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Unable to Read & Write- TK880-H



Alright everyone, I need some help. I'm afraid my Kenwood TK-880-H 40 watt may have a fried RJ-45 port on the front. The other day, I tried using a Midland microphone on it, when I plugged it in, it made the screen flash and wouldn't key up. I figured it just wasn't compatible. However, when I plugged my usual DTMF microphone back in, every time I would key it up, it would make the screen flash and fully reboot the radio and would not transmit. I plugged the Midland mic back in for kicks, and after pressing some buttons on that Midland mic in a random order, it oddly will now transmit and key up and everything works just fine again; no screen flashes or reboots. That is for the exception that the KPG49 programming software will no longer read or write to the radio on my computer. It will show "PROGRAM" on the radio screen, but then error out on the computer telling me to check the COM port settings and connection. I've completely wiped the KPG49 software from my PC and reinstalled. I have confirmed that the cable, driver, and software are functional by hooking up another regular TK-880 25 watt I had laying around and it works fine and as expected; but still no dice on the 880-H. I tracked down some firmware for it to flash via F-PRO, but the firmware upgrade option was not enabled via the KPG49 software, and if the computer won't read it, I can't reprogram it to allow that, and even if I could somehow get into that mode, the computer isn't reading the radio anyhow so to my knowledge there's no way to re-flash the 880-H. As previously noted, the radio is fully functional, but if I can't read or write to it, it'll be permanently stuck on its current programming, which for now is fine but not so much going forward. I should note that the Midland mic I tried using on the 880-H is now fried as well; it'll no longer work on my Midland MXT400 whatsoever. I'm afraid that the Midland mic somehow drew too much voltage from the Kenwood and friend one of the pins inside the RJ-45 port that the software uses to read and write to the radio. I wanted to post here before I tossed it into the shed to see if anyone has any ideas on how to resurrect my favorite radio! =(

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Oh, that's too bad. But thanks for the heads-up regarding Midland mic and TK-880. Pinout for the TK-880 mic connector (looking at the outlet on the radio, 1 will be on the right):

1 - Mic backlight
2 - 13.6V
3 - Ground
4 - PTT
5 - Mic ground
6 - Mic input
7 - Hook detection
8 - Mic data detection

Looking at the schematic, there is a fuse in the backlight circuit, but it should not have any effect on data. Need a service manual with schematics? Send me PM with your email, I'll send it to you.

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Hey guys, thanks for the replies! I fixed the issue by taking another front panel (screen, microphone jack board) from a regular TK-880 25 Watt I had and simply swapping it into my 40 Watt TK-880-H I was having the issue with. I found the service manual you posted and found out that these radios were intentionally built to be modular and repaired, you know, back when things were made to be repairable! This completely fixed the issue, and all but confirms that the microphone port was just fried in some way. It appears that most parts are completely interchangeable between these radios, including between the 25W & 40W variants, which is great and means we can keep our radios going much longer instead of tossing it in a bin and having to buy another one. She transmits, receives, and reads / writes on the computer just fine now. 

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