OpenGD77

Fuse was okay. I found a voltage regulator labeled 4B2F (the one I was trying pull power from for the gps module) has a short to ground on pin 5 which should be the voltage out. So I think that’s my problem. Does that make sense? I found 4B2X and 4B2K regulators on Ali express. They all seem to have...

Complete newb here so please forgive my dumb questions.

Is there a electrical/pcb diagram somewhere online to help me find components?

I tried to add the GP-02 GPS module to my GD77 for APRS and I must have caused a short. I checked the fuse and it had continuity end to end so I assume that means it is still good?

As you can probably tell, I'm new to pcb troubleshooting. Any further suggestions to find the short or fix my radio?

Well after much testing it appears I bricked by GD77. Not sure if I shorted something out or what happened but I removed all my changes and it still won't power up. Any suggestions for how to find the issue?

I confirmed the gps module works by connecting it to serial and seeing the NMEA sentences separately. The gd77 won’t turn on now that I have everything back together. I tried to connect the red/black wires to the 5 pin component like in the photo of the original post. Are those the best vcc/grd poin...

I got everything wired up based on the photos and info but it won’t power on.

@F1RMB can you provide a wire diagram so I can double check everything?

Thanks all this is super helpfull! @LY1RF can you annotate your photo? I don't have a dm1801 so unsure what you added and what was already there. I have both the gp-02 circuit board with the gps antenna taped to the back (which I removed like the original poster) and also the raw gp-02 module like y...

First off thanks for the amazing tutorial @F1RMB!! I have all the parts and my GD-77 is in pieces on my desk but I can't tell how the GP-02 is connected. It looks like you are only using the VCC and GND pads but its hard to tell in the pic which wires are going to which pads? Can you clarify or prov...

Anyone else tried this? Very interested in adding gps to my 77 but don’t want to screw it up.

Like the idea of a less invasive mod if one exists.

I’ve triple checked my programming and everything looks right (color code and time slot). The HT doesn’t timeout so it appears it’s talking to the repeater. If I change the frequency it does time out. Friends have confirmed they can connect to the repeater. Even another guy using a gd-77 with stock ...