The AM Forum

Does anyone know of a reference that shows date of manufacture [year only is okay] of Johnson and Hammarlund equipment if the serial number is known??  I know the info is available for Collins.

Have been looking for some time and so far, no joy.

Thanks.

http://www.hammarlund.info/home.html

I haven't seen any serial list or dating info for Hammarlund.  Above is a link to probably the best Hammarlund site.  You will have to noodle around to find everything there.  Much of the info is in individual files.

I can't think of any manufacturer off the top of my head, past or present, that correlated manufacture production date to the serial number other then Kenwood. When the original equipment and documentation left the factory together, sometimes you could roughly determine date of manufacture from the schematic title box or manual date if one was shown.

Although it is not a ham radio equipment manufacturer, Hewlett Packard did correlate the manufacturing date in their serial number for many years.  I do not know what their current serial number strategy is, but it the 60s through the late 90s they had a ten character serial number that was significant.  

It consisted of a two digit year code, two digit week code, one letter country of manufacture, then a five digit sequence number, which was reset to 00001 at the beginning of each manufacturing week.  Since we hams like to use lots of vintage HP equipment, I thought it might be of interest to share the scheme.

An example serial might be  1820A10234  Add 60 to the first two digits to get year of manufacture.  In this case 18+60= 78, so the unit in question was manufactured during the 20th week of 1978.  The fifth character "A" indicates the unit was manufactured in the USA, and it was the 10234th unit manufactured that week. My apologies for the apparent thread hijack, I just thought this might be helpful to some folks with their vintage HP instruments.

You are right.  I just looked and it is not on the site now.  Rod, K0DAS, published it a few years back.  I thought I got it off of the CCA site; now aI'm wondering where I got it.  If I can get it into a format that will e-mail, will send you a copy.

Thanks to all for information.  I have been on the Hammarlund site and have not found it.  May be someplace I have not looked yet.

Mitch,
There is NO LIST for Hammarlunds.

I merely provided the link to the Hammarlund Historian site as an interesting reference.

Henry Rodgers' site,

http://www.radioblvd.com/WWII-PostWar%20Hamgear.htm

Has a few pages devoted to early Hammy gear, with some S/N's vs year.

73DG

I have a Collins 75a3 that has no serial number.  What is this indicative of? 
The space where that serial number should be is blank.

Some of my collins radios have S/N Stickers.......perhaps your sticker came unstuck

Some of the A Line stuff had a number stamped on the rear apron, did you check there? The A-1 had a small Collins plate attached there with S/N. Can't recall the -2 or -3, been too long. The A-4 has the number silkscreen on the rear panel. I've attached a photo of one I just sold. The newer S-Line gear has those foil labels and as Steve mentioned, sometimes they are gone or the ink has been wiped clean by someone washing the rig.

Collins equipment serial numbers aren't kept per say on the CCA list or anywhere particular. Rod Blocksome did a survey on 75A-4 production some years back with respect to year/SN which is interesting, and I think there have been a few other similar efforts. Mainly they provide info on where to check (under the cal crystal, etc) to get an idea of production date. And a couple of other sources have actual lists for specific items, like the KW-1 transmitter registry kept by Uncle Ed/WA3PUN decades ago is now kept up by Bob/W0YVA. We host the 30K site here but it has been down for a while for maintenance. At one time there was a list for the Johnson Viking KW amplifier but no idea who, if anyone, is keeping it now.

Dennis has provided one of the best sites online for information on a variety of gear. Though there is no specific page for serial numbers, if you read through the articles you will often find the number blocks with estimated production dates listed near the end. He has a lot of great info on the Hammarlund Super Pros.

Dennis?? web site??

Yup.  :)

for those interested in the Blocksome surveys:


http://www.collinsradio.org/cca-collins-technical-archives/rod-blocksomes-collins-surveys/

Collins info per K0DAS.  Hope it is readable; had to convert it to Word more or less.