OpenGD77 on the Baofeng DM-1801

[VK3KYY]

I think there are some connections under the MK22 and also possibly under the C6000, so not all connections can be seen in photos

I have pushed an update for the C6000 Reset and Power Down pins and my radio now has startup beeps.

It also has key beeps but there is a problem of the noise, possibly from the AT-1846 during the key beep, which I don't understand.

DMR Rx is not working, which means some other GPIO pins are also not correct.

[VK3KYY]

DMR Rx is now working on the DM-1801!

I have not tested Tx, as I do not have an antenna socket connected to the PCB

I will test DMR Tx tomorrow, but I think it will probably work OK.

[Ik0nwg]

then can we also buy this radio? I see that you are making great strides .... you are tireless.
ciao Roger
Sal

[EB3AM]

DMR Rx is now working on the DM-1801!

I have not tested Tx, as I do not have an antenna socket connected to the PCB

I will test DMR Tx tomorrow, but I think it will probably work OK.

great!!!

[VK3KYY]

then can we also buy this radio? I see that you are making great strides .... you are tireless.
ciao Roger
Sal

The hardware in this radio is not as good as the GD-77. Rx is less sensitive, and also I hear some unexpected hiss with the beep sound, so I think the audio amplifier system is perhaps inferior.

But the radio is cheaper and also there is no supply guarantee for any radio manufacturer, so it’s safer to try to make the firmware work with many radios.

[Ik0nwg]

then can we also buy this radio? I see that you are making great strides .... you are tireless.
ciao Roger
Sal

The hardware in this radio is not as good as the GD-77. Rx is less sensitive, and also I hear some unexpected hiss with the beep sound, so I think the audio amplifier system is perhaps inferior.

But the radio is cheaper and also there is no supply guarantee for any radio manufacturer, so it’s safer to try to make the firmware work with many radios.

ok
then I will be faithful to the gd77. indeed to opengd77
thanks Roger
Ciao

[VK3KYY]

I think I may have blown up the UHF PA on my DM-1801

I can hear the Tx from the DM-1801 with my GD-77 on both VHF and UHF, but on UHF I found I can't connect to my hotspot or to a repeater.

So I measured the power output on UHF and its 0W (no power at all)

I checked the current consumption during Tx for 50mA, and on 2m it is only around 90mA, but on UHF its 800mA

I think probably the PA FET is short circuit

[EB3AM]

It is strange that it could have been due to the firmware, unless the power (the txPower value has a different management) and it was overloaded. Could you have a short circuit on the uhf board part?

I think I may have blown up the UHF PA on my DM-1801

I can hear the Tx from the DM-1801 with my GD-77 on both VHF and UHF, but on UHF I found I can't connect to my hotspot or to a repeater.

So I measured the power output on UHF and its 0W (no power at all)

I checked the current consumption during Tx for 50mA, and on 2m it is only around 90mA, but on UHF its 800mA

I think probably the PA FET is short circuit

[VK3KYY]

I just checked the FET's and they all seem to be the same resistance.

So perhaps its not that one of the FETs is short circuit.

There are some other small transistors, but I think that 800mA though those would make them hot very quickly.

I will need to look very carefully at the PCB, in case there is some small piece of solder that has fallen onto the PCB.

[EB3AM]

To quickly locate short circuits or hot components, I use a spray that freezes the board