Aug 262009

Radio Receiver & Transmitter BC-1335 (SCR-619)
The BC-1335 is an FM transceiver used in late World War 2, covering 27.0 through 38.9 MHz in 120 crystal-controlled steps. It is an improved successor to the similar BC-659 radio. The transceiver operates from either 6VDC or 12VDC, supplied from an external source such as a battery pack.

I purchased this set from another collector in August, 2009. My set included a DY-44 dynamotor, which allows the set to be powered fomr a 24VDC source. I’ve traded the J-72/GR terminal box (shown below) for a CH-291 battery box (not yet shown here). Rather than using original BB-54 wet cells, I installed six 6V gel cells (in parallel) in the box.

The set can use either an antenna whip which attaches to a swivel mount on the back of the transceiver, or a remote whip antenna. I have the J-72/GR matching unit which allows this radio to be used with an AB-15 antenna mast base, but I hope to get my hands on the correct built-in whip.

The SCR-619 set could be vehicle-mounted or carried on a special pack frame. In vehicular installations, the set would include Battery Charger PE-219, two each Battery Box CH-291, Mounting FT-506, and Terminal Box J-72/GR.

I hope to obtain the necessary accessories for a comple portable set. I’m missing the whip antenna used for man-portable use, but I can still use the set at a fixed location with standard AB-22/23/24 whip elements which screw into the mount on the rear of the transceiver. I’m also missing the rare FT-505 pack frame mount. I was able to borrow one of the few known ones for a while to photograph it, and I created a solid model of it in case I ever find the gumption to have replicas manufactured.


Schematic Diagram

Here is the BC-1335 schematic diagram from my April, 1945 printing of TM 11-879, scanned at 600 DPI, with and without some added annotations:

BC-1335-schematic.pdf (532k bytes)
BC-1335-schematic-annotated.pdf (771k bytes)
Here are some scanned diagrams from the manual:

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An overview of the kit that I bought. Not shown here are an AB-15 mast base and a set of whip elements which also came with the set.

The exterior of the BC-1335. The last picture shows the antenna mount on the rear of the set, with the top cover removed.

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Inside the top of the BC-1335. The unit includes a magic eye tube and test probe which can be used to realign the set without test equipment after changing crystals. Running spares for many components are also stowed inside. I think that the magic eye tube circuit uses a bias reference cell, which is probably quite dead in my set. Once I figure out where it is, I’ll see if I can fashion a suitable replacement.

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Inside the bottom of the BC-1335.

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Terminal Box J-72/GR.

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Dynamotor DY-44. I’m not sure how this unit is used with the set yet. I think that it would be connected to 24V power and plugged into the BC-1335’s 6V/12V power input plug, but I’m not sure yet.

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An almost-complete set of crystals for the BC-1335.

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The top cover of the BC-1335 includes a complete schematic, basic operating instructions, and a place to store extra crystals.

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When I tried powering up the BC-1335, the vibrator wouldn’t start. The spare vibrator didn’t work, either. Noticing that both vibrators had been opened before, I pried one open to work on the contacts. I had to sand the contacts with sandpaper to get them to make contact again. I don’t know how long they’ll last, but at least I have the set working for now.

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  14 Responses to “Radio Receiver & Transmitter BC-1335 (SCR-619)”

  1. Aren’t these sets great? I have a BC-1335 that is different from any other I have seen. In the spot where the spare vibrator usually is, this one has a toggle switch with 2 positions, marked ‘vibrator’ and ‘BA-70.’ The BA-70 goes in the battery box that the BC-1335 clips on to, but the power connector on the BC-1335 has 3 conductors: negative, + 6V and +12 V, whereas the battery box connector has, I believe, 5 conductors. Does this make sense to you?

    • I’ve just learned about the larger CY-740/PRC dry battery box (vs. the original smaller CH-191 wet cell box that I have), after getting a post-WW2 MT-702/U packboard mount that’s made to hold it and a BC-1335. I was told that the newer BC-1335 version that worked with the dry battery box had another connector added to the front panel for the battery input, though. A Google search turned up this page that shows the new connector at the upper right corner of the front panel. Does your “different” BC-1335 have the additional connector?

      • No, it does not. By the way, have you had success with the bias batteries? In case you are not aware, the bias batteries used back then were mercury. Nowadays, the button battery substitutes are alkaline, with reversed polarity. If you study the retainer clips, you will see that the alkaline cannot be used in the retainer, for they will not be in series. I had to remove the clip assembly and reverse the leads.

      • Also, the green eye will light without the bias cells in place, but I don’t know if tuning will be accurate.

        • I haven’t replaced the bias cells in my BC-1335. They’re only used as a reference voltage for calibrating the magic eye tube, and have no other effect on the radio’s operation. I just used a bench supply set to 0.4V as a reference in place of the bias cells while tuning up the radio on the bench.

      • I think I need new glasses! I took another look at that set, and there was the special connector for BA-70 use, in the upper right hand corner. By the way, I tuned the radio a week ago, and earlier today I bought a 6 volt auto battery and rewired my power cord to run the set off 6 volts. It powers up and there is the rushing noise in the earplugs, but now I have no side tone when I transmit. Frustation!

  2. I,ve got a minty n.o.s. PE-219 battery charger I’m willing to sell at a reasonable price (I haven’t got an idea of the value).

    Let me know if anybody is interested.

    Grtz Moos

  3. Hello! Nice site. About the vibrator problem: See here for the solution:
    (Sorry for the Duth language, I made this video for a friend in the Netherlands)
    73s, Luke AC5XP

  4. I just bought Serial # 2951 near mint inside; all the spares stolen but I have a near-full set of the case of crystals; I didn’t know they went with it until yesterday! I have a vib in the main socket of course, a BA-70 switch inside like Roland said but in place of the spare vib I have a 2 section electrolytic can octal-base capacitor marked C-84 A and B plugged in. Most interesting! Apparently they updated & modified them until they quit making them. I have the same 5 pin connector with Battery BA-70 stencil painted on under the connector on the upper right side as has been mentioned while the rest of the lettering is factory engraved…also seems an “update”. I don’t have that 5 pin connector to plug in but it did come with the 3 pin for the other one…got it from a ham radio swap meet so some ham did want to make it work apparently. What is the substitute for the old vib? I think I have all the tubes but all my holes are filled except for the spares. Bob Burchett WB6SLC

    • Congratulations on your new radio! I’m still using the original vibrator in mine. Once I woke it back up by sanding the contacts, it has continued working so far.

  5. Fine set! I have 150 n.o.s. FT-243 crystals for this set if interested

    • Are they still in the original CS-137 case? How much, shipped to Florida?

  6. All you vintage radio gents in 6-Land need to come by my Museum and check out this junque….it is free & open to the “electrical/ electronic enthusiasts” by just calling me first; typically M-F close to the end of the work day (it is at my shop where lives) and you can see a short video of it that is some 4 years out of date but still pretty relevant here:

    I have the BC set & crystal pack too but never got around to putting it on 10 meters since I have projects stacked up from what….20 years ago….still waiting for their time on the bench….this working for a living is not recommended….buncha crap I say. Bob Burchett WB6SLC

  7. How wonderful to read all these comments! I only saw two of these sets on ebay a few days ago and marveled at the complexity and achievement for design and construction circa 1942-1945. True precision exemplified. Ray, W8ISK