These are the common options. Every unit had a battery except for the 500 w/ opt 2. I never understood why IFR sold batteries with opt 2 (high stability TCXO) for the battery would time out in 10 minutes and the osc would not be stable until approximately 15 minutes. Usually, after 3 cycles of the battery, it is time to get it plugged back in. The std TCXO's (most common) are generally on time at startup or at least in the ballpark.

The software is basically like this:  "7.1-XX" or 6.1-XX" etc...The "XX" would reference:

VINTAGE

How old is my set?

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. I will not give exact dates until I can verify them. 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 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 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).

In my honest opinion, if you own a 1200 or 500, you 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.

All of the 1200S (w/ spectrum) had a Duplex/tracker module past SN 5237. This means that the duplex gen output has 2 levels, -40dbm and -15dbm instead of the -50dbm. The newer duplex tracker has an almost immediate response time on the offsets. Last but not least, it has the tracker hardware regardless of the unit having opt 12 or not. Many distributors got wise and installed an RF cable from the duplex tracker to the RF analyzer module, copied the software to an eprom burner from an opt 12 unit and WHAMMO! opt 12 is now installed in the unit. Only thing is that the duplex high is inop because of the amp that is lacking which sits next to the scope.... BIG DEAL! It only gives an extra 8-10 db of gain. Most people could care less. The real kicker is that the Super S has all the options, if you only knew the secret code you could turn them on! Another important point to ponder is the 500 to 500A difference and "can I upgrade?". Basically the 500A has the distortion meter, Sinad meter, and power meters which the 500 does not have. A customer called me about upgrading or modifying his 500 to a 500A. I told him to forget it. Believe me I will do the mod if it is possible. I have extended the range on a straight 500 so it will read FM 50khz range like the 500A, but if you want these added features, just buy the 500A and back off of the 500. I think I have blabbed on enough and with over 140 mods that I know about, I could make this little article stretch into a novel with chapters and all. Better yet, if you have a question, just email me and I'll do my best to help you out.

QUICK CAL

High Loop Circuit            Power Supply            Frequency Standard

High Loop Calibration

This is a quick check to see if your unit will stay phase-locked. A more detailed procedure is done upon thorough check of the modules.

1. Set unit to 000.0000MHZ and adjust R60 until you are able to just barely lock up the unit. Then adjust slightly more then STOP.
2. Set unit to 999.9999MHZ and adjust R61 in the same way as step 1.
3. Hi/Lo filter R65 is the next adjustment. The filter is located at the bottom of the unit, right behind the front panel, with 2 rf lines and a brown wire attached to it. There is also a number on this filter. Write the number down. This is the crossover frequency and you need to subtract 90 from this number.
4. Attach a dvm voltmeter to the brown wire on the Hi/Lo filter and set freq to 400MHZ. The voltmeter should read approximately -10 volts.
5. Slowly increase frequency until your voltmeter reads +10 volts.
6. Is the reading +/- 10 mhz from the number that you wrote down after subtracting 90 from it? If not, start this process over and adjust R65 until it is.
7. Gain adjustment R45. Set the unit to 50.04 MHZ and inject a 50 mhz signal at -30db.
8. Set the IFR spectrum analyzer to 10Khz/div.
9. Adjust R45 so the hump between the red lines is 4 to 8db. If the gain is set to high, oscillations will occur.
10. R32 500khz null adjustment. This is not important for phase lock, but it should be adjusted if you see a 500khz dispersion off of the carrier. To eliminate this, adjust accordingly while monitoring the output with a spectrum analyzer.

SPECIFICATIONS

             RF SIGNAL GENERATOR

250 KHZ to 999 MHZ in 100 hz increments.

             +- 5 Hz + Master Oscillator

             <100 Hz RMS (300 hz to 3 khz Bandwidth)

             2nd Harmonic < -30 dbc
             3nd Harmonic < -45 dbc

             -127 dbm to -20 dbm (10 db steps with 11 db
             range vernier) into 50 ohms.

             +- 2.5 db up to 800 MHZ
             +- 3 db from 800 to 999 MHZ

             +- 10 khz (when not in locked position)

             Deviation Range:
             0 to 50 Khz (with 1 khz tone).

             % AM Range:
             0 to 90% (with 1 khz tone).

             Frequency Response:
                          FM: 2 hz to 30 hz (DC when in var gen).
                          AM: 10 hz to 10 khz (30% maximum modulation above 5 khz).

             Modulation Sensitivity:
                          FM: .1 VRMS/Khz (-0 to +30%).
                          AM: .01 VRMS/Khz (-0 to +30%).

             Input Impedance:
                          10 Khz Ohms nominal.

             Duplex Generator

             RECEIVE/MONITOR

             POWER METER

             FREQUENCY ERROR METER

             MODULATION METER

             Ranges:                           2 KHZ, 6 KHZ, 20 KHZ, 60 KHZ full scale

             Ranges:                           60%, 200% full scale

             SINAD/DISTORTION METER

             MORE TO COME