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Re: TX/RX Relay

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  • titZelbop
    Hi Bruce, Yes ULNs are socketed. I ve swapped them with no change in behaviour. Do you think it is a bad socket?
    Message 1 of 19 , Dec 3, 2012
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      Hi Bruce,

      Yes ULNs are socketed. I've swapped them with no change in behaviour. Do you think it is a bad socket?
    • titZelbop
      Hi Bruce, It is the same as measured on pin 3 of the connector. I am measuring from the physical pin of the ULN. ~10.5V and ~1.05V. Measured a resistance of
      Message 2 of 19 , Dec 3, 2012
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        Hi Bruce,

        It is the same as measured on pin 3 of the connector. I am measuring from the physical pin of the ULN.

        ~10.5V and ~1.05V.

        Measured a resistance of < 0.1 Ohm between the actual pin on the ULN to the side of L1D that connects to pin 3. This should be the resistance of the path through the socket, board, ribbon cable and connectors.
      • Bruce KF1Z
        no, socket is fine, if you swapped devices and got the same result ( SOMETHING would have changed. According to the resistance I d say that is fine... My
        Message 3 of 19 , Dec 3, 2012
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          no, socket is fine, if you swapped devices and got the same result ( SOMETHING would have changed.
           
          According to the resistance I'd say that is fine...
           
           
          My supply is 13.7 volts.   you are using 12.0v  even ?
           
          Do you have a supply that is higher voltage that you can try?  ( most bench supplies are 13.6 )
           
          That drop on the relay may be right on the hairy edge with low supply voltage.
           
          Bruce
           
           
           
           
           
           
           
          From: titZelbop
          Sent: Monday, December 03, 2012 3:54 PM
          Subject: [GenesisRadio] Re: TX/RX Relay
           
           

          Hi Bruce,

          Yes ULNs are socketed. I've swapped them with no change in behaviour. Do you think it is a bad socket?

        • Bruce KF1Z
          May be worth checking that R6C is a 1k . Though I m not sure that would make the difference... After supper, I ll check my pin 13/uln2003 I was thinking that
          Message 4 of 19 , Dec 3, 2012
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            May be worth checking that R6C is a 1k .
            Though I'm not sure that would make the difference...
             
            After supper, I'll check my pin 13/uln2003   I was thinking that it "had" to be 0.7v  because it's just a transistor switch.
             
            very odd, in any case.
             
             
            Bruce
             
             
            Sent: Monday, December 03, 2012 4:47 PM
            Subject: Re: [GenesisRadio] Re: TX/RX Relay
             
             

            no, socket is fine, if you swapped devices and got the same result ( SOMETHING would have changed.
             
            According to the resistance I'd say that is fine...
             
             
            My supply is 13.7 volts.   you are using 12.0v  even ?
             
            Do you have a supply that is higher voltage that you can try?  ( most bench supplies are 13.6 )
             
            That drop on the relay may be right on the hairy edge with low supply voltage.
             
            Bruce
             
             
             
             
             
             
             
            From: titZelbop
            Sent: Monday, December 03, 2012 3:54 PM
            Subject: [GenesisRadio] Re: TX/RX Relay
             
             

            Hi Bruce,

            Yes ULNs are socketed. I've swapped them with no change in behaviour. Do you think it is a bad socket?

          • Bruce KF1Z
            Ok, yes, Pin 3 of SV3PB ( pin 13 of uln2003)... does indeed go to 0.69 v on TX. and 12.05 in RX ( with 13.76v on pin 2 ) So, that means I have 11.36v
            Message 5 of 19 , Dec 3, 2012
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              Ok, yes,
               
              Pin 3 of SV3PB ( pin 13 of uln2003)...   does indeed go to 0.69 v on TX. and 12.05 in RX   ( with 13.76v on pin 2 )
               
              So, that means I have 11.36v across my relay in TX  ( 12.05 – 0.69 )
               
              Where you have 9.45v  ( 10.5 – 1.05 )
               
              Maybe this is enough difference......
               
               
              I THINK that if you try a higher supply voltage, you may be ok.....
               
               
               
              Sent: Monday, December 03, 2012 4:55 PM
              Subject: Re: [GenesisRadio] Re: TX/RX Relay
               
               

              May be worth checking that R6C is a 1k .
              Though I'm not sure that would make the difference...
               
              After supper, I'll check my pin 13/uln2003   I was thinking that it "had" to be 0.7v  because it's just a transistor switch.
               
              very odd, in any case.
               
               
              Bruce
               
               
              Sent: Monday, December 03, 2012 4:47 PM
              Subject: Re: [GenesisRadio] Re: TX/RX Relay
               
               

              no, socket is fine, if you swapped devices and got the same result ( SOMETHING would have changed.
               
              According to the resistance I'd say that is fine...
               
               
              My supply is 13.7 volts.   you are using 12.0v  even ?
               
              Do you have a supply that is higher voltage that you can try?  ( most bench supplies are 13.6 )
               
              That drop on the relay may be right on the hairy edge with low supply voltage.
               
              Bruce
               
               
               
               
               
               
               
              From: titZelbop
              Sent: Monday, December 03, 2012 3:54 PM
              Subject: [GenesisRadio] Re: TX/RX Relay
               
               

              Hi Bruce,

              Yes ULNs are socketed. I've swapped them with no change in behaviour. Do you think it is a bad socket?

            • titZelbop
              Hi, I worked with a colleague to figure out the problem. The relays that were shipped with this board appear to be these ones:
              Message 6 of 19 , Dec 3, 2012
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                Hi,

                I worked with a colleague to figure out the problem. The relays that were shipped with this board appear to be these ones:

                http://www.datasheetcatalog.org/datasheets2/42/42032_1.pdf

                This is a POLARIZED RELAY as stated in the "Features" list, and we confirmed this by desoldering and testing one relay from the kit in isolation. We found that the contacts did not close unless the voltage was applied to the coil in the orientation shown in the datasheet.

                From looking at the schematic and tracing the PCB, we see that the voltage is applied to the coil of REL1C in the opposite orientation as specified in the datasheet. It seems that half of the band switching relays also have this issue.

                Can you please suggest a fix that does not involve desoldering all of the relays?

                Stephen
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