Test Equipment Anonymous

This should make tggzzz's day.

I have two 485's plus a parts mule. So why not have a third? Facebook marketplace find. It's dirty but complete. Not even a broken knob. And of course it's going to get my usual due diligence. But not today. It's the 4th of July and we celebrate our independence from you stinkin Brits. Later today we will be going to a cookout of hot dogs and burgers and then tonight celebrate with our own fireworks. (Illegal in New York State without the proper license but a half hour away at the Pennsylvania state line is a huge fireworks store)

All my project finds lately have been Facebook Marketplace finds. Prices are reasonable or even dirt cheap....unlike Ebay.

Am I imagining things or does it appear that this 485 might have a blue phosphor CRT?

Blue is good.

C911 and other beads on that rail aren't (or soon won't be) good.

tggzzz wrote: ↑Fri Jul 04, 2025 4:54 pm Blue is good.

C911 and other beads on that rail aren't (or soon won't be) good.

That and at least 2 dozen other bloody tants.

MED6753 wrote: ↑Fri Jul 04, 2025 5:52 pm

tggzzz wrote: ↑Fri Jul 04, 2025 4:54 pm Blue is good.

C911 and other beads on that rail aren't (or soon won't be) good.

That and at least 2 dozen other bloody tants.

That half dozen are difficult to find on the boards and even scattered across several schematics, and are 15V on a 13V rail.

The main PSU is easy by comparison!

The front panel cleaned up very nicely however the mild cleaner I used took some of the lettering off a few push button switches. The front bezel lens is a bluish tint which may hint at the phosphor of the CRT. We'll see. And we found our first issue. The Vertical Mode Switch assembly directly under the CRT is jammed solid. Both CH1 and CH2 switches are depressed. Only one should be depressed. That will have to be fixed before any attempt at power up. The cabinet is in good shape and no painting required.



There was cal sticker on the cabinet (couldn't read the dates) and two broken seal cal stickers on the back so it appears this scope got good service. This is the bottom view. Those two attenuator assemblies come out easily which should give me access to the jammed mode switch. That large board on the right also comes out easily which is the vast majority (but not all) of capacitors (both tants and aluminum). I did do a resistance check of all the rails and they aren't shorted. But that could change very quickly upon power up.



Top view. The scope was assembled by Cora Fendley. Those Tektronix women assemblers were without equal.

Oh and....I can't leave anything uncovered on the bench because you-know-who will pick at it with his teeth.

I was just wondering when the cat would enter the discussion.

MED6753 wrote: ↑Sun Jul 06, 2025 7:58 pm The front panel cleaned up very nicely however the mild cleaner I used took some of the lettering off a few push button switches.

I forget which 4x5 scope it was, but ISTR the universal solvent did that. Dihdrogen monoxide, of course.

MED6753 wrote: ↑Sun Jul 06, 2025 7:58 pm The front panel cleaned up very nicely however the mild cleaner I used took some of the lettering off a few push button switches.

I forget which 4x5 scope it was, but ISTR the universal solvent did that. Dihdrogen monoxide, of course.

mansaxel wrote: ↑Sun Jul 06, 2025 8:10 pm I was just wondering when the cat would enter the discussion.

He gave it a good sniff when I brought it home. Now that the cover is off he'll have to sniff it again and I'm sure he'll start picking at the wiring. He's broken wires before on other equipment.

Anything that comes into the apartment he has to check out and sniff. And he rips labels off Amazon boxes.

my fortress of solitude has been purged of all tek equipment.

your dalliance with cora fendley will not tempt me to go looking for a 485.....(but damn, that is a nice looking scope).

am looking forward to seeing pictures with blue traces.


ps oh crap......my statement about the purge was disingenuous. there is a tek tdr hidden under the bench. it has to stay because it is useful, hp made nothing like it, and well......it's just too cute.

What's the TDR distance resolution? Can it be stored a foot underwater and used in driving rain?

Here's a 485 blue screen, for your delectation...

tek 1502 with crt.

never saw one actually used in the rain. did see one used at Ft Benning to find an aerial splice case that had been replaced with a trash bag, and as a result was full of rainwater. (around 1986, right after outside plant maintenance was contracted out).

Yes, P-11 phosphor is definitely novel and beautiful.

nixiefreqq wrote: ↑Tue Jul 08, 2025 11:38 am my fortress of solitude has been purged of all tek equipment.

your dalliance with cora fendley will not tempt me to go looking for a 485.....(but damn, that is a nice looking scope).

am looking forward to seeing pictures with blue traces.


ps oh crap......my statement about the purge was disingenuous. there is a tek tdr hidden under the bench. it has to stay because it is useful, hp made nothing like it, and well......it's just too cute.

Uhhh....


Currently in the repair queue...


Those little self-contained Tek TDRs are one of the few I HAVEN'T snagged yet...

-Pat

nixiefreqq wrote: ↑Tue Jul 08, 2025 11:11 pm tek 1502 with crt.

never saw one actually used in the rain. did see one used at Ft Benning to find an aerial splice case that had been replaced with a trash bag, and as a result was full of rainwater. (around 1986, right after outside plant maintenance was contracted out).

Nice little things, apart from the battery and charger. I ought to flog one of mine.

I've been known to take one to hamfests, to see whether cables were 50 or 52 ohms

well ok. hp made a tdr.......but they couldn't have sold many. have you ever heard of anyone using one? it figures that cub would have one!

the military bought boat loads of the 1502/3 units. when the local wire chief at ft swampy or camp nowhere would take us around to perform site surveys it was not unusual to see one bouncing around in the back of the line truck (circa 1980-1986). I also seem to have a vague memory of seeing one in use at the filthydelphia naval slipshod in 1977-1980. (was employed at the time in the design division....code 272 - "cableways and test".)

ps code 272 was also responsible for cathodic protection and degaussing systems. I do remember performing midnight to 6am degaussing system magnetic compass compensations on a couple of pier side ships (with a manual in one hand and a screwdriver in the other). God help the poor bastard who trusted a compass after my wonky middle of the night adjustments.

We had a couple of HP 1818A's at Cossor/Raytheon. Don't think I ever saw one getting used though!