[amsat-bb] Re: FT817 service manual, repair or parts
hamoen at iae.nl
Fri Apr 25 12:47:22 PDT 2008
I had the same 2 yrs ago ... including smoke from within :-(
All the el.cap's in the 12V input line exploded.
They are rated only 16V or so, and there is NO protection at all
inside the 817 for wrong polarity or too high voltage.
As soon as you apply ~16V it's most likely damaged big time (!)
At first I hoped only the C's, then the 5V regulator, but it
turned out to be the main CPU that was dead. Felt also quite hot.
The main CPU is located at the front PCB. You hardly see it.
It tried here in the Netherlands at the local Yeasu, for a new
front PCB or new front, but they didnt want to help (or offer it
at the price of a brand new 817). Then I got help from Yaesu in the UK.
Very friendly, and the shipped it I believe for something like 50 dollars.
In any case much less as 500..600 for a new 817 !
On trick after that was to de-solder the old CPU and get the new one in.
And: I got an old part, so have only 2 colors for the display, and
I miss that 3rd bright nice color. Well, anything better as no 817.
(wife would NOT allow spending again 600$ due to stupid me applying
too much voltage to a new toy :-))
Hope this helps &
Hope your CPU is NOT dead.
ps1: I now have 2 diodes in the power supply cable to prevent wrong
ps2: I do not complain about the 817, everything comes at a price,
more safe/secure DC input design would have resulted in a higher price !
ps3: try a front from another HAM to trace down if you have the same issue.
ps4: I also had to remove a C in the HF Amp, also that one caused a short.
Managed to kill my 817 some time ago with a power spike from a dodgy power
supply. Found some burnt components and tracks on the main board next to the
ribbon cable leading to the front panel and LCD. This prevented the 12V from
reaching the front panel. Did a small mod to get the 12V around this burnt
track. Still no switch on from the 817. Then found another burnt component,
the 5V regulator next to the power switch on the front panel PCB. Temporary
replaced the 5v surface mount with a 7805 regulator, but still no joy.
Beginning to think that a lot more must have been damaged by the power spike.
Anyone out there got more of a service manual to try and track the fault?
Otherwise anyone got an 817 that has damage elsewhere from which I could try
and swop subparts / PCB to get mine working again?
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