Agilent Technologies 2712A, 2948 manual Modification for Potential Power Supply Short

Instrument Changes Model 8904A

7-9. MODIFICATION FOR POTENTIAL POWER SUPPLY SHORT

(Serial Prefix 2817A and below)

A problem has been noted in HP 8904A Multifunction Synthesizers with Option 002 (a second output) and with serial prefix 2817A and below. In these instruments it is possible for the heatsinks on the output transistors on the A10 Output Assembly (installed only in Option 002) to touch the bottom cover when the instrument is jarred. If the instrument is jarred often enough, the anodization (an insulator) on the heatsinks will wear through and could make electrical contact with the cover. Should this occur while the instrument is on, a 16 V power supply may short to ground. This may cause the power supply fuse to blow or it may intermittently cause the following error to be displayed

!!Reference Loop Reports Out O f Lock ! !

To prevent or solve this problem, it is recommended that an insulator (HP part 08904-00015) be installed on the inside of the bottom cover. The insulator has a peal-off adhesivebacking. Place it just behind the front perforations. It should cover any scuff marks left by the heatsinks.

7-10. CABINET PARTS COLOR CHANGE

(Serial Prefix 2914A and above)

NOTE

Serial prefix 2914A changes the color of the instrument covers and accessories. The old color cover and accessoriesare no longer available. If your instrument has serial prefixes 2913A and below, and you must replace one of these parts, we recommend that you order the full set of covers and accessories. Affected cabinet parts are items 61-67,and items 69-70(see table 6-3).

7-14 Firmware Updates/Hardware Modifications rev.15DEC89