Radio RRC: No Power

[VE3FU]

I switched power supplies at the Remote site and no longer have power on the Remote RRC.  I've confirmed that there is +12VDC on the connector (positive center), and have even tried with the +12VDC walwart supplied with the Control RRC.  Is there a resetable (or field replaceable) fuse inside the Remote RRC?  I'm currently at the Radio RRC site, leaving on Thursday (September 15) and would like to have this fixed before I leave.  I'm really hoping that I don't have to send this back for repair / replacement :=(

73,

Chris VE3FU

[sm2o]

There is a polyfuse which restes it self so that is probably not the problem. If you have got over voltage the protection diode or the EMI filter is damaged. In worst case the DC/DC switch is damaged and then it's nothing that can be done.

73 de mike

[VE3FU]

Thanks for the quick reply Mike.

Unfortunately that's what I thought.  I measure +12V on the plug, but when I insert it into the Radio RRC and measure the voltage inside the Radio RRC at the connector it shows 0V.

Do you think it's repairable, or would it be easier to simply purchase another Radio RRC?

Since it's already dead, I might as well try and see if I can repair it myself.  You mentioned that it could be the protection diode.  Can you point me to where the protection diode is on the board?

73,

Chris

[sm2o]

Hi see attached picture

/mike

[VE3FU]

Thanks Mike!!

I'll bring the Radio RRC back with me and use the picture to see if I can figure out which part I broke :=)

73,

Chris

[VE3FU]

Hi Mike,

I'm back at home with the Radio RRC.  Using the photo that you kindly provided I was able to check voltage levels at the points indicated in your photo.  Please see the attached photo for the voltage levels that I measured.

Obviously some of the voltages I measured are incorrect:

- The 11.5V on one of the EMI filter ports should be 0V, as measured on my working Control RRC.  (I believe the 12V on two of the EMI filter ports is correct, since that's what I measure on my working Control RRC).
- The 11.5V on the diode should be 8/9V, as indicated in your photo and measured on my working control RRC
- The 11.5V on the test point should be 3.3V, as indicated in your photo and measured on my working control RRC

I think the original part that was damaged was the EMI filter.  Since I'm measuring 11.5V at points where there should only be 8/9V, 3.3V and 0V, I'm concerned that other parts might also be damaged.

I know it's a long shot, but I'd like to try and repair this Radio RRC (it's already broken, so I don't have anything to lose, other than my time and the cost of a few parts).  Using the markings on the EMI filter (p/n TDK ZJY-2P01), protection diode (p/n ER Z351), 8/9V diode (circled in my photo, p/n V2E P314L), and DC/DC switch?? (circled in my photo, p/n LJYB), I'm only able to find the EMI filter on any Google searches or on any of the supplier web sites, like DigiKey or Mouser.  Would you be able to provide me with the manufacturer (or DigiKey / Mouser) part numbers for those parts?

FYI, I'm still able to connect to the Radio RRC using the USB port and the Microbit Setup Manager, but obviously it's limited in functionality.

Thanks again for all your assistance!


73,

Chris VE3FU

[sm2o]

Hi

I agree, it's the gnd path in the EMI filter which is broken, the filter is not important for the function, it's there for the CE/FCC approval so you can just replace it with two wires to verify that it's the problem

73 de mike

[VE3FU]

Hi Mike,

I shorted the two GND pins of the EMI filter together and now have the Radio RRC working again!  I will order a new EMI filter to replace the broken one before sending the Radio RRC back to the remote location.

Thanks again for all your help / support.

73,

Chris

[kl9a]

I am having a similar problem, except I get 13.5V everywhere I test.

Any other spots I should be checking other than what is shown in this thread?

Thanks,
Chris KL9A