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Magnum Controller Board PCBX-0335R6 Info Needed

DTB Radio

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Sep 14, 2005
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I'm working on an S9 with controller board PCBX-0335R6 and can't seem to locate any newer info that what is posted on the CB Tricks website (that shows the 0335R. There is no frequency display, but the displays themselves test good when directly connected to a common ground and the segment pins run through 1.5k to 12v (haven't tried with 5 volts yet). Channel display and basic radio functions are working fine, which seems to rule out the control board for the most part. 'Scoping the display pins shows pulsed data at normal 0-5v levels and proper ground or near-ground levels on the commons, but the displays don't light. My next step is to see if 5 volts lights the display units through appropriate dropping resistors.
 
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Going off no experience and the wrong schematic, but they should be close.

I think I figured out what LED displays it uses and their pinouts. These appear to be (what I would call) multiplexed common cathode digits. Each digit has a common cathode. So the positive pulses you are seeing go to the anodes, but what I don't think you are seeing is the three cathode pins being pulled down. They may be floating and appear near zero volt at times, but I would be sure.

Tracing those common cathode leads back to the channel selector PCB, it appears those transistors have their own supply jumper. I would start by checking that.
magnum.png
Edit: Looks like the blue wire should be ground, not power (common cathodes need ground, not power). I wonder where that jumper wire goes. I cannot tell with whats available online. Does that go to some lock detect switch or something so the display goes dark if out of lock?
 
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I see a youtube video shows that moving the NB switch to NB+ turns off the frequency display
 

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