Re: {Collins} KWM-2 help needed: S-Meter and others

On Jun 21, 2009, at 7:29 AM, Stefan Preiss wrote:...
just received my first Collins rig, a KWM2,


Good for you.. that will be a very fine radio and give many more years of enjoyable service.

4) V4 (6AZ8) is missing. Is there any replacement-type? This one is not
very common here.

There are a number of ways to locate substitute tubes. My favorite is to find the information about the tube you have at this website:

This site reports that a close or identical tube is:
Close or identical 	CV9857

I was not able to locate any other equivalent tube in a moderate search.

The best and most reliable source for Collins (and other) tubes here is Frank Krize. No doubt he has the 6AZ8, in addition to all the other tubes used in the KWM-2.

Krize Electronics
1373 Chapel Hill Rd.
Natchez MS 39120
 Telephone: 601-442-0973
Email:  k5svc@xxxxxxxxxxx

Frank Krize, K5SVC.  Frank is down in Natchez,
Mississippi . Frank has an ebay store but has all sorts of things and goodies in a big warehouse. He's A surplus dealer of long standing. Drop Frank at line at k5svc@xxxxxxxxxx or k5svc@xxxxxxxxxxx - I'm not sure which address is current.

Frank's store can be seen at

He lists on his eBay store

Here is my "master plan" to bring it back to life:...

3) Remove the tubes in the PA

The S-line transmitters have two RCA Phono jacks on the rear that connect the screen supply to the final tubes. These are for use with the 6 and 2 meter VHF external adapter. Normally they have a jumper inside the chassis for normal operation. The KWM-2 also has these jacks, labeled J-5 and J-6, PA DISABLE. You can disable the final operation by removing that jumper.

It is wise to NOT run the final tubes with screen voltage and no plate voltage (for instance by removing the high voltage rectifier). This can damage the tubes very quickly.

I suggest that you clean contacts of all relays carefully. (The preferred cleaner is Caig De-Oxit applied with stiff business card material. See for details on this world class product.) Cleaning the relays can avoid all sorts of odd symptoms and troubles that are hard to locate.


Roy Morgan
529 Cobb St.
Groton NY, 13073
Home: 607-898-3607
Cell: 301-928-7794

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