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Superstar 4900B Export Frequency Modification | Radioaficion Ham Radio

Superstar 4900B Export Frequency Modification


Superstar 4900B Export Frequency Modification

Export Frequency Modification
(23.815-30.555 MHz!!!)

Superstar 4900B Export Frequency Modification
Remove the top cover from the unit.  There are a total of 14 screws and 4 different types that have to be removed.  (3 flat head screws on top, 1 round head on the back, 4 round heads on the sides, 2 chrome screws from the handle (don't lose the 2 brass inserts) and 4 small screws from the rubber feet)

Locate the 4 position jumper block located next to the K3170 IC chip.  Move the two jumper blocks to the pins shown in the diagram.  Note: see diagram for  different conversion positions.

Export frequencies will be selected by the way you choose to place the jumper blocks.  If you choose the position shown in the diagram above (3 & 4) the display will indicate the frequency and band selection with the + or - A B C D E symbols.  The so called "A" channels (or "RC" channels) are designated with a small "A" symbol after the frequency indication.  If you choose to remove all jumpers, the unit will cover all frequencies with continuous coverage.  The desired frequency can be entered directly on the keypad.  The ANL button will function normally in this position and the step button will select all three segments of the frequency display.  This may be a little confusing for some users so choose your method carefully.

The "STEP" button can be used to select +1, +10, +100 KHz depending on the jumper placement.  Jumper blocks on 2 & 3 or 3 & 4 will only select 1KHz mode.  Removing all jumpers selects all modes.

To open the AMC limiter circuit, locate the small surface mount transistor approximately on inch from the 5 and 6 pin connectors at the front left side.  Carefully unsolder and lift the center pin up from the circuit board,  or remove the part entirely.

Clarifier Control:
The clarifier tracks transmit and receive on SSB operation only.  The control will move several KHz with No modification necessary.  Use "STEP" button for Frequency Offset Operation.

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