Sinclair ZX Spectrum 48K Future Proofing

[@dharma-wheelies]

I love the little bleep-bloop jingle at the beginning of your videos. It makes me smile.

[@JanBeta]

I stole it from the C64 game "Flip and Flop" (which is highly recommended). ;)

[@MiniWarzone]

It is always a pleasure watching you work on things. Whenever I see the circuit boards it reminds me of when I used to work for Toshiba operating VCD Sequencers and Avisert machines - that was a very long time ago now. Thank you for this video 👍

[@JanBeta]

Thank you. :) Cool that you worked for Toshiba. Used to be a good brand back in the day (I wonder if they still are?).

[@MiniWarzone]

I can tell you that the quality control was of a very high standard indeed and always inspired me to try and buy Toshiba products if I could. Actually I still have an old Toshiba laptop that is still going strong lol.

[@RMCRetro]

Great work she should give you many more years of colour clash. Those DivMMCs are a must

[@JanBeta]

Haha, I hope so. The DivMMCfuture is brilliant indeed. :)

[@stephaneschmitz8030]

I also have a divMmc (enjoy) but didn't use it yet. Currently I'm using the smart card v2 which is way enough for what I want to do (play some games). Big downside is that it does not support TZX which can be a showstopper for some ...

[@tarstarkusz]

The Spectrum is one of the worst computers ever built. I could not imagine anyone so cheap that they wouldn't put an on/off switch on damn computer! What is with that KB? If you must use a Spectrum, at least use one that has a keyboard on it!

[@peterveer7798]

@@JanBeta Satia nadella first computer

[@AllGamingStarred]

@@tarstarkusz I agree. Who would be so cheap as to put an expensive on/off switch on the computer? Potentially raising the price under $100? Maybe a price conscious developer?

[@vladeb1104]

I remember one of my first electronic lesson for beginners - "if it is possible try to replace 7805 into modern voltage converter". This video is an amazing practical example of that lesson. I've really enjoyed watching it.

[@JanBeta]

Yes, I think it's always a good idea to do it whenever possible. Especially in a small enclosure like this. I think I will retrofit a better switching converter in this ZX sometime though. I don't really trust the cheap one I used much... ;)

[@10p6]

Nice video. However I would not have used paste for the copper heatsink as it could fall off, but instead I would have used an adhesive heat pad to connect them together.

[@JanBeta]

Thanks! I used thermally conductive glue especially designed for the purpose. In my experience it makes a stronger connection than the adhesive pads but it’s a matter of taste really, I guess. I’ve used both with good (and lasting) results. :)

[@wimwiddershins]

Great video as always Jan. Watching you work is therapeutic for us. :) Remember: Always keep a smiling mind. Good wishes.

[@JanBeta]

Thanks Wim. Very much appreciated. :)

[@d0cjkl]

13:00 where do you get the replacement for the 7805? what search term on ebay?

[@JanBeta]

I think I just searched for "7805 replacement" and chose the cheapest option. I would recommend getting a better quality one though, like TRACO or RECOM who both produce very good pin compatible replacements (they are 10 times more expensive but really safe to use).

[@RetroRecipes]

Hi, it's Jan Beta! Not really, it's me! Brilliant work sir. You make a lot of people very happy. Keep it up, keep calm, and carry on. 👍

[@JanBeta]

Ha, now this gets confusing... :D Thanks for your kind words. Very much appreciated.

[@JamesPotts]

I work at an electronics company. Those wrist-straps absolutely make a difference.

[@JanBeta]

Thanks for clarifying. :)

[@borealis75]

I can relate to the therapeutic nature of fixing old tech. I get so tense if I don't get to fix stuff for a while, and real life problems are often quite complex, if not unsolvable :D

[@JanBeta]

Thanks Timo. Yeah, doing this helps a lot. Also the community is really friendly and uplifting. :)

[@jaycee1980]

Nice old rubber wedge there :) Things to watch for in Speccies, as im sure you know: Dead 4116's Dead voltage converter circuit. One of these usually causes the other ! 4116's dont like it when they dont have all of their supply voltages (+5, +12, -5) and typically fail by going short or partial short circuit. This in turn kills the voltage converter circuit, usually by killing TR4. Replacing the 7805 with a modern switchmode converter is definitely a great improvement on these. Sometimes it can also be worth swapping out the Z80 for a modern one.. the old ones are NMOS based and take more power than the more modern CMOS ones. They otherwise behave identically so it is a simple substitution. On Issue 2's like this one, sometimes the VR1/VR2 pots get noisy, and this can affect the picture. Issue 3 and later made these pots unnecessary. I've seen some people replace them with sealed preset pots or even multiturn trimmers.. i think multiturn trimmers is going a bit far, though ;)

[@JanBeta]

I indeed had to adjust the pots and spray them with contact cleaner on this one when I got it. Didn't know that about the Z80. Might be worth a try sometime. If only as an interesting experiment. :) Thanks for sharing your knowledge (again)! :)

[@MS-ho9wq]

20:10 Nah, that's not a no-name brand, that's a genuine Won Hung Lo product

[@ivan_pozdeev_u]

Great. Now you'll be able to show what the games of the 1980s were like to your great-grandchildren in a Mars colony ;-)

[@otopico]

I hope whatever is going on works out for you. Love your videos and it is something special to know that people are working to preserve some of these old computers. Great job as always.

[@JanBeta]

Thanks so much. I'm going to be fine, I need some time to sort things though. Did a little write up on the situation on my Patreon blog thingy in case you are interested: www.patreon.com/posts/intermission-17131571

[@electronash]

5:16 Most of the people who say that ESD wriststraps don't work probably haven't worked in the industry, or actually read up about it. It's a definite "thing", and older chips are especially prone to it, as the chip processes themselves were often more sensitive to getting zapped, and the internal ESD clamp diodes on each IO pin (part of the chip itself) weren't always so great. The older CMOS devices were often VERY sensitive to ESD, like the CMOS SRAM chips you'd find in older 386 / 486 motherboards for the cache. Almost any IC can be damaged by ESD though, but modern chips are thankfully more robust now. Either way, if you REALLY care about the device you're working on, you should wear a wrist strap, or at least use a properly Earthed ESD mat. The thing with ESD is that you never quite know if a few gates inside a chip have been zapped, and that damage may only start to show problems months down the line due to localised heating. It can and does happen to modern CPUs, for example.

[@JanBeta]

Thanks for the clarification. Exactly what I am thinking. If you care about what you are working on, you should minimize the risk of damaging it.

[@bluglouk]

Is the dot crawl problem still not resolved by the composite video mod?

[@JaySmith-cd1ln]

11:16 Wrinkled backside :) Thanks for the video Jan keep it up!

[@JanBeta]

Haha, I didn't even notice that it sounds kind of strange... :D

[@boherrmannsen8219]

+Jan Beta @Jan Beta 11:16 Wrinkled backside i think this is in fact a solder mask/stop to prevent the solder from running where it's not supposed to go, but not as good quality so it cracks and wrinkle whe it see's the solder. Could be wrong thou but it looks like a plausible explanation

[@JanBeta]

Oh, it's a combination of both in this case. The solder mask has cracks, too. EEVBlog Dave made some remarks about the wrinkly surface in one of his retro computer teardown videos and explains it. I can't remember which one or I would have linked it in.

[@peddersoldchap]

Moin moin herr Jan! Could you put the reference for the voltage regulator on the description, please? Thanks for your videos. Greetings from Portugal.

[@herrfriberger5]

The ULA has no support for sound, other than a simple 1-bit port shared with the cassette interface. Sound is generated by program code (as in the Apple II or IBM PC/XT/AT, for instance). The same goes for graphics. The Sinclair Spectrum has no hardware support whatsoever, except for simple color attributes and a 50 Hz interrupt. All graphic operations must be done by the Z80, including scrolling, sprites, text, etc. So it's quite different from the C64.

[@JanBeta]

Yes, it's a rather crude thing, I know. I didn't mean to say that the ULA is dedicated sound hardware. It's just (quite cleverly) used to behave like that with code of course.

[@AnotherUser1000]

Great video as always. But I have a question/suggestion: I was wondering for some time, if we can disable and disconnect the original internal switching power supply of the manufacturer altogether and replace it with a newer DC to DC converter like the one you used. BUT, with the ability to produce all of the +5 and +12 volts' supplies and feed them with some cables to the appropriate pads to the inputs of the rest of the circuit. Is there any kind of circuit on the market yet? Among the others, we will get rid of the squeaking sound of the original transformer as well.

[@JanBeta]

That's an interesting idea. I'd guess it's totally possible to do it. I actually have another issue 2 board I could experiment with (in much worse condition but working).

[@ivan_pozdeev_u]

You're attaching the heatsink with thermal _paste_ rather than _glue_ ? Won't it slide off eventually (with all kinds of arbitrary side effects)?

[@Fluffski2006]

The reason for the solder resist being crinkled is a combination of solder resist is to thin and/or flow solder machine speed set to slow causing the resist to crack and blister due to to much heat. That's the reason it's all over the pcb or anywhere the are a lot of large/thick tracks. I use to see it a lot.

[@Fluffski2006]

Oh and the reason why the "Sinclair" part was not affected is because that part was masked with heat resistant tape so the RF module could be fitted by hand after flow soldering. Nerd moment over. :)

[@benbaselet2026]

Definitely use an ESD safe environment when working with electronics, even with older stuff like this. The ESD mat is really important too. If you have a charged PCB and you touch it wearing your earthing strap on the wrist you can still easily destroy the part. There's no way to see or predict ESD but once you take precautions you can eliminate the problem, mostly. The amount of "mysterious" breakages will just be a lot lower.

[@JanBeta]

I totally agree.

[@TehJumpingJawa]

Be interesting to see some before & after temps, to see if that heatsink actually helps. Without airflow, nor conduction through the chassis, I can't see how it's going to make much of a difference.

[@networldworld4333]

Hell ! can you help ? i own a zx spectrum sinclair 48k that doesn´t load the games. They just get errors when first game screen opens or crash during the doalings and green little squares on some loading drawings. I inserted that to check the upper RAM chips : PRINT PEEK 23732 + 256 * PEEK 23733 the value result was wrong it was 32863 instead of 6553 »»»» I tested all the 8 upper RAM chips group on the board below (right side not the logical ones) using a fully working sinclair 48k and all 8 are good.

[@kcinplatinumgaming2598]

Just shows that Sinclair cut so many corners for reducing costs and that was also poor quality assembly and components ... but thats business for you LOL good video as per usual Jan :D

[@stevesstuff1450]

Also goes to show that even after so many corners were cut for reducing costs, etc, just how damn reliable those old machines were/are. I have a rev 3B version Spectrum (with composite mod), and all the components are still original, and it works perfectly! I think it helped on these slightly later 3+ boards that the heatsink was moved to the rear of the system, and was a long 'bar' that ran under the raised edge of the case behind the keyboard. At very least, this stopped the old problem of the keyboard covers lifting away on the right-side of the computer.... that was a constant issue during it's first year or so, and at the small shop where I was working back then, we had numerous complaints from customers about this!! Nothing we could do about it at the time, but after the rev 3 boards, no more complaints!!

[@justaman5418]

apple today does the same shit today and gets away with it

[@Marcmenardtechno]

Nice video! Yep, this is old enough that replacing the caps is a very good idea. I'm curious about the copper plate however: the heatsink compound is not quite a superglue, I'd imagine that if you want to be safe, you need a method to make sure it doesn't wander around inside? If this thing comes off, it might put a crimp on your day! Just a thought. Have a great day!

[@JanBeta]

Thanks Marc. Yeah, I'm a bit worried about the copper plate, too. The plaster seems to be pretty sturdy but I might add some foam to the top cover to hold it in place or something.

[@Marcmenardtechno]

Good morning Jan (ok, here it's morning anyway), I think the foam is both good and bad at the same time. Good because its springy, so if you cut it a little thicker than the actual case clearance above the chip, il will effectively immobilise the copper plate. Bad, in the sense that the foam will act as an insulator and trap the heat right where you want it to escape. Or, cut the foam so that it gets a big hole in the middle to let the heat escape. The dream solution would be to use a 3D printer... kidding of course. I'm projecting. That's precisely the kind of situation where I'd very much like to have one, to design a bracket for the part that is made to measure. That'd be nice... *sigh* Have a great day!

[@JamesPotts]

Jan, what brand of screwdrivers do you have? The handles look distinctive, but I'm unfamiliar with them.

[@rpgduck]

Would it be better to remove the RF Modulator completely or is it still needed ?

[@JanBeta]

Oh, it's not powered anymore so it doesn't really matter if it's still on the board. You could remove the whole thing. I like to keep it reversible although I probably won't ever go back to RF. ;)

[@tharkthax3960]

How long will that Chinese reg last compared to an older style reg? Couldn't a small vent be put into speccy? It's all fascinating! Nice caps those vishay, used them on the power board of an Atari 800 which worked a treat. Enjoy your videos, thanks 👍

[@alynicholls3230]

if that is a pal unit, changing from rf to composite is as easy as cutting a few connections in the tv modulator and soldering a wire on, i see you did this good man, replacement ram can be good too there is a guy in scotland sells replacement chips, you can increase it to 128k or even 256k though very few programs use it, there are switchable bios mods, rgb and vga mods, its truly amazing what can be done in 2018.

[@JanBeta]

Yes, I've seen those memory replacement boards. Interesting stuff. I just love how you can combine modern tech with the old systems these days. :)

[@DigiLab360]

Best two purchases of my life: ZX Spectrum and my Prusa i3 MK3S+

[@Wok_Agenda]

Great video Jan! One thing i do for regulators that get hot is i solder another one on top of it so the two are in parallel

[@jaycee1980]

You have to be careful when doing this... if their outputs are not exactly the same, you can get circulating currents.

[@ClassicTrialsChannel]

Back in the day, I bought a keyboard upgrade from dk'tronics for my rubber keyed 48k ZX spectrum. cost me £30. don't have my speccy anymore but I still have the box for the keyboard upgrade.

[@1337Shockwav3]

No S-Video mod? Does a great job getting rid of the dot crawl. Also that cooler solution is slightly questionable ... while copper has great thermal capacity and conductivity the heat exchange rate probably sucks due to the limited surface area ... once it has heated up it's gonna act as a cooking plate instead of a heat sink :(

[@baze3SC]

Btw, from my experience, the CPU can get pretty hot too :) But of course, it's much easier to find a replacement Z80. There are copper heatsinks for M.2 drives (available at Aliexpress) that fit the ULA chip almost perfectly.

[@wolcek]

Would it help to resocket ULA into a precision socket? Or maybe a low-profile one?

[@baze3SC]

@@wolcek I don't think it's necessary. But in order to improve thermal management I would add a low-profile heat sink to both ULA and Z80 and also change the linear voltage regulator to TRACO TSR 2-2450 which doesn't produce heat.

[@wolcek]

@@baze3SC I got the 1.5mm M.2 ssh heatsink, but it touches the top case. I was thinking about getting a low-profile socket, like Samtec ico-640-l, so the ULA will be lower, but still in a socket. The Z80 will wait for a heatsink for a while, but the TRACO (I used the 1-2450) is already there. Also the DC-DC mod for Issue 3, but I think the coil is failing - I have burnt my finger touching it, so that's the next thing on the list.

[@wolcek]

The low-profile socket works. I wasn't sure if it would fit into the holes, but it does. The ULA is a couple of mm lower, and the 1.5mm heatsink fits nicely.

[@dergrunepunkt]

Interesing vid Jan, I got a bunch of those switching 7805 drop-in replacement but wasn't successful in sourcing replacements for the 7812 for my commodores 64s

[@JanBeta]

I found the RECOM branded ones for 5V and for 12V. Quite expensive but supposedly very good. I’m going to make a video some time putting them in a C64.

[@JosipBasic]

Link for those regulators?

[@Nguyen_Phuc08]

I actually replaced the voltage regulator on 3 of my Spectrum 48K with this - www.digikey.com/en/product-highlight/r/recom-power/r78-series

[@benbaselet2026]

I found a bunch on ebay searching "voltage regulator 7805 replacement" but most of the Chinese sellers are away right now.

[@JosipBasic]

Thanks.

[@JanBeta]

They are generic drop-in replacements for 7805 voltage regulators. I got them from ebay but I guess the same things are available from elsewhere, too.

[@karlbrgesteen5775]

Any thoughts on how safe/stable these are? Could they potentially do damage if they fail?

[@tanaseav]

you could use a thermal pad and put the buck converter exactly where the regulator was. :)

[@Malcott]

Some very useful ideas. Can you give the make/model of the voltage regulator, I like the idea of losing the heat sink :-)

[@JanBeta]

You can search for a drop-in replacement for a 7805 voltage regulator. There are very good ones (like TRACO brand for example) and the cheap generic ones I used.

[@Malcott]

Thanks I think I found some like yours on eBay.. the seller is on holiday until 20th February :-)

[@fortnitegod2647]

Back at his best the famous Jan Beta great vid for the Sinclair members out there. Keep up the great work another zeddy that'll work for years to come..😁...Kim

[@JanBeta]

Thank you Kim! I hope the Speccy is going to last a while now. :)

[@Markchill2]

do you know a good place to buy capacitors in bulk thank you

[@JanBeta]

I usually order Panasonic FCs from reichelt.de but I don't know if they ship internationally. Another German supplier I use is Conrad.de. If you are looking for recapping kits for specific old micros, retroleum.co.uk is a good place to look. :)

[@Markchill2]

@@JanBeta Thank you very much

[@airingcupboard]

Sorry things are a bit tricky at the moment. Good video as usual :-)

[@JanBeta]

Thanks! It's (hopefully) going back to normal soon.

[@stephaneschmitz8030]

These small switching modules are nice but cannot deliver more than 1 amp which is not enough if you cannot several extensions devices to the speccy. That's why I prefer the UBEC modules, which can deliver up to 3 amps (which should be way enough!). I have used several ubec modules in a C64 PSU, in a timex 2048 and in a speccy 48k, no problem at all.

[@JanBeta]

Thanks Stéphane. I considered using another (beefier) switching converter, too. This speccy still works just fine (even with the DivMMCfuture connected) so I guess it's okay but I don't really trust the cheap converter. I might use a RECOM one (used those in my C64 and they are absolutely great).

[@stephaneschmitz8030]

Indeed I don't really trust the cheap modules as well. Is there a short circuit/over voltage protection on it ? I have the same here but I'm not sure i'd use it in a speccy.

[@EdwinNoorlander]

Is everything okay with you?

[@EmmittBrownBTTF1]

The main reason the ULA gets hot is the fact the Sinclair exploited 80% of its logic, Feranti recommended using no more than 70%.

[@JanBeta]

That's hilarious. Kind of overclocking chips today. :D

[@JanBeta]

*kind of like

[@1337Shockwav3]

That's a new one for me. Wonder if the Saga made ULA remains way colder because it has more (unused) gates.

[@8bitdreams217]

Jan, i think Your Speccy works as 16k not 48k, as the black screen (self test) on power on takes longer on 48k as yours There was a poke code to check it Also your test program doesn't show upper 32kb memory...

[@JanBeta]

Oh, as far as I can see, the test program went through the upper RAM as well without any problem. I'll have to re-check.

[@dreamvisionary]

So, you're worried enough about ESD that you wear a wrist strap but then you place a polythene bag on top of the ULA and use a synthetic cloth to wipe connections! 😂

[@JanBeta]

Yeah... You're right. I didn't think of that obviously... :/

[@sarreqteryx]

too late now, but you could have probably pulled the pins out of the switched mode regulator, put them in the opposite side, and had the reg lay down the same direction as the original part. if you're worried about it contacting and shorting out, kapton is your friend

[@JanBeta]

Yeah, I had that idea, too, but it works just fine like this. Doesn't look great obviously... ;P

[@PureAudioTones]

As usual another great video that i learned a new thing. Can this dc-dc converter be used in C64 psu? Raplacing the voltage regulator may be?

[@JanBeta]

I think this particular one is too weak as it's only rated for 1A. You could use a DC-DC converter with a higher rating without any problems I think. (I'm planning to do a video on C64 PSU mods soon, too.)

[@jaycee1980]

Regarding Vishay as a brand, they are very good.. the capacitors are what used to be Philips components division :)

[@JanBeta]

BC Components, isn't it? I recently bought some "Vishay" caps online and got old ones that were probably 10 years old or so. Had a nicer blue, though... ;)

[@jaycee1980]

Yeah... BC was spun out of Philips originally :)

[@SHGRetro]

Awesome video once again! I have the full collection of the spectrum range apart from the QL because that was just not a real Spectrum. Might future proof mine one day!

[@JanBeta]

Thanks Stu! I love the Spectrums. I at least want to get a 128k model some time soon. The QL is an interesting beast, too. Both from a technical and a historical point of view.

[@HuntersMoon78]

I forgot about the centre negative pin, connected the wrong power supply and blew the arse out of the regulator

[@JanBeta]

I think that's happened to a lot of people over the years... :(

[@maicod]

you got the magic smoke for sure ;)

[@elmariachi5133]

I would love to see a video about soldering the RAM-Expansion für a Commodore C16 one day :)

[@JanBeta]

Shhh. Don't tell anyone but I already have a (broken) C16 that I want to do some videos on in the future. ;)

[@elmariachi5133]

That's great! The C16 was my first computer.

[@LemmyCaution66]

Great video as usual. Very interesting. Thank you.

[@JanBeta]

Thank you!

[@aki_128]

Only C64 people use a joystick to play games on the Spectrum!!! :-D Cool video, anyway! Kudos for ISSUE TWO! Thanks for that one. Btw. a sort of ULA test includes an old Test Program (by Sinclair Research available on WorldOfSpectrum site). Who knows what exactly does it actually test, but it's in there. But yes, if the ULA was faulty (as well as RAM/ROM or Z80), the Speccy couldn't run at all probably.

[@jusb1066]

the oem spectrum joystick was awful (well so was the c64 oem) but that connector type was common, thus it wasnt so much a c64 as a generic atari plug and workings , which is what the commodore 64 used as a standard :) so the spectrum adaptors all used this connector

[@JanBeta]

Haha, you may be right about the joystick thing. I tried playing games with the speccy keyboard and it felt strange to me (obviously) so I'm glad I have the joystick interface now... ;) I heard about the test program. Going to use that next time. Thanks!

[@jusb1066]

ive just experienced a bad cap, sure it was only an led bulb, the light worked one day, not the next, i pulled it apart, the cap looked fine, it measured the correct uF, but the ESR was 20 ohms! imagine it had been creeping up till it was too far, modern caps are a pain in the butt!

[@benbaselet2026]

Rember to also test the rectifying diodes when you are at it. Leakage through bad diodes may kill caps too.

[@jusb1066]

yes i didnt do that, it was a cheap chinese buld, just meant as an autopsy, wasnt going to repair, just curious f what failed when nothing had burned or popped.

[@JanBeta]

Yeah, they often use the cheapest stuff around that is bound to fail pretty quickly in these warm environments. Planned obsolescence, I guess. Even if I sound like a conspiracy nerd. ;)

[@ScoopDogg]

My sons been pestering me ages for a games micro computer machine, said he was getting bullied for not playing faught night, anyway finally saved some money and bought a 48k spectrum. It was £299 on the box price, but i got it for £200 as i was a veteran in a wheelchair, I checked with police and its not stolen, which worried me a bit that it might have been, he even came to my house and installed it. Just waiting for the hdmi to sinclair lead and sinclair net box adaptor and 6mnths internet, he said he will bring everything and fit me 6mnths internet for £50 obviusley not including the Satalite Dish thats extra. Anyway my question is will 48k (most tvs not even 4k) be too powerfull for mid range steam gaming and youtube videos, he assures me it will be ok. Money is very tight since my disability and my wifes funeral thankgod the games free. I just want the little lad to feel happy for once (hes had a rough year losing his mum and a dad who cant walk) I just want him to join in online gaming with his school year, and show em. Sorry for my spelling, using phones buttons P.S Only joking, i got this sent to me by a friend winding me up as a joke, he got me 100% , i was nearly in tears ready to buy this kid a new computer lol... Just wanted to look up the said ZX Spectrum and came here.. Subbed n liked for the wind-up lol

[@wizpin]

I never had a zx too, I cannot be bothered much about them. I prefer my good old c64. But I like the 7805 replacement parts. I have never seen them before, but just ordered a few on ali x.

[@JanBeta]

They supposedly work very good. There's much more expensive solutions with all kinds of protective circuitry, too. I recently bought a 7805 replacement from RECOM that I want to try. It was around 10€ though.

[@FireballXL55]

If you touch the heatsink or 0V rail on the the PCB you do not have any charge with respect to the PCB, your wrist strap would not help you if the PCB was statically charged when you touch it. I have never worn one in my life I just follow the rule of touching the 0V on the PCB I am going to work on. The wrinkled effect was caused by the flow soldering the solder wicked under the solder mask to give you that effect.

[@benbaselet2026]

Touching ground will discharge the stattic from you of course but just moving your hand around a bit will put kilovolts into your body again. Also it's not wise to discharge yourself to the board, you should be gounded with the board.

[@maicod]

I think I recognize Conrad bags there :) (holding the axial caps)

[@JanBeta]

Yes, ordered them from Conrad. I was pleasantly surprised that you can get them that easily. I had been looking for good axial caps for a while.

[@gile849]

Great video, Jan. My favorite computer :) I have mine zx from 1984.

[@JanBeta]

Thanks! Cool that you still have the original one from back in the day. :)

[@gile849]

Jan, where are you?

[@marbyyy7810]

Sucks that the spectrum is a real pain to get working on ntsc

[@fkthewhat]

How did I get unsubscribed :( good thing you are still on Twitter! Hope you are well! Also, ein neues Lötkolben?

[@JanBeta]

That's the secret algorithms of KZbin I guess... Had that myself a couple of times. Oh, and it's the same Lötkolben as usual. Did some perspective experiments for this video so maybe that made it look different.

[@lelandclayton5462]

I wouldn't trust that 78xx series regulator replacement. A LDO I prefer is from the BAxxDD0T Series. Can handle more current and has current protection.

[@JanBeta]

Yeah, it's not very well made and cheap. A proper regulator probably is a lot more reliable. I had some people recommend the cheapie I used for the Spectrum. Mostly it seems to work fine at least for some years.

[@LastofAvari]

"Jan" rhymes with "fun". Coincidence? I THINK NOT! Thanks for the video :)

[@forevercomputing]

ESD straps don't work because someone didn't SEE an IC damaged? /facepalm

[@JanBeta]

Yeah...

[@insanedruid3143]

Actually I just had one that really didn't work as it had a totally open connection due to a broken wire straight from the box. Was one of the cheap blue ones, too. And yes, not 1MegOhm or 10Megohms safety resistance, just really fully open.

[@JanBeta]

Mine came from the iFixit tool set I got a while ago. Seems decent quality (like the rest of the set). Did you see the straps that don’t have a grounding wire at all? I loled when I learned that those are a thing.

[@TzOk]

The resin or plastic from which DIP cases are made is not very heat conductive. The silicone structure in large chips is in the middle, so putting 3 separate aluminum heatsinks on one big DIP IC like you did on C64 has really no sense. Only central heatsink will do the job, while side heatsinks won't even get warm. Copper plate is a much better solution. What happened to your desoldering station? By removing caps like you showed on this video you are risking damaging of pads and vias. As for ESD straps - they do work (except for Chinese wireless ESD straps of course), yet they have very limited use in case of TTL chips. They are much more important when working with MOS/CMOS chips. Your table mat probably is static dissipative (ESD safe), but it also should be grounded. P.S. Mats and straps are static dissipative, not anti-static. Anti-static surface just prevents static charge to build up, while static dissipative surface will dissipate (discharge) the charge even if it is externally applied to that surface.

[@maicod]

I guess he wanted to show that a desoldering station is not perse a must have albeit much handier

[@JanBeta]

Yeah, that was the intention. Also, I would have had to store the C64 away again to set up the desoldering station. ;)

[@douro20]

The Z80 is NMOS, as well as the static RAM.

[@herrfriberger5]

The dynamic RAM (no static RAM in Spectrum).

[@chiclone-tests71]

I'm more the "better weld 5 cars completely, than solder one point"-Type... I borrowed a good soldering station from my cousin to repair an old keyboard, and a power-plug adaptor for truck, with the keyboard i totally failed! :D - 2 wasted hours for nothing.

[@JanBeta]

Uh, that's bad. I might get back to you when my car needs some welding, though... ;)

[@rossdag4232]

GOOD IDEA JAN WITH SWITCH MODE REPLACEMENT BUT ALL U HAD TO DO LOWER VOLTAGE ON POWER SUPPLY TO 7.5V DC ADRIANS BASEMNT DID IT TO HIS WORKED A TREAT MUCH COOLER HEATSINK IS VERY GOOD JUST BE CAREFUL ITS COPPER EASY TO SHORT JUST LITTLE TIPS FOR YOU SEE YA EPROM YET?. BYE

[@robbyxp1]

Be very careful what anti-static mat you buy. the cheap ones are horrible, get damaged easily, and smell! I bought a 228156 - Anti Static Mat, Bench, Rubber, Beige, 0.6m x 0.9m x 2mm (no longer made but similar available). A good hose down, a few days hanging in the shed, and it does not smell..

[@JanBeta]

Oh, thanks for the tip. :)

[@josephnealescratchcards]

Awesome video

[@JanBeta]

Thanks Joseph! :)

[@RDJ134]

Cool and learnfull video :)

[@JanBeta]

Thank you! :)

[@Dkentflyer]

Great video Jan and thankyou for making this video.Will send you a message via patreon ;)

[@JanBeta]

Thanks! :)

[@JackBealeGuitar]

Not sure how helpful this will be, but most guitar effects pedals run of 9v, centre negative. May be worth looking at these for power supplies, plus as they are for music they tend to be ultra quiet. Check out voodoo labs, t-rex, boss or even one spot supplies

[@JanBeta]

I am in fact using the power supply I used for the Speccy on my DIY kit Rat pedal, too. ;)

[@JackBealeGuitar]

Jan Beta are you a musician too, I know I liked you 😀. The rat is a great pedal

[@JanBeta]

I play the bass guitar (and a tiny bit of guitar, too). Not doing much at the moment though sadly.

[@Tupster]

LIPS is one of the better brands.

[@JanBeta]

Definitely one of my favorite brands! ;)

[@enitalp]

Sinclair's Daddy is dead

[@JanBeta]

Yes, heard the sad news, too. :(

[@gile849]

One dislike, probebly C64 gay :D

[@JanBeta]

There's a couple more now. Maybe it really is about the old Commodore-Sinclair rivalry... ;)

[@gile849]

Yes, like intel - amd :)