Re: B&G Sonic Speed failure
Looks like you found the document: https://amelyachtowners.groups.io/g/main/files/B%20&%20G%20Sonic%20Speed%20Information/SonicSpeedTroubleshooting.pdf
The red led not working means that somewhere in the "loop" there
is a problem: (transmitter on Sonic speed board, transmit sensor,
ultrasonic waves through the water, receive sensor, phased lock
loop, Automatic Gain Control amplifier)
I guess you measured the internal power supply already, but did you measure AGC, is it between 1.8 and 2.5V?
Most likely causes:
* something in the water path between the 2 crystals ( and that includes fouling and loose rubber caps although unlikely since your resistor values are good)
* defecitive board, test by swapping with another one.
I have several Sonic speed boards if you need one to test.
Hope this is helpfull in some way.
sv Malaka Queen
SM2k #348 @ Newry Northern Ireland
Op 10-10-2021 om 10:30 schreef David Crisp: