QYT KT-8900 RF Module failure with review

[@Atomshamradio]

I had the quad band one 2m 440mhz and 300 mhz its only 25 watts it worked pretty good i sold it 4 years ago . I bought it from radio oddity

[@thomasfreedy]

I just bought one of these, should I replace the foam with an aluminum heat sink?

[@Radionut63]

It sure needs a better heat sink. Dont forget the heat sink compound.

[@ericyell898]

wow! thanks for this video and for putting me wise about this radio.

[@Radionut63]

Glad to help!

[@pd1jdw630]

Looks nice for a little radio. Sad to see that chip burnt. And it’s no wonder why. Is there a replacement chip? Ore is this some sort of obscure little critter.

[@Radionut63]

I have searched online, there is a replacement part, but i am not sure if i really want to repair this thing, i have a few VHF/UHF radios here now, so i really do not need to spend anything on this one. Save it as scanner receiver is what i am thinking, set it up in the car. ;-)

[@pd1jdw630]

@@Radionut63 good enough for a scanner. But in any way you gave us a video why to be cautious about this little radio.

[@Arijit_VU3ICT]

Bcoz this Chinese uses hyper mode they use RD07MUS2B mosfet in final which have only rated at 6w output while they over drive it to 20 watts.. thats why you will get a bullet mark in final mosfet.

[@graham2803]

Just my two cents but I recently purchased one of these and dove into some research about it. The final, according to one website, is also made by NXP. From the factory it is a AFT05MS006NT1 which is indeed rated at 6W. The replacement that seems a better or even best fit is a 20W+ rated AFT09MS015NT1, made also by NXP. DigiKey sells them for around $6 or $7. If it were me, get an aluminum heatsink and some thermal paste put on the final as soon as you can. Hope this helps! EDIT: If you don't want to replace the final, you can also turn down the power output. There is a centermost potentiometer on the main board that controls the output power. I'd put the output around 5 to 10 watts. I know it stinks, but these manufacturers need to practice better RF engineering - it's sad it takes an everyday ham to know how it works. Also, get the model with a cooling fan. Many of the newer models have this, but it's not difficult to install one on the back.

[@aventurasobrerodasoficial]

Hello I had the same problem, but in my case this component is completely burned. How can I identify to replace it?

[@Radionut63]

If you do replace it, may i suggest you install a much better heat sink then what is used at the factory, the original one is pretty much useless as you have found out.

[@Verduras5caminos5caminos]

Buenas tardes como se llama ese módulo quemado

[@Atomshamradio]

Yeah it was a qyt

[@Atomshamradio]

Thats a old trick put a peace of wax on a transistor if it melts its shorted

[@ericyell898]

20 watts? notta chance, well, not for very long anyway. it makes you wonder though, why go to that extent of building a fairly good radio at not a bad price and not go just a little bit farther with a bigger heat sink or some other method of cooling it?i know there's limited space but why the hell not make the radio just a little bit bigger?

[@Atomshamradio]

The one i had was alittle bigger

[@1112223333111]

ditch that sponge. it must be using pressure to push in the heatsink underneath. I'd use a block of hardwood. bet theres no paste under there

[@okcrum]

The sponge is a thermal pad. I doubt the guy who made the video wants you to know that because he blocked my post saying it. Also, no one else here knows what it is either. That's the state of the art in ham radio. In another fun fact that transistor is designed to run at 150C case temp and 250C internal temp. Video dude probably can't read the schematic.

[@1112223333111]

better off using thermal adhesive and gluing a heatsink to it. Baofeng mobiles are like this too. total garbage

[@Atomshamradio]

I smell burnt chips

[@Atomshamradio]

How the hell the person cooked that radio maybe a missed matched antenna probably a cheap junk one you have to be careful thiers cheap copy cats out thier

[@Atomshamradio]

What the hell