[Milsurplus] BC-603 Dyno.

[WA5CAB at cs.com]

Bob,

As the only markings on the DM-34 and DM-36 are on the dynamotor and nothing on the base, I'll assume you thought you had a DM-36 and therefore have a 24-28 VDC supply.  If that is the case, all that you need is some tinned buss wire and some solder.  You don't need any other parts.

This is the 2nd case of this I've heard of (DM-36 dynamotor on a base wired for 12 volts).  The other one was here just last year.  In 2001 I bought a batch (around 40) NOSB DM-36-C and -D from a guy who had stumbled across them somewhere.  Over the ensuing years, I sold most of them, but kept a few for service work and in case I sold a BC-603 or 683 and the buyer also needed it set up for 24 volts.  Last Fall, I was working on a customer's receiver and must have run it for half an hour while trying to figure out why the discriminator wouldn't tune across zero when for some reason I decided to check some voltages and discovered I had 24 instead of 12 volts across all of the series pairs of tubes.

So the short answer is that some depot screwed up.  And all you have to do is rewire the Jones plugs jumpers.  Fortunately going from 12 to 24 you'll remove more than you install.  And all components are the same in the two dynamotor units except the dynamotors proper and the plug jumpers.  If you don't have the wiring diagrams of the two dynamotors, let me know and when I get back to Houston Sunday night, I'll email them to you.

<hoopmonk at snet.net> wrote:

>A while back I purchased a BC-603 and a dynomotor separately. I recently tried to get it up and running and If I wasn't such a novice I probably would have noticed that them thar tubes was really a glowin! . After a lot of head scratching and a lot of studying the manual I discovered that what I had was a DM-36 24 volt dyno mounted on a DM-34 (12 volt) base. Why would anyone do that? It actually seemed to work "sort of" but I am thankful I didn"t run it very long as I didn't have a proper antenna. I don't know how much damage I did to the set if any at this point. Anyway, If anyone has any of the following in this order of preference that are excess to their needs please contact me off list.
>
>A DM-34 dyno complete or just the motor with leads intact.
>A DM-36 Base complete
>A DM-36 plug J801
>
>Thanks
>73
>
>Bob Weaver
>
>W1GTH
>