Hooked on HP... Does 16701B work with 16700A/16702A?

[ZaneKaminski]

I have acquired quite a few 16500/16700 measurement modules which I want to put into my 16702A system, so I need the 16701A/B expansion frame. The 16701B is typically much cheaper than the 16701A. Why's that? Is the 16701B compatible with the earlier 16700A mainframes?

Is there anything else I should watch out for when acquiring the expansion frame? What about the cable which connects the two? It seems pricey and rare. Is there a cheap substitute?

Zane

[helius]

The 16701B is compatible with the 16700A, 16702A, 16700B, and 16702B mainframes. It appears identical to the 16701A.
The cable looks like an ordinary shielded 100-pin twisted spectrastrip. I don't think there is any magic to it.

[ZaneKaminski]

Okay, thanks. What are the differences between the -701A and -701?

Edit: Or when you say it "appears identical," do you actually mean that the units are physically very similar? At first I thought you meant that they present an identical interface to the 16700-series host.

[MarkL]

...
What about the cable which connects the two? It seems pricey and rare. Is there a cheap substitute?

There are two cables available (at least that I've seen): 16701-61602 which is 12", and 16701-61604 which is 36".  The 36" one is more rare.  Occasionally you can find someone selling the expansion chassis with the cable.

I wanted to turn my 16701B around so I could easily access the inputs on some 16534A scope cards I have for it, so I decided to make a 60" cable.  It cost me around $75 in parts from Digikey.  That's not exactly cheap but still better than $200 for the 36" one on ebay.

I used flat (non-twisted) 0.025" ribbon since that's what HP/Agilent used for the interconnects inside the chassis to get to the back connector.  My cable is not shielded like the real one (no problems so far), and I had to use the latches instead of thumbscrews since that was the only shell I could easily get.

If there's interest I can dig up the parts list and some how-to photos.


I'll have to defer on chassis differences question; I don't really know.

[helius]

By "appears identical", I mean that it has the same slots (5 LA modules and 2 emulator cards), and the same cabling (100 pin bus) as the 16701A. The extension chassis are mostly passive, so I don't see why they wouldn't be equivalent in use.

[gslick]

As far as I know the main difference is that the early 16701A expansion frames were 2 fan models and the later 16701A expansion frames were 3 fan models, while all 16701B expansion frames were 3 fan models.

The 2 fan models have 2 fans on the side and none in the center strut. The 3 fan models have 1 fan on the side and 2 in the center strut.

I believe this change was required due to increased cooling requirements of newer analyzer modules, and possibly that is what this document is about, although it doesn't mention the details of the hardware upgrade:

http://literature.cdn.keysight.com/litweb/pdf/16715-92007.pdf
Frames with the following serial numbers need to be upgraded to operate with 16715A, 16716A, 16717A, 16718A, 16719A, 16740A, 16741A, 16742A, 16750A/B, 16751A/B, 16752A/B, 16753A, 16754A, 16755A, 16756A, or 16760A measurement modules.


So while either a 16701A or 16701B expansion mainframe should be good with either a 16700A, 16702A, 16700B, or 16702B mainframe, some early 16701A expansion mainframes may not be supported with all analyzer modules. (Also some 16700A and 16702A mainframes may not be supported with all analyzer modules.) This may really be a case it works at your own risk even if not officially supported.