Question: What are the compatability issues and solutions for the 8566B spectrum analyzer? Answer: Metric/Inch Hardware 85660A serial number 2503A03431 and below has inch (English) hardware used to mount instrument covers/feet/handles to the front and rear frames of the 85660A RF section 85660A serial number 2516A03432 is the first instrument with metric hardware 85660B serial number 2511A01565 and below have inch hardware 85660B serial number 2516A01566 is first instrument with metric hardware 85662A IF-Display sections serial number 2403A09287 and below have inch hardware 85662A serial number 2517A09288 is the first instrument with metric hardware Color Change For dress panels, cabinets, handles, etc. Latest color began on the following serial numbers: 85660A s/n 2942A03716 shipped around 10-31-89 85660B s/n 2747A05729 shipped around 4-28-89 85662A s/n 2848A17467 shipped around 4-28-89 A5A2 Rotary Pulse Generator Replacement Changing from the old RPG (5060-0329) to the latest (0960-0684) in the 8566A/B requires changing A12. Also, the latest RPG has different physical dimensions and will not fit into the early A5A1 keyboard (filing the Keyboard is risky since traces are close to the material you must remove to install the latest RPG). See Service Note 8566A-26 or 8566B-05. You have two choices when dealing with an RPG failure in an older 8566A (prefix 2416A and below) or 8566B (prefix 2430A and below) 1.Change the lamp (Agilent p/n 2140-0016) in the failed RPG. 2.Install the new RPG (Agilent p/n 0960-0684) and the following additional assemblies: [see table 1] (besides the risk of filing away a trace, the early keyboards had contact problems) [see table 2] (if A10A6 PLL2 is 85660-60254 or prior) [see table 3] (if A10A6 PLL2 is 85660-60276) A10A6 PLL2 Phase Detector / A12 Front Panel Interface A problem was noticed where the instrument would not display a PLL2 UNLOCK message in frequency span 0 Hz. The A10A6 assy was modified (and renumbered 85660-60276) and a diode (A12CR5) was removed from the A12 Assy (A12 renumbered to 85660-60285 for the "A" and 85660-60290 for the "B") to correct the problem. The chart in the KEYBOARD/RPG section above shows the compatibility issues. A3A6/A3A9 Noise spikes cause KSW to fail If the A3A6 Control board is 85662-60022, and the original A3A9 T&H board (85662-60012) is changed with the 85662-60165, spikes appear on the display. So, if changing A3A9, you must also change A3A6 to the latest part number (85662-60146). A11A3 YTO / A20 MAIN Coil Driver Replacement Beginning with serial prefix 2409A on the 85660A RF section, we started loading a compensation pack (A20A2) on the A20 Main Coil Driver Assembly. The Agilent part number of A20 was changed to 85660-60206 when the compensation pack was added. Each compensation pack is customized at the factory for the best linearity of a specific A11A3 YTO. The A11A3 YTO replacement kits (NEW = Agilent p/n 85660-60213, RESTORED = 85660-69213) includes a compensation pack "matched" to the YTO. The A20 Main Coil Driver can be ordered as Agilent p/n 85660-60219 (85660-60206 with a "standard" compensation pack) or Agilent p/n 85660-60206 which has no compensation pack loaded. A11A3 YTO Replacement Install the restored YTO (Agilent p/n 85660-69213) or new YTO (Agilent p/n 85660-60213). Remove A20 Main Coil Driver and locate its Agilent part number. If the A20 part number is 85660-60039 or 85660-60133, discard the compensation pack supplied with the YTO kit. If the part number of A20 is 85660-60206 or greater, replace the existing A20U2 compensation pack with the compensation pack supplied with the YTO kit. A20 Main Coil Driver Replacement If the A20 being replaced is Agilent p/n 85660-60039 or 85660-60133, order Agilent p/n 85660-60219 (85660-60206 with a "standard" compensation pack). If the A20 being replaced is Agilent p/n is 85660-60206, order 85660-60206 and remove the compensation pack from the failed A20 assembly and install it in the new A20 Assembly. A7A4 M/N Output Assembly / A7A5 M/N Motherboard The early A7A4 (85660-60113) M/N Output Assembly was replaced by 85660-60267 which has better phase noise. To achieve the better phase noise, a 20 volt supply trace had to be provided from the A7A5 M/N Motherboard. The early (85660-60020) M/N motherboard had a 20V trace added and became the 85660-60265. The 20V supply shorts out when an early A4A4 M/N Output assembly is inserted into the current A7A5 M/N Motherboard. A7A5 M/N Motherboard Early Motherboards without 20 volts running to pin 9 of the XA7A4P1 connector are p/n 85660-60020 (85660A prefix 2539A and below. 85660B prefix 2607A and below). Latest Motherboard with 20V at XA7A4P1-9 connector is 85660- 60265 (85660A prefix 2623A and above. 85660B prefix 2611A and above). M/N Output Assembly A7A4 EARLY assemblies which had circuit board edge connector pin 9 grounded are p/n 85660-60113 (85660A prefix 2529A and below. 85660B prefix 607A and below). LATEST assemblies accept 20V, and are p/n 85660-60267 (85660A prefix 2623A and above or 85660B prefix 2611A and above). If the early A7A4 M/N Output Board must be inserted into the latest A7A5 Motherboard, cut the ground trace on pin 9 of A7A4. This situation may arise if the A7A5 Motherboard is replaced on an early instrument. The latest A7A4 M/N Output Assy can be used with the early Motherboard without any problems. A6A10 Miscellaneous Bias/Relay Driver and A10A11 Slope Generator 85660A prefix 1950A and below did not have External Mixing capabilities built in at the factory. (serial prefix 1827A through 1950A can be modified with the External Mixer Mod Kit, Agilent part number 85660-60143). When we installed external mixing, the A6A10 (85660-60011) and A6A11 (85660-60012) were replaced with two other assemblies. The 85660-60011 (A6A10) and 85660-60012 (A6A11) are no longer available, and you cannot mix a current board assembly with either the 85660-60011 or 85660-60012. If either the 85660-60011 or the 85660-60012 fails, you must order p/n 85660-60383 which is a set of boards consisting of the latest A6A10 and A6A11. A6A10 (85660-60180 or 85660-60127) needs to have R47 changed from 3.16K to 8.25K (0698-7258) if the YTX (A6A8) is replaced or the YTX flatness adjustment range is not adequate. The factory began loading the 8.25K resistors around 660A serial number 2311A02344. All 8566Bs shipped from the factory have the 8.25K loaded. A6A12 YTX Driver Assembly Note the 85660A and 85660B use different A6A12 assemblies so YTX tracking can be optimized. For the 85660A ONLY; order 85660-60374 to replace the early 85660-60273 or 85660-60235. For the 85660B ONLY; order 85660-60366 to replace 85660-60235. The 85660-60366 allows the hardware in the instrument to support the 11974 Series Preselected mm Mixers. Option 462 Firmware installation Option 462 (6dB RBW) retrofit kits include replacement firmware date code 10.10.89 for those instruments with serial prefix 2937A and below. The 10.10.89 firmware is used in the "standard" instrument as well as the Option 462. Therefore, there are many "standard" instruments that will not require the firmware to be changed when installing the Option 462 kit. The Installation Note included in the kit instructs you to check the firmware date code of the firmware already installed in the instrument, and only use the FW included in the kit if the FW date code is below 10.10.89. 8566B Option 002 TURBO instruments have FW date code 15.2.91, and if the 10.10.89 FW is put into a TURBO instrument, the front panel INSTR CHECK LEDs remain lit and the front panel locks up.