Maxtrac No RX or sound

[firebug24]

Hi all
Just got in a maxtrac D43 model that was supposely had a lightning hit. Powers up but no on beep. Programmed ok but no RX either..

Anyone got a clue on this radio to get fixed ????
thanks
steve w

[firetech792]

Just a wild guess but if your Maxtrac has the 16 pin accessory connector in the rear, make sure the black plug is there. There is audio jumpers in that plug. If the plug is missing, audio won't be jumped to the internal speaker.
If the radio has the white 5 pin plug, then it won't matter wheather its there or not.

[AEC]

Aside from the obvious; have you turned the internal squelch pot down or pressed the monitor button to see if you have any sound?

If you get sound from the speaker, then I'd say most of your receive section is fine.
From the I.F all the way to the VCO.

Look for detector audio, picked off from U51 receiver chip.

Does the busy LED light, or remain lit by chance?

Look around with a 'sniffer' probe with a service monitor tuned to an I.F frequency, like 45.1 Mhz. first I.F and see what the results on the monitor look like.
You can also sniff a signal at 44.645 Mhz. as well as a lower level at .455 Khz.
First I.F amp. is Q51
A second stage of amplification is Q52, which feeds U51

Do you get a quieting sound when the probe is brought near those crystals?

Detected audio can be found on U51-5/J6-3.

Do you detect an on-frequency signal at 45.1 0r 44.645 Mhz?

If not, one or more of the crystals might be defective, and this will shut down the receiver.

Audio output from U51 is via pin 5.

Y51A and Y51B are ceramic filters

[kc7gr]

If that radio had truly suffered a lightning strike, I doubt that you would be able to read or program it.

With that in mind, one thing that does happen with the Maxtrac and Radius series is that the volume control pot will fracture. This is particularly true if the radio has been dropped. Suggest pulling the front panel apart, and checking the pot with an ohmmeter.

Happy tweaking.