HP 5316A - Option C10?

[CatCow]

So I picked up a few 5316A's recently, all of them with the 1 GHz C-channel input(Option 003) - one has what is called the C10 option. It is not mentioned in the manuals I have found, nor in the old catalogs. It is mentioned in two places in all the internet that I have found so far, and is described as a parallel connected 50 ohm input for both channels A and B, and that they should be terminated when not in use. While the C channel seems to do fine in testing down to about 1 MHz, it is listed as 50-1000 MHz, so I suppose the 50 ohm input for the A channel will be handy since I mostly do radio work.

I just find it odd that I can't find any official documentation or other mentions of this option anywhere. Does anyone recognize this option or have experience with it?

I have attached some photos, showing the rear input BNC's(seems a little close to the AC power input), the route of the coax through the middle, and where it is soldered to the front panel inputs.

The only issue I've run into is that two of these units showed up with errors - one I'm still working on, the other started working after reseating all the socketed IC's and fiddling with the external reference switch.

ETA - Third unit fixed. Note to self - don't use electrician DMM that only reads to tenths of a volt. 5V rail was actually 5.14v, spec says 5v +/- 0.01. Once adjusted using my o'scope, the counter was perfectly happy. I really need to hurry up and buy a good bench meter. So if you have one of these with the GPIB LED's flashing in an alternating pattern and the external reference switch isn't dirty or stuck, check your voltages carefully!

[dacman]

Another way to describe option C10 is Rear Channel A and B Connectors.

[bitseeker]

Ah, so you bought that one with option C10. Glad to see you got them all working. So, is a 3478A or 34401A next on your shopping list?

[CatCow]

Ah, so you bought that one with option C10. Glad to see you got them all working. So, is a 3478A or 34401A next on your shopping list?

Another eBay lurker? I need to dig around a bit more and see if the claims are true that they are really 50 ohm inputs. These equipment acquisitions tend to snowball badly, this was originally meant as a companion to a Fluke 6060B that I had to repair - an interesting story in itself(maybe I should post that separately), as I try to gather up more RF test gear. I really need a service monitor or spectrum analyzer(radio repairs and filter characterization), and then I'm looking at higher bandwidth analog o'scopes, and I've started collecting parts for a GPSDO project to feed the external reference ports on some of this gear... But to get back to your question, I am currently leaning towards a 3478A. Trying to keep it cheap, and the HP looks to have better specs than the similar age/price Flukes(not to mention worrying about dim VFD's).

[bitseeker]

Another eBay lurker?

LOL. I've run into many folks from here on eBay. You may have been outbid by some in the past.

These equipment acquisitions tend to snowball badly

Yep, that's why the TEA thread was started.

But to get back to your question, I am currently leaning towards a 3478A. Trying to keep it cheap, and the HP looks to have better specs than the similar age/price Flukes(not to mention worrying about dim VFD's).

It's a pretty nice meter alright. A few things to note: (1) no continuity function (in case that's important to you), (2) LCD doesn't have a backlight (which may be fine depending on your lighting), and (3) the calibration data is stored in battery-backed memory, so be sure that there's no cal error and then back up the data when you receive the DMM. There are threads here about how to change the battery.