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Thursday, 14 November 2013

My FT847s got no nose...

So how does it smell?

Like an electrical burning.....

This morning in a state of sleepiness I agreed a 4M Meteor Scat sked with a European station. I started to TX on the 2nd half of each minute. After wondering why the power out was so low for a while I realised that I hadn't got an antenna connected! By this time small whiffs of the magic smoke were emanating from the back of the radio.

I've done some tests now the smoke has cleared and I have RF out on HF, 2M and 70cm so I conclude that the PA must still be intact. I don't have any RF out on 4 or 6M however.

There's a low pass filter (LPF) for those two bands and I suspect the smoke may be from the components in that filter somewhere. I've had a look at the top side and the inductors in the filter look intact, the damage must therefore be on the underside of the PA board. I've had that board out before when I did the PA mod for 4M, and it's quite tricky as you have to remove the PA transistors from their heatsyncs.

As I am going to A71 land again on Monday - I'll take this to have it looked at - with a bit of luck it'll be fixed before I get back.

Cat agrees with my diagnosis:

Muppetry, egh?

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