Uniden schematics will transmit but not receive

I don't know what this radio is, but perhaps I can help. First of all, 6 watts is output power and has nothing to do with receiving. With such a short transmit distance, my first suspicion is something very wrong with the antenna. Has the SWR on the antenna been checked? Let's start from there.

There is no "linking" of these radios. they simply have the ability to have silent receivers until a digital or subaudible tone is received that turns the audio on allowing you to hear the transmitted signal, this allows you to set the radio to only hear the correct transmitted signal...
http://www.manualslib.com/manual/733780/Uniden-Pmr845-2ck.html?page=15#manual

Need more information. Which channels don't work? Not all channels are authorized. Typically, the radio will not fail in such a way to allow some channels to work but not others.

Sorry David
It has been my experience over the years that manufacturers generally do NOT want to give folks like us the option of repairing their equipment. You can try asking the Uniden service department, but I'll wager they want a minimum of $100 for the schematic/service manual, which pretty much puts you into the price for a new DSC-capable radio.
Welcome to the world of disposable electronics.
Good luck
-Steve

Possible programming problem. Your receive frequency may not be set the same as your transmit frequency, or your PL code may be set differently between the radios. Check your programming.

Best regards.

Just to clarify something, you say that your hand-held VHF can receive a clear transmission from the Uniden, now which of the radios are buzzing, the Uniden or the HH?. If it's the hand-held buzzing try transmitting on the low watt on the Uniden, get some distance from the radio, because if the hand-held are to close to the on the Uniden on high watt you will get a buzzing, the signal are overpowering the receiver of the hand-held, try getting the minimum of 30 feet away. Good luck.

Hello there:
You can find a local uniden dealer using google www.uniden.com and then you will see find a authorized dealer than all you have to do is call them ok

You may have a sub-channel/privacy channel activated. Unless the person/s you are trying to talk to have the same channel and code set they will not be able to hear you. Check your manual for specific instructions on how to reset it to the default.

Check the input voltage into the radio while in transmit. The voltage maybe dropping as you go into transmit which causes it to drop into receive. That in turn allows the voltage to come back up. With your finger still on the PTT it tries to transmit again, etc. This could cause a feedback squeal and other symptoms.

While there might be a multitude of answers to this question. The first would be the radio is in need of repair, or not programmed correctly.