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Dak X Clarifier Unlock Procedure?
- Thread starter SteveSteve
- Start date
Got it on file at the shop somewhere. A resistor comes loose to disable the transmit-only clarifier voltage. We mount a 78L06 3-terminal regulator astride the two outside lugs of the clarifier control, with a 10uf capacitor to keep it stable. A wire from the main 9-Volt regulator feeds into it.
I'll see if we have any pics, or a written procedure next time I'm at the shop.
73
I'll see if we have any pics, or a written procedure next time I'm at the shop.
73
DAK Mark X clarifier mod:
Remove R24 and R25, both are 18k 1/4W resistors at the front-right corner area of the main circuit board.
Separate the center and clockwise lugs of the clarifier control where they are soldered together. Solder the wire that WAS connected to both of them, now to the center lug only.
Add a 10uf electrolytic, at least 25 Volt rating with the negative side on the ground (CCW or counterclockwise lug. The positive side to the empty lug, the CW, or clockwise lug. Don't solder it yet.
A 78L05 or 78L06 3-terminal regulator works better than a zener diode for this. With the flat face toward you and the legs down, the left pin is output, the center is ground and the right-hand pin is input. Solder the center lug to the ground side of the clarifier, the CCW lug. Solder the output (left) pin to the clockwise lug where the positive side of the capacitor is connected.
Lap-solder a wire to the remaining input (right) pin of the 78L05, connect the other end to the positive side of the large main filter cap near the audio chip.
A 78L05 should get you the same clarifier-frequency settings you had before. Using the 78L06 will move the channel center to the left a bit on the clarifier knob, and will cover a little wider frequency range than before.
Good luck. The Mark X has more little demons hiding in it than any other CB base that comes to mind.
Except maybe the Tram D201.?
73
Remove R24 and R25, both are 18k 1/4W resistors at the front-right corner area of the main circuit board.
Separate the center and clockwise lugs of the clarifier control where they are soldered together. Solder the wire that WAS connected to both of them, now to the center lug only.
Add a 10uf electrolytic, at least 25 Volt rating with the negative side on the ground (CCW or counterclockwise lug. The positive side to the empty lug, the CW, or clockwise lug. Don't solder it yet.
A 78L05 or 78L06 3-terminal regulator works better than a zener diode for this. With the flat face toward you and the legs down, the left pin is output, the center is ground and the right-hand pin is input. Solder the center lug to the ground side of the clarifier, the CCW lug. Solder the output (left) pin to the clockwise lug where the positive side of the capacitor is connected.
Lap-solder a wire to the remaining input (right) pin of the 78L05, connect the other end to the positive side of the large main filter cap near the audio chip.
A 78L05 should get you the same clarifier-frequency settings you had before. Using the 78L06 will move the channel center to the left a bit on the clarifier knob, and will cover a little wider frequency range than before.
Good luck. The Mark X has more little demons hiding in it than any other CB base that comes to mind.
Except maybe the Tram D201.?
73
