Question about 880 Programming

[PCRadio]

I bought two Kenwood tk-880's off of ebay to use for GMRS or HAM 70cm, or both. And also a cable and the 49G software

The first radio is a tk-880 with no version listed. I got it programmed just fine.

The second radio is a tk-880-1 ver 2.0. When I try to read and program the radio as I did the first one, the red transmit light comes on, goes off, then the program says theres a communication failure. Ive reseated the cable, checked the other radio (successfully programmed) again without changing ports or closing the software, and even tried a second programming cable. No luck.

Last thing I tried was to clone Radio 1 to radio 2. Still no luck.

I pulled the radio open and noticed that there are 3 wires added to the radio. Purple wire comes from the bottom board near R12, R116, LOK, and E markings. It goes from the bottom of the board up, and is twisted together with 2 wires soldered in from PTT and MPTT behind the Display. I am not sure the purpose of these custom wires, and may be the issue.

Could someone offer me a little guidance on what this might be, if it could be causing my issue programming the radio, and what I might check next?

Many thanks in advance.

 

[buddrousa]

My guess is to bypass bad traces on the motherboard or it could have been an addon board
I thought about it if you look are the mike traces cut like the mike port was used to make a repeater

 

[PCRadio]

It didnt look to me like the traces were cut. I've (hopefully) added some pics here of the wires and solder locations. I tried to program it with them the way they were, and also cut the twisted ends apart and also tried that with no luck.

 

[PCRadio]

It appears to be something with the front board (the tx/rx board?) the one with the display and RJ45 mounted on it. I swapped that from one radio to the other, and am able to program whichever radio has that board attached.

I dont know enough about them to know if the programming is contained in this front board or not, but it appears so.

Found another thread with a similar issue...turned out to be a cable in his case...but since the cable works...

"...There is either an open in the RX path back to the PC, or a bad TTL-RS232 level converter that has failed...."

Continuing to see what I can find.

 

[WX9EMS]

You're right, programming is contained in the control head (schematic refers to it as the control section). The board mounted in the chassis is the RF board (rx/tx section). The read/write function is initiated through the CPU (IC511). Examine the CPU, EEPROM (IC512), and FlashROM (IC510) and surrounding areas for damage. The service manual can be found on Repeater Builder.

For what it is worth, I have a TK-760G that exhibits the same symptoms as yours and the CPU is damaged and thus will not read or write.