Casio CQ-1 Diagnosis and Repair

Casio CQ-1 Diagnosis and Repair

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I usually, have a lot of projects, up in the air waiting for parts getting, stumped, and trying to think of something in the background while I work on something else so, when, I make videos about something, and then say, I'm going to do a follow-up and take forever to do that it's not because I don't want to do that video it's, just something it's gonna take me time to get back to but. Today we're. Gonna get back to this the. Casio, cq1. Released. In 1976. The Casio cq1, is a four, function, calculator clock. Calendar. And stopwatch. And. It has an eight digit vacuum, fluorescent display, no. I think this is a very, pretty calculator, which isn't too surprising because that's something Casio, was quite good at in the 70s, now unfortunately, I haven't been able to show this calculator running yet and that's because well. It. Does. Not work, I was. Sent this in by a viewer who was hoping. That I would be able to get it running and that's, what I'm going to try and do today now, the, first, time I showed this in the mail video that I opened it on I, didn't. Have, the, correct, batteries. For. The backup, so I wasn't, a hundred percent sure that. It would actually work without those. But, turns. Out that wasn't, the problem so there, is something actually wrong with this which, does. Seem to be common I've seen several, other instances. Of this calculator, not functioning, as well so, I think there's something that just goes wrong, with these now. When I got this in the mail video I'd tried to open it and troubleshoot it initially. To see if I could figure out anything was wrong and, unfortunately. I couldn't easily, find, anything, in particular that, was suspect other than this, diode now I didn't, cover what I did here in the, mail video but let me briefly explain it, this diode was originally, on the other side and it's. Right underneath the display and I'll show you when I take it out but the, diode.

Here Was shorted, so I was thinking perhaps it. Had been blown and was shorted across but, it turns out it's not the, two, sides of this diode are actually connected to the speaker. Which is shorted. Because that's how a speaker works so I have. Tried to work on this already but that was as far as I got and that didn't change anything all. Right and as I get it open and look in here we can see that right. Down in here there's, kind of a missing point. And that's where that diode was it's yeah. That was a total pain to remove. There, so that's why I didn't bother doing it on camera but, yeah, now we can see in here so it's it's. Time to start trying to diagnose. This thing okay. So the first thing I want to test here is whether or not power from the battery is even getting into this thing so I'm, gonna go ahead and install, that now, and then. I'm going to use my, multimeter, here to. Check whether or not the voltage is getting into, the calculator, so. Let's just, test, here, and here. Yep. I get 1.3, and, now I want to make sure that I'm actually getting that on ground, so I wonder where ground is on. Here, it's. Not that one it's. Not that one. Hmm. About, that that's big. And wide. Nope. Nope. Hmm. Gotta. Have it coming in from somewhere, so where. Does. It go. Hmm. Interesting. Let me track, down where that side, goes to on the, circuit board so it's actually connected to the other. Board that's mostly, used, for holding, the buttons and in reading the data off of those and connects. The actual. No it doesn't connect to the display the display is actually on here and that's what this, rows for the, display, is just it's really hung in there in a very awkward way so anyway, let me figure out where that finally, attaches to here, okay. It just goes from here. To here, and. If. I switch over to voltage we can see that I do get, a reading, from. The battery come. On you. Were just working there. We go, 1.2. Volts I do get the reading, from the battery but it's it's, kind of spotty so that that this, side still a bit dirty if I move it down there yeah it gets to a cleaner, area, but. That, connection that's pretty bad maybe I should just try cleaning, that and see what happens yeah. That is not good looking let's. Uh give that a bit of a scrub. It's. Looking better. Yeah. It's really dirty this is just gonna take some effort all. Right there we go now I've got that battery terminal looking a lot better I almost. Think it's brass because it looks like it was tarnished. I ended up taking a wire brush to it and just scraping, it with that and that did a lot more than scrubbing. With a toothbrush and CLR did so yeah. I don't know what's going on there brass would be a very weird choice but, maybe. I don't know let's. See if that helped at all. Unfortunately. That's not any better. One. Difference is now I, don't. Hear the speaker, when I rotate the battery so I think, power is, getting through to the rest of the board normally. Now so we, can start to try and track down where the issue is on here. Okay. So I've been digging around for a bit in here and I've got a, pretty, good lead on what the problem is so first, of all I want to show you that I have my really, noisy, old power supply connected here and it's, connected, to here which.

Runs Down to here, and, that does, trace. Around the board to a few places, but. One interesting thing is that the ground, input, from the battery isn't, actually. Connected, to any, of, the, chips or the really, important components, so, what's. Going on here is that this, inverter. Circuit is actually acting, as a. Voltage regulator, that, powers everything else so the, ground from battery isn't directly connected to the important stuff like the negative, rails on the capacitor, not, connected, to battery ground, so, the. Ground, doesn't, directly, get through here now. One of the problems I was having is, that I can't actually get a voltage reference to anything and when, I do turn something on or when, I do turn it on I should say the, voltage starts, to slowly drift one way towards, ground so, something. Isn't quite right which, means that it's probably, in, the, voltage regulator, circuit and, I'm. Pretty sure I, found, the, problem, it's, actually, very, identifiable. We. Can see this bent-over capacitor, on the voltage regulator circuit here and if. We pry. That up. Mmm. Yeah, that. Transistor. Doesn't, really look too good, there. So. Yeah. I'm pretty sure, something. Went wrong with that thing at some point, and we're. Not getting a proper voltage generation, now so. It looks like I could probably replace, this, part and have this thing back up and running which great. I'm you, know I really want to do that the, only problem I have is getting, my hand a replacement. For that now, I like, to usually do these videos and as short of time as possible and well. I could try and possibly. Order that one online it doesn't look, like it's a part that's continuing, to be made I could trace them an equivalent yada, yada but. I do have, this. On hand and s. 8550. Now, these are both 20, volt 700. Milliamp transistors. PNP. So. This. Should, be a pretty, equivalent drop-in. Replacement. There's. Just one problem you can see here, this has the, pinout listed emitter collector base. Well. This, is emitter. Base, collector. So. I'm gonna have to switch these, two pins. Over, here to, be able to get this one to fit in there and. It gets even more fun because, this. Separate, board here. There's. No way to get to the bottom of the components, on here I'll have to remove this, whole, thing.

To Be able to get this out so. Yay. Whoo. All right it's, finally. Man that was not. Easy it's almost like they didn't think anyone was ever gonna bother trying to repair one of these, now. Little. Little no here don't be surprised if one day the blue is d-mat disappears, you see how cloudy. And terrible. The image looks right where the transistor is well watch this. BAM. All. I did was put black, under it and it looks better. Yeah. The blue. ESD mat kind of reflects a lot of light up into the camera and causes, issues, I can make, it a little better too I can block a little more light yeah. So the. Yeah. Who would guess that a bright reflective, surface, isn't the best thing to film off of now, that it's loose we can really see that it's definitely toast, at Legg is all crusty. And black and it looks like there's a crack here that runs up along the case of the package so. Yeah, thing. It. Had a catastrophic failure. Hopefully. I am going to be able to replace it without, too. Much, difficulty, but, we'll. Have to see how that goes. Okay. There we go one dead. Transistor. It's uh. Yeah. Let's, see how this goes trying, to replace it I'm really you know hoping. This. Would definitely be the fun. Way to get the wrong pin out of transistor, to fit in there not. The best way though but, the fun way. This. Is the much more boring practical. Way to do it though and I, should. Probably just go ahead and leave it like that. All. Right all that's left to do is just to put that back, in there it's gonna be pretty boring you basically, already see me do that so let's just go ahead and skip to the next part, all. Right I pretty much put it all back together because I remember when I did the mail, video someone. Told me you needed these batteries, in here for it to turn on and there's, no way to really conveniently, hold those in there so. Let's. See what happens. Okay. That's. Really. Disappointing. Hmm. You. Know it seemed more disappointing, ah, there. Was something. Was. That oh. We. Have something, oh. I. Think the battery terminals are still kind of dirty maybe the coin-cell ones are. That. Looks. To be. Functioning. Maybe. Time. I. Don't. Know how. To. Use this okay, comp. Maybe, that's the computer one. Plus. Two, equals. We. Just calculated, on a cq1. Okay. So clearly, this. Thing's at least partially, functional now all right. Set.

Man. I don't, know how to do anything. On here now one. Two plus. Three equals no okay so time. Lap. I don't know. Would. Stopwatch, be how. Would I do that. St. I don't know what this is. Hmm, Oh edits. I'm clear, okay. Those. Don't do anything time. See. What time does. Time. Doesn't want to do anything okay. Well. There's, no guarantees at that blown, transistor, was the only, problem on. Here. Whoa whoa haha. So. What I do I pressed equals off. Equals. Okay. Getting. Closer. That. Looks like, minutes. Seconds. Milliseconds. If you know sub seconds. None. Of those are doing anything come on. Work. Equals. Okay, so. Clear. One. Of these has to do. Something. Period. So. Maybe these buttons. Aren't. Working right now I. Think. I need a manual really. Okay. So my first instincts, were right here, it's, the buttons so I can press time. Really, hard and. Then it will start the, stopwatch, all, this. Thing's really sweet. Now. I can also. Go. To set. And set. The time so if I want to set it to the, current date which is December. 27th. 2018. One, eight, one. Two. Two. Seven. And. It. Now has the date and now I can set the time the current time is, 9:40. A.m. nine. Four. Zero. BAM. And, then I believe it's plus. Time. Larry, oh now I, don't. Know. Quite. How you up there we go 9:40. On the 27th, I don't, know how I show. The date. But, sweet, okay. So. Compute. Time. How, do I see the date, or set an alarm maybe I got a press real hard to, set an alarm ah. Now. That's oh well. Hold on here holding. That no. I think. I need to get back into here and clean these out. It's. Oh so convenient. To get to all, those buttons in there and got it take. Out every single one of them screws. Actually. Got. Into, this. Calculator. This deep last time I just didn't show it all on video like I said. In the mail. Video well add the little thing. On-screen had a lot of false leads. On air the first time around, I'm. So, happy this thing's working this. Is nice yeah. That. Makes me really happy. Okay. How. Does this have. To have spent a while all right there we go oh they're just carbon. Pads. That's. Not good. Smell. Like a whole lot I can do about carbon pads not working. Huh. We have like some secret buttons down here. Actually. Hold on these are. Those. Are super, weird are these all connected. How. Does this work hold on these aren't these. Aren't interleaved. Like, your, usual carbon, pad buttons. They're. Just solid pads, and, they're, all connected, even. Huh. These. Look like just carbon. Grids. I have never, seen that before that's super, strange wow, I didn't notice that last time I was in here well obviously. Huh. Okay. That. Means there's gonna be something. Like connect. It down to, the bottom, here so weird, how how, does that work so. Okay. There's an open, pad they're hoping, pad there okay. All. Right, so, then, there should be. Some. Here there there and there alright so there's. Many, pads wow, this is crazy okay so. These. Are the, touch, points, that make, up like, one row or column and, then that's that whole thing, Jase, is. They. Really wanted to save i/o on this thing yeah. Except for these buttons, each one of those gets their own oh, man. Alright so who. Maybe. I should try. Pencil. Eraser on those a little bit those are the failure point those are rubbin constantly. We're. Good just try it and graphite, from a pencil on there yeah yeah. That's. That's. Different, I've never seen, matrix. 2 karbonpad, it's matrixed, in the carbon. Huh. No. Unfortunately this thing's a massive, pain to put back together because it has a little plastic tabs all over the case and that's, how it goes together and comes apart and I know eventually if I keep trying to open this thing and put it back together they're. Gonna break and then it won't go back together right it does have one, screw that holds it together but that's almost token, I don't even know why it's there that could be that. Holds, it way less than any of the tabs do so yeah. I'm just gonna go ahead and do all of the. Procedures. I can think of on here to try and resuscitate. This, all at once and then just, hope that that was enough because I don't want to keep trying to open this up and put it back together and, eventually.

Get It to work so let's just do it all right now. Number. Buttons felt, fine but I'm just gonna go ahead and, be. Sure about this whoops. Guess. There's no reason not to take, that off but huh. Okay. Let's. Try getting, a little. Carbon. On here, or graphite. Aid. In the conductivity. All. Right since these ones really kind of felt flying over all I'm not gonna do, these ones too much let's just stick with that and see how that goes all. Right I've got it all buttoned, up now after cleaning off the contacts. For that I can, set it to stopwatch, give, that a press not too hard and it. Works now. One thing I find confusing is, this says start/stop that says lap that, does not lap that starts, and stops it and it's, not that these are somehow shorted, in doing the same thing if, I turn it off set, it back to that I can hit lap and then, it does that which is different. But. Then it continues, going, on so I don't really know but hey. It's working too and I can go back over to calculate, or, compute, you. Know twelve times. Three equals, thirty-six, and it's, working just fine, so, this. Is clearly, a successful. Repair which, is just awesome, now. I will say there is still one further problem, I don't know how I got it to turn on but I got the alarm to turn on and the speaker, output is, extremely. Weak but. That could be my fault after I messed, with that diode, in there and I'm. I'll. Live without the alarm that's not a big deal it's. If. Anything that's just gonna be less annoying maybe it might have an alarm because often, the batteries, get low but yeah. For, now it's. Working and this was a very satisfying repair, it's been really driving me nuts eing this sit on my shelf in the background of stuff. And just not working, I'm sorry. It took me this long to get to it I'm just kind of having a problem getting to the male videos I usually do. My videos when I get something new. That's really, exciting and I get all this male stuff in at once it's really hard to pick what to do and then, while. I'm sitting there thinking I should, do this I should do that I usually get something else that's not male and then if I do that I'm not putting preference. Over one male item over another so I'm. Sorry I'm gonna try and get to do the male stuff, more, it's, just I also. Want to do other stuff that I'd get, in so like the next things definitely, not going to be a male video but pretty. Sure you guys will be ok with that well. I hope this was, enjoyable. And maybe, you guys learned something especially. About replacing, transistors, that, was kind, of fun all I did was bend the legs around but yeah, I hope you guys enjoyed that and I'll see you next time.

2018-12-31 01:35

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An addendum I meant to say in the video but forgot to. I glanced over the fact that the calculator has a connector to be powered from an external power supply (model # AD-1S). From what I've seen online, this should just be a 1.5V center negative DC power supply. I wouldn't be surprised if the transistor was blown from someone connecting the wrong PSU as almost any of them will be a higher voltage.

+rogerwilco99 Are you actually talking about the past, or describing the present?

I guess they figured circuit protection wasn't worth the cost or effort. As for fixing one of these, the cost to repair one would have likely been more than the loss on replacing it or close to it. This unit was probably designed to be disposable. Even in the '70s, it was getting cost prohibitive to repair electronic devices at the component level. Repairing computers, etc, back then meant replacing a bad board and sending the board back to a depot for repair or disposal. Consumer electronics, except for higher ticket items like TVs and higher end stereos, were mostly throw away items by then.


To think that these things cost hundreds of dollars back in the 70s and 80s.

Repping another person's merch might be weird but I've heard Gamer's Nexus makes a good ESD mat and it's (mostly) black.

RIP transistor.

1:06 LMAO that battery running away

Very clean repair! I bet the tetris method for the diode would look funny for whoever would open it up next!

I remember a casio vacuum fluorescent display calculator at home from like 1983. In retrospect, I see it's slightly odd these were still around, being more a mid to late '70s thing. Those are aesthetically nice, and would be cool to have one around, but for the time period they were somewhat impractical for a battery operated device compared to LCD display calculators, whose battery life was like TENS of times superior. That calculator I mentioned, which was just a pocket calculator, even had a socket for a power adaptor, so go figure. After some searching for the model, I can tell you it was rated 0,2W. Does not sound like a lot maybe? For a calculator it IS a lot

• Oh, "getting stuuumped". That makes much more sense. I thought you said something else. • For the time-lapse segments, consider muting the video and playing muzak from the YouTube audio library instead. • 12:49 - It tried to get away but it was too late, you saw it. • 13:38 - I don't suppose there's a manual for it on ReplacementDocs…

18:10 processing processing XD

I felt exasperated just watching you take that board out.

THIS is a comment thanking you for a great year of content. Keep it strong druaga2.

Will you do a Windows XP PC Build the videos is coming Oct, 25th, 2021, P. S. LGR Videos the before f***ing ideas the videos not stolen will be needed 20th anniversary of win xp


I know it's kinda not related, but as you seem to have some experience with casio products, are casio wristwatchs any good? I mean i saw some cheap ones like the retro model, but i dont know if they are durable.

I was thinking about this when you dissasembled that keyboard to replace the cap connectors....but now I am saying it - YOU REALLY NEED A VACUUM DESOLDERING PUMP !

speeded up sound fucking annoying

VFDs look so cool. I wish more products still used them.

that transistor is a 2SB561. The equivalent are 2N4954, 2SA1534, 2SA683, 2SB562, 2SB598, 2SB621, 2SB621A, 2SB698, KSB564AC, KSB810, KSB811 or KTA1283.

you got a pro tech toolkit?

Nice repair, 'tis a very interesting little calculator, time, alarm... gadget!

Your video quality has upgraded to 4k60! What camera are you using? I thought you liked Nikons but I didn't think they were capable.

I got a Blackmagic Pocket Cinema Camera 4k. I wanted to get one of the new Nikon Z Series mirrorless cameras after they teased them nearly a year ago. But they made some really poor choices with those. I did a video on modding a Nikon to MF3 lens adapter where I joked about it a bit: but really, if I have to by an adapter to use my F-Mount lenses on a new Nikon, why shouldn't I play the field instead with a different brand altogether? So it's their own fault really. The Z7 or Z6 couldn't do 4k60 which was a must for anything I was going to buy. And they didn't offer a lot in a quality increase. Still no ProRes or even bother to list the bitrates. After looking at other options once the specs were released on the Nikon, I "settled" on the BMPCC4K. By "settled" I mean, got a MASSIVE upgrade! It is a real video camera, not a photo camera pulling double duty. I will say that I don't recommend it for most people though, it's a camera geared towards manual operation. It doesn't even do continuous auto focus and the auto exposure is laughably slow. I always use my cameras in full manual since it gives me the best control, so switching to a manual centric camera only helped me shoot better. I love this camera, it was the right choice for me. I'm shooting in ProRes 422 in a log color space and editing with the included full version of Davinci Resolve, which works on Linux. I'm not done getting more image quality out of this setup. At some point I'm going to get a speedbooster lens adapter which will correct the sensor size difference between the Nikon APS-C lenses I'm using and the BMPCC4K's MF3 sensor. I'll also be getting a new GPU which will let me better leverage Resolve and it's powerful noise canceling. I've done some tests, it does a great job without sacrificing quality. But my 2GB GTX 960 can't handle doing it on full 4k60 footage. And some lighting upgrades are going to be up soon which will reduce some of the glare I had in this video but also just give me more light to work with in general. At some point I'll be doing a full walk through video of my setup, so if there is more you want to know feel free to ask because it could be good to add that in.

3M Scotch-brite pads are you friend for cleaning metal contacts and PCB traces.

There are day name abbreviations across the bottom of the display (SUN MON TUE etc) but not sure how those work. Possibly a blinking decimal point over the current day? The date you entered, December 27th 2018, was a Thursday. But while displaying the date, there was a blinking decimal point above FRI possibly indicating that the day was Friday. I checked and December 27th 1918 was indeed a Friday. So it seems this device may not be Y2K compliant. EDIT: This got me searching around... I found another video which explains the display and seems to indicate that the device was indeed Y2K compliant at least as of March 3rd 2012.

+AkBKukU I just edited my comment and added a link to another video I found. He demonstrates the cool date calculation features as well.

That's funny! The video was running long with the keyboard part of the repair so I didn't want to put too much more time into looking at the nitty gritty details of using this. That makes sense though.

On the next mailbag could someone please send this poor boy some desoldering braid and an electric desoldering pump?

I always like and enjoy your videos. Thanks.

I suggest you use fiber brush to clean the dirty contacts.

Why not just do the mail bag items in a "first in, first out" type of fashion. Like sort them by when you get them in even though you do the mail bag at once, I'm sure you don't get them in all on the same day. That way no one can accuse you of preferential treatment.

I like opening all the mail at once, it make it more fun. But for some items I need to get more stuff, order parts, or do a lot of testing. They aren't all equivalently easy to make videos on. And not all of them are going to get unique videos either (I'm not going to do a dedicated video on each version of Ubuntu for instance). So it is variable which ones I'll do when, but in general I will try to do them in FIFO order baring delays and other non mail videos.

your on-screen multi-meter is sick -- nice setup man, I love seeing your channel/project videos evolve. keep it up man

I had one of those when I was in college in 1977. I'd had to use a slide rule up until I got that. I wanted the same Texas Instruments SR-50 calculator it seemed everyone else had. But I got this for my birthday in '77. The wall wart you could power it with was bigger than the calculator. I unfortunately dropped it getting off the campus bus one afternoon and didn't hear it fall. I DID hear the crunch as the bus ran over it, though. Not much hope of repairing it after that. Fortunately, my grandmother bought me an SR-51 calculator for Christmas that year (they were almost $200 back then - in 1977 dollars (about $650 in today's money)).

The Lap Button Actually works, as in it freezes the display so you can note the time passed whilst the watch continues in the background. Look at how the watch jumps forward in time after the second press.

Also watch working right, it display only when you press button, because it is battery powered.

Really enjoyed todays video, glad to see that it works now!

Lots of fun! Great video!

impressive job! I am admiring your video.

The "lap" button seems to work as intended: It displays the time so far, but the stopwatch continues to run in the background. This Casio should have all the cool date calculations my childhood Casio Lighter calculator had: You should be able to calculate the number of days between dates, display which day of the week a given date was etc...

Yep, gives you time to write the laptime down, this is how stopwatches have always worked iirc.

I'm used to the lap button on stop watches starting a new timer but still running a total in the background. So you could time a single lap and the entire thing. I guess this way does something similar but you wouldn't see the time between lap 1 and lap 2 with it like this. So I guess it works, it just sucks.

Wow! This calculator was in a mail order catalog I had in the late 70s and I thought it was such a cool looking device but have never seen one actually functional until now. Thank you SO MUCH for making this video!

Idk why but every time I get a notification from your channel I think to myself: "that's great Abu-Akbar has a new video"..

Now you made me google Abu Akbar LOL

A polarising filter should help with the reflected light from the ESD mat, just remember to remove it before trying to film an LCD display!

Also, make sure you get your cash from an ATM machine.

+AkBKukU You've got a 3d printer, right? ;)

Yeah, but It's a massive pain with my setup. My lenses rotate the threads when focusing and the macro shots are done with a reversing ring. So I'd be adjusting it for every single shot. Maybe if I had an ND mount for between the body and lens I would do it. But those aren't cheap.

I recently found a unsonic 21 calculator in the original box and what makes it unique is that can play black jack. It all works except if try to run it from batteries. Found calculator for only $3 at flea market.

That's super cool, I love finding stuff like that!


Thank god your a youtuber I love watching your videos and your voice is so soothing. don't ever let anyone tell you your content is bad, never let anyone get you down, Your content makes my day

hardware Druaga1

Druaga1 if he had any idea what he was talking about ever

Less weed though :D

holaaa 182



Newb! This is the first video of yours I've watched and it made me feel so embarrassed for you dude... Hehe this is a simple fix and you're stammering all over the place. Bro... stop making videos now. You're a NEWB. A lot of us watching are laughing at you. OF COURSE those are non-interleaved carbon pad buttons! I knew it before you even opened the case. It quite obvious, NEWB. You've never seen it before... Hehe, doesn't surprise me newb. Stop trying and give up, kid. Just kidding, of course! Loved the video!

Speakers don't work from being shorted. They're a load like anything else. They have a dopant or a coil with 4 or 8 ohms of impedance. That's not a short.

Looks like that 2SB561 transistor let out the magic smoke. Probably someone over-voltaged it with an incorrect mains adaptor,

Great job. Talking through your trouble shooting thoughts is very helpful.

The moment I saw it has a VFD and you said it was dead, I tought: "SMPS failed". And hey, I guessed right :D

+AkBKukU Brilliant summary, thank you. I considered the BMPCC4K myself but there were two dealbreakers for me: 1. No IBIS 2. No autofocus. I know for "product videography" you use a tripod and manual focus anyway, but auto is really nice for macro lenses, you get the focus and then switch to manual, much nicer than fiddling around. I look forward to your "my video production method" video. My only recommendation is that you try to shoot 10-bit, since the log colorspace is irreparably mangled by an 8-bit colorspace. Keep up the great work!

+Retro Retiree That's slightly wrong. It's not a leap year when divisible by 100, unless it's divisible by 400. So 2000 was a leap year, and programmers who didn't know the rule got lucky.

Many people even systems people didn't know or forgot the leap year rule for the year 2000. It is a leap year if divisible by 4 but NOT a leap if the year is divisible by 400 hence it is one day out.

I had one of these, it was stolen from my desk at work., along with my Parker fountain pen. That was a bad week. I'm still rather upset after 40 years.

Great video but, dude, get a smaller soldering iron tip. Your life will improve dramatically.

U need a desoldering gun

Nice! Glad to see it working, was wondering when you'd get to it. I wonder what happened to that transistor to make it explode...

I had to double check to be sure, but the BMPCC4K can't record as low as 8bit, 10bit is the minimum: Blackmagic is working on an open RAW format that will record in 12bit with some more real world file sizes. When FFMPEG gets support for that I'll switch to it, I keep all my footage after re-encoding it to h265 for storage space. They have what seems to be a pretty good manual for the API: and there seems to be a lot of interest, so I don't think it will be long.

You should at least keep the blue ESD mat on the thumbnails, it gives a nice unique visual identity to the channel

I have one of those things - the Radio Shack version. Bought it new back in the 70's. Mine doesn't work either. I've been meaning to tackle the repair for a while. No idea if mine has the same fault(s) as yours, yet. Thanks for the vid.

It sure is a handsome beast, shame it doesn’t have a synth in it like the vl tone.

Stumped or stoned? HMMMMMMMM

I understood literally nothing in either of those sentences.

+Retro Retiree Heh, my first "real" job was a summer spent on Y2K fixes on a university mainframe. I'm not sure if we handled the leap year part at all. That's certainly a while back to remember.

+James Potts: So I see. I must have remembered it incorrectly. It was quite a while back I worked on that.

Never had one of those in college, but then again I wasn't born until the year after you used it in college :D

+BilisNegra I think he was pretty clear that this was the case "even in the 70s." Do you have conflicting evidence? Depending on the cost of the board, it may have been a poor use of time to repair it. Especially since the boards would have been manufactured rather cheaply in Japan (especially for a Japanese brand like Casio), but repair of an American unit would likely have to be done locally with US labor prices. By replacing a whole board with a whole spare, you can send back a stack of boards to harvest any valuable enough components. If nothing on the board was particularly expensive, you can skip that step and freight cost and just toss the bad boards.

To be honest, you have a fantastic multimeter there, but you are using a low quality soldering iron and desoldering tool. Please consider upgrading those sooner than later, because a low quality soldering iron will use too much heat and damage certain boards. A "solder sucker" tool is just a pain to use, I'd recommend to replace it with a proper desoldering tool with a built-in vacuum. Other than that though, glad to see you found the issue with the calculator and spent time working on it, I'm sure most people would have just thrown it away.

Cool repair vids man! Keep it up! Let nobody get you down!

The 34401A is great, but the other tools I'm using are at the same caliber as well. I'm using Metcal MX-500 soldering irons (I did a "repair" video a while back on one: The tips manage the temp and you can buy them rated for maximum output ( ). It's the best iron I've ever used. I had a fat tip on in this video because I knew it was all through hole and that I could go quicker than with my fine SMT tips. I think all the macro shots made it look like a plumbing iron with how close I got the camera. The Soldapullt I'm using is actually really good( ), it isn't your $5 one from a local hobby store. It's consistent, strong, cleanable, and you can get replacement tips for $3 and even a full refurb kit ( the brush is the bulk of the cost ). A vacuum iron is on my list for convenience, but the Soldapullt is worth using for small stuff. I probably would have used a powered one here if I had it though since it was through two PCBs.

T h i s .

the pill daily organizer box for small screws is a great idea lol. I've been using small ziploc bags for years

would a polishing bit on a dremel be better for the terminals? since the scratching can increase oxidation

solder suckers actually work surprisingly well once you get a go0d technique and you aren't afraid of damaging the tips in the process, since you have to get the whole tip almost in complete contact with the pad for the vacuuming to work well

Watching this video the other day made me go buy sa spares repair unit on ebay, upon getting it home imagine my disapare asi found the only problem being the original button cells were in the unit still... Not much fun to repair but an awesome calculator :)

Do you no any methods to restore a faded cfd even if the caps are good


its just so star trek

12:11 that's not boring for us who love technician stuff and engineering

+Sparky Awesome story! Glad I sent it to him to fix so you could relive that :)

I owned one just like it, when I was a kid. My father had a drug store, and would sell a few transistor radios, but it was a small store, so he never reslly had many electronic items. I was one of those weird kids, who took old radios & TV's out of trash piles & tinkered with them, sometimes even managing to fix them or at least harvest usable parts for projects. Dad got a Casio CQ-1 in stock around '76 or '77 & I was completely smitten with it, even though I could only look at it through the glass display case. Stopwatches were mostly mechanical, so mostly expensive, in those days, so it was the stopwatch function, which I mostly wanted. Anyhow, I suppose, that Dad noticed me looking at it, everytime, that I'd come to work (your kids were exempt from child labor laws then. Don't know if that's changed or not). Anyhow, Christmas morning came, & lo & behold, Dad gave me the Casio CQ-1. I used it a few years, but it finally quit working, but, by that time, my interest in electronics had switched to girls, who I also sometimes rescued from trash piles, (kidding, but looking back, it seems like it. Of course, I'm no prize myself ), Anyway, I never got around to fixing my CQ-1, & it was eventually discarded. I got back into electronics as my job, when I joined the Army & tinkered a bit now and then, but now, that I'm an old guy, I find myself returning to it as a hobby. It's a great time for it, because of the Internet, mail order parts, etc. Great video. I admire your perseverance! ...I'll bet it was the same fault on my CQ-1, but alas, it's long gone...

Guess you didn't run track, when you were in school? You use the "STARY/STOP button to start and stop, just as it says. Push it to start. Push it again to stop. The "LAP" button is for splits, like if you're timing a two lap race & want to see how fast the first lap was, without stopping the overall timing of the race, you push "LAP" when the first lap is complete. The displayed time will stop, and you can see how long the first lap took, while the stopwatch is still running in the background. You then push "LAP" a second time, and the overall race time is displayed again. When the runners cross the finish line, you push "STOP/START again to stop the overall time.

What's that solder sucker you are using?

hey! Can you help me with the Casio digital diary sf3300A?

If you still have that QL10, it's rare now. Don't sell it! (Or at least do at a high price)

best cocntact cleaner is sandpaper and eriser

Why didn't you jump in the transistor first to make sure it worked before removing that power board?

I had a Parker Jotter taken off my desk around a year ago, so I feel your pain. Things haven't been the same since TBH.

Ummmm... 12x3 DOES equal to 36. So it isn't broken.

Yeah I learned something. A pencil to repair those pads. Imma try that one on a dead remote I have.

And it worked !!!! Thanks man.

Make it a dark blue esd mat. I love the blue too much to see it go... Or maybe a dark green. The choice is yours! -gee eye joeeeeee-

i wonder if there are any instructions on the backside of that damn thing......

OMG a Casio-lator!

@Sparky Awesome story! Glad I sent it to him to fix so you could relive that :)

@BilisNegra I think he was pretty clear that this was the case "even in the 70s." Do you have conflicting evidence? Depending on the cost of the board, it may have been a poor use of time to repair it. Especially since the boards would have been manufactured rather cheaply in Japan (especially for a Japanese brand like Casio), but repair of an American unit would likely have to be done locally with US labor prices. By replacing a whole board with a whole spare, you can send back a stack of boards to harvest any valuable enough components. If nothing on the board was particularly expensive, you can skip that step and freight cost and just toss the bad boards.

@rogerwilco99 Are you actually talking about the past, or describing the present?

@AkBKukU Brilliant summary, thank you. I considered the BMPCC4K myself but there were two dealbreakers for me: 1. No IBIS 2. No autofocus. I know for "product videography" you use a tripod and manual focus anyway, but auto is really nice for macro lenses, you get the focus and then switch to manual, much nicer than fiddling around. I look forward to your "my video production method" video. My only recommendation is that you try to shoot 10-bit, since the log colorspace is irreparably mangled by an 8-bit colorspace. Keep up the great work!

@Retro Retiree Heh, my first "real" job was a summer spent on Y2K fixes on a university mainframe. I'm not sure if we handled the leap year part at all. That's certainly a while back to remember.

@James Potts: So I see. I must have remembered it incorrectly. It was quite a while back I worked on that.

@Retro Retiree That's slightly wrong. It's not a leap year when divisible by 100, unless it's divisible by 400. So 2000 was a leap year, and programmers who didn't know the rule got lucky.

@AkBKukU I just edited my comment and added a link to another video I found. He demonstrates the cool date calculation features as well.

@AkBKukU You've got a 3d printer, right? ;)

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