JUMA TRX2-VM Voice Memory - Troubleshooting

[OH2CBD]

I managed to get the crucial chip and build two units of the voice memory option and the external keyboard. Both units seemed to work (they recorded my speech/RX audio and played it back) and I celebrated...

...until I found out that nothing is broadcasted to RF even the recording is clearly audible from the speaker while transmitting.

I started the troubleshooting by checking that control from CPU works. It does, Pin J7-1 ("Play to band") rises from 0V to 5V when I press transmit command. This should enable the switch IC4 (I use 74LV4066 instead of 74HC4066, is it a problem?). Bias 1,78V is OK as well. For IC2 I'm using TLC277 instead of TLC272, it was mentioned in the parts list. It shouldn't be the problem since playback to speaker works well.

What should I try next? I'm about to probe the MIC-line with scope until I get to local club. Should I expect similar kind of signal output from recording as it is while I'm speaking to microphone? My suspicion is at signal levels...

Thanks!

-Joel OH2CBD