Thank you!

Yes, good luck with the move as well. Hope you're moving to the West Coast. :) Would love to meet you.

Thanks 👍

I wish him all the luck in the world but I’m not interested in C64’s at all, also they have bern done to death with other creators, maybe Atari content might be good, hopefully it’ll be varied.

@@SteveInScotland More Atari content would be fantastic!

nope not my z80... works fine in the z80-mbc2... gotta be bad logic or bad ram...

I came here to say something similar - this CPU might work as a replacement for a Speccy CPU right?

@@bencollier3758 For normal operation it should if only M1 is damaged, but for example Divmmc devices need a working M1.

A check of the circuit diagram would answer your question. Yes. RAM A/D bus is separated from the Z80 by buffers/muxes under control of the GA.

BUSREQ is only actioned by the Z80 at the next clock, which may be too high latency for noise free video unless actions such as locking the CPU out for whole line times are taken.

Thank you! No, I didn't get a chance to test that Z80 on another board. It would have been interesting to see if it was just the M1 line or if it was completely dead.

Exactly. Whenever I have to resort to blindly swapping chips I feel I have "failed" the repair 😃

I thought about getting a 240V outlet just to run European computers, but I think it'll be simpler just to use a good voltage transformer. We'll definitely set thing up for an EV at some point though 👍

@@NoelsRetroLab Be wary of those voltage transformers. Tech Tangents did a video about one within the last year and he had to completely redo the internal wiring of the one that he got. I am planning a short move of my own and I want to install 240v outlets in my new place so I don't have to use that sketchy transformer. I bought one from a flea market a few months ago and I'm kinda scared to use it. I will use it if it's the only way to get something working, but only for a few minutes to test it.

Get a subpanel installed in your lab, then it is easy to run the circuits.

@@NoelsRetroLab Unless it's different in the US but all canadian homes are wired for both 110 and 220v. The drying machine in on the 220v circuit, so as long as you link to it and have a proper isolated circuit with easily identifiable outlets (not hard since they're completely different between Europe and NA), you should be fine.

@@Fularu same in the USA, normally 240 is for water heater, dryer so 240 is not normally a wall outlet. Getting the subpanel in the lab then you can have European outlets installed.

Reading the specs we see that the 200MHz, 100MHz and 70MHz models in this line all share most of the hardware including sampling frequency. All three run at 1 GS/s shared between the two channels which means it's a bit limited above 100-133MHz *IF* both channels are enabled - as the number of samples per "wave" goes down it's forced to guess more and more, it only have 2.5 samples per wave at 2*200MHz which isn't very much, it's way too close to the Nyquist limit (effectively 2 samples). This is pretty standard, even say premium brands like Tektronix sells "shared dual-channel 1GS/s" scopes in 50/100/200MHz variants, I suspect the difference is a software-limit and possibly more expensive capacitors on the front-end and/or better probes - and for some of these (non-chinese) scopes you can upgrade frequency via a license code (IE provably no HW difference on those). This sampling limit slightly reduces the "value" of that higher frequency but it all depends on what you're going to use it for and it's not THAT uncommon to only use one channel, but it all depends on what you want to do. Only you can judge if it's worth, checking, something like 33% extra? My feeling is that 1GS/s is overkill for retro computers of this vintage, I'd argue even the 40MHz scope you mention should be overkill for 8-bit micros. I suspect you could use these 1GS/s scopes to tackle vintage Amiga/Mac/PC up to perhaps 75-90MHz for the 100MHz variant, and up to perhaps 150MHz using the 200MHz models (with judicious use of single-channel mode in some cases). OTOH having overkill on the sampling speed means you get a display that can be easier to interpret due to "nicer" wave-form displays and models cheaper than this often isn't in "scope form-factor". Ref: Adrian's Digital Basement showed that even a shared 48MS/s scope-to-PC (Hantek 6022BE) was mostly usable for these types of computers (up to 4MHz 8-bit), the wonky trigger and clunky software was a worse problem than the sample rate! He later tested a handheld shared 250MS/s scope and the main complaint was some rough edges in the software (Hantek 2C42, 40MHz). If you're in the market for that kind of handheld another options that often gets mentioned is the Owon HDS242 (another 250MS/s scope). I don't have either so I can't comment personally, I see that there's plenty of people who discuss them on KZfaq. And do watch Adrian's videos too.

He could buy a step up transformer and power everything off that.

I haven't confirmed that story. An alternate version I read is that /M1 on the expansion board is very easily shorted to Vcc/Gnd and so it's often damaged on the Spectrum. Not sure which one to believe 😃 As for the voltage differences, you're right. I'm definitely getting a good transformer to be able to run all the European computers here.

@@NoelsRetroLab You will have to get one that converts 120V 60Hz to 230V 50Hz.

@@NoelsRetroLab I've just looked at the edge connector on the Speccy schematics, and M1 is right next to a 12V line. LOL. So that would explaine a lot.

@@NoelsRetroLab Most newer stuff is likely multi-volt but, yeah, always check first. Older stuff can be picky, but MOST US houses (IE apartments is more variable) have either 240V (homes, some offices) or 208V (larger offices & industry) easily available but it's obviously still at 60Hz. Yes, US is officially 120/240 or 120/208, not 110. Still, you may still end up with a transformer for some things. If you DO need 230/50Hz or 240V/60Hz the cheapest way to get that for small loads tends to be via 12V, 24V or 48V DC intermediary. IE an US car/lorry/telco AC->DC converter plugged into mains, then feeding that DC voltage to an EU/UK car/lorry/telco DC->AC converter, probably with "pure sine wave" or a similar label (and it should specify a single-digit THD or THDv at 100% load) since if the hardware cares about frequency it may well get upset by "square wave" or "modified sine-wave" (only marginally better). Also, *some* online (IE battery is always in the loop) UPS can do this if you have 208V or 240V, but it depends on them having a way to override output voltage (not that uncommon) and frequency (less common, auto-sense is defintely default but I've seen models which had it). Exploring this probably starts making sense around 500W+? Usually the spec sheet doesn't actually SAY whether you can force frequency so you'd likely have to read the manual to find out that part and again you'd want some kind of pure sine wave (see above for spec). Or bringing over a power generator as part of the move can also work but you need to be careful to get one that's rated for "electronic loads" and honestly even then the power qualify isn't always THAT great.

Perhaps, if it was just the M1 line. I suspect it was mostly dead though.