Compliled by Gerald, VK3GJM. 13/05/2021

4 hex files read from a fully functional HP-8673C Sweep Signal gen, s/n 2447A00182, option 004. However in this case Option 004 does not have a rear connector?

There will be 2 -3 additional read files to follow, 1 each from 2516 and 2716, however both EPROMS are L.U.T and are direct solder, I am not prepared to risk extraction yet. 

One additional file if can be read from a DIL 24 PIN PAL, TBA.

PCB designation, IC No, and respective EPROM label.

1.	A2A8-U3-08673-80018.hex
2.	A2A11-U5-08673-80038.hex
3.	A2A11-U6-08673-80039.hex
4.	A2A11-U7-08673-80040.hex


Some observations of the unit's reported issue.

Prior to purchase it was reported as 30dB down, failure internal amp.

However, the result was a bad 10 and intermittent 30dB pad connection where the contact fingers meet the 10 & 30 dB pad, and non-reliable contact on the atten in/out position contact for all is worth cleaning, therefore any 30dB step always failed to de-energise the solenoid as the relay did not know it's current position and the 10dB failed to step in from 0 to -10 dB step range.

I found Deoxit D5 to be the superior cleaning fliud and specific stick buds for cleaning fibre throu housings to be the most suitable stick that provided enough surface cleaning power in the restricted space.

A word of caution if you have never tackled an attenuator before, the contact fingers, attenuator pads and all respective push rods, stand-off posts etc are not to be stressed. It is also critical to look at all o-rings.

VE2AZX put out a good doc as reference for those wanting to tackle attenuator fixes.

Only use SMA torque tools to re-tighten SMA, many recepticles are APC-3.5 type, so clean both before re-assemble with D5 or Alcolol ensure any metalic residue is removed.

There is some commonality with the 8672 and 73 series. My aim is to create an single page excel data table of common modules, function and compatibility across the range. 

In the coming weeks I will align vol 2 schematics with the excel data table for better cross reference and this ensures all respective schematics are tabulated. 


As the status changes with more work to copy EPROMS and PAL, I will update these notes accordingly.

Happy reading, repairing and measuring.