[Exotics] RA6790GM-23

[exotics@mailman.qth.net]

Here's an up dated list to the one I sent yesterday. Corrections and=20
additions.........
Thanks to those who sent me what information they had and some further=20
contacts.......
Besides the (old) basic manual on the R-2174( ) P /URR I also have the=20
Racal factory service course manual from 1980 when I went to learn all=20
that was to be learned about the R-2174.............

RACAL RA6790GM-23
There is some control function but not complete response. I'm using the=20
test procedures from the R-2174 (P )/ URR manual so I don't know if it is=20
all the same. I haven't been able to find any documentation on this=20
receiver as yet.

--A1 LPF  08385  ?  same as R-2174

--A2 1st Mixer  09635 REV C   -  08386 in R-2174

--A3 2nd Mixer  08191 REV B  -  same as R-2174

--A4 IF/AF                       -  08465  in R-2174
        A4A1 IF Filters  4100506-501 REV E
        A4A2 IF/??        4100505-501 REV B
        A4A3 IF DET     4100568-501

 The A4 PCB is broken down into 3 separate PBCA's.=20
 A4A1 has the three XTAL Filters with 350 Hz, 750HZ, and 1.4KHz BP.=20
 A4A2 looks like switching and amps.
 A4A3 is in a shielded container and looks like the detector.=20
 All three PCBA's fit into the same area as a regular A4 PCB.

--A5 ISB                                                     -  08390-2 in =

R-2174
        A5A1 Looks like a data interface  4100369-501 REV A
             A5A2 ???                                      4100215-501 REV A

 In the area where the ISB A5 PCB would go is two PCB's ID'ed as A5A1 and=20
A5A2.=20
 These are some sort of data interface.

--A6      totally different from the R-2174
        A6A1  ACSII Interface  08391 in R-2174
A6A2  Microprocessor  08392 in R-2174
=20
        A6A1 ACSII Interface            Not installed
        A6A2 Microprocessor (Z80)  4100030

--A7 1st LO/SYNTH   09134  -  08361 in R-2174

--A8 2nd LO/BFO  096?? (numbers obscured/unreadable)  -  08387 in R-2174=20

--A9 didn't check yet
        A9A1 RCVR Xtrol Assy  -  08388 in R-2174
        A9A2 LCD Lamp Bd Assy  -  08946 in R2174

--A10 didn't check yet
        A10A1 P/S Assy  -  08389 in R-2174
        A10A2 20V Reg Assy  -  08593 in R-2174

There is line audio/no phone audio. No detected signal at the audio. No=20
signal indication on LCD.

Tonight I will check and compare the signal routes against the R-2174=20
manual and see if I can get some signal thru the receiver. Didn't get to=20
it???.

RICH  @B> }