wrong pic shown in radio installation manual pages?

[WRMorrison]

This may be difficult to follow, but I'll do my best...

Drawing SC-B-28678 shows the power cord connections for the mounting MT-297. While the drawing doesn't specify which vehicle installation it's for, I believe it's for vehicles other than the M38 (the M38 obviously used this mounting, but I believe it was wired up differently).

I've clipped the image and rotated it to depict how it would look if you were looking at the front of the mount with it upside down. The way that they have the power cord, it would exit from the right side of the mount. But, this would mean that the cord would be on the left side of the vehicle since the MT-297 would be turned around when mounted on the FT-285 mount in the vehicle.. This wouldn't match up with the cable assembly (G758-5701808) mounted on the right side of the M38.

The cable on my MT-297 comes in on the left side (shown right, upside down), and would route the cable on the right side of the M38, which should be correct.

The cable that was originally in my MT-297 was pretty long, and had battery terminal ends on it; no plug. I found a NOS cable assembly (G758-5701808 mentioned above) on eBay, and I'm trying to install it. I guess I'll install it the same way as my existing cable.

-Rich





^ I forgot to mention that in this pic of my mount, I have already removed the positive lead from the lug and it's sitting off to the side.

[wesk]

This may be difficult to follow, but I'll do my best...
Drawing SC-B-28678 shows the power cord connections for the mounting MT-297. While the drawing doesn't specify which vehicle installation it's for, I believe it's for vehicles other than the M38 (the M38 obviously used this mounting, but I believe it was wired up differently).

Any time you try to start a conversation about a component drawing number it will be extremely difficult to get any folks to accurately follow your thoughts.

Drawing SC-B-28678 is strictly a component drawing of a component used in several different systems. The determination if this drawing applies to your system, mounted in an M38 can only be made from the main drawing for your system, mounted in an M38. It is in that drawing that component drawings are posted if they apply to that system.

To properly introduce this new topic the opening sentence should say: I have system AN/-XXX-X installed in a M38 per Army drawing SC-X-XXXXX which references component drawing SC-X-XXXXX for power cord connections to MT-297.

Also keep in mind that component drawings are meant for use by trained Army radio technicians and often apply to several different installations which would easily be discerned by a trained technician experienced with all the different systems.

[WRMorrison]

At any rate, I installed my new cable as shown above in red/green and it works (mount is receiving power and distributing it to the sets). I haven't actually gotten the radios to work yet, but I'm working on it.

-Rich

[wesk]

At any rate I'll go ahead and display the info you left off your post for others to understand your dilema.

AN/GRC-7

Also I believe you must not have noticed the drawing 28678 notation just below the Illustration pointing out that you are looking at the bottom view of the mount tray.

[WRMorrison]

I understood the note at the bottom, but rotating the pic was a lot easier than rotating the 50# mount on my desk... Also, "Front - Underside exposed" was a bit misleading (at least, to me). In my mind, the "front" is the side with the locking levers.

And yes, AN/GRC-7 in my case.

-Rich

[wesk]

Also, "Front - Underside exposed" was a bit misleading (at least, to me).

I am sure an Army radioman would have known the illustration was upside down.

I was Air Force and we were able to figure those out!