Way back in 2014 I bought a HP 83480A scope mainframe, without plugins. It was pretty cheap at US $112, a whim buy, and I'd expected to buy some plugins fairly quickly, assuming they'd be in similar price range.
Oops! Turns out the plugins are still compatible with current high-end Agilent/whatever-their-name-is-now, and are ebay-priced in the thousands.
So the scope frame sat around without modules.
Till now. The modules I wanted (HP 83482A : 30 GHz integrated optical channel and 40 GHz electrical channel) are still up in the thousands. My second choice (HP 83485A : 20 GHz integrated optical channel, and 20 GHz electrical channel) are usually pricey too. But a couple came up closer to my range. After some bargaining, I got two for US $450 each. The pair are exactly the same functionally, except produced before and after the company changed from HP to Agilent. More than just the logo on the fascia changed, so they look a little different. No matter.
It's interesting that almost always, when such modules are listed on ebay they are missing the _essential_ APC 3.5 f-f gold plated port-savers, and SMA shorting or 50R caps. Which just shows that the sellers have no f-ing clue what they are selling, because these inputs are rated +-2V MAX, and this is not a joke. Reading the manuals, the absolutely required anti-static measures are extreme. For instance rigorously shorting the internal conductor of coax to the shield, and both to the module frame, before connecting the cable to the port. Coax cable is a capacitor, and can accumulate enough charge to kill these delicate ports.
I've seen one of these type inputs get static-blown by some fool (my boss at the time) casually touching it, and it cost multiple thousands and a long delay to get it repaired.
Why are the port-savers almost always missing on ebay units? Yet the prices are still thousands, as if the units are 'known good' - which without static protection on the ports, they are absolutely NOT.
Maybe ebay sellers think "oooh, pretty gold connector, I can sell that separately." So they remove them, very possibly static zapping the input in the process, but also not knowing....
These APC connectors are easily damaged by mishandling. One thing NOT to do, _ever_ is rotate the mating connector. This can spall the precision gold plated mating surfaces. Instead one MUST rotate only the outer stainless steel nut, while holding the inserted connector motionless apart from being pulled carefully inwards. Then torque to a precise tightness.
Another thing to NEVER do, is insert an SMA connector into the APC 3.5 port on the sampler. They do fit, but SMA have looser tolerances and can (likely) degrade the APC 3.5 connector. Hence the use of sacrificial APC 3.5 female to female connectors in these ports. One end only ever touches the port's APC 3.5 and just stays there. The other end gets SMAs attached. Once it's become worn, it's replaced.
Anyway, this seller's modules were minus the APC 3.5 and shorting cap. Typical. Which means they might be blown. I explained the static issue to the seller and asked if he could please form some al-foil over the ports, for shipping. The modules would be handled by staff at my US reshipper, and they of course can't be expected to understand the static damage risks with exposed APC ports.
So what did he do? In preparing to pack and ship he very kindly screwed SMA bulkhead f-f connectors into all four ports, then 'closed' them with short SMA cables. Sigh. By the time he sent me photos it was too late, done and posted. I sent him a page from the manual about care and handling of APC 3.5 connector ports, so maybe in future he'll know.
They arrived yesterday, after some nerve-wracking hickups. No shipping damage.
Fortunately he only made them loose finger-tight, and visually the APC 3.5 surfaces look OK still. I hope to try the modules tomorrow, fingers crossed.
Here's inside one.
Now I have to find four of those APC 3.5 (f-f) port protectors. So far, no luck finding any. Maybe I'm searching wrong, but I can't find any on ebay, or even who makes them. I don't expect to be able to afford new ones.
Anyone know where I might find four of these, in reasonable condition? (Not that I can properly gauge them. That's another thing I need to buy at some point.)
In the meantime I can 'borrow' some from a HP 54121A sampler head. But swapping them back and forth defeats the aim of minimizing wear on the ports.
Edit to add: This is what APC static-sensitive ports should look like at all times when not actually in use;
And this is what they typically look like on ebay. For such prices you get to roll a dice: