i have a problematic HT440

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clinton_radloff
Posts: 15
Joined: Mon Dec 19, 2005 10:54 pm

i have a problematic HT440

Post by clinton_radloff »

Hi,
i have a problem with my HT440.

1. channel 2 does not work. anyone tell me why.
2. i broke the squelech knob right out of the radio. no knob at all. i pulled the pole out of the switch so its OFF all the time. does it really matter.

please help.
Clinton
AEC
No Longer Registered
Posts: 1889
Joined: Wed Dec 22, 2004 7:56 pm

Post by AEC »

HT440s and the HT90 are almost identical, both are crystal controlled.

If channel 2 is not working check the rock, and the solder connection....could also be a broken crystal caused by a sharp drop to a hard surface.

The squelch control is needed, if it's not a whole assembly, you will probably not have squelch action, or the squelch will be on 'high' which may prevent you from hearing stations that are aat the radio's noise threshold.

That radio uses one standard oscillator, so if one channel works, chances are that the second one has a defective crystal, or is out of resonance for the circuit to function.

Use a resistive load with a frequency counter to listent to the oscillator if the crystal is functioning, it should be on the fundamental of the crystal frequency.

I'm guessing around 40 Mhz. as i don't have my HT440 service manual out for reference.

Look on the top of the crystal for the fundamental frequency, it may also be an overtone crystal as well, I don't remember which.

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