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I have a board we are trying to repair. We are unable to get any technical documents from the manufacturer, no schematic or BOM for the board. This has multiple switches, think metal dome you press for contact. The component in question has a location at each switch. It's designator on the board is TG (TG1-TG28). Not every one has a component near it as in the picture, marked as Q5 in this case, nor are all of them in parallel with a single resistor. A resistance check shows the resistance of the circuit and a capacitance check shows nothing. It looks similar to a SMD capacitor, and as such has no markings making it extremely difficult to diagnose or locate a replacement. My question is two fold, what does TG stand for and what might the component be?

enter image description here Source: PCB Silkscreen Marking

enter image description here

enter image description here

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    \$\begingroup\$ It would be helpful to know what the board is and what it does, where do these TG components connect to, etc. Please zoom out the picture and show more general view (if that even is your picture, or did you paste it here from another question here, which asked the same thing here : electronics.stackexchange.com/questions/649814/… ). \$\endgroup\$
    – Justme
    Commented Jul 8 at 17:20
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    \$\begingroup\$ @Justme The board in question is the user interface for a medical injector. My best guess is that it's part of an anti-bounce circuit but without any documentation I can't be certain, which is why I posed the question. I have added additional pictures for reference. \$\endgroup\$
    – user388256
    Commented Jul 8 at 17:30
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    \$\begingroup\$ Pull it off the board and measure it with and LCR meter \$\endgroup\$
    – Voltage Spike ♦
    Commented Jul 8 at 17:42
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    \$\begingroup\$ The ID question is fine, but maybe you should not be repairing medical devices, as someone's life may depend on it. Well, OK, maybe if someone's life does depend on you getting it fixed. \$\endgroup\$
    – Justme
    Commented Jul 8 at 18:18
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    \$\begingroup\$ @Justme Wow, this device is not a "life saving" medical device. As stated before, the manufacturer won't release the technical data (even to their own technicians) so we have to figure things out on our own. Research can be tight so we sometimes reach out for help. All I'm asking for is help identifying a component. I thank you for the input. Lastly, the reason I'm posting a new question is because the previous one hasn't been answered yet and I'm not allowed to comment on it to get it going again. \$\endgroup\$
    – user388256
    Commented Jul 8 at 18:33

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I think it's a capacitor, the frequency doesn't change the capacitance, it looks like a cap. It's most likely not an inductor or ferrite. You could be more sure if you had a more complete LCR meter or if you could put it in an RC configuration and sweep it with a frequency you could be more sure.

It looks like a simple RC, I cant tell but it looks like could be an RC in front of the FETs, maybe on the gate or drain.

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  • \$\begingroup\$ That does make sense for what I'm assuming is a de-bounce circuit for the switches. Thank you for all the feedback. \$\endgroup\$
    – user388256
    Commented Jul 8 at 20:10
  • \$\begingroup\$ Yeah, that was my thinking also. \$\endgroup\$
    – Voltage Spike ♦
    Commented Jul 8 at 20:17

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