hp 211B square gen

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mansaxel
Posts: 282
Joined: Sun Oct 23, 2022 5:52 am

hp 211B square gen

Post by mansaxel »

So, this week I stumbled over a hp 211B on the less interesting local auction site -- the site's normally got next to no collectors items, but a lot of used cars and shipping is normally not discussed; more of a "come and get it" site.

Price was SEK 200, which is about EUR 17.

Condition looked OK on the picture, with the hp logo missing, but otherwise OK.

As I got there yesterday, the seller told me that it was ex-hp-property, him having worked at their repair facility back when hp not only peddled printer ink but was a real company. It had been retired and he'd got it to use at home, which had not happened (and he'd not been at hp for many years), so he was selling it. Had a nice short chat, and I went home with another Golden Age instrument in the back. Literally -- later inspection showed the gold plated PCB et cetera.

It of course, at its age, (introduced 1967), has the dreaded PH163 mains inlet, and there was no supplied cable, but instead a reasonably well done (shrink tubing included) bodge of a normal Schuko cable that snaked out of one unused BNC hole in the back. I have preciously few of the PH163 cables, like 2, and they're on the 5221A and the 200CDR, so decided to draw from stocks one of my Schurter 2561 IEC 60320 C6 inlets, bought to replace PH163 when needed.

I separated the back panel as much as possible and drilled out the rivets (3mm drill) from the inside. Spinning rivet syndrome was encountered, but dealt with using pliers. The 2561 mounts from the outside, whereas the PH163 normally was fitted from within. Hence, the flanges of the 2561 cover the edges of the cutout. Some filing (I'd guess about 50 pushes of a coarse half-round file) was needed to widen the hole and allow one of the original rivet holes to mate with the new 2561 flange. The other 2561 hole ends up matching the PH163 large hole, since the PH163 cutout is considerably longer than the 2561, but with some care the new connector flange covers the entire old hole except the remaining rivet hole. I dealt with this using a large washer on the inside and clamping the new inlet using that. Looks pukka from the outside, is sturdy, and the last remaining rivet hole can get a separate treatment, should this become desired or necessary.

As I was doing this, I'd gotten a wire from the power switch to the voltage selector severed, which was discovered when the milky orange power switch lit up but nothing was seen on the output. Power switch and light are ahead of that as can be seen below.
mains inlet schematic.
.

I found my gorillaism and reattached it, and measured the resistance between L and N on input, found it to be higher in "230V" than "115V", and plugged it in. And, it works. It's basically within tolerances for frequency and amplitude, can do a whopping 30V on the "600Ω" output, (albeit only to 1MHz), and does 5V on the "50Ω" output. The trigger output makes a nice pulse train. Wiped off the dust with a humid cloth, and done!

Reflections:
  • Do the C6 mod. PH163 is shite. The mod is simple. Mnem spoke, on Discord, of an alternative that involved mutilating a C13 cable to fit, but that felt horrible to me, and I had the new inlets.
  • There are bargains in the business, but not in the usual places. Yay for the seller who cares not.
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mansaxel
Posts: 282
Joined: Sun Oct 23, 2022 5:52 am

Re: hp 211B square gen

Post by mansaxel »

Some pics:

Image

Panel is in good condition, bar missing logo.

Image

The leftover holes, one from where the old mains bodge entered using a BNC cutout, one from the PH163 jack, can be seen clearly. Also noticeable is the lack of a serial number tag.
25 CPS
Posts: 248
Joined: Wed Nov 16, 2022 8:10 pm

Re: hp 211B square gen

Post by 25 CPS »

Very nice!

I'm in agreement about the PH-163 cords and connectors. I haven't yet modified anything since I have a cord for each device plus one or two spares, but the cause for one of those spares is a frequency counter that has a damaged input socket. It's way down the list of projects but it needs to be modified. I'm not going to replace a damaged PH-163 connector with another one. The cord, that's a perfectly good spare for other devices with PH-163 connectors.
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bd139
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Re: hp 211B square gen

Post by bd139 »

I'm not sure I'd keep those PH163s even if they do still work and you have a cable. The socket is usually backed with what looks like a bit of FR2/bakelite or something horribly brittle. I had a hamfest 3400A which had one and it actually disintegrated in my hands when I was removing it.
mansaxel
Posts: 282
Joined: Sun Oct 23, 2022 5:52 am

Re: hp 211B square gen

Post by mansaxel »

Oh, and regarding the C6 inlet -- what I had in stores was the older Schurter 0724. It is discontinued, and the 2561 I claimed to have fitted is its replacement; I searched for a link without thinking of that, and therefore they're not the same. Looking at the drawings the difference is that the 2561 has countersunk M3 holes, and a flatter front panel. But the cutout and internal volume occupied are very close if not identical.
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mnementh
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Re: hp 211B square gen

Post by mnementh »

Yeah, something I remembered since posting that; back when I used to molest a C13 that way, they were almost always just connectors floating in the molded vinyl, and you could do all of that with a minimum of assache.

Nowadays the connector is a hard plastic block inside the molded vinyl, and that is going to be a lot harder, if not impossible.


mnem
necessity may be the mother of invention, but poverty is the daddy.
25 CPS
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Re: hp 211B square gen

Post by 25 CPS »

bd139 wrote: Wed Sep 13, 2023 6:42 am I'm not sure I'd keep those PH163s even if they do still work and you have a cable. The socket is usually backed with what looks like a bit of FR2/bakelite or something horribly brittle. I had a hamfest 3400A which had one and it actually disintegrated in my hands when I was removing it.
Image

I actually think that is what happened to the damaged socket on that one frequency counter. The ground pin got pushed in through the back of the socket there.
mansaxel
Posts: 282
Joined: Sun Oct 23, 2022 5:52 am

Re: hp 211B square gen

Post by mansaxel »

25 CPS wrote: Thu Sep 14, 2023 1:54 am
I actually think that is what happened to the damaged socket on that one frequency counter. The ground pin got pushed in through the back of the socket there.
The horror! Replace it with a C6! Destroy! Erase! Improve!

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