Hytera Two way Radio help!

[Tator_Soldier]

First post on this forum, hopefully I can get some answers as I'm new to the electronics repair scene. I have 5 Hytera TC-600 two way radios. All of them have been reprogrammed (to the best of my ability) to have the same settings and channels. Squelch is set to 2, with power output on high. Two of the radios will receive signal when on squelch setting 2, the other 3 will transmit but will not receive unless the squelch is opened ALL the way, even then it's a quiet signal. Why would this be? is there a setting that I can mess with to try and remedy this (side note, I noticed a tuning option in the programming software, but I'm not knowledgeable enough to trial and error with those settings) or if there's some type of testing I can do on the electronics to check functionality. Just need somewhere to start. I recently acquired an oscilloscope with 50mhz capabilities, AN/USM-281 to be exact.

Any and all help would be appreciated!!!

[CJay]

Your 'scope is unlikely to be useful in this case.

GFirst, the TC-600 was avaialble in VHF and UHF versions, make sure they're all the same version (I'd be surprised if you could program a VHF with a UHF data file).

Can you clone between radios with a cable? If so I'd consider cloning a working radio to a non working one.

Were they new when you got them or, as I suspect they might be, were they second hand?

If they were new, return to supplier if cloning doesn't fix it.

If second hand were they meant to be working?

If they were sold as seen then check antenna connections, first swap a good antenna onto a 'faulty' radio.

If it works order new antenna.

If it doesn't then check the antenna connection, make sure it's not loose or that there's physical damage to the connector, also check antenna socket solder connections to the board

[Tator_Soldier]

Your 'scope is unlikely to be useful in this case.

GFirst, the TC-600 was avaialble in VHF and UHF versions, make sure they're all the same version (I'd be surprised if you could program a VHF with a UHF data file).

Can you clone between radios with a cable? If so I'd consider cloning a working radio to a non working one.

Were they new when you got them or, as I suspect they might be, were they second hand?

If they were new, return to supplier if cloning doesn't fix it.

If second hand were they meant to be working?

If they were sold as seen then check antenna connections, first swap a good antenna onto a 'faulty' radio.

If it works order new antenna.

If it doesn't then check the antenna connection, make sure it's not loose or that there's physical damage to the connector, also check antenna socket solder connections to the board

Thank you, yes you are correct that they are second hand. Bought at the Ohio hamvention of this year, sight on seen with knowing only that they just turn on. They are all the same VHF model, 150-174mhz. I believe it is possible to clone between them, but I do not have the cable to do so. I'll check the solder connections now!

[Tator_Soldier]

I disassembled the radio not find nothing wrong with it. However I did change the frequency of the "faulty" receiving radio to be either one step above or below the frequency of the transmitting radio and that seemed to help as the squelch would open on either one of those frequencies, just not the exact transmitting frequency (i.e Tx= 151.82 Rx=151.82 closed squelch, while Rx=151.815,151.81875, and 151.825 can open the squelch. Best results have been from 151.81875). My new theory is that the three radios are out of tune. Is there anyway I can tune these radios by myself? The program does not let me pick any exact frequency, there seems to be presets for it so I cannot simply "make up" for the radio being a few hz above or below what it should be. In the service manual there are references of variable capacitors that can be adjusted.