Testing Thousands of G15 Germanium Diodes

[@Heater-v1.0.0]

Hmm... 1956 hey, That's the same year I was built. Maybe I should get my diodes checked.

[@sapientsatellite]

Check your capacitors also, hope they aren't leaking

[@AlchemyAmiga-C64since198]

@@sapientsatellite The brain RAMs also get old and don't refresh as well anymore.

[@UsagiElectric]

The G15 is tough as nails and refuses to quit, so I'm sure you're just as tough and tenacious!

[@timradde4328]

Same here. Hello.

[@williamsquires3070]

Yeah, all mine have turned into zener diodes either random voltage drops. 😆

[@ibm3480]

I was taught in Electronics school that you always adjust an analog meter to ZERO with power OFF. You adjusted with power on, and not to ZERO. I can hear the voice of my teacher in my head, screaming, for doing that. LOL 😂

[@UsagiElectric]

I didn't show it directly on camera, but I wanted to see if when adjusted such that Lloyd's specs are on point, does the needle drop down to zero. This was a way of confirming just how far off base we might be. It did indeed drop back down to zero, and once powered off, I confirmed, the needle was still at zero. In the video, it seems like I blazed through it, but in reality, I spent about 15 minutes confirming and double checking the needle position and cross referencing against any and all notes and documentation we had.

[@ibm3480]

@@UsagiElectric I'm just giving you a hard time! 😉 I have NO DOUBT that you are more than competent and capable in the field of Electronics Technology. The Bendix G15 is literally my dream computer. I was given a Bendix volt meter off one as a kid and always loved them ever since. I still have the meter even today. I absolutely LOVE watching the G15 slowly roar back to life! Keep up the great work!

[@stevebabiak6997]

12:35 mark, it’s the only way - adjust the meter set screw to zero with zero current / voltage depending on the type of analog meter.

[@marcofixit]

I found myself screaming at the TV about this.

[@rickhole]

@@UsagiElectric You are forgiven. I, too, crimged at that first adjustment. but later I saw the meter at zero and concluded you had fied it.

[@roxannes5455]

It's like Quantum Leap - you don't get to disappear until you're completed the task you were set out to do. I assume that Al is talking to Ziggy just off camera. Keep up the amazing work, this series has been fascinating, thanks for sharing it.

[@RayR]

Great stuff. Especially how Lloyd reverse engineered the diode tester. Lloyd=GOAT!

[@renecyberspaced1286]

@Usagi Electric The 12AV7 tube is NOT a substitute for the 5965 (E180CC). The 5965 and other tubes specially made for flip-flop circutry, has to withstand being biased into sharp cut-off for extended periods, hence the more rugged construction, a lot more heat has to be dissipated in cut-off. Unfortunately the 5965 and the E180CC are wrongly considered an "audiophile" substitute for the 12AU7 - ECC82 types, so prices are stupidly high for tube wich is prone to hum, noise and microophonics. For anyone who doubts my claims, please read the Philips datasheet for the E180CC. Much ❤

[@VincentGroenewold]

The thing I love about this channel is the in-depth stuff, but not too complex, the really old systems (not just 8-bit) and the community. Reverse engineering stuff is amazing, people helping out with coding etc. Love it.

[@exidy-yt]

Two steps forward, one step back. It's the cycle of life. Considering these diodes are the same age as my father, the fact that such a small number only have failed is astounding. Also Lloyd, if you are reading this, you are a GOD among men. Never forget it. You and Dave are making magic here, but he'd be going at 1/10th the pace or even slower if not for your help. Thank you.

[@Colaholiker]

Given how rare these machines are now, I am tempted to say that the value (at least to those who collect machines like this) of a working G15 today is even higher. Of course, commercially not so much, as you can get orders of magnitude more computing "oomph" for orders of magnitude less "ka-ching". Your "see you in the next episode" didn't work for a simple reason. Everyone knows that your videos end with a good portion of your "furry family members". So unless you "roll the fluff", we know the video isn't over. 😄

[@UsagiElectric]

A working G15, I can't say for sure, but a few have changed hands over the past year. A G15 with MTA2 tape drive, two typewriters, and some other small stuff sold at RR Auctions about a year ago for $60,000. More recently, a G15 with a typewriter, and an MTA-2 tape drive from the LCM sold on Christies Auctions for around $20,000. So, it seems the value of these machines is still pretty impressive, but still well under $100,000 today. I was wondering how many people I would catch out with the fake ending, but I also know y'all are all really here for the fuzzy family at the end!

[@denawiltsie4412]

@@UsagiElectric The timeline ratted you out. I was curious why you were giving the end while so much time was remaining.

[@JamesHalfHorse]

It amazes me that I have meters, component testers including a curve tracer but the Bendix engineers knowing others would be having this exact problem solved it with basically a battery, a couple resistors, some rotor switches and a meter. Small and rugged for it's time compared to carrying a curve tracer and a scope considering scopes back then were very heavy vacuum tube jobs that required their own cart and were very fragile. I am having to repair my RF analyzer now because of a bad screen when being transported even in a special anvil case and it's within the last 20 years modern.

[@denawiltsie4412]

They yield on early semiconductors and diodes wasn't real great so the parts were well checked before they left the factory. Infant mortality was also more of a problem so parts failing a few weeks or month into the field was also an issue. I would expect a well equipped service man to have a tube tester, diode tester, multimeter and scope when they visited a customer site because that many parts will produce a failure sooner than latter.

[@JoeBurnett]

Love my Sunday morning coffee watching Usagi!

[@BIGD-lg1qd]

Long Live Lloyd

[@mcolville]

No idea how you get one of these videos made every week. Major highlight of my weekend! I mean, you do SO MUCH, not only al the work on the machines, all the trial and error, but you also record AND EDIT 20-30 minute videos EVERY WEEK?! Madness!

[@heckelphon]

In the final scene of all, is the bowl pushed aside as a "Thank you for that" or a "Now refill, please."

[@UsagiElectric]

It's a "I want more banana!"

[@Ranger_Kevin]

Buns always want more nana 🙂

[@LeonDerczynski]

Super cool concept, sorry production was laborious, thanks for seeing it through!

[@SergeWallace]

As an old fart I always loved the crinkle paint finish on the 50's electronics. And yes I have a early DEC 11/70 in my garage.

[@NiallWardrop]

I remember reading that tube computers (or anything with a sufficiently large number of tubes) couldn't theoretically work because the MTBF is such that there will always be at least one bad tube; the reason they do is because MTBF isn't the whole story, due to production variations some will fail early and some not, if you start with a whole new batch and replace them as they fail eventually you end up with all the better ones. The machine then works reliably until the tubes get into the end of life section of the bathtub curve at which point it is necessary to start again with a new batch. The other thing was never to switch the machine off as it is switching on which puts the most strain on the tubes, obviously not practical for hobby use. All this used to be observable with incandescent light bulbs in any building with enough of them.

[@UsagiElectric]

The G15's MTBF was actually quite a bit longer than other tube computers of the era, often going for weeks of 24/7 operation without a failure. There's a few things playing into this. Only having 460 tubes brings the numbers game to a much more reasonable level. Also, the G15 is primarily using indirectly heated Noval tubes, which had much, much better life and reliability than the older octal or directly heated tubes used in machines like ENIAC. Also, filament warm up and start up is the hardest time on a tube, but the G15 has a clever soft start that sequences in, slowly increasing the voltage to the filaments over the course of 60 seconds. That means that all the filaments last much, much longer.

[@denawiltsie4412]

They used a couple of design tricks to extend the tube life. They ran the filament cooler either by a lower voltage or by designing the tube to handle a higher voltage than what was applied to it. Tubes normally ran much higher plate voltages between 45 and 90 volts. It surprised me a bit when I found they were running around 24 volts. Mean time between failure is a worst case calculation and often you will find that parts far exceed the numbers it produces after you get a few early failures out of the way. Running anything below specs will extend its life. I have a chandelier that uses 12 - 40 watt bulbs and was purchased in 1986. I have only replaced on bulb and that was because it broke while cleaning it. The trick is on high it produces so much light and heat that it's always on a dimmer running at perhaps half its full output.

[@stevebabiak6997]

MTBF is a mil-spec calculation based on component type, component count and stress applied to each component. You could have a poor design that never overstresses any parts but fails reliably far sooner than the calculated MTBF. And you could have good designs that run for longer than the MTBF.

[@DataToTheZero]

​@@UsagiElectric I was actually going to ask if you would consider using a soft tube starter. I'm glad to hear they included one, Bendix really thought of EVERYTHING!

[@spencerharding]

Magnificent work, especially on reverse-engineering and documenting the tester. Also, i noticed you were using Australian Central Time in your scheduling tool, which I can totally understand as a guess at the best average timezone to use for the country, but in actuality, over 80% of the population lives on the east coast, so it would probably make more sense to use AEST unless a disproportionate number of your Australian viewers are tuning in from WA, SA, or NT. And, yes, technically Queensland is also in a different timezone because they don't do Daylight Savings Time, but we all just make fun of them for that, so I wouldn't factor it into your considerations...

[@PilkScientist]

In Usagi's case, I think that might be because Japan uses the same zone as central Australia. So he defaults to that, when choosing time zones for international comparison purposes.

[@larryk731]

You are rapidly becoming one of the world experts in 1950s computer technology.

[@solemnwarning]

The wiring in that diode tester, well, the G15 itself too really, is a work of art.

[@niksgarage]

Loving the lacing cord on the back of the panel. Reminds me of my first job to pay my way through university, working for a company making instruments for the North Sea oil rigs.

[@jamessmith4229]

I am older than this system and got to play with one in high school in the early part of the 1960s. Pure magic watching this come to life. Tic Tac Toe next!

[@datasilouk1995]

I've got this terrible pain in all the diodes down my left hand side - Marvin (The paranoid android)

[@Discretesignals]

Lloyd is one smart person! He did an excellent job REing that tester.

[@tarstarkusz]

I hope you know germanium transistors and diodes were made well into the 90s in Russia and are still available in the millions as new old stock.

[@brianh.4185]

“The problem with this diode tester is the bad diodes within it…”

[@tommythorn]

Awesome. The natural follow up question: so how will you be testing the valves?

[@RaymondSwanson-u9y]

And the point to point wiring. That's going to be a job!

[@UsagiElectric]

There are only about 460 vacuum tubes, so it's a much more feasible task to tackle that problem one by one as issues crop up during machine testing. I'm working under the assumption that the majority of them are okay, and we're just going to troubleshoot the machine slowly and surely. I do have a tube tester, but it's not a very good one, so it won't highlight issues with emissions and balance on the flip flops or things like that. So, if we find a flop isn't behaving and the tube filaments look fine, we'll get into some more in depth testing at that point!

[@ejcrashed]

Man, Lloyd is some kind of G15 deity at this point

[@volvo09]

I love the G15, excellent progress! I wonder how many of those testers are left... Can't be many kicking around.

[@UsagiElectric]

Surprisingly, I think I've seen more testers than actual G15s! I have one, Bob still has two or three, Lloyd has two, the G15 that sold at RR Auctions a while back had one with it, and so on.

[@bradnelson3595]

From the very start of this project when you first gave us an overview of the machine and all those diode cards, I was wondering how in heck anyone was going to be able to check all that. We're getting there. That is, you're getting there. We're looking over you shoulder and trying to keep out of the light.

[@Renville80]

I think the carbon composition resistors should be taken into account; I have seen one vintage radio / TV restoration site where the person said he checks them and replaces anything that has drifted out of tolerance (gold band = 5%, silver band = 10%, no fourth band = 20%). That might have to be the next step after the diode test if the computer still acts like it hasn't had its morning coffee.

[@Dr_Mario2007]

Totally agree with you, Carbon resistors tend to do weird things the older they get.

[@jaut-76]

18:03 no shame for been crazy. That VC was fun.

[@UsagiElectric]

It was indeed!

[@joshj88]

This is a welcome Sunday treat!

[@TheFanOrTheMask]

you are the best channel on here, in my view, such persistence, energy and effort

[@jimktrains0]

Being a yinzer, techie, and working at the supercomputing center in college, I have no idea how i have never heard of the large scale systems museum!

[@adrielrowley]

Lloyd sure is a treasure to the community and to history. That Bendix tester is sure nifty. I sense a future video will be testing all the vacuum valves. 🤪 Cheers, Adriel

[@MichaelAStanhope]

Are you going to be at System Source on the 18th of October? It would be good to see you again!

[@Dr_Mario2007]

UsagiElectric - It's getting exciting that Bendix G15 is getting closer to run the codes through it's ALU circuits... Yay! Still needs a few works, of course, something I am looking forward to when you get back from the trip. I am glad that Lloyd gave you a hand fixing up that absolutely ancient computer as former Bendix technicians are as rare as hen's teeth nowadays. (BTW, for weird reasons, KZbin refuses to let me tag you.)

[@wtfusernamecrap]

Dude! I started shouting at the TV when you tried to end the episode the first time! 😅

[@UsagiElectric]

Hahaha, almost had you!

[@rickhole]

I remember a TV commercial from decades ago, for, I think, a motor oil, the machanic states "You can pay me now, or you can pay me later." BY ALL MEANS check all the diode cards now. Not doing so is going to cause you grief tracking down which card is causing the fault. You will end up spending more time in stressful panic debugginf than you will take leisurly and calmly checking them now.

[@EdwinSteiner]

"You are all a little crazy!", he said, while testing more than 3000 diodes in order to run his vacuum tube computer at home. ;-)

[@EileenF-ng4lq]

Glad I could see myself doing X Windows things in the laptop screen ;D Really happy i could watch this live as well. This was beyond a blast

[@munyxxi]

loved the little gag !

[@bmobert]

This was wicked cool. Always fun. Thank you

[@MotownBatman]

Good Sunday Morning! Blast from the Past is a Great Flick, Funny as Hell Well Done Sir!

[@Flying0Dismount]

You need to find a old Huntron "Tracker" unit.. They were basically an oscilloscope and sig gen in a specialized config that displayed curves kind of similar to a curve trace but in a much simplified manner and could be used in-circuit. These were the best tool to quickly check diodes and transistors in-circuit and quickly gave a visual indication of whether a component was functional.

[@lunabell-2]

$600k is like 2 houses or .2 of a hospital bill in the US

[@mwwhited]

In many parts of the US it’s about half a house

[@colinstu]

@@mwwhited in my area in US that can be anywhere between 3-6 houses. but lol depending where in CA that would be 0.25-0.5 of a house.

[@monad_tcp]

The price of the computer was probable just 1 one house back then. Inflation is 2% per year, house inflation is 9% per year. Its caused by demand/offer I guess. I think the problem with current society is that the housing system is never reset, so the prices keep increasing forever as cities grow. I imagine that cities with 500y had a couple of resets because they basically would burn to the ground from time to time. Well, I count on this system to basically retire as a millennial, I just bought 2 houses in a city that's is still growing. Then I'm going to live on rent from gen-alpha working 3 jobs to pay for it.

[@colinstu]

@@monad_tcp we need more housing inventory. Until zoning is changed in more areas to allow for higher density, more in-fill, etc to simplify the process of resolving this - will continue to run into high demand and low supply and ever increasing prices on a scarce resource. "Resets" have happened and they're detrimental absolutely everyone (bc they're also when recessions happen, so even those who have less money who could not afford before until a reset - will also likely have their financial situation changed via layoff and price fluctuations of everything else).

[@rickhole]

The diode checker meter circuit. When you have a meter with a series resistor it is easier to see it as a voltmeter. That meter is indicating forward and reverse voltage drop across the diode. You can consider the meter resistance and series resistance in series as if it were a resistor in parallel with the dioade with an ideal voltmeter (no current flow) in parallel. The meter is probably 50 microamps at full scale

[@DAVIDGREGORYKERR]

The DEC PDP11 is one brilliant machine which I have used at the College of Further and Higher Education at Trostan Ave Northern Ireland.

[@simonkormendy849]

One way you could test those germanium diodes is with an Oscilloscope that has a built-in component tester, my old Dick Smith Electronics DSE Q-1804 20MHz dual-trace analog scope has a built-in component tester that temporarily puts the scope into X/Y mode when you press the component test button, it is great for testing transistors and diodes.

[@willjackson1955]

Better way if his scope has no such capabiilty is to build a 5-component Octopus IV tracer 6V transformer, two resistors to bring it down to 1V pkpk, two banana plugs and that is all! Same functionality, in a pinch

[@CollinBaillie]

I reckon both of these are probably pointless, given that the normal method of checking the parts made them look om. Did you watch the full video? These diodes are seeing reverse voltages of 24v. Neither of these two suggestions would offer significant enough voltage to show the reverse leakage issues discovered using the official tester. Similarly for the forward voltage drop when they're seeing 30v forward applied.

[@willjackson1955]

@@CollinBaillie Of course the simplest modification would be to bump up the test voltage to 30 Volts Peak to peak using a suitable transformer, that's easily done. My own Octopus has adjustable voltage and current limits to check Zeners and diode leakages

[@skeezixcodejedi]

As soon as this machine was unveiled so long ago, my biggest worry was.. the wire wrap. All the components can be tested and replaced somehow, but the wirewrap.. surely isn't documented, and looks like thousaands and thousands of them, so.. what if there are some loose ones? some opcodes go weird, and be really hard to find. *prays*

[@UsagiElectric]

There's some good news on this front! It isn't wire wrap, it's actually all soldered, so it's a very strong connection. But also, we have the full schematics, so if an OpCode isn't doing what it's supposed to do (and the Diaper test routines test all the OpCodes), we can trace the logic through the schematics and check point to point connections.

[@skeezixcodejedi]

@@UsagiElectric Wow, thats super lucky the schematics are captured, and good point about DIAPER (or writing your own test program.) Amazing work as always!

[@ricardog2165]

@@UsagiElectric In Tracy Kidder’s 1981 book, “The Soul of a New Machine” he said the MIT hackers manipulated connections on the PDP processor to add brand new opcodes!

[@rickhole]

You have built up a huge TEAM USAGI. I suggest you design a suitable T-shirt for Team Usagi to purchase!

[@tenaciousdre]

Just a thought but 4x 9v batteries would be 36v if you wanted to eliminate any active electronics and phantom power draw while not in use. Also if 36v is too high just add a few diodes in series with the batteries as a voltage drop.

[@neccron9956]

In this case, adding diodes in series with batteries would cause an issue if a test was measuring something less then the forward current of the series diodes.

[@cameramaker]

7:45 ... oh my OCD, why are those banana plugs in wrong - swapped - colours? :D

[@UsagiElectric]

I can't tell you how many times that tripped me up when testing individual diodes!

[@OscarSommerbo]

Booting might have been mostly luck with 2% of all diodes bad. And, Thanks Lloyd, again!

[@raphaelschneider7852]

You glued the batterie pack onto the factory stamps?

[@georgestephens2593]

I saw that too and cringed!

[@Scott-i9v2s]

He said "Double-sided tape"...

[@raphaelschneider7852]

@@Scott-i9v2s Yeah, it’s still not good for the ink xD

[@cheeseparis1]

so much enjoyment in this video... this testing tool is great! Looking forward to seeing this computer calculate one milllion decimals of pi

[@flamshiz]

not marking which slot they came out of is craziness to me. that's my first instinct. especially on a legacy system, I'd keep the configuration as close to original as possible just in case the assembly order is meaningful

[@volvo09]

They are all supposed to be identical, the slots are labeled and the components color coded by function. It's designed to be worked on like this.

[@UsagiElectric]

As volvo09 said, the slots are all keyed and all the cards are labeled and color coded by function. Every card should be completely interchangeable with other cards of the same type. I actually specifically chose not retain the same configuration as it's a good way of highlighting failures we may not have caught yet. It can be a little frustrating and time consuming to track down though, haha.

[@flamshiz]

@@volvo09 oh I have no doubt that it was designed to be interchangeable. but with something that old, I would think maybe some board warpage or some corrosion patterns or something might mean that returning something to its original slot could help make better contact or something that wasn't immediately apparent

[@neccron9956]

Even if they are the same card, it is good practice to replace any component/card back in its original location (not just for this project).

[@marksterling8286]

Great video had me on the edge of my seat, have a safe trip.

[@EsotericArctos]

That screw on the front is the Mechanical Zero. When the device is OFF and the meter is reading nothing, you use that to adjust the meter to read exactly Zero. Any other adjustments should be electrical calibrations. What you did may work, but it is not the correct use of the mechanical zero and it may affect the accuracy across the dial. Yeah I know, I am being pedantic. lol. I do love your videos, and this tester will definitely save you a heap of time.

[@aetch77]

Yes, absolutely, you're making progress. The G15 has 60 less faults than it did before.

[@theelmonk]

I guess Lloyd would have noticed any problems, but | have an oscilloscope tester with rotary switches to run through a selection of voltage levels, matching the Y gain controls on the oscilloscope. Because every test needs to run twice through the ranges and back to zero, those rotary switches are worn down so far that the contacts don't make. This would be a big danger on the diode switch here.

[@jwhite5008]

you are correct but since a diode is tested both for forward and reverse direction, and there are multiple of them, all combinations are tested - if 10 cards all seem to have bad diode #5 in forward direction then it's suspicious enough to check the tester itself

[@johnopalko5223]

Greetings, fellow nerds! Just a quick straw poll since I see a number of you are roughly my age. How many others here can trace their obsession with computers back to reading _Danny Dunn and the Homework Machine?_ I read it when i was 8 or 9 years old (1963 or '64) and it started me on the road to ruin. It also led me to a lifetime of working with these beasts, so I can't really complain.

[@stphinkle]

You may want to install a larger battery or a plug for a wall wort. I suspect that the tester with a meter, inverter board, and others will eat the AA batteries pretty quickly. 6V to 33V is about 6 times the voltage which requires like 6 times the amperage to convert, not counting the no-load current draw of the inverter board. Also I think the meter mechanism takes some power too to move.

[@Bob-1802]

At 15:15, I would say that: if the diode has higher internal resistance, its voltage drop will increase so LESS current will be shunted at the ammeter. The needle will go up showing a diode failure.

[@cdh76]

If the voltage drop is higher, then more current flows through the 10k and the ammeter since there is a higher voltage across them.

[@Bob-1802]

@@cdh76 Indeed, simpler explanation.

[@tedcollins4684]

Tool for the job! Thanks for sharing!

[@janno288]

it still is happening. I cant refresh youtube anymore without seeing a recent uploaded video from you

[@semuhphor]

One set of batteries, or did you have to replace them?

[@UsagiElectric]

One set of AA's easily lasted the entire testing! I could probably get about a week of a couple of hours a day of use out of a set of batteries. It's surprisingly good!

[@mrnmrn1]

The majority of the power consumption probably is that 7 segment display on the boost converter board. I would find a way to disable that display when not needed.

[@Mmouse_]

The soldering lover in me says "replace them all!" the preservationist in me says "are you mad?!" Edit: if this machine wasn't what it is... It would be scrapped, it's like trying to repair a car that's been driven off a cliff, bounced down the side of the cliff face then landed in the sea and sat there for a few years.

[@dodgem259]

Funny you mention the car analogy because that is exactly what happened to one of Britain's car manufacturer Land Rover. They were looking for one of the very first ever produced Land Rovers and it was eventually found in a farmers field. Everything about it had deteriorated or rusted to bits, the body work all damaged, the frame rusted to bits, the interior destroyed by the elements and yet Land Rover said they are going to get it back to new condition and have it permanently on display in their museum.

[@jwhite5008]

replace more than 1000 diodes? this is quite a lot of work that he does not need doing Also enthusiasts tried and successfully repaired a bunch of old computers that sat on the ground in a barn collecting rainwater and dirt since probably 1980s, see for example Adrian's basement and Epictronics channels, this one is in nowhere near as bad condition

[@UsagiElectric]

Ultimately, only around 2% of the diodes were bad. That's an incredibly good yield! If you had a computer with 100 ICs in it, and two of them were bad, it would sound crazy to replace all 50 ICs. Many of the G15s did get scrapped. Through the 70s and 80s, these weren't special machines, they were just old, heavy and hot. Bendix made around 400 in total, but I've only been able to account for around 10 to 15 still existing today. I'm sure the actual number is probably double or triple that, but that still means less than 50 out of 400 surviving, which is pretty wild!

[@GianmarioScotti]

Worth noting that the 12AV7 is a twin triode, so it counts as two active components in one.

[@unRealityFPV]

Reverse engineering the diode tester is actually insane. Wow.

[@Richardincancale]

One step at a time - you’ll get there!

[@Alexis_du_60]

0:09 That's impressive on its own to me, they don't build 'em like they used to!

[@jhpyle2]

Lloyd is just the best!!

[@terryraymond7984]

At least shes moving forward little by little cool

[@uomoartificiale]

Th fakeout was hilarious 😂

[@bigjd2k]

Next thing is going to be “these diodes keep breaking down, let’s replace all of them” 😮

[@LongnoseRob]

Even if it does boot further then before, still very nice progress!

[@pragmax]

21:20 - You're still here? It's over. Go home. Go.

[@richardbrobeck2384]

Restoring early radios and other electronics I have been finding more and more bad Germanium Diodes and transistors .

[@TommyCrosby]

He has a computer the size of a refrigerator, in the house? BONKERS!

[@HelloitsThatguy]

Swedish fish is my favorite candy lol, spotted some on the desk

[@DataToTheZero]

I hate to ask this. But is it possible that because that the computer was halting early in the boot process some of the diodes hadn't seen current since it last ran? And when you tested it the diodes tested okay but were actually marginal and ready to fail when fully loaded? It seams to me that the tester really wasn't apply as much current load to the diodes as they'd see in operation?

[@FredBedderhead]

I really like chatting in discord with you and everyone, there was 58 bad diodes

[@andreas7136]

The simple fact, that this diode tester exists, tells me: This computer needed al lot of service in the time.

[@bloodyhell302]

I have the same opposite problem trying to fix an old Paia drum machine; it tests as a failure in circuit but working properly outside.

[@LordHonkInc]

Regardless of whether the cable management of the tester was original or if Lloyd did it just to be neat (it _looks_ to be the former, but I can't rule out that Lloyd just so happened to use twist ties instead of the more modern standard of zip ties, so ¯\_(ツ)_/¯), in either case I really like how it's done. I wouldn't bat an eye if it turned out to be just a bodged-to-hell rat's nest of wires, but it looks better than anything I ever cable managed. Very cool!

[@semuhphor]

Excellent.

[@frankowalker4662]

Awesome diode tester.

[@ibanezleftyclub]

It would almost seem more logical to just replace all germanium diodes in the entire machine, since we all know the reliability of 70 year old diodes. Plus the cheap bulk cost of silicon diodes these days. I know it’s a ton of work, but imagine having to keep going though that each time one fails.

[@gameyord7182]

Hey bro, check all of the filaments just in case, haf of the thing could be working, but maybe there's an amp or something that aint working because of a vacuum failure or a blown filament 😅

[@tom23rd]

I was literally changing "encore encore" and yup, it worked 😂

[@williamsquires3070]

Now, someone needs to make a tester for the tube boards, too. 😅

[@andljoy]

That wire loom, so sexy!

[@youngmonk3801]

this diode tester secretly wishes it was a DJ mixer with a cross-fader, and level adjustments...maybe even an input selector

[@terryraymond7984]

yeah I think I would like to see what the Bendix does now

[@colinstu]

For currency conversions, do you adjust for inflation first and then calculate the currency conversion? Or do you do the currency conversion at the historical exchange rate first and then adjust that number for inflation of that currency since then? Think latter would be more accurate?

[@SergeWallace]

Yes, I would have come up with a panel grid row and slot numbering system to get the cards back in the same slot. Else it's a basket case... Moves the problems.

[@me0262]

We have no idea how to use it, we have no documentation. But we have a Lloyd.

[@stealthdrifter4556]

Great video, but you didn't show how you test the clamp cards.

[@crazyedo9979]

So you lit the BAT signal for these diodes. Please use a fume extractor next time you do such kind of solder job. And write the operation instructions down for the next operator.😁