David,
1) Do you have a copy of the service manual? That's
pretty much essential for what you are trying to do.
2) Given that the PLL, as noted below, seems to lock with the
original front panel, that could indicate that the unlock signal
(UL) on pin 18 of J4002 on the panel, sent from pin 33 of J1008 on
the main board, is not getting through.
3) The PLL adjustments are covered on pages 16 & 17 of the
service manual, and the circuit is very briefly described on page
12.
Good luck,
Robin, G8DQX
On 14/12/2024 14:47, David via
groups.io wrote:
toggle quoted message
Show quoted text
I have just replaced the front panel PCB on a friends FT817ND
(Lot82).
I had called Yaesu UK and the told me that the board was
compatible (CS1909409).
?
It was a straightforward replacement except for desoldering
the AF-SQL/RF pot.?
I had to snip the pins of the old connector to remove it but
I do not believe that I damaged the pot and it seems to test ok.
On powering up the LCD screen display blinks and there is no
audio.? I am able to change frequency, mode, etc and all buttons
and dials seem to work.? However, the ?AF-SQL/RF pot does
nothing.
Searching the web I am told that this is clasical of the PLL
not locking.
?
I plugged in the original board and this seems to lock (PLL
wise).? I have no screen (reason for replacement) but using
'FT817 Commander' software I can 'see' the frequency, mode etc
and all seems to be well on the receive front.? Audio is
working.? The radio shuts down when I try to transmit but this
may be RF getting in somewhere it shouldn't (the whole radio is
out of its container).
?
I obtained all the parameters from the service menu on the
original board and programmed it into the new one hoping that
this was the answer.? No difference.
I presumed that I would have to do a full alignment and I
started this.? I did not get very far:-
?
Reference Frequency Adjustment - No problem - freq and
voltage fine.
?
VCO VCV Adjustment - voltage wrong and not adjustable as PLL
not locked.
?
PLL "Unlock" Display alert - unplugging the Ref Unit the
voltage is 5mV on J2002 (pin1) but no change in the display.?
The voltage is 25mV with the unit replaced.
?
2nd Local Adjustment - No problem
?
3rd Local Adjustment - not possible as no transmit
?
And thats as far as I got.
?
Am I missing something?? Is this board really compatible?
Is there something specific that I need to alter (pot,menu
item etc) to allow the PLL to lock.
?
Any help gratefully received. Thanks.
?
Best wishes,
David G7IBO
?
