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Modifications And Updates

NEWER 447/497 CPU BOARDS
     New CPU Boards

RADIO MODIFICATIONS
      SR-490 Backlight Mod


VARIOUS PROBLEMS & CURES: (Courtesy of Strykerradios.com)

01/01/07 - The Stryker SR-440HP is now powered by three IRF520 Mosfet transistors.

04/01/07 - Excessive White Noise SR-440HP, change R35 from a 0 ohm to a 3.3K ohm. This has since been changed on all production radios (SR-440HP & SR-490HP)

07/08/08 - Stryker SR-440 / 490 Dimmer Modification

07/09/08 - The most up to date SR-440HP schematic, it has many update that previous versions did not have.

07/09/08- For increased modulation on the SR-440 / 490 you can change R249 to a 47K.

07/10/08- Stryker SR-490HP Dimmer Fix

08/13/08- Fix for transmitter from hanging up on the SR-440 and causing low receive after keyed. Locate R213 on the final board, located in the output section. Add a 1.2k Ohm 1/4 resistor in parallel with R213.

09/08/08- If you're using an FC390 frequncy counter with your SR-440/490 and it scans frequencies add a 22PF across C98 to increase injection to the mixer. This works 100% of the time.

09/08/08- Loss of TX on SR-490HP radios, touch up solder connection for L-36 on the rear PA board. The connections will look fine to the eye, but touching these up usually takes care of it.

9/08/08 - Loss of TX on SR-440HP radios, touch up solder connection for L-34 on the rear PA Board. The connections will look fine to the eye, but touching these up usually takes care of it.

Mic Wiring

Stock
1-Shield  (ground)
2-Yellow (audio)
3-Red     (transmit)
4-White  (receive)

Astatic
1-Shield & Blue
2-White
3-Red
4-Black
Yellow NC

Turner
1-Shield & Red
2-White
3-Blue
4-Black
Yellow NC

Sadelta
1-Shield
2-White
3-Brown
4-Green