Hi George, KA3HSW
The 3SK121Y is a Dual Gate MOS-FET in package SOT 143R and it can be directly replaced by the very inexpencive BF998R with same package
See the cross reference here:
http://www.go-ic.cn/admin/newspic/20061127185602infineon.pdf
The Noise Figure of the BF998R is 1 dB at 800 MHz
See the data sheet here:
http://www.nxp.com/documents/data_sheet/BF998.pdf
I hope this helps.
73" de
i8CVS Domenico
----- Original Message ----- From: "George Henry" ka3hsw@att.net To: amsat-bb@amsat.org; "Mark L. Hammond" marklhammond@gmail.com Sent: Thursday, March 18, 2010 4:54 AM Subject: [amsat-bb] Re: Devices in Icom preamps AG-25 AG-35
For the AG-35, it's a 2SK121Y. Not sure about the AG-25.
As others have mentioned, because of the proximity of the relay, one of
the
easiest ways to replace it is to cut the leads on the old device, then
bend
& trim the leads on the new device to "straddle" the old leads & solder away. Way easier than removing the relay...
George, KA3HSW
----- Original Message ----- From: "Mark L. Hammond" marklhammond@gmail.com To: amsat-bb@amsat.org Sent: Wednesday, March 17, 2010 5:29 PM Subject: [amsat-bb] Devices in Icom preamps AG-25 AG-35
Hello all,
We either had two bad preamps to begin with, or they became casualties during transport to K4T, but regardless--the Icom preamps we took appear to have bad GAsFET devices in them.
Can anybody tell me what is the device in each unit (AG-25 and AG-35)? And are they something a skilled ham can reasonably replace?
Specific suggestions for a parts source will be appreciated, too.
73,
Mark L. Hammond [N8MH]
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