltage on each pin.
As I said, the original device works perfectly. It is plugged into the 2 pin socket on the foil weapon, and LED lights/buzzer sounds, when tip is depressed. I assume the capacitors regulate the length of time the LED & buzzer operate. At this point, I feel as if I’ve made an error but don’t know what it could be. I have been successful in producing many LED/Darlington / externally-powered, remote signaling lights for our fencing scoring machines, but I don’t have a background in electronics.
Wes
Capacitor type can really mess with timing, so try to find replacements that closely match the originals. Checking voltage on key pins will help you pinpoint any issues.
Thank you guys, these comments are going to be helpful in determining the mistakes I’ve made.
Since the pin connections on the original circuit were not difficult to locate to the various components, I had to think my cap substitutions could be the error. The info on testing you gave, should show me the difference between the voltages of the original and the breadboard.
I will get back to the forum with results, a bit later.
Wes
If you can post an easily readable schematic (PDF, PNG, JPG, etc.) more people can look at it and try to help. Many of us are not reading the forum on a device that either can or, does have, KiCAD on it and copying the file to a system that can read it is bit too much extra work to do when giving free help.
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