[Collins] R-388

[telegrapher at att.net]

Here's some info i dug out of the R-388 manual i obtained from Robert 
Downs last week for review by all who have assisted with comments on my 
questions.  Additional info at the bottom by Gerald of Collins fame and 
fortune.

As you can see i've kind of left a couple of questions unanswered.

To back up, i have a 2nd R-388 manual that has a couple of change 
notices in it.

TM 11-854/T.O. 31R1-2URR-121 C2 says:

The receivers procured on Order 25635-Phila-53 do not have a speaker 
jack on the front panel.

Then a following note says:

On Order NO. 25635-Phila-53 the break-in Off-On switch replaces the 
speaker jack on the front panel.

Another page more towards the front of the manual states:
On order No. 37003-PC-62, Radio Receiver R-388/URR is provided with an 
antenna protection circuit (Fig. 11.1)

The manual i have shows the circuit that is a relay driven by a 2N697 
transistor.  There are other circuit component changes as well.

got to digging thru the two 388 manuals to see where i had seen this 
info.  SO now at least i can partially date the receiver.  Just don't 
know what set of serial numbers may have been affected by the 
37003-PC-62 or were included in the 25635-Phila-53 order number.

My J-3 has a break-in switch in place of the speaker jack that 
previously was in that hole.  It also appears to have the relay for 
antenna protection mounted under the chassis at the rear near the 
antenna connector.

Does anyone have any data, kind of like the 390 group as to how many 
different 51J types were built, contract dates and serial number ranges? 
  Would it be correct in saying that these were all Collins built radios?

I have a Sams Photofact folder for the 51J-3 but it shows nothing other 
than component placement, alignment data and schematic basically.  The 
date on it is 12-54.  Both the speaker and headphone jacks are in place.

Fun isn't it when some dummy asks a question like this!  Any and all 
input is really appreciated.  Maybe i can put something together and put 
it on the list sometime in the future as i do not have a personal web 
page arrangement.

Larry
W0OGH



Gerald wrote:

> On Mon, 2005-08-08 at 19:35 -0700, telegrapher at att.net wrote:
> 
>>Interesting situation.
>>
>>Thanks
>>
>>Larry
>>W0OGH
> 
> If there are other differences, they aren't great. Some have a standby
> switch in place of the front panel headphone jack. I haven't traced that
> circuit through mine or detected how it works yet.
> 
> Mine has a gray panel and a round emblem where the name tag should be,
> yet inside there's a pencil note showing an early serial number R388.
> 
> It also has a product detector mod done very neatly and the AGC mod made
> very tentatively. Both work well.
>