Whats is this switch? (6 Pins with FD written on it)

identificationswitches

Hi this is a beginners questions.

We are trying to repair a sub-woofer and have diagnosed that its the power switch is causing the problem, The only problem is we can't find a replacement.

Although i don't expect anyone to find a replacement but if you could tell us a bit more information about the switches type/name would be really helpful.

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Best Answer

I assume being a power switch one push turns on and another turns off? If so it's what I'd call a DPDT latching push button, although there may be other names as well as sometimes different terminology is used between regions. A search on e-bay at the moment for example using that term shows this product which looks pretty similar:

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As well as checking physical dimensions of course also be careful when looking for a replacement to make sure it has the necessary voltage and current rating.

The usual configuration for that sort of switch will be when actuated / pressed in the middle left pin will be connected to the rear left pin, and the middle right pin will be connected to the rear right pin. When disengaged they middle pins will connect to the front pair of pins instead. When used as a simple power switch if you look at the PCB you'll probably find that the front two pins aren't connected to anything.

Related Solutions

Electronic – Emulating a switch with open drain outputs

Since you'll be driving the switches with an MCU, the 2003's inversion won't matter, so it looks to me:

                 Vce   Vcc    IC           $/pkg   $/dev
                  V     V     mA   n/pkg   DKEY1   DKEY1
              |------|-----|-----|-------|-------|-------|      
     ULN2003     50     0    500     7     0.59    0.084
     74LVC07     6.5   6.5    50     6     0.45    0.075

like the extra penny per device for the 2003 is well worth its extra robustness and versatility.

Here are the data sheets for the ULN2003 and for the 74LVC07.

Switch matrix with ring counter

I'm going to suggest that you learn about shift registers. 4 pcs of a 8-bit parallel-to-serial shift register would work very well for you and would need a maximum of 3 lines to your controller. Some of those lines can even be shared with other functions if you are clever.

The CD4021 is a nice part that I use in many of my designs. You will need a pull-up resistor for each input. I use SIP bussed resistor networks - 10 pin package gives you 9 pullup resistors in a very small space.

You can also mount the shift registers very close to your switches to minimize the number of wires to the controller.

Best Answer

Related Solutions

Electronic – Emulating a switch with open drain outputs

Switch matrix with ring counter

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