JI1FGX/DU9 Mindanao, Philippines Amateur Radio Diary IOTA OC-130
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Access until yesterday
Introduction. [Lily Diary]
Diary of Life in Mindanao

25/06/08  AutoCWType_Ver1.4.1
25/06/07  Introducing the Shack
25/06/06  A portrait illustrated by ChatGPT
25/05/26 Windows full-width half-width switching
25/05/17 OK2ZAW BCD to 16 converter
25/05/16 For 3.5MHz zepp antennas
Stepping motor this and that
25/05/15 3.5MHz stepping motor plan
25/05/14 3.5MHz tuning coil installed
25/05/11 3.5MHz antenna installation completed
25/05/03 JTDX automatic operation program Ver0.4.3
25/04/26 Drone Habsan ZINO
25/04/25 Time setting Ver0.3
25/04/24 AutoCWType_Ver1.3
25/04/23 FTDX3000 LCD repair preparation
25/04/22 Installation plan for 3.5 MHz Twep antenna
25/04/21 AutoCWType_Ver1.1
25/04/20 10,14MHz antenna installation completed
25/04/19 JTDX automatic operation program Ver0.4.1
25/04/19 Antenna pole installation at 14 MHz
25/04/18 ThinkPad X390 repair completed
25/04/17 Search is now available.
25/04/15 Preparation of 10 MHz dipole
25/04/12 Hexbeam Part8
25/04/06 ThinkPad X390 is broken.
25/04/05 Time Setting Program
25/03/31 JTDX Automatic Operation Program
25/03/30 Automatic log sending from CWType to Hamlog
25/03/21 Hexbeam Part7
25/03/20 FreeDV Part3 First QSO
25/03/18 FreeDV Part2 QSO in shack
25/03/16 Hexbeam Part6
25/03/15 FreeDV Part1 installation
25/03/09 Hexbeam Part5
25/03/07 Hexbeam Part4
25/03/05 28MHz antenna modification
25/03/01 FTDX3000 is broken!
25/02/28 Pile up at 50MHz FT8
25/02/28 DXV500ZS linear amplifier repair
25/02/27 Pipe and rebuild plan for tower
25/02/26 Direction of Japan from Ozamiz
25/02/26 28MHz does not fly.
25/02/23 DXV500ZS linear amplifier repair
25/02/22 Hexbeam Part3
25/02/21 Hexbeam Part2
25/02/18 28MHz antenna construction
25/02/17 18,24MHz antenna height construction
25/02/16 Z26NS Cosovo
25/02/14 21MHz FT8
25/02/12 Antenna repair at 7,21 MHz
25/02/08 CW operation at 21MHz
25/02/05 DXV500ZS linear amplifier failure
25/01/19 Input Director
25/01/14 Temporary License Renewal
DXV500ZS linear amplifier repair in Samway (2025/02/23) 
Diary for February 05, 2025but
Samway's DXV500ZS linear amplifier is smoking and won't turn on!
The fuse is not blown, but one cement resistor is heating red when the switch is left ON.
I emailed Mr. Ohashi at Samway.
He diagnosed a broken 100 ohm cement resistor, a bad relay, and probably a bad FET in Q1!

It was shipped via EMS on February 6 and arrived on February 21. This is still early.
Arrived parts

Relay RY1 G2R-1 DC12V 1 piece
Resistors R4,5 Cement 100Ω 5W 2 pcs.
FET Q1 2N7000 1 piece
Parts Total
EMS Shipping
660 yen
$352
$132
1,144 yen
1,900 Yen
I had trouble removing the relay.
And the Chinese-made desoldering wire you can buy at mail-order stores in the Philippines doesn't suck it up at all.
Pump-type desoldering equipment is not powerful enough

So I had no choice but to destroy the relay and remove the terminals.
 
As expected, one of the two cement resistors was broken.
The FETs are interchangeable 2N7000 and the arrangement of the legs is different, so this is what it looks like
2N7000 is a new part
S (source) is in the same position, but G (gate) and D (drain) are in different positions.
  
I'm not sure if I'm getting presbyopia lately, but I can't see the small FET letters.
I sent an email to Mr. Ohashi to see if the wiring of the compatible FET legs is correct, so I won't be able to energize it until Monday!
February 22, 2024   February 26, 2025