I’m fairly confident in the repairs I made to the 5V SMPS and it seems to be working fine. To validate the LCD, I removed it to rule out any issues. No performance change noted.?
With a departure from that, I remembered some QDX troubleshooting which resulted in finding sorted PA mosfets. I did originally have to replace Q507 and the PA’s due to shorted failures.?
I’ve been probing the board with my DMM and decided to remove the PA’s. Sure enough, the high current draw and 4.6V drop cleared up without them in circuit. Early this morning, I started fine tuning the inductors and did some basic RX tests etc. Despite the PA’s dumping power, RX seemed fine.
So, What in the world would cause the PA’s to be gated and dump all that power to overload? Why would this happen in RX? There shouldn’t be current flow if I’m not mistaken.?
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Additionally, pressing the encoder to turn the radio on does not work. I actually have to press my fingertip to Q105 to latch it on. Pressing the encoder to power down the radio “works” but there is a current draw of 0.065A until I remove the plug. Trying to restart the radio does not work until it is unplugged.?
I’m starting suspect IC503 and the MCU. I’m not wanting to reinvent any wheels so any and all advice to move forward is graciously appreciated!
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