[R-390] RE: Field Changes

[Laird Tom N]

>From the WC9M archives:

Hope this helps,

Tom Laird WC9M
Moline, IL.

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The manual I have lists the field changes and shows some information and schematics. It does NOT contain the field change bulletins and is not a step by step guide. Most of the changes are quite simple and should pose no problem to a proficient tech. Others will be of no interest as they pertain to "convenience" changes made to shipboard receivers.

 CHANGE     AUTHORIZATION      APPLICABILITY      IDENTIFICATION

 1             EIB 526          all          Lead connected between
                                             pins 2 and 7 of tube socket XV603

 2             EIB 542     shipboard only    Two soldered jumper leads on TB-101

 3            EIB 702      shipboard only    "AN" type connectors for            	                                          terminating audio and AC power  	                                          cables on rear panel

 4        EIB 655 + others  shipboard only   Diode load test jack located on  	                                          front panel

 5           EIB 664      shipboard only     Shorting plug connected to J104 on  	                                          rear panel

 6           EIB 702      shipboard only     Rectifier tubes V801 and V802 removed	                                          

 7           EIMB   shipboard installations  Decals located on VFO in supplementary radio
                       see EIB-911           assembly and RF amp-spaces only lifier chassis	                                          "Modified by FC7"

 8          EIMB   Selected ships only       Elapsed time indicator mounted on front panel


That's the info on identifying the field changes. Most are self explanatory. FC2 modifies the attenuator pad on the line output side to match a 450 ohm load. FC5 allows use of the whip antenna connector with coax cable. A shorting plug is iserted in J104 that grounds the J107 side of the connector. Then cables to J105 and J106 are swapped. I have no idea what FC7 does! Roger N1RJ