A lot thanks, Al.

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It solved for me: I switched a dozen of times between 6m (rear antenna) and 2m (front antenna) and it solved. I hope forever, but I'm not confident; however I know what I have to look for.

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Pietro I2OIM

I just put in my order for 2 modules and expected to be in stock mid November?

I had similar odd readings on my 817N...twice...

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High SWR, odd power and swr readings...turned out it was the finals on their way out.

Thankfully they are relatively cheap and quite easy to replace...but be warned, i replaced mine, all was working perfectly, until i plugged the battery pack back in, then it started all over again...

Yes the finals had blown again...!

I ordered a new power board, but before fitting it i checked the battery pack and one cell had died, seems it dumped the current straight into the mosfets..what a crazy "Undocumented Feature", but since replacing them for a second time, and buying a new battery pack all has been good for the past 2 years or so..

So check your battery pack and don't leave it in there constantly is my advice.

And use some high quality, non conductive thermal paste, mine was very dry which doesn't help moving that heat into the sink.

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Hope that helps

Hi Pietro,

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I too had an issue with instable power and swr with my FT-817, which took me quite some time to track down.

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The final unit has some kind of gray shielfing foil on top. With the shielding removed, the power and swr on a dummy load were stable.

After assemling the shielding and the case, the erratic behavior started again.

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In the end an additional insulating piece of a plasic foil between the pa board and the gray shieling foil cured it for my unit.

It may or may not be a solution fo your unit, but it would be a simple try.

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Good luck, 73

Chris

In that context, defaulting to the front panel BNC makes sense, or, at a minimum, isn't a 'mistake' when considered logically.

The power consumption of the antenna select relay is 20 mA/hr (??), if an operator kept that relay energized for the entirety of their operating session, how much shorter would their operating session be? In un-squelched receive the radio consumed 450 mA, full-power transmit 2,000 mA. In pure, un-squelched RX, it would reduce operating time 20 mA / 450 mA, or about 4.45%. If keying down constantly, 20 mA / 2,000 mA, or about 1%. If we were running constant, worst-case FT8 (15 seconds of RX, then 15 seconds TX, -continuously), then the reduction in operating time would be 20 mA / 1,225 mA, or about 1.6%.

That's a loss of about 1 minute for each anticipated hour of operation.

Is this really something we need to consider as a meaningful "waste" of battery power?

I don't think so, but I understand opinions vary.

/soapbox

Pietro,

Sorry to have been away for a few days.? I looked at your pictures of the display and the SWR does seem a little high.? The radio cuts back on power when the SWR goes up to protect the finals.? In the photo the radio is making power.? Now, many people have reported that the output relay does seem to go intermittent from time to time.? I believe that is do to either dirty contacts on the relay or reduced input voltage that is preventing the relay to make the switch.? Just for myself, I know the contacts are somewhat self cleaning when the relay operates.? Since I have several memories programed, on HF, VHF and UHF, I programmed one memory to use the front antenna connector.? By switching between that memory and a normal memory using the rear antenna connector, I can exercise the relay several times rapidly.? As a reminder, Yaesu designed the radio so that the front connector is the normally closed contact of the relay.? To use the rear connectors, power is supplied to the relay coil.? AS this is the most often used output, Yaesu kind of missed the definition of "low power" since the radio uses more power for the rear connector than the front.

I had a unique situation on my radio in that in UHF, the SWR always showed a little higher than the VHF.? And it showed different that an outboard SWR meter.? So I went looking for an issue inside the radio.? What I found was a small cap that must have fallen into the radio during assembly in the UHF SWR circuitry.? All of the other parts were correct.? So I removed the cap, readjusted the SWR bridge and checked the software.? Now the internal SWR meter agrees with an external meter and I no longer have HSWR warnings.?? My previous 817 also suffered from the relay contact issue.

Good luck

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Al Skierkiewicz
WB9UVJ

Mike Davis WA1MAD

I got the pin diodes but suddenly, yesterday, it starts to work at full power. Astonishing, disorienting...

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I2OIM

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Which Display? Power, SWR or?

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I2OIM

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Pietro, just for a little more info can you take a picture of the display when this is occurring and post it here?

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--

Al Skierkiewicz
WB9UVJ

@?Al WB9UVJ

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Thanks Al.

That's what I was hoping for. No luck...

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Pietro I2OIM

Thanks to both. I'll check the diodes

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I2OIM

Hi Peter, I had the same problem on the FT817 and I solved it by replacing the Q3003 and Q3005 HSU277 diodes. I hope this helps

@ Al WB9UVJ

No, it neaver succeded. I check antenna connectio tryng wit a different one (2m/70/23cm vertical) and the problem remain.

Some days it work at full power, other days it work bad with the two antennas...

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73,

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I2oim

I didn't check it. The 2m bans works on the front connector, a will try.?

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Tnx, 73

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Pietro