TYT TH-9000D Locked Up

Geoffrey, are your TYT radios still working okay after your fix?

de Jim

 

Add two more TYT TH-9000 radios to go tits up. Same issue... display giberish and locked up.

Geoffrey appears to have a different issue going on. All of the failures I have had have never lost 5v to the cpu.

 

1. Keep emailing TYT until we get a response. contact@tyt888.com

 

I finally received a response from TYT. They said they read this thread and watched the youtube video and their engineer says its a bad CMX138. The CMX138 is the voice scramble IC. LOL

I guess the terms "display scrambled" didn't translate well.

They want $28 for the part that will not fix the problem.

No more TYT products for me.

 

Do you / Did you have voice scramble turned on ?

 

Sure ... per FCC rules which are quite clear, I think, on this issue ...

 

Add another failed TH-9000 to the list.
Same issue.

 

After many hours reverse engineering the TH-9000 I have come up with a repair.
I have successfully repaired several and have enough components to repair three more.
The repair is not for the faint hearted, requires a hot air rework station, keen eyes or microscope and a steady hand.

The problem is a design flaw where TYT used a dsp device that has an absolute max VCC rating of 4.5 volts.
In the circuit they are powering it off if the 5 volt 7805 regulator on the main pcb. The CPU located on the display board has its own 5V regulator located on the display board. The problem is not the CPU.

I am interested in purchasing your dead TH-9000 to use as parts. They must be complete radios with no attempted repairs.

 

N5MRG I have a TH-9000D that would like to ship to you if you still want them. It has the jumbled screen. I have no need for it and if you can fix it and use or do something with it. It is complete and has not been messed with. I will pay shipping.

 

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https://tinymicros.com/mediawiki/images/e/e8/TYT_TH-9000_VHF-220-260MHz_Schematics_2.pdf
There you are. 73 de KD4SR