The ‘ol Hawk drive on the new mini Centurion has been giving me all sorts of grief, so it’s time to get a little more methodical in my troubleshooting approach. And one of the steps that I took to get a handle on the drive, was writing a little assembly program to automate some drive operations. I wanted it to setup the drive, do a format write, read it back, and tell me what the status was. Then increment to the next sector and do it all over again. Sounds easy, right? Well, assembly can trip even the most seasoned programmers up, but I think we skated by with relative ease this time! Centurion Wiki: https://github.com/Nakazoto/CenturionComputer/wiki If you want to support the channel please hop over to Patreon: https://www.patreon.com/usagielectric Also, we now have some epic shirts for sale! https://my-store-11554688.creator-spring.com Come join us on Discord and Twitter! Discord: https://discord.gg/p7UsfHD Twitter: https://twitter.com/UsagiElectric Intro Music adapted from: Artist: The Runaway Five Title: The Shinra Shuffle https://ocremix.org/remix/OCR01847 Thanks for watching! Chapters 0:00 Introduction 2:10 A refresher on the CPU 3:40 Let’s write some Assembly 6:15 The top of the program 9:19 How to do long delays 11:28 Setting up the cylinder address 13:24 Starting the main loop 14:43 Speedrunning the main loop 16:04 Checking if we had a successful read 17:50 What happens if the read is bad? 20:09 Incrementing the cylinder/head/sector 21:42 Our delay subroutine 22:31 Assembling it 24:57 Giving it a test 27:00 Kitties! ... https://www.youtube.com/watch?v=OvkRROqKK4k

The 555 timer is one of the most popular chips in the World, but hot on its heels is the 741 Operational Amplifier. In this episode we take a look at the state of the 555 timer kit and, since we’re waiting on parts, take a stab at building a 741 Operational Amplifier! Check out this episode about our first foray into OpAmp building: https://youtu.be/UvN7tck61DI And check out this episode for more information on the HP Oscillator: https://youtu.be/EAkiPeC1Xqw Artist: C7, Jamphibious Title: Mega Man 3 "Shadow's Lounge" https://ocremix.org/remix/OCR02710 If you want to support the channel, please hop over to Patreon: https://www.patreon.com/usagielectric We also have some epic shirts for sale! https://my-store-11554688.creator-spring.com Come join us on Discord and Twitter! Discord: https://discord.gg/p7UsfHD Twitter: https://twitter.com/UsagiElectric Thanks for watching! ... https://www.youtube.com/watch?v=Qp4l-RWHbes

Initially this episode was going to just be about fixing an issue that cropped up on the HP 150A tube scope, but I recently got my mitts on some other, excellent vintage all tube HP test equipment, and I just had to show it off! So, tag along as we repair the 150A and then go through and take a closer look at all the HP equipment waiting to be restored. If you want to support the channel please hop over to Patreon: https://www.patreon.com/usagielectric Also, we now have some epic shirts for sale! https://my-store-11554688.creator-spring.com Come join us on Discord and Twitter! Discord: https://discord.gg/p7UsfHD Twitter: https://twitter.com/UsagiElectric Music: Artist: Emunator Title: Small Steps (Just Breathe) https://ocremix.org/remix/OCR04179 Intro Music adapted from: Artist: The Runaway Five Title: The Shinra Shuffle https://ocremix.org/remix/OCR01847 Thanks for watching! Chapters 0:00 Intro 1:23 What’s wrong with the 150A scope? 4:35 Repairing the 150A 6:31 What was done 9:02 Testing the 150A out 11:14 What’s next? 11:41 HP 412A DC VTVM 13:20 HP 400H AC VTVM 15:04 HP 711A Power Supply 17:35 HP 211A Square Wave Generator 19:17 HP 521A Frequency Counter 21:54 HP 608D VHF Signal Generator 24:26 Outro 25:57 Bunny! ... https://www.youtube.com/watch?v=6miz6zr4dTg

I have a soft spot for old test equipment, particularly old HP test equipment. My HP-150A is my all-time favorite oscilloscope. It’s rock solid, looks gorgeous, and is stunningly good. It also weighs about nine million pounds (that’s roughly four million kilograms). I was lamenting that I needed a front-end loader to pick my 150A up to a good buddy of mine, Chris Fala, and he said “I’ve got an HP tube scope that won’t send you to the doctor for back pain.” Chris is an absolute legend and hooked me up with said scope, which is the HP-120B you see here today. It’s not currently working though, so let’s dive into it. Should be easy, right? Right? If you want to support the channel please hop over to Patreon: https://www.patreon.com/usagielectric Also, we now have some epic shirts for sale! https://my-store-11554688.creator-spring.com Come join us on Discord! Discord: https://discord.gg/p7UsfHD Intro Music adapted from: Artist: The Runaway Five Title: The Shinra Shuffle https://ocremix.org/remix/OCR01847 Thanks for watching! Chapters 0:00 A bit of reorganization 2:34 Scopes! 4:43 Testing the test equipment 5:40 Throwing electrons at the 120B 7:25 Deep cleaning time 12:43 6U8 vs. 6GH8 14:05 Testing after cleaning 15:21 So close, let’s dig in deeper and find out what’s wrong 17:38 Thor: “Is it though?” 19:35 I fought the HP and the HP won… 21:56 Battling someone else’s modifications 24:11 Please work correctly, for my sanity’s sake 25:48 Nailed it! 26:48 What am I going to do with another oscilloscope? 28:46 Derpy cat is derpy ... https://www.youtube.com/watch?v=hDgjKUY_Riw