Collins 32V-2 FM Adapter

[Mike/W8BAC]

As the new sun spot cycle kicks off I have turned my attention back to my 32V-2 repair project. I disassembled the front panel (no small project for me) a few years ago to replace the yellowed MHz and KHz dials and after finally finding the parts to finish (thanks Skip K7YOO) I'm putting it back together.

I picked up a Collins FM adapter a long time ago and I want to use it now. The PTO plug is removed (unplugged) and the FM adapter goes inbetween the plug and PTO. A two wire cord is wired to someplace on the 32V-2 but I need information on this. Also, a switch was installed on some of these adapters to switch between FM and AM. My adapter does not have the switch, only the labeled hole and a plug. I think I need the switch.

I'm looking for a schematic and any other operating information regarding this adapter. I'm hoping one of you might have some information. Thanks!

Mike

[WA5VGO]

Emailed you what I think you are looking for.

73,
Darrell, WA5VGO

[Mike/W8BAC]

  Thank You Darrell!

I have been looking for information on this for a long time. I'll clean up and re size the scan so it can be posted here.

Collins must have made a few different versions of this adapter. My box has a silk screened hole for the AM/FM switch but the hole has a chromed plug in it and no evidence a switch was ever mounted plus mine has only one cable exiting the box, an audio cable (I think). Otherwise, the circuit is similar and it shouldn't be hard to figure out and make mine play like the original.

A lot of work to play 10 meter FM but it might be fun. It's worth it to keep this box from ending up in the land fill. Thanks again.

Mike

[Todd, KA1KAQ]

Probably duplication of what Darrell already sent, but since it's currently on the bench for the condenser replacement, I snapped a few quick shots of mine along with the original large drawing which I don't think the scanner here will handle well. Shots of the adapter inside the rig with cabling locations, too. 

[Todd, KA1KAQ]

And the drawings, which seem to hold their clarity when zooming in. If there's anything else you need while I've got the beast out of its cage Mike, just let me know.

[Mike/W8BAC]

Thanks Todd,

As described above, I wonder why my plug in is so different? I'll post more when I have time to investigate. How dose yours sound on the air? Are they worth bothering with?

Mike

[Todd, KA1KAQ]

Boy, I tell ya Mike - the knowledge and info on the FM side of things is scarce at best. I'd defer to Skip, he forgets more in a night than I'll ever know about Collins gear.

If I had to guess, I'd say yours is missing a switch because it was meant to be wired into a circuit that provided for switching elsewhere, from a front panel control as an example. It may have been a later model as mine with the internal switch even appears to have a few changes/updates to the original drawing. What makes the 'later model' issue hard to believe is that Collins moved away from NBFM pretty quickly in the early 50s. You might recall that the two KW-1 prototypes had a slightly different mode switch with positions for AM, CW, and NBFM. By the time they went into production, the NBFM feature had been dumped. So having a later model adapter with the switch omitted to enable front panel switching seems thin, at best. I've never seen a 32V of any model with anything other than the typical CW-CAL-PH mode switch.

I've had mine on the air once back in the 90s, but the other station wasn't set up to copy FM and didn't have a clue about slope tuning, so the reports were bad as expected. IMO, it's well worth getting yours set up to play around with when things pick up on 10.

If you get a chance, would you mind posting a shot or two of your adapter? I'm wondering if it's a 148B-* model or something else. Mine is a B-1. If it's a different model entirely (made for other manufacturer's equipment for example), that could explain a lot.

[Mike/W8BAC]

I was just wondering out loud Todd. I have the same question, if the switch is missing than the mode would have to be switched someplace. When I first got it I figured everything was done between the input and output jacks and the single wire hanging from the grommet was a switch. Later, the question of modulation insertion came to me and I noticed the wire was shielded.

It's a mysterious piece. It has the Collins decal but it is in bad shape (the decal) and no model number is available.

I had my luggage stolen on a flight from Detroit to Rio De Janerio in February. Yup, my camera was in it and I haven't found a replacement yet so no picture for a while. Thanks for the help.

Mike