On Mar 12, 10:11*pm, Bruce in alaska wrote:
In article
,





*terry wrote:
We have a non working Raytheon GL-9 small boat radar; probably 10 to
20 years old?

Investigations seem to indicate that the receiver section of the
printed circuit board of the mast mounted scanner, transmitter
receiver unit is defective. It appears that there is no *noise reading
at TP5 (test point) on the receiver/modulator PCB CNM179 printed
circuit board. The complete mast unit is numbered # M52559.

Other functions (e.g. the controls of display unit) seem to be OK.

Some of the parts seem to be made by JRC (Japan radio Co.).

We were able to download the user/installation manual but not a
deailed circuit diagram and test readings.

Anybody have any advice about the possibility of having the mast unit
repaired, hopefully *somewhere in eastern Canada.

Any advice appreciated.

Are you sure it is the Receiver/Modulator board, and not the Xband
LNA/DownConverter that feeds it? *The Test Point, you mention above is
the Baseband video Output of the whole Receiver, and only means that the
whole receiver "Could" be dead. When you turn the Gain control Full Up,
and the Sea Clutter Full Off, do you get sparkles on the Display? Are
you reading this with a VOM, or looking at this Test Point with an "O"
Scope?

--
Bruce in alaska
add path after fast to reply- Hide quoted text -

- Show quoted text -

Oh yes by the way we had gain at max and sea clutter etc. at minimum
as specified. Right now we have the unit on the dining room table with
the output magnetron unplugged for safety. Operating from a portable
12 volt lead acid battery of suitable capacity.
Terry and Alfred
PS. Hi Z Scope good to 200 megs connected to TP5.