# Story

I recently aquired (second-hand) a Yaesu FT-252 handheld in unknown condition. It turned out to mostly work, but was found very weak. Investigating it in the HAM club we found that the PA IC is very likely to be at fault, as we could detect signals going into it, but no signals getting out at all. We also found that it's most likely to be shorted, as we measured $$\<5\Omega\$$ between one of it's (non-ground) pins and ground.

We tried to search for this part, but could not find any info on it. We tried to search for "W62Y106", "2Y106", "W6 2Y106" and most similar combinations with no success.

One of the members of the HAM club suggested that we might just replace it with some "generic" 5W RF PA suited for the 2m band.

## Question

a) What could be the part number of this IC (marked "W6 / 2Y106"), so we can find datasheet or order it?

b) What other RF PA ICs could be used as a replacement, that we can buy?

## EDIT:

Here's a picture of the board showing the parts nearby. We removed the part so we can test it, and it measures similar to a gate-shorted mosfet.

• Yaesu produce service manuals. Have you tried looking for one? Jan 16 at 14:55
• Yes, but we had no luck. We could easily find the operating manual, but not the service one. Jan 16 at 15:31
• Investigating it in the HAM club ... use the HAM club to put out a call worldwide Jan 16 at 22:10
• @Sasszem, It's of no use for your answer, but could you please provide me with close picture of what have been put in place around the component ? It would greatly help myself because I'm developing an amplifier using said component. (see answer below) Jan 17 at 9:42
• @LucasVivi I'll take & add an image later, but now I can only tell we measured ~7.4V of DC bias on one of the pins. Jan 17 at 9:58

a) What could be the part number of this IC (marked "W6 / 2Y106"), so we can find datasheet or order it?

The component is probably a Toshiba 2SK3075 or 2SK4037 or 2SK3476 Those are mosfets capable of outputting 5 Watts

The 2SK3075 have been thoroughly used by Yaesu, notably in the FT-2400M. https://toshiba.semicon-storage.com/us/semiconductor/product/mosfets/detail.2SK3075.html

The package (PW-X-4) is a Toshiba package (of that I'am sure). Here a list of similar component on Mouser : https://www.mouser.lu/c/semiconductors/discrete-semiconductors/transistors/rf-transistors/rf-mosfet-transistors/?mounting%20style=SMD%2FSMT&package%20%2F%20case=PW-X-4

b) What other RF PA ICs could be used as a replacement, that we can buy?

I'm trying to build a 10 Watt amplifier for the 70cm band, I searched a lot for a component capable of this power and didn't find many if any. I think you better of replacing with one of the component listed on Mouser.

Based on the list and depending on the polarization of the transistor, and the component put at his input/output. You could maybe find the closest match thanks to the test fixture circuit recommended in the datasheets.

Note: Replacing an RF PA with another is generally a bad idea. Depending on the polarization point, and impedance matching required at the input and output. Which may/will not be the same for different components. Even the need for DC blocking.