curiousmarc

Power supply ElectroBoom moment

My HP 85645A 26.5 GHz tracker died while I was filming a video. To be fair, it never worked well and was shutting down randomly.  But now it would not start up at all. Switched power supply problem, less daunting than an RF problem fortunately. Complicated, custom, over-engineered supply with a lot of odd voltages. From the mid 1990s.  I got the middle finger from Keysight support : t...

Gyro Table Update

Got the cables!

1st Tweet from the Teletype

I have a Twitter account, @curious_marc, but I almost never tweet nor even look at the account. But I made an exception.

New goodies: 2kW power supplies and gyro testing table

I was finally able to pick up my latest auction buys, both related to future space electronics experiments. The first two are high power supplies, which we'd need to power up some of the upcoming gear, including the Shuttle Computer. It's an electron guzzler: liquid cooled, not 2 kW, but still 400W in a small form factor. And a gyro testing rotating table. Not very big, but weighs 80 lbs. Must ...

What the team is doing during lockdown: John tests a whole bunch of power tubes

John, who is also a Patreon here, goes through a pile of big tubes with his monster tube tester. 

Anyone got a 91 pin aerospace connector?

Anyone got the mating part for this in their space parts bin? You can still buy them, but the price tag is something like $2,000 a piece and you need to order 10... This is for Mike's Apollo Computer Buffer Unit.

Mike powers his Apollo Computer Buffer Unit

Here is a short video of the first power up of Mike's AGC Buffer Unit. Mike explained that they abused an MECL logic gate to use it as an analog differential amplifier ("all logic circuits are made of analog parts", as Don Vonada would say).

From Mike's update:

The core of the problem is the way they're abusing the MC306 chips to form differential receivers. This works great if the ...

What the team is doing during lockdown: Mike Stewart reverse engineers an Apollo Computer Buffer Unit

Mike got an Apollo Computer Buffer unit from one of the last RRauction. This box was part of the ground support equipment, and allowed launch control to upload launch related parameters that could not be woven in the Core Rope into the AGC. This box is a serializer that takes a 16 bit input and transforms it into a transformer coupled serial bitstream that is fed to the AGC. 

From Mi...

What the team is doing during lockdown: Ken Shirriff reverse engineers AMD's 2901 bit slice chip

Ken Shirriff just wrote an article about his reverse engineeinrg of the AMD AM2901, a very popular bit-slice processor chip, which many machines used at the time:

http://www.righto.com/2020/04/inside-am2901-amds-1970s-bit-slice.html

Apollo TTY Art!

I am continuing to abuse my Baudot TTY thanks to my new Blue-Box-of-Goodness interface. The print quality is very high, but boy, 45.5 Bauds is slow as molasses. This one took almost an hour to print!

March 2020 Channel Update

Quick update of the lab activity during the Covid-19 shelter in place. Stay safe and healthy.

Tetris Songs

The sound track of the Tetris game, as masterfully interpreted by my Mac SE/30 on a subtle background of disk drive rumble. I got many requests for it, so here it is.

Blinkenlights Sign

This post is verboten to German speakers. The picture is the more or less original sign of the 1950's Blinkenlights joke I have in the basement. It's not German at all of course, it's colloquial English phrases substituted with made-up German words. Carefully made up so they use English roots, so that any English speaker understands them immediately (snap the spring works = schnappen der Spring...

New stickers, shirts and coupon for Patreons on Teespring

Couple more shirts from the last few episodes and an AvE inspired OSHA sticker . Still need to make one for the Soyuz clock... 

https://teespring.com/stores/curiousmarcs-store

Use this coupon code for Patreons and you'll get 20% off:

CMPATREON

Marc

International Atomic Space Clock

I connected the HP 5061A Cesium frequency standard to the Soyuz space clock! It was a little more complicated than I expected. But I think I just made the most accurate vintage international atomic space alarm clock ever. Note that the face of the Soyuz clock does not show the comma at the right anymore, which is a sign that it is clocked by the external source. And Tintin was there to witness ...

Hoffman Radio CV-89A RTTY demodulator

Looks at this nifty visitor from the 1950's! Came through my door courtesy of ePay, and packaged well enough so it was not in pieces. Which is amazing considering how incredibly heavy this is. It is used to demodulate FSK signals used in Radio Teletype (RTTY) transmissions, and was probably what our Teletype Model 19 was attached to when it was in service in the Navy. It has 14 tubes in it. I p...

Carl manages to light up a real DSKY panel!

Carl's been working on Marcel's real DSKY electro-luminescent panels (from this episode: https://youtu.be/B5j-8Jpaemc?t=679). He also has a real Block I DSKY power supply module and two relay modules, also from Marcel. He just managed to light a digit and some lines from the panel with a broken corner! He thoroughly do...

Channel Update: Space Items Galore

Quick video about the amazing goodies that the team has brought to the lab recently. We had an impromptu gathering a few week-ends ago when Marcel said he would bring in the Cesium clock for the Soyuz clock project. Then Ken decided to drop the Titan Missile Computer he had in the trunk of his car (what, you don't have one in yours?), then everyone converged and brought their latest goodies. No...

I broke my Sony RX-10 camera!

We had a little bit too much excitement in the lab and the tripod fell over with the camera on it. It still appeared OK. I didn't realize it, but the internal and external sound went dead. Pretty obvious when I looked inside, the mic connector got torn off the PCB, taking the traces out with it. Nothing that a little bit of creative wiring and soldering couldn't fix. Incredibly difficult to ope...

Ken's Schematics and Notes

Ken scanned his raw schematics and provides some guided notes for the intrepid reverse engineer. 

Sorting through my HP Documentation

Mini behind-the-scenes video about the tyranny of keeping documentation under control, which is a huge amount of work. And don't worry about the hand, this was a while ago, it has fully recovered by now.

Soyuz clock uncut footage

Enthusiast level bonus footage. Mostly uncut footage from our discovering and playing with the clock after we first powered it up. 

Original Demonetized version of the Soyuz Clock Video

This is the original upload that got a copyright strike within 1 (Soviet Space Clock) second! The only difference is the Red Army Choir version of the Soviet anthem at the end. Big upgrade from the copyright free version I had to settle for in the official video. Starts at 15:05. This one is far superior. It should make your hammer and sickle tingle. Enjoy!

What should the Soyuz clock relay do?

The Soyuz clock has the capability to close a relay contact at a set time. Actually, that's the one and only thing it can do to control the ship! The relay contact is accessible from the back connector. That would usually trigger something like a retro-rocket firing. What should we hook up our space clock relay to?

Soyuz clock is up and running!

Good old indestructible Soviet hardware!  We checked everything methodically and powered it up super carefully. But we might as well have applied any approximate voltage and flipped the switch. It came out of its 30 year slumber beautifully. Took us a little while to find out how to set the time and the event alarm up. Not very user friendly with only one button! Now the question is, what ...

Fossil Data Fossilized on 8" IBM Floppies

We are helping an international team of Paleobotanists to retrieve data from IBM 360-era 8" floppy diskettes. It contains a large amount of coded digital information about plant fossils from the Carboniferous, over 300 million years ago.

My big vintage radio tubes are radio-active!

I didn't know, but when Antoine visited and I showed him the big tubes from the previous post, he immediately told us the glass seals on my tube probably contained Uranium because they looked greenish. And therefore would be radio active. Gulp. To which Ken asked, would they then glow in UV light? I plugged a black light bulb in my workbench light fixture, and we all went oooh and aaaah as the ...

Inside Russian Chips

Ken has been looking at the inside of some pink Soviet chips. Not the very one from our clock, but the same ones he got from eBay - non military rated of course. He is so spooked about the Berylia ceramic comments on YouTube that he will only hold the chip by the leads. It you ask me this is a plain regular Cr loaded Alumina ceramic package. And BeO (which is white) is not dangerous to the touc...

ASR33 Done! Reader Finally Working

The ASR33 is finally done, along with two more from our guests that were equally sick. Boy  these machines are finicky!

We broke chips to find out if they are real

My friend Antoine (you'll get to meet him soon) just showed us a new method to recover chips from plastic packages without using nasty chemicals. Which is timely because I suspected some vintage chips I bought from China might have been fakes. We freed the chips. Ken's verdict: they were the real thing, a rare injection process from TI in the 1970's. Antoine loves chips, see what  he once ...