What a lucky guy you are!! My wildest dream would have been to work at Microwave Division in Santa Clara, California with the famous Doug Writting, the father of the legendary VNA, HP 8510....what a beauty should have been!

Interesting, thanks for the story.

Oh cool. What type of Radar systems did you work on? Aircraft systems or ground to air stuff? If you’re allowed to talk about it of course heh.

@@bend1483 T84, T85, FPS6 at RAF Neatishead when I first joined up.

Im dying with laughter 🤣😆

@@BitKing_Ross hahahahahahah

I can only wish you and your equipments a long and happy life together. If you're doing it right you get to have both and they smell great.

What an excellent journal that was.

If enough of us support right to repair we might be able to make it happen.

This is the difference of built in USA vs china.

Mike Eral are you sure about that? Do US company’s supply repair diagrams?

@@RingingResonance sadly, I think no matter how many times we tell "right to repair" they're going to carry on making crap that maximises profits and comes with no service manual. :(

I think the bigger problem for companies that try to differentiate with good engineering is that there would be a Chinese counterfeit available on the web the next morning...

Welcome to the club...

Dunno about 'recapping transistors' but all of those axial tantalum electrolytics need an ESR check at the very least. I'm sure Marc took care of that off-camera.

Dipped tants like to crowbar rails waaaay too much. Maybe they have an e-stim fetish. . .

Agreed! It was supposedly inspired by airplane cockpits. Horizontal sliders for time related settings, vertical ones for amplitude.

CuriousMarc that’s very interesting where is the pitch and yaw though

@@tickertape1 Comes only with the optional stick and flap control options ;-)

Stop by and ask if there are some weird old ICs in some ancient drawers. Maybe, just maybe..

Is it hot in here to anyone else? I'll be in my bunk!

I always put a big glob of leaded solder on a joint before I suck... nice bit of fresh solder for the reasons you say and a good bit of lead to alloy any of that lead free stuff that doesn't seem to be so keen on actually melting.

Message Marc

It's a 5081-3010. U2 on board A3. If you have one I'll gladly take it. You can contact me from my About... page: kzfaq.infoabout

Sorry CuriousMarc, looks like the 5081-3010 failed on me as well, have 2 working 5081-3009 a 5081-3027 and those 2 ceramic hybrids left over: i.ibb.co/qJzcWtY/DSC-0226.jpg

Thanks for looking! Interesting on how this particular circuit seems prone to failure.

In what universe is Philips (PM) better quality than HP????

Well done, congrats!

Drool ;-)

That's fast! Must be done with a step recovery diode? For TDR or some other kind of risetime test, different application. Still fetches a pretty penny on eBay!

@@CuriousMarc It uses a tunnel diode. I got a non-working one fairly cheap and was able to repair it with tunnel doides from Russia. The unit was originally intended for testing oscilloscopes I believe. I used it to test my HP 54110D - another oldie but goodie.

Yes, Boblingen is or was an electronics hot spot in Germany. I don't know who started first, but HP development center was there as well as IBM.

Sure but I have to build it first and see if it works...

@@CuriousMarc Thank you for your reply. Sure this is what I meant. A link in part II, if it works. :)

You bet. Circuit board has arrived, time to do some soldering...

What's the fun in buying working gear when you have an entire electronics lab for fixing stuff? Buy broken, fix it, and add it to your arsenal to use in fixing more broken equipment. ;)

Yes, I know ;-)... The new stuff from Keysight is still amazing - we buy it for work. But at well over a quarter million for a scope or a VNA, and 5 digits for most other instruments, that's not feasible even for a very well healed amateur lab. Even at work, the sky-high prices cause intense debate and tension for capital expense allocation. However, their old stuff is still spectacular to this day, and is an amazing bargain for what it does. Bad news, most of the time, if it's from eBay, it's broken. Good news, unlike the newer stuff, most of the time you can repair it. And they even give you the doc, including schematic with principle of operation walk-through!

@@CuriousMarc This is why I will always support right to repair. I've bought a couple old TDS series scopes off ebay for cheap. My first one was a working one that I upgraded from a TDS540 to a TDS784 with a color screen and wll, but it needs calibration. My second one was a 754 I bought incomplete and broken for even cheaper. It had a memory problem on the acquisition board. Luckily they still sell that memory chip on digikey and I was able to fix that problem and complete the scope minus the internal CRT what was so dim you couldn't see it. Okay I'm bragging now. ;) For a lowly hobbyist like me I have a pretty good setup what with the polynomial waveform synth I got for cheap and was also able to repair. Did I mention I had an emergency repair of my TEK465 the other night? Shorted tantalum cap on the 15v rail. Fix in the amount of time it took me to take it apart and put it back together because I got lucky on the first cap I unsoldered and tested. The right to repair is critical for humanity.

Yes that’s my second one. I wanted to be able to have both X and Y controlled ramp pules on the core memory matrices. HP catalog was huge! I have a lot of instruments, but that’s still a tiny part. I have a good sample of the main types though.

These are resistors. You can tell they upgraded the design and replaced one resistor with two to spread the thermal load. I checked them and they are OK. Just cosmetic varnish discoloration from the temperature these reach at steady state.

I remember in our lab project making a differential amplifier we had to go through a bag of transistors to find two which complemented each other

A 2N3906 transistor pandemic?

1974 design.

The last time I saw heatsinks that particular colour they were a beryllium alloy. We were only allowed to work on them under a fume hood!

Yes that was filmed a while ago when I was still working on the power supply.

@@CuriousMarc ahhhhhHHHHHHHHHH!

There are people who sell the acquisition ASICs for first-generation Infiniium oscilloscopes. That said they don't often go bad; the contact surfaces usually just need a cleaning after a while.

In this case the instruments are cheap enough that you just buy two bad ones to make one good one. Only crackpots like me would go through the trouble of making a replacement circuit ;-). Apparently these ECL-like circuits were pushing the envelope of technology at the time and do fail quite often.

No, this is tiled. The nicest tile you're ever going to see in a machining room though...

No, it's ECL level, differential, impedance matched. CMOS would be way too slow, wrong levels, single ended, and not impedance matched. But you could do something with modern ECL circuits. You'd still have to adapt the levels with some special purpose analog circuitry, as the HP levels used here are not compatible with modern ECL.

On my TDS540 it was a matter of changing some config resistors and removing four small caps on the front end of the acquisition board to unlock 4gs/s at 1ghz bandwidth. It's not calibrated anymore, but would def be worth getting it calibrated if I had the signal generators that where fast enough.

@@RingingResonance marc seems like someone who has the equipment to calibrate it :)

The supply is fine and repaired. This is out of order. It was filmed a while ago during the power supply repair, while I was in a lull waiting for components.

@@CuriousMarc That's good! By the way, tell Ken I'm still waiting for a video about his analog computer

@@cda32 I have many videos to make with Master Ken: some on the analog computer, some on the Titan missile computer, some on the reverse engineering of the Russian ICs... But we'll have to wait for the pandemic to subside.

Can I add another vote for the analog computer!!!!

English isn't his native language...

@@douro20 Wow, this is incredible, you'd think most non-native speakers would have some sort of accent; Marc doesn't seem to have one at all. 🙄 I was telling him so he could improve his English skills, not to ridicule him, you twat.