Видео

That's funny when you were programming in Z-80 assembly for ZX Spectrum 128 with AY-3-8912 chip, and nothing of this is a surprise to you. :)

Back in the far past I had a friend mod my Spectrum 48k to have both RF and composite in the original output connector. Both the RF and composite shoved no artifacts when I used them on different monitors and TV’s. As far as I recall the mod was done using a single bipolar transistor as emitter follower and a few passives, to inject the composite signal “onto” the RF output. I do recall this was a theoretical stretch as the transistor barely supported the required bandwidth, but the monitors I used managed to display a fine picture with no distortion. The addition of the composite signal did not degrade the picture quality on connected TV’s. I assume a high pass or to in the RF antenna signal path attenuated the composite signal sufficiently as the integrated bandwidth limit / low pass filter in the monitors composite input cut the RF away.

Hacía como 40 años que no escuchaba esa marca 🙂

No te preocupes, yo te lo puedo guardar😜

Another bs memory mapped IO nut

I'm not sure if there's a name for them but I recently added a set of needle finger probes for precise probing on high density boards. if you find yourself working on high density boards a lot I highly recommend them.

hey noel , thanks for the channel its filled to bursting with tips and tricks so an amateur like me can tackle our problems

Your video reminded me that I have a partial set of 6581 lithographic masks somewhere in storage. Wish I could find someone with the remaining masks to make a full set, and then a foundry that could churn out a batch of original SIDs.

Last step: decapping the counterfeit chips and seeing what it is under a microscope!

That's exactly the microcomputer I had in my early teenage years, the Spanish model with the Spanish keyboard, including Ñ key. I have great memories of my first Basic 1.1 programs, even learning some machine code; my first experiences with the CPM DOS; great but really expensive videogames on 3" discs, and tons of not-so-expensive games on external tape. Later on, I only used the TV tuner for the screen.

If folks ONLY want to learn (re-learn) BASIC programming in BBC Basic, then that is also ported to MANY platform (such as this modern Windows Laptop I am writing on). If, on the other hand, someone wants a dozen computers for a Summer School, or after school club, then the Agon Light makes more sense. If folks want something to fiddle with, with only a modest cost at risk if their projects go wrong in a big way, then the Agon Light also makes sense. As for me, being someone that got to use the RML 380Z and the BBC Micro at school (I was in Year 12 when the BBC Micro was released), and also being someone that had a ZX81 back in .... 1981 (purchased from, iirc, WH Smiths, the newsagent & bookseller), I think I will relearn some BBC Basic first (running in Windows), and then think about buying a little computer AFTER that (not before). Just saying.

One statement per line was pretty well normal for many 8bit computers; it was rare to see one that supported it

I do hope it'll get a faster CPU

The drisk drive power cable is too thin what a cock up.

Yeah, I suspected you had a fake when you started having issues soldering it. As others have mentioned, whatever they do to those poor chips to relabel them seems to oxidize the pins or something, and it's fairly common that fakes are harder to solder until you clean the pins. The flux you put in only gets you so far... Anyway, great video as usual, a lot to learn from your persistence and analysis skills.

Wow

Yo I need help how do I ground myself using a European outlet or can I just put it in using the little adapter?

Another person who does not know that the red / white rca are not for video but for audio the cable contruction is different.

There was the Amtrad CPC664 (codenamed IDIOT) and the CPC6128 (codenamed BIG IDIOT). 🤣

other than soldering "skills" that board routing is atrociously wrong.

I've had similar dry solder joints but I do find if I use an eye glass, something like x20, I can see clearly a good or bad joint. Cheap and important investment.

I made exactly the same mistake and learned exactly the same lesson with fat test probes! Good-bye MCU!

component tester, temperature meter, signal generator & so on ....

I recently built a Spectrum 48k from a kit. All works okay with composite mod, but on one TV it doesn’t display colour (monochrome only) and the picture is slightly shifted down the screen. Other TV is fine. I’ve been comparing two signals to see what difference may exist. There is some variability in DC offset. Could this account for behaviour with the two TVs?

May I suggest you get yourself a set of Probemaster probes. They are very pointy and gold plated. It makes a considerable difference. I am very happy with them. The most basic set will do.

I got similar from Microchips. 4% of chips were versions with 10bit ADC, but I ordered ones with 12bit. Microchip said it's within error limits and will not send correct replacements.

To make things easier, get yourself some "ERNI - TE CONNECTIVITY 394911-E" "IDC Connector, Right Angle, IDC Receptacle, Female, 1.27 mm, 1 Row, 6 Contacts, Cable Mount" Order Code: 4060487 from element14/farnell.

For those of us with no nice microscope…. purchased all smd’s assembled from pcbway….done!

For measuring on these fine pitch layouts, you should have a look at probe master spring loaded micro-tip test leads! They make a WORLD of difference on stuff like this!

Those chips probably were harvested from random crap in China then laser printed with the new part number. If so the solder not sticking to the legs makes sense especially if they used a chemical cleaning process on them to make them look unused.

That was a lovely explanation. I might want to do experiments on my dear Viccy.

its the pb-free tinning on the pins. increasing temps can help with that. or buy un-tinned ic.

you need a better flux.

Would have been better without the RR voice over. We watch your content for you :) Those who want to be bored to the point of vomiting blood can head over to the RR channel

Great job Noel, glad you got it finally working! And about the microcontroller: I had several problems with my Kung Fu card, I bought it a longer time ago on ebay and when it did not work anymore (sometimes it did, then no longer), I opened it up and was shocked about the soldering of the microcontroller and components. The controller pins were mostly loose, no connection to the pcb, I cleaned everything with Isopropanol and resoldered the chip, but as in your case, the solder had no intention to make any good connection. It took a lot of cleaning, flux, and good solder and a huge amount of patience to get the chip back onto the pcb, that was as in your case, the chip had no goog connection and refused to work. Luckily I finally got it working again and had no trouble since... so I can exactly imagine how frustrating it is to solder in such bad connection conditions... Greetings, Michael...

that atmega looks super coroded. I guess that the chip is held by baked flux as those joints look cold as heck...

I'm sure I'm not the only one who is asking himself.... Why????🙄

This is a great lesson in problem-solving. It also warns us to be careful about the chips we buy. Most counterfeits that I have seen have blurry lettering and incorrect logos. Try to find images of genuine chips online and compare. Another great takeaway from this video is that there is now a new source of SID chips for the Commodore community. Hats off to whoever created it.

Regarding the probe tips: First thing, I always shaped the original probes to a sharp tip. Use a file, belt sander, whatever gets it done. Sharp pins work well and do not slip nor short pins to each other. Solderability is also a problem. Pre-tin procedure sometimes helps.

It looks like the leads of your microcontroller are pretty heavily oxidized, and your flux is not enough to let this work. At least in the microscope you should be able to see that you aren't seeing solder color / texture on the microcontroller pins, but instead you are seeing the original metal finish of the microcontroller pins. I know I used to etch my own circuit boards using an acid solution, and lots of parts I had in the same room oxidized, and became very hard to solder.

Too long a video to come to a conclusion that chinese sellers have counterfeit less than one Dollar IC's. And I never experienced an original IC so difficult to solder: it probably had "a very bad experience" from manufacturing to your PCB.

Hmm, I forgot about the exploding green acid bomb and the rocket motor in my bedroom..

My railgun I think was the worst. I was 14 or so. It was the 80's, I had a computer and a big giant spool of fine transformer wire, a 2400 baud modem which could access the university and ask the engineers for help. I started bay making electro magnets, I would hand wind them while sitting in class or on the buss. I learned what shapes would make what fields, it was something to do.. I decided to make a railgun. I may Post a vid of how I made my first one if people are interested. It's really simple. just a curved plastic tube and the magnets placed at tangents.. I wanted something an order of magnitude stronger at least. And I did.. Id sink ball bearings into a block of wood. But then I got an Idea to increase it more as I was only getting about %1 of the energy I put into the large capacitors, the timing was bad. So I added sensors and started programming a parallel port interface It took about a month of work.. And it worked spectacularly.. But it worked too well and I was in a basement. I had forgotten newtons first law.. and yeah, the steel ball went one way really fast.. and the entire thing, table and all went the other direction ! It all wound up a ball of wire in a pile with the table on top, I used the nicely wound magnets for other things. . I never found the steel ball it went through the 4x4 and I suppose into the basement wall , but It was old field-stone and mortar and I couldn't tell, it was very loud.

The ATMEGA8 is more expensive _now_ - because it's on 'final lifetime buy' status. It was cheaper when the relabeler did its thing. Once the current inventory is gone, there won't be any more. Pretty soon all the distributors will send you to Rochester Electronics - at Rochester Electronics prices.

We would say "wenns bärt, dann bärts" which means "When things go wrong, they really go wrong all day long"

SWITCHLESS BOOT SELECTOR is th new bees knees.

Noel. You can test to see if a suspected chip is rebadged by rubbing the chip with a cotton swab soaked in rubbing alcohol. Fake chips the label will rub off. But you knew that already. Great video. Really enjoyed it

I should start to make RUclips videos too. ALL of my electronics projects go wrong. Buying chips from Aliexpress is one of the biggest contributors to that. I totally felt your pain when I saw the soldering challenges. I spent all day Saturday doubting my soldering skills due to dodgy CH340 chips from Aliexpress. When I was a kid I used to kill many ICs trying to desolder them so I've always been wary about how long to keep the iron on pins. That's the whole reason I've been too chicken to solder a Spartan 3 FPGA onto a PCB. Drag soldering scares me - always worried a bridge will form underneath the IC somewhere where it can't be seen. The other mistake I make is trying to design a PCB, getting it manufactured, waiting 2-3 weeks for it to arrive and then discovering there's a mistake or I haven't added something. Just did that - didn't add the ISP pins to program my AtMega2560.. I'm glad to see that other people experience this pain. I keep thinking it's just me and that maybe electronics and I were not to be :-)

I'd use some solder paste instead of a wire for that chip. Has included flux and a lower melting temp (lower temp difference = easier for it to stick), much easier to work with small pads. You can also place it before you add the chip, so that it is much less likely to not make contact

A fourth takeaway you really should have gotten from this is *DON'T JUST IGNORE ERROR MESSAGES.* If you had not just blithely ignored that warning about the incorrect device ID, you could have saved yourself a whole lot of time and hair-pulling by just realizing early on that your chips were not actually what you thought they were. *The software tried to tell you* but you just didn't even pay any attention. *It even correctly identified the chip for you* and you completely ignored that too.