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Old 7th May 2012, 7:12 pm   #1
g4aaw pete
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Default FRG-9600 wide FM module question.

I have a Yaesu FRG 9600 receiver with a fault in its wide FM module. This is centred around a MC3356P i.c. which has a frequency input of around 45Mhz

The voltages measured around this chip are incorrect and I’ve decided to replace it.

My question is, if I mount the replacement in an i.c. socket on to the circuit board, am I likely to introduce spurious responses? The original is soldered directly to the board.

Shown, is the board with the chip removed.

Regards
Pete
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Old 7th May 2012, 8:19 pm   #2
Andrew2
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Default Re: FRG-9600 wide FM module question.

I wouldn't recommend it, Peter. The stray c in an IC holder could detune the circuitry or cause instability.

EDIT: Further thought has me thinking that the 45 MHz bit is not used on WFM, the rx converting to a seperate 10.7 MHz block for that function. I'll do some checking.
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Old 7th May 2012, 8:27 pm   #3
HamishBoxer
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Default Re: FRG-9600 wide FM module question.

Carefully clean holes with solder Braid Not sucker before replacement.

David GM8JET
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Old 7th May 2012, 8:38 pm   #4
g4aaw pete
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Default Re: FRG-9600 wide FM module question.

Thanks for your view Andrew.
The i.c. has two inputs.
45.754 Mhz and a local osc. signal. The chip incorporates a mixer function to produce an audio output.

I’m inclined to agree with your remark about stray ‘c’ in the circuit.

Thanks David.
A valid point!

Regards
Pete
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Old 7th May 2012, 8:57 pm   #5
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Default Re: FRG-9600 wide FM module question.

Yes you are right, Peter. The block diagram is rather unclear on this, but the description clearly says the 45 Mhz signal goes into the module.
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