COBRA 200 GTL DX, RF DRIVER MOSFET REPLACEMENT - RD16HHF1

Replacing the RF driver MOSFET in a COBRA 200 GTL DX, common fault with these radios as the MOSFET's are static sensitive and can fail easily.
It was said that the early versions of this radio also had the GATE bias voltage set to high at the factory resulting in premature failure.
Driver bias adjustment = VR21 ( 3.2v Gate voltage)

Category:

Science & Technology

Tags:

• COBRA
• 200
• GTL
• DX
• REPAIR

[TRANZMATCH]

hi i find with cobra mike modulation to low and flat what type of power mike would you recomend for this rig thanks.

[weazle66]

@TRANZMATCH Most people i know moan about the flat audio on these radios, i think any decent power mic would be a improvement over the original.

[TRANZMATCH]

ware can i buy rd16hhf1  in uk.

[weazle66]

@TRANZMATCH  Try Knight's Electrocom, they normally stock them.

[DIESELDOG956]

Can you use other up grades on the driver

[weazle66]

@DIESELDOG956 I have never tried as i have a good supply of RD16HHF1's and they are quite cheap, the IRF520/ERF2030 is not the same as a RD16HHF1 so would not work as a direct replacement - i think others may have all ready tried this without much success.

[TRANZMATCH]

hi thanks for your help ordred one with knights electrocom 73 derek g0omf.

[xtranaut]

Is this driver replacement common in all radios in the series? I have a 3rd generation Cobra and all but one of the suggested cobra fixes to inherent problems was necessary so they must have corrected some shortcomings as they learned.

[DIESELDOG956]

Can you use a 2030 or a 520 for the driver

[weazle66]

@norseleague If the radio has good output power but just no modulation then i doubt that the MOSFET driver is the problem.

I would recommend having someone who knows these radios well check it over for you to find the problem.