FL3 later version?

[Robert]

Hello,

Thank for posting all of this information on Datong products. I have an FL3 which I think
is a later version.

The two most obvious changes are the model numbers etched onto the pc boards.

The service manuals refer to an auto notch model of 710-0341; on my board the number
is 710-342. The filter board in the manuals is 710-0171; mine is 710-0172.

I haven't examined the filter board too closely, but the only change I've noticed so
far is a larger filter capacitor (C9); it's value in the FL2 information is 1000μf; on
my board it is 1500μf.

On the auto notch board, there appear to be additional circuitry than what is shown
in the board diagram:

 - in the lower left corner there are three resistors, two capacitors and a transistor
   not shown in the service manual.

 - trim pot VR5 isn't installed on my board, but jumper "b" inside the pot's outline is
   present.

 - there is another capacitor (0.01μf) installed to the right of R25.

 - C18 is 1μf electrolytic in the documentation, 10nf (I think!) ceramic on the board.
 
 - R34 is 10KΩ on paper, 100kΩ on board.

 - At the top of the board there are two more resistors and a diode not shown in the pcb
   drawing or schematic. These last components have one of their leads soldered on the
   board, but the other leads are soldered together and left "floating" - if that's the correct
   term, in the air.

Does anyone know why these changes were made and why weren't they documented?

If any one is interested, I'll draw a schematic diagram of what I have and uploaded it.

Thanks for reading,

Robert Bolstad