ZX Spectrum 128K "Toastrack" Inside and Out 

Thanks! Glad you're enjoying them.

Thanks! I'm sure you'll get the Toastrack eventually. Hard to resist :-)

There are two versions of the toastrack. The Spanish version by investronica and, of course, the Sinclair version with all those fancy system menus. 😎

The +2A/+3/+2B kept that for RS232 interface but the manual had an error documenting the lines, so if you had a custom cable made up according to the manual it would never work. I tried to use my Spectrum as a terminal at university but suffered from this...

Awesome! Thank you!

Glad you like them. I bet there aren't many Investronica Toastracks in Canada :-) Good luck with the C64!

Yeah, making some progress with the C64: calgarycommodore.freeforums.net/thread/109/doing-repairs-on-pal-c64

Right. That's due to the new ROM in the UK models. Things were changing quickly at that point in time.

@Franko Walker A fellow named Paul Farrow in the UK has developed a clone of the keypad, and published it as a DIY project on his website: www.fruitcake.plus.com/Sinclair/Spectrum128/Keypad/Spectrum128Keypad.htm in case you would like to build one yourself; mind you, it does require you to program a PIC16C54 microcontroller (which is compatible with the original PIC1652) in order to get it up and running.

@@BertGrink Neat! I just wish the keyboard was used for more things :-) Any keyboard killer apps out there?

@@NoelsRetroLab None that I have heard of, I'm afraid... Would You like me to write one? I might be able to do that if I concentrate very hard! hehe In the mean time, why don't You take a look at a short video I made where i give a brief demonstration of a Custom Menu i have made for the +3: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-O9iItWoZ4ek.html You can also download a disk image for use in an emulator from sites.google.com/site/bertyfromdk/home/speccy-amstrad-related-stuff/custom-menus-on-the-spectrum-3/BertoMenus_V0.1.dsk?attredirects=0&d=1 I made it so that i could get a look "behind the scenes" of the BASIC system and get a better understanding of the inner workings of the +3 Syntax ROM. Other than that, it isn't terribly useful, though ;)

@@BertGrink That replacement menu is great. Love it! First I should look for a patched Spanish ROM that allows the numeric keypad to be used for regular typing, otherwise it only works in inmediate mode. O I should just get the UK ROM I suppose.

I mean I literally laughed out loud at that point ! Maybe too many years of R: Tape loading Error

Haha, you may be right. They have a very similar shape.

Yes indeed, it's a British Telecom BT631W. It can be still found at BetterBox, for instance if you want to experiment with Spectrum's serial port.

Holy grail is probably a bit of an exaggeration. It's my favorite model because: 1) It has the best looks and still looks like a classic Spectrum 2) It has 128K and AY sound 3) It's not huge 4) It's the last true Sinclair ZX Spectrum. There weren't as many units manufactured as the earlier ones or the +2, so on top of all of that, it's more scarce, which drives prices up unfortunately.

@@NoelsRetroLab thanks, I never realised that they made fewer numbers of this model. Will have to check on my one to see it is kept in good condition.

Yeah, just like Noel said, it's relatively rare and there's the sentimental part of it being "the last true Sinclair". Although Sinclair didn't care much at that point and Investronica was the real driving force. Also, at least half of all "toastracks" was made after Amstrad acquisition, judging by the IC timestamps and the number of them that have Amstrad-branded ULAs. Still, many people (including me) have a soft spot for this model and it would be a shame not to preserve every one of them that made it to 2021.

I didn't know about the keypad being completely different. Interesting! I wonder how many games/programs there were out there that supported it then. And yes, I should have definitely covered the RS232 interface. It was on my list and then totally forgot about it. It probably didn't help that I didn't have anything to test it with, but I should have mentioned it.

@@NoelsRetroLab , The keypad was not included with the UK version of the Toasty (which is the one that got exported), only with the Spanish version, so very few people outside of Spain even knew about the keypad's existence. It is mentioned in the UK version's manual, but only prototypes existed, it never went into serial production. So, no games/programs explicitly support it, AFAIK. If they use the OS for reading the keyboard, it might, by accident, work. :-) However, the bug that you demonstrated, i.e. the keypad not working in the full-screen editor mode, has been fixed in the UK version and it is (or, rather, would have been) actually quite useful for BASIC editing, as it has function keys for moving the cursor by word, as well as stuff like HOME and END. All these functions are also available from the main keyboard through some undocumented key combinations, but it is much less convenient. Interestingly, the driver/decoder software for the keypad is in the 48k compatibility ROM (a.k.a. ROM1), but it is turned off in 48k mode. Moreover, in the UK version, it is the ONLY difference with the original 16k/48k ROM, and, hence, one of the main sources of incompatibilities (it occupies some of the originally FF-filled spare space between the calculator and the font, expected by some games), despite the feature not really being used. Even more interestingly, the keypad's driver is still present in the gray +2's ROM, despite the lack of a keypad connector on that machine. It has been finally removed from the +3's ROM (which is identical to that of +2A/B).

@@daniel1nagy Now you're making me want to make a whole video on the keypad, just going deep on it :-) I wonder if some Spanish software might support it natively since here it was included in that model. Hmm... I'm going to have to do some research!

@@NoelsRetroLab the best I can do is to ask around on FB.

@@daniel1nagy The +2 grey has a keypad socket on the rear, between the RS232/MIDI port and RGB. The +2A black has an identicle looking port in the same place labled AUX. Don't know what it's for though, I keep forgetting I have a +2A.

The membrane can be replaced easily and the keys can be salvaged from a faulty 48K+ (plenty of them are still available). There's still hope :)

Gracias. Lo de los subtítulos (o lo de doblarlo yo mismo) me lo ha dicho mucha gente, pero es mucho trabajo. Si alguien se anima a arreglar los subtítulos a partir de los pre-generados por RU-vid, los añadiría sin ningún problema :-)

I agree it's inconsistent, but at least I'm calling them the way they were pronounced by the people that created them. Calling the Spectrum Zee X Spectrum just feels... wrong, but so does calling it Zed 80. Sorry :-)

@@NoelsRetroLab I think it's correct to say Zee-80, because it is an American Chip; I do the same, but i also say Zed-X Spectrum, somehow it just _feels_ right ;)

Yes, the 128K uses 16 x 8KB RAM chips. Each of them is a 4164, which are cheap and easy to find. Just about any 4164 will work. If you use the ZX Diagnostics ROM, then it can even pinpoint which one is failing.

@@NoelsRetroLab Noel, just a quick question. My toast rack had obvious signs of repair and there were 150 ns chips mounted on. Is this common? My gut feeling is that they should have used 130 ns ones (?) Not sure what the original spec was.

@@baze3SC I've never had speed problems with memory chips on these kind of computers. Memory access was slow enough for the most part not to matter. Looking at the ones I have for spares, they also seem to be 150 ns, so I think that's fine. I wouldn't worry about it unless you're seeing some symptoms of something going wrong.

I believe you can't. For games that require 48K compatibility there are usually some POKE commands you can do (I think they patch the game), for example Knight Lore.

Type "USR 0". This will switch to 48K ROM but memory paging will stay enabled. Many consider this mode the best as far as software compatibility is concerned because you can run both 48K and 128K software. However a small number of 48K games (notably the ones from Ultimate) require OUT 32765, 48 before you run them. They contain some debugging code that inadvertently messes up with 128K memory paging so you need to disable it first.

No, they definitely had the AY chip. I think they're identical to the UK ones minus the ROM (and the numeric keypad). Maybe you're thinking of the Investronica Spectrum, which I have other videos on. That one has a ULA closer to the 128K, but 64K of RAM (only 48K usable) and no AY chip.

You should be good on any Spanish toastrack, UK Issue 6U toastrack and the grey +2. UK Issue 6K toastrack made by Samsung needs R137 = 15 Ohm. On +2A / +3 you could just use the AUX port but I think the keypad scanning routines were removed from ROM so you'd have to interface "by hand". Is there a specific "new board" that you have in mind? Some re-created clone perhaps?

It's a wonderful system. Just make sure you do take it out and enjoy it! 😃

@@NoelsRetroLab This thing is that the antena cable is not working good..so image of the computer is not good..most games also dont work..I am looking forward to buy a new antena...is the spectrum 128 k inves

@@yeraysantanaaday6827 Really, just ignore the antenna output. The 128K Investronica outputs beautiful RGB signal. Get a cable to connect it to SCART and you'll be all set. The fact that most games don't work is worrysome. Some 48K ones don't work, like the Ultimate ones. You need to do an OUT command to fix that (I think it's towards the end of this video). But if more don't work, then there's something slightly wrong with it. Maybe bad RAM?

@@NoelsRetroLab Thanks a lot, you are right there is the RGB..I go to a computer shop and buy the cable to conect to tv..the Ram is ok becaus it loads combat school 128 version...and other games.

@@NoelsRetroLab He did OUT 32765, 48 to disable the RAM bank paging.