Re: Potential Ultralight Radio – Grundig Mini 300


I finally opened the case of my Mini 300 to take a look at what's
inside, but made no adjustments. My guess is alignment would similar
to the E100.

To disassemble, first remove three screws (two in the battery
compartment) and slowly lift the back from the bottom slowly to detach
it from a hook at top right (from the back). The hook could be broken
if not done correctly. Once unhooked, the back is free to set aside.

Now remove the two screws holding the main circuit board to the front
of the case. Below it you will notice a second circuit board attached
to the front case above the speaker. It's the frequency
counter/display circuit and there's no reason to remove it.

There is an approximately 5 x 0.7 cm. (1.9" x 0.27 ") ferrite bar
antenna at the top of the main circuit board. It looks like a shorten
version of the one in the E100. Like the E100, the antenna coil is
held in place with wax, so the 600 kHz adjustment should he easy. I
didn't identify the 1400 kHz adjustment point - it's one of the eleven
on the front of the circuit board.

To reassemble the receiver, first secure the main circuit board to the
case front ensuring the band switch is in its correct position. Then
hook the case back to the front checking to see the battery
compartment springs fit back into place. Finally replace the three
screws holding the two halves together.

My opinion is the tuning control on the Mini 300 keeps it from being
used for serious DXing. It's extremely tricky to use and takes a very
practiced thumb or forefinger to get it right on the desired
frequency. A 3.5 (1.4") cm. tuning control wheel is coupled directly
to a small variable capacitor. It would probably benefit from some
type of venier tuning apparatus.

Richard Allen

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