So you have an IFR 1200, 1200A or 1200S? Do you want to know how old or more about it?
Many people want to learn more about the history of the technology they are using. The IFR 500’s and 1200’s have a unique and fun history. Almost all of the history is trackable via the serial number. I will mention several serial numbers in this section and although I should be pretty accurate, I have not cross-referenced this with IFR. As I recall, IFR would select a few units for example SN 5010 to have an upgrade yet SN 5011 – 5022 would not (???). In other words, not everything was uniform.
Here’s a little history of the IFR 500’s & 1200’s. What you need to remember is that the RF block diagrams for the 1200 and 500 are identical, hence, many modules are interchangeable between the 2 units. The IFR am/fm-1200 was in production for approximately 20 years, and an assortment of upgrades were made during that time. The basic “keel” was designed by Harold Silem who died shortly after early production. In the Early 80’s IFR launched the basic 500 and the basic 1200 with Spectrum Analyzer; both with serial numbers starting from (SN)1000. The IFR am/fm-1200A non-Spectrum box started at SN 1000 also. I would guess that there are 25,000 of these units on the planet (possibly more).
If you own a 1200 or 500, you may have the best product IFR has ever produced. They are reliable, very well-engineered and for the most part, almost all failures can be repaired. My only fear is that I am going to have a CRT failure, even though they are durable, and very few failures occur with the CRT (not the scope modules), getting a replacement is because of price and availability. Other than that either box is awesome! People ask me “were there any bad years?” and the answer is NO! Every 500 or 1200 was at the least “good”. Now you might want to take into consideration that they had 20 years to make improvements. So, if you own a 500 with an SN of 5000 or above, or a 1200S with an SN of 10000 or above, it should have had all the bugs or minor flaws eliminated and you have a field tested box for well over 10 years. Obviously, I would prefer to have a 1200 Super S. If you are fortunate to find one at a decent price, BUY IT!. Otherwise, we have to deal with the older units which are great but may have some minor hitches.
On this site you might find the term “Blue PC boards”. These boards were a nightmare. Any excess heat can destroy a pad and possibly ruin the entire board. The very early sets had almost all blue fiberglass boards in them especially the SN 1000 & 2000’s. I was able to pick up an old junk 1200 of this vintage with all of the blue pc boards in top shape. I now use it practically all the time. My point here is, BE CAREFUL WHEN WORKING ON THESE BOARDS!, they are easily damaged. As far as I know the older power supply (SN 4490 and below) are no longer being serviced at the factory. They will only sell you a new style. I will still work on these old power supplies, but they creat noise and cause a 45khz spike noticeable on the Spectrum Analyzer. The new power supplies addressed this snag. A new power supply is very $$$ and the old ones are still okay as long as all the modifications are done on them.