0080 A 128k RAM upgrade for the Speccy, some recovered SIDs, USB-C Cable testing and a new DMM

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On our next super mini mail call we have a few goodies for the Commodore 64, the ZX spectrum and a few things that are essential tools for testing stuff.
-- Video Links
USB Type-C cable tester:
caberqu.com/ho...
121GW multimeter from EEVBlog:
eevblog.store/...
ZX Spectrum 48k RAM expansion:
github.com/gol...
Spectrum RAM diagnostics:
retroleum.co.u...
blog.retroleum...
github.com/bre...
Adrian's Digital Basement Merch store:
my-store-c82bd...
Support the channel on Patreon:
/ adriansdigitalbasement
Adrian's Digital Basement (Main Channel)
/ @adriansdigitalbasement
-- Tools
Deoxit D5:
amzn.to/2VvOKy1
store.caig.com/...
O-Ring Pick Set: (I use these to lift chips off boards)
amzn.to/3a9x54J
Elenco Electronics LP-560 Logic Probe:
amzn.to/2VrT5lW
Hakko FR301 Desoldering Iron:
amzn.to/2ye6xC0
Rigol DS1054Z Four Channel Oscilloscope:
www.rigolna.co...
Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
amzn.to/3adRbuy
TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
amzn.to/2wG4tlP
www.aliexpress...
TS100 Soldering Iron:
amzn.to/2K36dJ5
www.ebay.com/i...
EEVBlog 121GW Multimeter:
www.eevblog.co...
DSLogic Basic Logic Analyzer:
amzn.to/2RDSDQw
www.ebay.com/i...
Magnetic Screw Holder:
amzn.to/3b8LOhG
www.harborfrei...
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
www.ebay.com/i...
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
www.retrotink.com/
Plato (Clone) Side Cutters: (order five)
www.ebay.com/i...
Heat Sinks:
www.aliexpress...
Little squeezy bottles: (available elsewhere too)
amzn.to/3b8LOOI
--- Links
My GitHub repository:
github.com/mis...
Commodore Computer Club / Vancouver, WA - Portland, OR - PDX Commodore Users Group
www.commodorec...
--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
Nathan Divino
@itsnathandivino

Опубликовано:

30 сен 2024

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Комментарии : 263

@sarahgoo5541 6 месяцев назад

Another vote for a speccy video or two, or three …

@caberqu 6 месяцев назад

Peter from caberQU here, thank you for the in depth review of the C2C caberQU! It is a pleasure to develop these things and even better to see people liking them.

@tomn5660 6 месяцев назад

What about USB-C to USB3.x A cables? Thanks

@caberqu 6 месяцев назад

@@tomn5660 That's a good question, we have the A2C caberQU for this exact problem, which can test USB-A to USB-C cables.

@ChrisDreher 6 месяцев назад

Just got my caberQU a few days ago (despite USPS's efforts). Works great. I've been deep diving into PD as a result of this.

@caberqu 6 месяцев назад

@@ChrisDreher That's great to hear, thanks for the feedback

@EEVblog 6 месяцев назад

I've got one too, very handy!

@EEVblog 6 месяцев назад

Thanks Adrian, glad you got it. No point spending time trying to troubleshoot the old one, it's likely a tolerance issue on the range switch contacts, pressure and thickness of the PCB on those first batch units.

@MicrophonicFool 6 месяцев назад

Just ordered C2C Cable tester. I have been entirely perplexed by all the different cables and also the fact I can find none in my possession which transfer more than USB 2

@richarddinsdale6722 6 месяцев назад

The ZX Spectrum plus was a keyboard "ahem" upgrade only....Loading tapes on any early british 8 bit was always a joy/challenge. The spectrum compared to the oric was a dream to load tapes...

@ThePoxun 6 месяцев назад

it also has a reset button which was actually a huge improvement over having to pull the power.... which is literally a button with mod wires soldered directly to the reset pin.

@richarddinsdale6722 6 месяцев назад

@@ThePoxun Just noticed the reset button, you can hardly see it ! Also the plastic legs to give the ideal typing angle........

@tarlcabbot2551 6 месяцев назад

ZX Specrum was my very first computer (I was about 10 I think)! LOVED it!!

@byondead 6 месяцев назад

Hey Adrian, you will be surprised on that uni t clamp meter. You say it's the range button and i thought so as well the first time in mine. But i was wrong. The battery compartment is like a clam shell. The battery compartment has spring contacts to the pcb. Grab the case and twist/flex it. It will flake out. What i ended up doing is soldering the battery contacts to the pcb with wires.

@the_beefy1986 6 месяцев назад

I have a question (and please don't interpret this as a request for shorter mail call videos): what exactly does "super mini" mean in terms of these videos? They don't seem so mini to me, which is fine since I enjoy longer videos :)

@TheInternetHelpdeskPlays 6 месяцев назад

I think the original idea was to make mail calls about a single item rather than cover 5 or 6, like in the mini mail call.

@FaithyJo 6 месяцев назад

It's also running joke as to how he tries to make short videos but ends up making them way longer

@granitepenguin 6 месяцев назад

They started out mini, but quickly grew to maxi, and it's been the joke ever since. If you go back and watch the first few, they are actually fairly short.

@RobA500 6 месяцев назад

The ZX Spectrum plus is just a regular 48k Spectrum in a new case, Sinclair even sold kits to upgrade the rubber keyed machine.

@andygozzo72 6 месяцев назад

i know, i bought the upgrade keyboard direct from them, still got it 😉 £20 for the keyboard to do it yourself, £30 if you send it to sinclair for them to do it for you

@GrumpyOldGit-zk1kw 6 месяцев назад

The Spectrum Plus is still only a 48K machine. The first 128K version had a large metal 'toast rack' heat sink on the right hand side. The ROMs will also be different as the 128 had two separate modes (48K and 128K) and a small built in menu.

@TheMadmagik 6 месяцев назад

yup the zx spectrum+ 128 has a 128K legend on the right hand side.

@docnele 6 месяцев назад

I had Issue 3B board in 1985. I had colour always a bit "off". Spectrum tape checks: check oxidation in 3.5mm socket. Don't connect both of them, if you load programs connect just aux. Tape recorder/ player MUST be set to mono. It also must never put to max volume. Border stripes must move "lively". If everything fails, use screwdriver to adjust the tape head. Else hardware.

@r00tyschannel52 6 месяцев назад

For the 128K ram, you can use the 128k rom (not +3 rom, it looks for the disk controller on startup and will hang if not found) with the advanced basic interpreter. That won't work without the 128k ram since it does a bit of a ram page swapping diagnostic on startup, but does not need the AY chip unless you try to use extra sound commands beyond beep. I know this because I wrote a z80 emulator and extended it to a ZX spectrum emulator. The 128k ROM wouldn't initialize until it successfully swapped through all the pages. The problem is, the rom switching is done via the same output ports (and by extension the same logic) as the ram switching. So, unless that expansion supports putting multiple pages (2 roms for 128k) of rom on that flash chip, I don't know how you'd use it properly. I would expect it must allow you to load roms onto it somehow.

@BenState 6 месяцев назад

Im wondering if Deoxit may help your range switch issue? *edit, you mentioned it. I'd try, what do you have to lose?

@DiazFelix 6 месяцев назад

The spectrum plus is exactly the same as the regular speccy. It has better keyboard and a reset button, nothing else.

@Thelemorf 6 месяцев назад

More digits doesn't really mean higher precision. Personaly, I dont want a multimeter that you have to turn on and off on the mode select knob, thats a bad design imo.

@fixitalex 6 месяцев назад

@adriansdigitalbasement2 Do I get it correct that ZX Spectum was not popular or even known in USA? I've heard about NTSC version but never saw it.

@rastislavzima 6 месяцев назад

It was sold there as Timex Sinclair 2068

@SophieFeet 6 месяцев назад

Would definitely like a speccycentric episode sometime... I designed and built my own FPGA-based "super Spectrum" ZX Prism... 512K, 256 colours, different resolutions, built-in DivMMC and virtual tape etc. One day I hope to make it an open source project that others can built but for now, there's only one and it's over here in Australia!

@lovemadeinjapan 17 дней назад

I have that too, it is called a MacMini 2009, it costs 25€, and it runs an emulator.

@SophieFeet 17 дней назад

@@lovemadeinjapanUm. No, it's not an emulator and i designed and built it myself.

@lovemadeinjapan 17 дней назад

@@SophieFeet Sure, bit if you go FPGA, you can as well emulate. The only thing I think FPGA is a legit route, is to keep old arcade machines up and running, so you can create the specific RGB 31kHz signals.

@SophieFeet 17 дней назад

@@lovemadeinjapanYou're welcome to your opinion. I don't share it. having spent years working on the hardware, microcode and firmware for it, i finally have my dream machine.

@lovemadeinjapan 17 дней назад

@@SophieFeet That sure is a cool process, you must have learned a lot! I just don't want FPGA's in my retro machines.

@AzagXul666 6 месяцев назад

Adrian's little sid-dances always make me smile. :)

@ProdigalPorcupine 6 месяцев назад

Me too! Adrian's such a likeable, funny fella.

@mogwaay 6 месяцев назад

I'd be really interested to know if the 128k RAM expansion would turn your 48k into a 128k as the ROM was very different, really interesting to see a follow up using it and making the mod - also troubleshooting your bad tape loading as I'm sure you could fix that. As others have said, more ZX content always welcome 😊

@lovemadeinjapan 17 дней назад

The Harlequin board does that: it turns a 48 into a true 128 with RGB.

@digitalarchaeologist5102 6 месяцев назад

Might have been said before in the chat, but I love how Adrian actually says "Zed X Spectrum" and not "Zee X Spectrum". Just feels so much more authentic. I think I only discovered Zee because of sesame street as a kid

@nickwallette6201 6 месяцев назад

This illustrates the point: USB has gotten WAY TOO COMPLICATED. It's not "universal" at all anymore. Is it USB? Is it high speed? Is it Thunderbolt? Which version? Does it carry data at all? Or is it just a power cable? Either way, how much power can it deliver? Who knows! USB was supposed to solve the problem of having multiple ports, like serial and parallel and PS/2 mouse and keyboard. Instead, we have one port, and nobody knows what it can actually do. _That's not better._ We really should have kept legacy USB and just added Thunderbolt as a _separate interface_ for high-speed data. Charging? I really don't care. My laptop can charge from USB A power bricks. It takes a full day, but that's fine. If I need something faster, I can use a dedicated power brick. Can't we just do that? >

@matthewhill388 6 месяцев назад

Too true. I've only recently realised that USB-C can be USB2.0 and not a backward-compatible USB3.x. more fool me. I thought it was standardised. What's more, is that I have USB3.0 cables that aren't recognised by some devices, but are perfectly fine in others.

@twocvbloke 6 месяцев назад

The range switch issues &tapping on the switches on the multimeters makes me think of this joke; "Man goes to the doctor, says 'It hurts when I do this!', so the doctor says 'So stop doing it then!'" :P

@brocktechnology 6 месяцев назад

Shield should be connected at only one end. If it's connected at both ends it's a ground loop.

@WhiteBream 6 месяцев назад

Nope, that's only in analog audio. All other shields must be connected at both sides, just like with a single core coax.

@nickwallette6201 6 месяцев назад

@@WhiteBream No, not quite. Ground loops are not an "audio" problem. They're a signal problem. They affect every signal, whether you can hear it or not. Some cables use ground as the signal return, so you can't do anything about it. (Coax.) Other things, including some audio cables (XLR / or mono differential on TRS) don't use the ground as a signal return, so you can lift ground on one end without a problem. All that said, ground loops only exist when there is a difference in ground potential that is big enough to have a significant influence on the signal's interpretation. So the best cure is for that not to happen to begin with. When devices are floating (battery powered or double insulated), then it's not an issue. When devices use a safety ground, that ground should not be carrying current, and both devices should have low impedance paths to the same common point. Then, the shield of an interconnect isn't acting as an equalizer between two different reference points.

@brocktechnology 6 месяцев назад

@@WhiteBream I humbly disagree, The exception is when the shield is the only ground(and a common ground is necessary). This is normally the case with analog audio and RF coax. The issue is that if the shield forms a loop with a superfluous ground conductor external noise signals are inductively coupled to the signal conductors. The truth were hoping for is that all ground pins(not signal negatives) are connected to shield at both ends with no other ground conductors. I can't think of a simple way to test for that off the top of my head.

@WhiteBream 6 месяцев назад

@@brocktechnology When a shield gets interrupted (for example by not connecting a connector shield), everything beyond the interruption forms a dipole antenna against the outside of the shield of the cable. So quite the opposite effect of the intention of the shield. Search for "Unveiling the Secrets of Return Currents: Theory and Practical Demos" for more info

@webfreezy 6 месяцев назад

I'm still using my METEX multimeter I purchased in 1992 - first one - still working without any issues.

@markdavies794 6 месяцев назад

Still using my Fluke 77 from 1984 but also use a few others.

@dmc716 6 месяцев назад

Greetings from Serbia...

@terrylutfi8888 6 месяцев назад

I have the same ANENG, used to give random resistance reading in continuity mode. It turned out to be the rotary switch acting up. Just clean up the gel and dirt on fingers on the PCB, do not reapply any gel or lubrication, it will get dirty again. The EEVBlog multimeter might have the same issue, it's worth cleaning that one too.

@SenileOtaku 6 месяцев назад

A USB-C cable tester. Yep because it's such a good thing that we've finally established consistent and stable standards...

@lovemadeinjapan 17 дней назад

Plugs in my 2 port Firewire HD into 2 different computers with 4,5 m long cables at the same time, only to find out I just created a working NAS.

@networkg 6 месяцев назад

Don't recycle the little red meter. Autograph it and auction it for charity.

@ad5mq 7 месяцев назад

Anything with a physical rotary switch will wear. Good application of contact cleaner will help generally. This is where Fluke shines - the switches last a really long time and work even in high humidity reliably for many years. I have one that was actually submerged in a flood, after disassembly, drying, contact cleaning and reassembly it's worked fine for nearly 20 years. VERY expensive however. Deoxit will work ok, surprisingly wd-40 will help in a pinch. I usually used tuner cleaner when I had charge of repair/calibration for the physics department decades ago. Cleaning contacts will not disturb calibration as long as you don't get it in the pots (normally on the accessible side of the board)

@briangoldberg4439 6 месяцев назад

yeah, I was just saying this. I had to take apart my good expensive MM and clean the wheel with Deoxit once, but it's been fine for many years since I did that. I'm sure it's a humidity thing

@oliverw.douglas285 6 месяцев назад

In working with rotary dial switches, whether it be Fluke, Simpson, or Triplett, the switch oxidation can occur, simply from use in moist environments, & general 'wear & tear'. Motorola use to sell a contact enhancer call Stabilant which works well.

@BenState 6 месяцев назад

@@oliverw.douglas285 Probably quite similar to fader lubes?

@jeffreypomeroy6173 6 месяцев назад

Funny enough, i had three flukes that were stored together in a cabinet and 2 of the 3 died. The only one that didnt was the ammeter type which was the cheapest one. The only one i had left was one that i kept in a humid garage. I am assuming the ones in the cabinet died because i had some massive N52 magnets stored on the shelf above and me pulling the multimeters out induced some random currents in the meters killing them.

@oliverw.douglas285 6 месяцев назад

@@jeffreypomeroy6173 I don't expect strong magnets would be good for DMM. Fluke's are typically resilient to RF Fields.

@jasmijndekkers 6 месяцев назад

Hi Adrian, Nice goodies. and thankx for sharing with us. Greetings from Steven from the Netherlands

@terryraymond7984 6 месяцев назад

cool I didnt know Dave designed that meter awesome

@matthiastilly5480 6 месяцев назад

Reminds me on finally buying a decent multimeter.... The one I have I got for Christmas when I was like 6 or 7 and it was already cheap by then.... so now it's almost 40 yeaers old, but still works!

@tigheklory 6 месяцев назад

Deoxit on the contacts would be better than not doing that.

@ajsnz 6 месяцев назад

It's real Serbia Special today. ZX Renew resells products from RetroRadionics who did the ZX Omni, ArcadeR joysticks, replacement keyboard membranes, metal plates and even reproduction ZX Spectrum 48k cases amongst other things. RetroRadionics operates from China and is run by Djordje Mitic. Djordje is from Serbia :)

@briangoldberg4439 6 месяцев назад

also just FYI, I've had continuity issues with several Multimeters, including my very nice expensive one; all it took was taking it apart and treating the main selector wheel with Deoxit to fix it, and it hasn't given me any trouble for years now

@Phil-Sands 6 месяцев назад

The ZX Spectrum + is just a ZX 48K in a new case, it's 48K.

@kevkabluebird1032 6 месяцев назад

For measuring low resistances i have an old (but surprisingly accurate (lab tested)) bench-multimeter (30 kg) from the sovjet-era. Its a bit slow in auto-ranging, but finding shorts does work pretty well. It can measure mOhms and other very low values.

@robertkiss7273 6 месяцев назад

Regards from Serbia

@theoriginalbabycub 6 месяцев назад

Yes please a big episode on the Spectrum stuff, mix it up a little instead of always PC, Mac, C64. Perhaps a live stream speccy repair marathon and a look at that Speccy with the acreen.? Why not bring some of the stuff you've been hoarding in the basement sent in years ago out and prioritise them to make some videos about these other things? Place them in your video rotation, otherwise you'll probably never get to them and people have been good enough to send stuff in yet it sits languishing for a long time. I think some greater variety would be a good thing.

@lovemadeinjapan 17 дней назад

That Frankenstein Speccy was HORRIBLE! Who came up with that shit? If you want a full speccied one, get a Harlequin board. It fits in both the meat-keys and 48+ version, and it does 128k, YM sound and RGB output, without ruining the looks or case with random holes.

@ouch1011 6 месяцев назад

The EEVBlog 121GW (1.21 gigawatts…nice) is currently US$215. The Aneng meter is $26. For a basically 10x price difference, I don’t think it’s fair to expect even remotely comparable quality and precision. Test equipment that doesn’t work 100% of the time can be annoying, but it can also be deadly. If you’re working on equipment that is high enough voltage to shock you, having equipment that doesn’t reliably show correctly can lead to accidental live work (which is exactly why there are requirements for live-dead-live testing methods).

@Cherijo78 6 месяцев назад

The c2c tester is cute, but given that it only tests one cable type, and you'd have to get multiple devices for different types, it gets too expensive too quickly IMHO. Meanwhile, devices like the "treedix USB cable data line test board" that can do multiple types of cables (a 2.0/a 3.0/c 3.2 to b2.0/b3.0/c3.2/microB 2.0/MicroB 3.0/miniB 2.0/lightning) already exist for half the price (15 us$ on Amazon). I'm willing to pay higher community member designed device prices for good products, but to me the focus on doing only one USB cable type is too much of a desk clutter to bother with.

@siberx4 6 месяцев назад

For that cable tester, it _can_ actually tell you a little bit about the current rating of the cable indirectly. All USB C cables are rated for 3A or 5A, and 5A cables (among other cable types) _must_ have an e-marker chip. If you have a cable with an e-marker chip hooked up, one CC LED will glow at full brightness and the other CC LED will glow dimly. This means that if you do _not_ see this pattern, the cable _must_ be a 3A cable with no e-marker chip. Put another way, 3A USB2.0 cables don't require the chip, but cables that are either 5A or USB3 *do* require the chip. It's not a full answer though, because you can have e-marker cables that are only 3A if they're high-speed USB3+ cables; to tell those apart you need a tester that can talk to the e-marker chip, but in my experience most 5A cables are marked as such and so you mostly just need to confirm that a cable is _not_ 5A capable if it's unmarked.

@DevilishDesign 6 месяцев назад

I believe the AR on the 6581AR means that it's the pirate version ;)

@suvetar 6 месяцев назад

Great stuff Adrian, I love the multimeter especially ... Now I understand that you can "make" a multimeter with a RPIs or similar with a clever little harness with safety diodes. If you've any advice or could even do a video about that, it'd be *fantastic*!🤓 The Ikea battery thing is real now, my Dad works at a UK store and said that they only do rechargable ones now in the UK, so I daresay its international now (of course it is, UK and Sweden!). It's for sustainability reasons, for some reason! Hope that helps. Are your Ladda's, 18650's?

@dempseydiscus 6 месяцев назад

Only real difference between the 48k and the plus model is basically the keyboard and the plus you got there is not a 128k model. The 128k toastrack model looks exactly like your Plus, but with a giant heatsink on the rightside (the toastrack) and it also says 128 on the case.

@dotcom624 6 месяцев назад

Some of my meters and other equipment do not work reliably if given incorrect voltage using rechargable batteries (rechargeable are ~1.2V instead of 1.5V). Could this be the issue with the multimeter? I’ve had alkaline AA’s last for years, but had issues with rechargeable. Besides NiMh and alkaline had a universal remote (nothing as good as the old Logitechs, RIP) had issues with anything except non-rechargeable lithium. Poor voltage regulation in either case? Honestly, I have no idea, and just spitballing here. Also as a kid had an RC car that freaked out and didn’t work after new batteries, but after checking, one was overvolted and fixed after changing.

@marklewus5468 6 месяцев назад

One more comment about batteries. The alkaline leakage is not your bad luck - they are ALL susceptible to leakage, regardless of brand, even if not discharged. It’s not unusual for me to buy an 8-pack of AAA duracell or energizer batteries and a year later a couple of the unused batteries are starting to leak. And yes, these are stored in a controlled (65-75F, 18-25C) indoor environment. So much for the “5 year storage guarantee”!

@marklewus5468 6 месяцев назад

About battery leakage - unlike 3V lithium manganese dioxide cells which can leak, I have never had a 1.5V AA lithium-iron cell leak, even after many years. This includes Energizer and Chinese brands. I think it has more to do with the chemistry than the manufacturer. I much prefer Li-iron to NiMh as rechargeables have a very flat voltage curve & thus they go from ok to fully discharged without warning.

@mworld 6 месяцев назад

I also bought a multimeter from Dave. It's a BM786 and has 4 decimals of precision and is slightly longer (taller).

@andygozzo72 6 месяцев назад

instead of modinfying the speccy to 'permanently' deactivate the upper ram for that 12ïk expansion, maybe use one of the unused 'fingers' of the expansion slot as a 'ram cs' input', and link that finger on the 128k unit to 5v or ground, depending how you do the cs in the spectrum ...? that way if you unplug the expansion, it'll revert back to normal 48k ..? the mod described in the web link uses 5v to disable so wiring a diode from the point mentioned in the link, to a spare finger, anode to finger, would do it, pull the finger to 5v to disable upper ram...

@kirbyyasha 6 месяцев назад

Those 121GWs look like great meters, however, long as my Fluke keeps going I will keep it going. I do love it and have abused it and still super accurate.

@hisheighnessthesupremebeing 6 месяцев назад

Talking about crappy probes that come with cheap multimeters you should see the ones that came with my Fluke meters ( two 87V and one 179).. considering the price of the Fluke equipment the crappy plastic probes they provide you with is an insult

@FaithyJo 6 месяцев назад

Thank you Adrian! I was having a positively foul day until I got the notification for a new video! ❤ Keep up your hard work, we love your videos!

@marjon1703 6 месяцев назад

Still have and use my "wallet" multimeter from Tandy/Radio Shack. Over 30 years old and still working fine.

@otis7359 6 месяцев назад

Anybody knows where to get that Chinese Spectrum with LCD? I probed Aliexpress to no avail.

@DAVIDGREGORYKERR Месяц назад

Why can't the Spectrum output a SPDIF signal that can feed a DAT machine and then load it back as a SPDIF signal and convert it back to the actual program so you can play the game.

@nitehawk86 6 месяцев назад

0:30 Does this actually work? Because I have tried 2 of them from amazon from different chinese manufacturers and they were both crap. None of the lights would light up consistently.

@aladinsane5771 6 месяцев назад

Well... on DMM's and other measuring tools there's really only one brand i would recommend, not cheap but never had a Fluke fail on me...

@Ramdileo_sys 6 месяцев назад

All this testers are made in the same way....... they have exposed copper traces on the board that are touch by metal brushes.... every time you turn the selector switch .. the brushes bend down making them more flat = worst contact....... is just like the mode switch of the old VHS machines... and you Adrian see Dave from 12VoltVids cleaning those damn VHS switches thousand of times.. terribly unreliable........ you need to remove the board.. clean the traces.. put some contact cleaner on them.. and bend back a bit the brushes ... to make them springy again and also clean and contact cleaner on them....... something I like to do is.. put some thick grease in the balls that make the selector switch jump... before they wearout the plastic.. and the selector switch star "misplacing" the brushes over in the contacts....

@CeZero4 6 месяцев назад

Im looking also for 1 or 2 SIDs 8580 for my synth. Unfortunately they rarely available and you need to sell 3 kidneys to get one SID.

@siberx4 6 месяцев назад

People who leave the factory screen "protection" on devices drive me crazy. They're not designed or intended to be left on; their purpose is to protect the screen _during the manufacturing process_ so that you get a pristine screen when it shows up at your door. They're not designed to be good to look through or to stay on indefinitely, so invariably they're optically awful and peel up on the edges and collect all kinds of nasty dirt and grit. Either remove it and use the screen bare (if you like to live dangerously or don't care about scratches) or install a proper protector _designed_ for use while it's installed.

@firesurfer 6 месяцев назад

Any electronic device with mechanical parts will be flakey by design except for really high end devices. Stop tapping it!! The mechanical parts are not designed for it.

@playswithblades 6 месяцев назад

It is amazing to me how youtubers with high fan count can distort reality and features of everyday implements or testing equipment based on just "i feel like it". I don't even want to comment on the multimeter rant, every point was wrong on one level or another, other than there is a real difference between cheapo multimeters (everyone should stay away from them but for all of the wrong reasons stated here) and expensive one (that Mr. Guy in the industry is also a cheapo and after nearly 40 years of digital multimeters existing - my oldest is a König that is now nearly 30 years old and still works like day one, I do need to calibrate it each now and then - those faults should not even be a thing on today's equipment, even the cheapest. Yet, here we are!), but none of the real reasons was raised here on the real and probably life threatening differences between the cheap, the semi professional, professional grade and the really expensive ones that can earn back their value because they are used for certification or really difficult troubleshooting (blown cap is not difficult, that's just annoying).

@mogwaay 6 месяцев назад

Ive found issues with the selection switch on a couple of my old multimeters. Ive tried cleaning contacts, but hasn't really helped much...

@ilya_mzp 6 месяцев назад

I have to take my aneng multimeter apart periodically because of the same issue. I clean up the switch with IPA and put a bit of silicone oil onto the PCB. Works perfectly after that, very consistent, but it doesn't last more than a year.

@ChrisJackson-js8rd 4 месяца назад

I have an ancient hp4357a that's great for tracing shorts. even in modern motherboards and gpu's with big complicated vrm's you can usually trace the short down to individual component with 7.5 digits. even tho it's kinda beat up and slow and a hasn't had a proper cal in decades it can make very precise comparative measurements across a circuit.

@rmx77 6 месяцев назад

i know the joystick ports on the original spectrum were on the cartridge add on as far as i know. i remember having the original sinclair 1000 but never used it and then it eventually got thrown out. i miss it already. there are lots of computers i want to end up with but finding one isnt cheap sadly.

@joesaiditstrue 6 месяцев назад

that ZX Omni would be even cooler if you could put rechargeable AA's inside it, and use the power brick to charge them

@klaatubob 6 месяцев назад

Re: the meter, i have 2 comments. #1, if i have to use a screwdriver to open the battery compartment, in not interested in using it. #2, rechargable batteries often have different voltage from regular batteries. Could the behavior be because it's working with a weaker starting current?

@hfiguiere 6 месяцев назад

6:00 A lot of the USB-C power cables only do USB 2.0 (and are advertised as such).

@blinkinglightsandsmokingcaps 6 месяцев назад

Sinclair produced a kit to upgrade any regular ZX Spectrum to a Spectrum Plus. Other than a new case and keyboard the only other addition was a reset switch, which connected to either side of a parituclar capacitor on the main board.

@chloedevereaux1801 6 месяцев назад

curious, i have just seen this video on my youtube...... this is the first time i have watched it and there's already a comment from me??????????

@scottschmude8255 6 месяцев назад

As someone who uses a DMM almost everyday at work I personally wouldn't trust anything that wasn't a fluke. But with the range switches have you ever taken them apart and cleaned off the contacts?

@bruwin 6 месяцев назад

Honestly, I'd throw the Aneng meter in the trash. I've got different ones from Aneng and both are unfused! They also claim to be able to measure up to 20 amps, but there's not so much as a bus bar or even a thick trace for the amperage side. They're somehow even worse than the meters you used to be able to get for free from Harbor Freight, and that's saying something.

@jwhite5008 6 месяцев назад

Please disassemble that multimeter, I really wonder what the problem is It's not very useful when it misbehaves like that anyway I'm sure you can reassemble it if you don't lose the tiny balls inside like I did...

@d.lewischampie7657 6 месяцев назад

What tektronix scope were you fixing? I couldn't find the video.

@timrb 6 месяцев назад

"What's going on down here in the basement?!" Maybe moisture? Are the contacts getting corroded inside?

@GlennFisher-h7j 6 месяцев назад

Was wondering if have c64 from 86 had gotten when I was in school couple months ago I lost sound do you think it's the sound chip

@AmadonFaul 6 месяцев назад

Is the basement super humid? That can make the copper contact tarnish faster. Maybe you need a dehumidifier.

@andygozzo72 6 месяцев назад

those multimeters likely just need the switch contacts cleaning, , i've had to do a few...

@gryzman 6 месяцев назад

David is good when it comes to electronic stuff, but otherwise - I can't stand him talking about other issues. Good to see that he sends replacements for free tho.

@thomasschlitzer7541 6 месяцев назад

Check the batteries of the meters. Continuity/resistance mode relies on good batteries. With a bad battery voltage and current can still fine.

@frogz 6 месяцев назад

so uhh... spray some contact cleaner into the dial and give it some work and it should get back to good

@andrewlittleboy8532 6 месяцев назад

We’re all missing Mr Lurch! No output for 5 months.😢

@dawnmitchell8213 6 месяцев назад

What would be the equivalent Fluke meter to the EV Blog and which would be better?

@proesterchen 6 месяцев назад

Just pull the multimeter apart and look at the dial. I've never taken you as someone afraid of a few screws.

@suvetar 6 месяцев назад

You can test this in basic by the way: 9 REM Start here 10 LET M = &8000; 19 REM end... 20 LET END_ADDR = &FFFF 29 REM ... because Rammy 30 PRINT "Bleatings commencing!" 40 FOR ADDR = M TO END_ADDR 50 LET VAL = INT(RND * 256) 59 PRINT "Writing:"; ADDR 60 POKE ADDR, VAL 70 LET VAL_READ = PEEK(ADDR) 80 IF VAL VAL_READ THEN 90 PRINT "Moo @ "; ADDR 100 ELSE 110 PRINT "Read:"; ADDR; " Okay" 100 END IF 120 NEXT ADDR 130 PRINT "/Bleating." This may chug and you can remove the print statements and the else, apart from the "Moo" line; also couldn't test from here, but the Hex for the addresses might need to be 32768 and 65535 if there's an issue but unlike the C64, the speccy is fine with Hex :) Go Z80!

@suvetar 6 месяцев назад

You could just poke an incremental number too instead of rnd for more speed...

@agw5425 3 месяца назад

Just open the multimeters and use deoxit on the range switches, they are bound to oxidize eventually with use or with out.

@pbradleyking 27 дней назад

A person with one clock knows the time. A person with two clocks is never certain... bad test equipment is worse than none.

@kelvinstokes996 6 месяцев назад

Just pop 'em open and deoxit the switch. Easy fix.

@Verightess 6 месяцев назад

Look Usb-C has become the new DVI 🤦‍♂️

@blockbertus 6 месяцев назад

Have you considered humidity being a bit too high in your basement?

@atarimex2643 6 месяцев назад

Holy moly! ….that multimeter is $225 in Amazon. I have the same one normally shown on the Retro Hack Shack channel….a red cheap Innova 3320…but works just fine. I think I paid like $20 bucks almost 9 years ago for it.

@wbfaulk 6 месяцев назад

The Innova 3320 is a 2000-count CAT II multimeter, while the 121GW is 50000-count and CAT III. ACV precision: 1mV vs 1μV. DCV precision: 0.1mV vs 1μV. Current precision: 10μA vs 1nA. Resistance precision: 100mΩ vs 1mΩ. Also, the 121GW can measure capacitance and frequency, neither of which can be done with the Innova. That said, the Innova has a battery testing mode that the 121GW doesn't have. None of this makes the Innova bad, but it is generally less capable. If you don't need those extra capabilities, great; you saved yourself $150. But some people do. (Count has to do with display precision. 2000-count means that it will measure a thing with 4 digits of precision until the first digit gets to 2, and then it jumps to the next range. So for example, you could measure a resistor at 1.999Ω, but if it was over that, you'd be measuring it at 02.01Ω. Or 19.99kΩ, but 02.01kΩ. Whereas 50000 means you might be reading the same resistors at 1.9991Ω, 2.0009Ω, 19.991kΩ, and 20.099kΩ, and you'd lose that 5th digit of precision once the first digit reaches 5.) (And CAT II vs III has to do with safety ratings. I'm not terribly knowledgeable here, but it usually has a lot to do with physical build quality.)

@atarimex2643 6 месяцев назад

@@wbfaulk thank you for the in depth description of the excellent capabilities of the professional multimeter shown on the video. I certainly don’t need all the bells and whistles for the amateur work-hobby that I do. Obviously, they not comparable, as I said the innova is a $20 dollar multimeter that works for me…I was just surprised to see the price tag on the other one, but I guess is worth it for an electronics technician.

@fattomandeibu 6 месяцев назад

Most Spectrum games I remember that were 128k, would typically have 3 voice audio as the "extra bits" for the higher RAM model as they'd typically want to keep 48k compatibility without having multiple versions.

@duncansnowden6857 6 месяцев назад

I was about to say the same thing. The main reason to have a 128 back in the day was the sound chip, not the memory. It would be interesting to see how compatible an expanded 48K Speccy is with 128K software, though. I can imagine some issues it might run into, but I don't know how common they are in the real world.

@kyorin6526 6 месяцев назад

@@duncansnowden6857I'm curious about this too. How did the 128k Speccy know to load in the extra goodies back in the day?

@duncansnowden6857 6 месяцев назад

@@kyorin6526 As far as I recall, most programs weren't smart enough to adapt. You'd either have two different versions, with the 128K one simply crashing on 48K machines, or, if the only difference was AY sound, it would just “play” silently on a 48K machine. Waggling the I/O ports that control the chip on 128K machines doesn't do any harm on a 48. I'm sure there *are* ways to check and adapt intelligently, but I'm not the guy to ask.

@kyorin6526 6 месяцев назад

@@duncansnowden6857 I'm sure I had a game called Chronos back in the day that somehow loaded extra stuff on the 128, it was probably just the sound/music that was different though.

@fattomandeibu 6 месяцев назад

@@kyorin6526 It was a setting you selected at startup whether to be in 128k or 48k mode at boot up on 128k machines. Or at least on the later Amstrad ones.

@KernArc 6 месяцев назад

Regarding the range switches in all of Adrian's multimeters, it's simple: his house has been built atop an ancient Native American burial site. Can't think of any other sensible explanation.

@granitepenguin 6 месяцев назад

They're heeeeerreee

@GYTCommnts 6 месяцев назад

We should go total inception and try to repair the old multimeter using the new one. 😂

@AnthonyRBlacker 6 месяцев назад

Or just use a Fluke meter and be done with your problems.

@jxke 6 месяцев назад

I’ve broken many multimeters by accidentally connecting it to electricity while it was in resistance mode. I didn’t know that it could instantly damage them until I took my HAM radio test and saw that as a question.

@granitepenguin 6 месяцев назад

yup, it's a quick way to learn what fuses your meter takes. :-) step #1 when changing modes; remove the leads from the circuit.