Hi Folks,
I purchased an 8840A/AF. When I turn it on it cycles on and off with the relay clicking. First thing I did was to check the voltage rails and they all seem ok with the exception of the
-8.2Volt rail. It reads 5.2volts. I ended up checking everything from the Bridge to the test points in that section and all was good. Two mysterious discoveries were made..
R601 is supposed to be 560 ohms and it had a factory installed 1 kilohm resistor? Next I discovered I cannot find anywhere CR617 (8.2v zener)
![Huh? ???](https://www.eevblog.com/forum/Smileys/default/huh.gif)
?? I have searched Hi and low and it does not seem to be in the circuit, in fact it is not even listed on the parts location?
![Huh? ???](https://www.eevblog.com/forum/Smileys/default/huh.gif)
?
ANY Ideas?
I am also trying to figure where this -8.2 volt rail goes and where it is used.
Any help would be appreciated.
I have verified all the capacitors, zener diodes, (except CR617), replaced the regulators, resistors in the section of TP603,604,605,606.
I realize most was not necessary because the parts were ok.
Help Help ( the manual can be found all over the net , it includes schematics)
Garry
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