Re: Unexpected Blowing of Fuses on Transmit


I think same problem with RV3 if skewed then lead is cut and connection intermittent.
This would lead to sudden jump in current thus fuse blowing.

The ladies at HFSignals are twisting the RV3 to accommodate the heatsink and causing


At 01/12/2019, you wrote:

Hi and regards from the UK.


I have a uBitx V5 which has been working great for the last few months and I have been loving it. I have incorporated a few mods – Allison’s power mods, AGC & Dr Ian Lee’s firmware – latest mod was about a month ago.


Yesterday it blew the 2A fuse on transmit. I have checked everything I can think of from the mic to the cables to the power supply, checked earths, checked for shorts all to no avail. In the meantime, whilst continuously testing it, I have blown a further 6 fuses. I even turned RV1 down to practically nothing and still the problem continued. I also replaced the FET’s just in case, but unsurprisingly, that made no difference. It receives perfectly, but as soon as I transmit, bang goes a fuse.


I am a relative newbie – currently studying for my Full license, so, far from experienced. My test equipment consists of a DMM.


Any help to point me in the right direction would be enormously appreciated as frankly, I am at my wits end.




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