In reply to G8ADD:
Ouch! Makes you wonder whether we should have insurance against our blunders!
73, Gerald
In reply to G8ADD:
I have had two FT857 in for repair and to be honest I would advise anyone thinking of buying this rig to invest in the protection Yaesu thought it suitable to leave out. Yaesu have obviously decided that the PA devices are to be used as sacrificial fuses - not cheap and very difficult to replace.
The two models I had for repair one had been reverse voltaged and one had been overvoltaged. The reverse voltage one was repairable but needed several surface mount devices on the back of the main board replaced and burned tracks repaired. The overvoltage rig had similar problems but in their wisdom the designers have fed the 13.5 volt unswitched voltage via a voltage divider to one pin of the main microprocessor. This divider gives 5 volt onto this pin when 13.5 volts are applied to the rig and this pin has an absolute maximum voltage rating of 7 volts. When 24 volts are applied from a CB power supply the result is a rig beyond economic repair.
My advice is to invest in a big stud mount zener diode (15 or 16 volt) and a fuse block and put this in the main power lead. The amateur radio community should also pressurise the main manufacturers to build in essential input voltage protection, it is there on most older rigs why is it missing from modern ones?
I FEEL BETTER FOR THAT RANT!
73
Barry GM4TOE
In reply to GM4TOE:
It’s cost engineering. Replacing a regulator with a voltage divider is junior bush league engineering which has most engineers wincing. Sure the pin may only need a few mA but if the line your dividing down is unregulated you’re simply asking for boundary conditions to produce devices failures. On a piece of equipment that will be subjected to poor power supplies (in a car / portable) making the device less tolerant to spikes/overvoltage almost seems negligent. The designers are saving pence per unit by forcing the user to condition the power supply before attaching the device rather than incorporating a reasonable degree of tolerance in the device itself. Definitely the sign of a piece of consumer grade equipment!
The move to permanently power PA devices is not new but is becoming the norm as the size of radios drops and the use of software controlled “soft” power switches becomes standard. There’s a big cost saving to be made if the power switch doesn’t have to cope with 20A for a 100W radio. You get huge advantages in usability too. My TS570 is never really powered off. You can send commands up the RS232 port to turn the radio on which means that even when it’s off, the CPU and serial ports are energised so that you can remotely start it. The downside comes when you forget the set is powered all the time and start poking about with the covers off and then there’s a pop and sparks from the screwdriver. (Yes I jumped but the PSU reacted faster than a fuse so there was no damage other than to my nerves.)
You do get the feeling that the 817/857/897 are worse than many consumer devices for the way they can be totalled so easily. You’d think that Yaesu would be adding protection in now based on the number of reports of fried sets that do the rounds. Perhaps the warranty repair costs and the damage to their reputation are low enough to make increasing the BOM cost not worthwhile.
Andy
MM0FMF
In reply to GM4TOE:
Well said, Barry! I would love to know why the Yaesu designers put a pair of fuses in the main power lead, they were about as protective as a can opener when it came to the crunch!
I hope this part of the thread will be taken as an Awful Warning by all users of the FT8*7 series!
73
Brian G8ADD
In reply to G8ADD:
Why not connect a high current Schottky (i.e. fast) diode behind the fuse that blows the fuse on reverse polarity should you be concerned?
In reply to DF9TS:
An excellent idea!
73
Brian G8ADD
In reply to G8ADD:
Yes someone should suggest that to Yaesu.
We should stop now because I feel a temporal loop is about to form where someone will post that the fact that Yaesu stopped fitting idiot diodes caused the demise of their rig! 
Andy
MM0FMF
In reply to MM0FMF:
Funny you should say that, Andy…!
73
Brian G8ADD
In reply to G8ADD:
I aint the sharpest tool in the box, but let`s face it - red to red & black to black 
even the proles on the generation game could get that right.
In reply to G1INK:
In my case the stupid thing was not so much getting the colours wrong, but trying to get them right whilst blinded…not to mention a frantic haste to get back into an Es opening to Spain!
I didn’t know you were a fan of the Generation Game!
73
Brian G8ADD
In reply to G8ADD:
"I didn’t know you were a fan of the Generation Game! "
Ey up Brian, they don`t make em like that any more hi!
That was quality entertainment unlike the garbage they charge us to watch these days. Bring back the cuddly toy - thats what I say !
73
ps - sorry to Mike for straying off topic.
In reply to LA5SAA:
I am not much of a CW op, but I have both rigs and I can tell you the relay noise on the 706MKIIG is quite loud and disturbing to me. Also, the receive current drain on the 706 is much greater then the 817…
Gerd was absolutely right. Actually I find full break in operation on the 706 almost impossible unless there is a lot of noise in the room as the clicking of the 706 relays really sets me off.
With either rig I would suggest picking up the narrowest CW filter.
Now I also have a K3, and I can tell you the K3 is dead silent when it comes to relay noise…and a QRP K3 kit with no options is close to the price of a Icom 7000, the replacement of the 706…
Of course the K3 is much larger.
The 7000 also has 2m and 440 and a voice/cw memory keyer from what I understand…it may also have silent relays.
73,
Tom
In reply to N2YTF:
Hi again. Thanks for a lot of interesting info.
To Tom and others: If the relais in FT-817 is more calm than the one in the IC-706, I will go for the 817. I work 90% CW, but I never used full BK - and did not miss it either ;-).
By the way, I am quite happy with the IC-706, but it’s a power eater, as you know, and even on QRP a “big” battery will be required. Saving quite a lot of weight and still having the same operating time like with a 706 set-up is quite important for me.
Thanks again
73
Mike