I have a DX-390 being sent to me for repair. It has the "classic" front end RF
preamp transistor failure due to static discharge to the whip antenna. Could
someone tell me the ID of this transistor and it's approximate location in the
390. I don't have a schematic for this radio and any info would be helpful.
I'm assuming it's a JFET and something like an MPF-102 can be used as a
replacement.

Thanks,

Frank
Frank

"Fcathell" wrote in message
...
I have a DX-390 being sent to me for repair. It has the "classic" front
end RF
preamp transistor failure due to static discharge to the whip antenna.
Could
someone tell me the ID of this transistor and it's approximate location in
the
390. I don't have a schematic for this radio and any info would be
helpful.
I'm assuming it's a JFET and something like an MPF-102 can be used as a
replacement.

Hi Frank, there's a helpful posting at www.mods.dk.

Tom

I have a PC Board right here
The only 2 transistors on the side of the board next to the Ext AM antenna
SW
Q-1 K435 D (2SK435 D)
Q-2 is a smaller transistor that reads ?
3330
S F5

From what I can make out the schematic Says
Q1 = 2SK291 Q
Q2 = 2SC330.....?
Q3 = 2SK291 R


"Fcathell" wrote in message
...
I have a DX-390 being sent to me for repair. It has the "classic" front
end RF
preamp transistor failure due to static discharge to the whip antenna.
Could
someone tell me the ID of this transistor and it's approximate location in
the
390. I don't have a schematic for this radio and any info would be
helpful.
I'm assuming it's a JFET and something like an MPF-102 can be used as a
replacement.

Thanks,

Frank
Frank

The trans is in a standard TO92 case
labeled SK152. This is a high transconductance
FET. I've replaced a lot of them. The MPF102
is a POOR replacement IMHO. Get the correct
trans, and put some 1n914's in parallel with the
antenna jack to prevent the problem from occurring
again.