The HF PA is under the main board, tricky to get to but doable

73

Get

On 24 Aug 2023, at 18:56, "ik0oky via " <yahoo.it@groups.io target=_blank>[email protected]> wrote:

Many thanks? indeed for the hint.

Will have a look at the testing procedure in the service manual

Yes, 144 and 432 Mhz are fine.

Regards

Emilio IK0OKY

Il 23/08/23 22:40, Andrew Lenton ha scritto:

Ok then the PA transistors are not been driven, 100 Watts is over 20 Amps, so it is not the low pass filters.

You will need to probe the HF PA, check the bias pots? are are creating the correct quesiant current, are you able to measure the input to the PA board, it should be 100 mW

73

The TX strip does have a set up procedure, and a number of test point to check

I presume VHF and UHF are fine?

73

Andrew

Get

On 23 Aug 2023, at 19:39, "ik0oky via " <yahoo.it@groups.io target=_blank>ik0oky=@groups.io> wrote:

Roughly 5 A at 50 Mhz? with an unstable reading on the power supply

?

Il 23/08/23 10:51, Andrew Lenton ha scritto:

How much current is it drawing at full throttle

Get

On 22 Aug 2023, at 21:27, "ik0oky via " <yahoo.it@groups.io target=_blank>ik0oky=@groups.io> wrote:

Dear FT 847 owners,

after 20 + years of honest service few days ago my FT 847 started to
loose output power on HF and 50/70 Mhz.

Now on HF and 50/70 Mhz it delivers only less that 10 w out.

I suspect some "boiled" component in the LPF bank or the final devices
gone....

It has been used intensively on 50 Mhz ft8 but never at full throttle power.

Any hints? for a similar experience are welcome.

IK0OKY Emilio