Noel, another great video! I'm glad you kept the debugging portion in the video. One of the tings I love about your channel is the journey (building, debugging, and trial\error) that gets you (us) to the final destination. Not only is it fascinating to watch, but it helps me better learn diagnosing issues and how to repair them. So, please keep the debugging portion in your videos.
[9:36] My initial reaction was "OMG, you are shorting the signal to the ground, attenuated signal is at the middle pin", glad you have finally fixed it later :D
Joder macho, no sabes que gozada es por fin ver a alguien en RUclips que sabe soldar como es debido. Se agradece no tener que gritar a la pantalla. Great Job!
@@NoelsRetroLab un placer, soy un gran fan del canal. Como ingeniero en electrónica da verdadero gusto ver a alguien que sabe de lo que habla y trabaja bien. Sigo a muchos pero ninguno que haga las cosas bien al 100% excepto tú, te mereces muchos más seguidores, como creador de contenido se lo difícil que es darse a conocer pero creo que te espera un buen futuro, como ya he dicho, el canal es de 10
Thanks! Yes, I guess I should have known it would be better. But since the video in my mind was going to be about something else, all of this was stuff getting in the way! But lesson learned: Keep all this stuff in because it makes for interesting videos, failures and all.
Thanks! Yes, those sounds are engraved in our brains, aren't they? I can still tell what kind of data is being loaded by the sound of it (code, data, or a loading screen). Kind of crazy!
I love when videos about DIY hardware show the mistakes too; reminds me that no-one is a super-human, and we all make mistakes, and it's all part of the process to make something nice, to go through those mistakes, whether you are just starting out or already creating stuff. Not failing means not doing anything, and it's important (and interesting) to see others make mistakes too, as not only do you learn from your own mistakes, you learn from others' mistakes too!
Sounds good. The only reason I thought of cutting it is because this was not the video I had in my mind I was going to make. But I should know by now that sometimes those end up being even better 😃
The troubleshooting process is the most important part! When I build things, something always goes wrong. I'm pretty basic at the investigation, so I learn a lot from watching someone experienced like you. I love your videos!
TZXDuino Reloaded was already updated with these changes and the fixes to the board so it's even easier to build! That was fast!! Thank you Edu Arana! github.com/arananet/TzxDuino-Reloaded
@Mr Guru Please do not take this as an insult: You know how it looks, taking free cookies, complaining about that there is no free milk? :) And why did you talk about a reverse engineered schematic instead of making one? :P Just to think about what you demand. One can have the completely opposite opinion.
I don't have an SVI328, nor desire to have one - so your video is so much more interesting for the sake of diagnosing a fault; I'm glad you kept that in.
Another great vid Noel. By coincidence I've been playing with an Arduino to pipe programs into my 1978 Science of Cambridge (Sinclair) MK14 replica computer with some good results, so I appreciate how frustrating this must have been and how great it felt when it finally worked!
Very cool! I'm glad it worked. What kind of source data did you start from? Did you convert original sound files to something like a CAS format and then play it back from the Arduino? Or were those files already available? The more rare the computers, the less stuff there is out there already ready to use.
@@NoelsRetroLab Well the MK14s cassette interface was an optional extra so I just connected the arduino directly to the serial in pin and generated the pulses directly. The MK14 has only 640 bytes of memory fully expanded so programs are usually just hex listings! Its an extremely primative computer, with a 20 key keypad and a 8 digit 7 segment display. Its built in monitor routine is only 512 bytes long but does have cassette routines to support the optional interface. Its not TTL serial, its a combination of 4mS and 16mS pulses for 0 or 1 respectively. The MK14 is quite rare but there is a surprising amount of info out there, a couple of years ago I designed a replica and built it, and several other people have built my replicas too. The only hard part was getting the 50 year old memory and processor chips.....
Yes, I've designed boards and found glitches afterwards that required cutting traces and adding jumpers. Sometimes things work great in the breadboard stage but suffer in the copper layout stage. Especially things like shielding. Like your videos but the only "game" computers I ever had were the Radio Shack color computer and the Atari 2600. Glad to see you using the 'scope to analyse things. I've done a ton of logic design and the 'scope is the most valuable tool for troubleshooting logic flow.
Yes, that happens. I'm starting to do some hardware design myself now, so I'm sure I'll run into that as well. Do you ever use logic analyzers? They seem really useful in theory for more data, but I find that you need at least 24-32 channels to really get anything useful out of them (certainly not the puny 8 channels of the one I have!).
Glad you helped the project, no project is perfect from the very beginning. What my opinion is the TZXDuino don't have to be that small, make the trouble shooting and building hard, even SMD have large size component.
at that age would have loved having a courier job (did paper route instead - but those are nearly extinct now). There wasn't nearly so much of creeps that prey on children back then as there is now
Cool video to finish a stressing day at work. Thank you for not cutting parts of it: showing mistakes naturally is the magic of your channel !!!. I guess Iĺl make one of those, as it will be useful for Sinclairs and perhaps C64s. Cheers mate
Noel you use a tip, ring and ground stereo plug and cable. Old cassette players were MONO so you only need tip and ground. You may be shorting out the ring to ground. It is not needed so I would suggest you remove the red ring wire from the connector on the computer. That is how I load Spectrum games. I hope that helps. Best wishes from France.
Right, I knew that about the ZX Spectrum. In this case it doesn't matter because the SVI 328 has its own adaptor, so there's no potential confusion there (and the audio jack in the TZXDuino is stereo).
TZXDuino is a great piece of work. So is MaxDuino, which is a spinoff (kinda) project from TZXDuino. I prefer MaxDuino with my ZX Spectrum because the code is constantly updated with new features and optimizations. I've contacted RC Molina, and he was more than helpful with some problems I had. I know some Arduino, I am not a programmer with any definition of the word, but I can write some code for my needs and I can understand (mostly) how other people's codes work. The only criticism I have about the MaxDuino code is it is always like a development copy rather than a release version. All the changes made from the beginning are commented out but still there, this makes it very hard to follow and makes heads and tails of it. MaxDuino is a multiplatform software, meaning, it can be run on different MCU's, using different types displays, can decode different types of file formats for different 8bit computers, with different kind of settings for each. But, everything is integrated into one piece of firmware. Anybody with a decent level of coding knowledge can work with this, but for the novice level it can become very complicated and frustrating. The firmware barely fits into an Atmega328 because of all these different options. Granted, if you know what you are doing and manage to comment out the parts you do not need for your specific hardware (MCU, display) and the 8bit computer you intend to use it with, not everything is compiled and the firmware gets considerably smaller. I wish dear Mr. Molina came up with a version that is cleaned out of unnecessary old code, with better comments that explain how to tweak (or set up) the options optimally for its use. A user manual explaining the menu settings etc would have been great too. With each new version I spend hours reading the code and cleaning it from everything that I do not need to come up with the smallest code I can do. Oh, by the way, you can add a buzzer to the output pin with a series resistor (470 ohm to 1K works best) if you want to hear the loading. With ZX Spectrum this is not needed but apparently SVI needs it.
I have looked at the GithubV directory. Unfortunately, there is no circuit diagram there yet. This makes improvements difficult. In the layout, I can see optimisation possibilities in the pictures. Continuous ground plane on top, avoid islands. The space is there to also use CH1206 designs for passive components. Holes for spacer bolts for the display. Mounting holes on the PCB. Optional push-buttons for operation from above. GND via stiching.
I agree with you. The author prefers not to share the circuit schematics unfortunately. On the other hand, it's probably simple enough to start your own project (especially if you avoid the amplifier). You seem to have a lot of good ideas of where to take it. Do it! 😃
The way you shorted the potentiometer, you actually shorted the audio signal to GND... that's why it plays very quiet in "amplifier ON" mode (the switch is labelled correctly). Two bottom pads are GND and signal IN, the top pad is signal OUT.
When, the first time or the second time? I don't think the potentiometer was connected to the audio signal, but to the gain signal on the amplifier (first time I left it unconnected).
@@NoelsRetroLab For the first time. I wasn't aware of the circuit at first, but now I found the old v1.4 project and there was a bug in the circuit design, the left bottom pin of the potentiometer, should not be connected to anything, but it was connected to GND (so you've connected one side of C4 to GND, and pin 1 - unconnected). The potentiometer is indeed in the GAIN control loop, not in the audio path. The right bottom pin goes to the C4, and then to pin 8, the top pin goes to R5 and to pin 1. Pins 1 and 8 should be either not connected at all, or connected via a capacitor and a resistor in series.
@@NoelsRetroLab They slot in and have a barb on the bottom to lock them in place. The slots at the front of the connector allow you to lift the barb if you need to extract a contact.
You made the right call, I really enjoy the debugging stuff regardless of the system! I should see if there is a tape player for the STM32 blue pill as got one for Xmas and would like a convenient way to load to my speccy
Thanks! Good to hear that feedback. The STM32 should compile just about the same things as Arduino, right? With some pin interface differences but mostly the same. I noticed that MAXDuino even has options for multiple microprocessors so I bet you can get it to work on the STM32.
You can program Blue Pills directly from the Arduino IDE by changing a few options: idyl.io/arduino/how-to/program-stm32-blue-pill-stm32f103c8t6/ (I have one of the £2 STLinkV2 adaptors off ebay and find it to be 100% reliable.)
Excellent video, recently found your channel and I am thoroughly enjoying watching these retro-tech based videos. Greetings from the Netherlands. Las videocomputadoras Spectravideo son sistemas interesantes! The tape edge connector is similar to the C64 one. I had a dedicated SV tapedeck at some point but gave that away to a friend. The joys of proprietary connectors.
BTW: if you have some fine (gauge) wire, you could run it from the board to a regular size 10k potentiometer (such as one salvaged from a dead transistor radio).
Right. That was plan B until I noticed that the whole amplifier part was not working as intended, even with the correct resistance, and that the unamplified part worked fine on this computer 😃
Nice video. The SVI328-mkII was my first computer back in de eighties. I still have several Spectravideo machines including my first 328 (albeit "slightly" modded) that I still use today. With respect to turbo tape loading, SVI328 machines do not support turbo tape modes, the firmware only supports 1800 baud plus-minus tape jitter corrections. Later MSX machines do have dual tape baud rates, default 1200 baud and a 2400 baud turbo tape mode, the earlier SVI328 does not support this turbo feature.
@@NoelsRetroLab Machine has a Z80B at 6Mhz (mkII machines work fine at 6Mhz) switchable to 3.5Mhz original. Other mods are in the attached SVI605 super expander, floppy controller is modified to work with 80 track drives, made my own memory boards with a memory pager also supporting the native bank switching, flash storage board emulating an ATA harddrive, 68000 coprocessor board, GPIB board for interfacing with my test equipment. Most of that stuff was developed many many moons ago. I am a software developer by trade. Today I mostly use the 328s for running CP/M natively and for occasional vintage gaming. BTW. SVI328 machines can run MSX-1 games and MSX Basic 1.0 software unless the software directly addresses the MSX hardware (hardware is identical, IO map differs from MSX) using a software MSX-1 emulator that runs a modified MSX-1 ROM bank switched to bank 0 page 01 replacing the 328 ROM at runtime. There is also a hardware MSX-1 SVI606 adapter accepting MSX cartridges similar to the SVI603 Celeco adapter, unfortunately the hardware MSX adapter is ultra rare and considered a holy grail. Several MSX-1 Konami games run fine with the software 328 MSX ROM.
Ok, if I know anything about Op amps. You need some resistance to get amplification. If you simply drop 0 ohms across a op amp feed back loop you will get unity output or no gain. Try using a SMD resistor across those points instead of that jumper.
That chip footprint Noel showed looks like its an LM386 power amplifier rather than an operational amplifier, that has a gain select on Pin 1. Thats usually got a capacitor between it and pin 8 to set the gain. I think if you just short it it to pin 8 it moves the gain up to ~200x which would explain why it was picking up the 150kHz interference signal and amplifying it!
Hi Noel, thanks to your videos I was able to bring my SVI 328 back to life. I am missing a key as well, where did you get your replacement? Thanks in advance
Thank you! I actually got an MKII and an MKI recently, so I'm all set in that regard. But much appreciated. I have some more SVI 328 content planned in a couple of months from now too! 😃
@@NoelsRetroLab I also have a Super Expander and a original tape recorder. My SVI328 is currently not turning on and you motivated me to start working on it. Thanks!!
You can order them from hobbyretro.com/tienda for example. They don't have any right now but they have the new boards ordered and should get them in soon.
Also, I noticed that - while you were soldering the Arduino Pro Mini PCB to the main board - you forgot to solder some of the pins on the bottom of the main board; though it’s possible that these are just unused GPIO pins for this application.
@ 20:47 - Seems like somebody that proggramed it used a PWM to efectively reduce the overal amplitude of the signal but PWM carrier should be filtered out. But the author probably assumed that the supported computers probably do not have enough bandwidth or have their own input filters so they will not see this carrier. Not so elegant sollution but what did you expect from arduino based project ;)
Hey Noel, I was just wondering, when you were building the board, you used a LOT of flux, and I saw it melt and make pools all over the place. At the end of the day, how do you clean all that off to make the board look professional and neat?
Didn't I show the cleaning process here? Sometimes I cut it to make videos shorter. I apply isopropyl alcohol over the board, brush with well, and then, before it dries, put a rag on top, and brush over the rag. That soaks in the alcohol with the flux and takes it away from the board. I'm sure you'll see it in some of my other videos. Works like a treat!
Absolutely the right call to leave the debugging bit in. It is both interesting and satisfying to see the problems being fixed. BTW, why do you keep your daughter in a cupboard? Are you concerned she might get a place at Hogwarts?
Bummer! And seriously, who would steal a 728 in 1992??!?!? Hopefully you can get another one not very expensive now. So much fun to be had with these machines!
@@NoelsRetroLab I had played Moon Lander & Jump Jet on mine, and other games. Plus I learned Basic programming on mine Well the next computer my dad had purchase was a IBM 286 with 1 meg ram 256 VGA grafix card 20 meg hard drive and Super VGA screen.
I think the graphic on the screen, when loading this game was normal, not 100% sure (so long ago). Cload only work if you have a basic program header first. Bload was for binary file (machine codes files) Load was also for basic program, but slower (can't remember if it also could load machine code programs) Cload"",r load basic program and run it You could also write something like run"" it was the same as the load command but it also automatically start after loading But I think you should try to read up on Load, run Bload "filename" Cload "filename"
Right. I saw there were games that loaded with CLOAD and some with BLOAD. I did find two other games with an identical loading pattern loading data onto screen memory, so I think you're right and that was the way it was intended.
@@NoelsRetroLab I know that the game you tested also ran on a sv-318, that computer only had 16kb of memory, so maybe they used the video memory as a loading buffer, but I don't know about that. But it's good to see you got the sv-328 up and running 😁👍
Strange that they didn't specify an exact part number from a major manufacturer for that USB connector in their required bill of materials. They should. octopart.com could then be used to find a source or suitable replacement. That would save time for builders.
If you look at the BOM there's a number there, but since I wasn't ordering components from a major vendor (didn't have 50€ to buy to avoid huge shipping) I ended up buying it from Ali and there the number was pretty useless.
What do you mean you can't save to them? This one has an SD card and you can take pics and take videos of what you're doing. Or do you mean something else?
@@NoelsRetroLab Ah, I'm so sorry. I was reffering to the TZX SD card not the Microscope in the second sentence. If you write a program, you can't save it to the SD Card. It can only load. I typed it in my head, but it obviously did'nt reach my fingers. LOL.
Yes, it always feels weird to use a piece of technology like this for something like this or even as a coprocessor or add-on, realizing it's so much more powerful than the original hardware.
I totally get it. I was put off/scared by SMD as well, but it's just a matter of getting used to it (and maybe having some kind of magnification, even if it's just a magnifying glass). I recommend starting with some of those SMD learning soldering kits from Ali or Ebay.
It's a shame the shipping is 4 times the cost of the PCB. Not PCBWay's fault...just the way things are. But on the bright side, those PCB's would have cost thousands only a few years ago.
Noel. You also mentioned the MSX cartridge slot, that is not compatible. Just I've found some info about a guy that has a solution for this. I suppose that there could be built some kind of cartridge adaptor circuit, that enables de cartridge port for standard MSX cartridges: hansotten.file-hunter.com/uploads/files/svi728cart.txt
Neat. There are still some significant differences between the 328 and MSX, so even with that a lot of things wouldn't work. I'll get into that in a bit of detail next video actually.
@@NoelsRetroLab But I've seen already some developments to improve the MSX compatibility for SVI-328, 728 and 738. It may be interesting to see some of them.
I will probably build the updated version and test it on an Amstrad CPC 464 with the audio jack mod. But it's going to be a few weeks. I can confirm it works great on the Amstrad and without the amplifier. Good luck with it!
Nicely done! If you would like to make a few cartridges (like on the picture) feel free to use this repository: github.com/Wierzbowsky/SVI-328_Cartridge
If you've got to solder smd components on to the pcb ANYWAY... it seems so wasteful and over complicated to solder a pro mini on the board too... it would be so much simpler to just put an ATMega on the board instead.
Would it? I haven't used an ATMega by itself before. Would you program it the same way you do an Arduino? Which type of ATMega microcontroller would you recommend for something like this?
...so glad you left the debugging of the Arduino in, makes for a more true-to-life experience when dealing with these kinds of devices.
Good to hear! Yeah, there are always unexpected problems that crop up.
Noel, another great video! I'm glad you kept the debugging portion in the video. One of the tings I love about your channel is the journey (building, debugging, and trial\error) that gets you (us) to the final destination. Not only is it fascinating to watch, but it helps me better learn diagnosing issues and how to repair them. So, please keep the debugging portion in your videos.
Thanks! That's what I was leaning towards, but great to hear that feedback. Cheers!
If you build it he will debug.
[9:36] My initial reaction was "OMG, you are shorting the signal to the ground, attenuated signal is at the middle pin", glad you have finally fixed it later :D
Joder macho, no sabes que gozada es por fin ver a alguien en RUclips que sabe soldar como es debido. Se agradece no tener que gritar a la pantalla.
Great Job!
Jajaja, gracias! 😃
@@NoelsRetroLab un placer, soy un gran fan del canal. Como ingeniero en electrónica da verdadero gusto ver a alguien que sabe de lo que habla y trabaja bien. Sigo a muchos pero ninguno que haga las cosas bien al 100% excepto tú, te mereces muchos más seguidores, como creador de contenido se lo difícil que es darse a conocer pero creo que te espera un buen futuro, como ya he dicho, el canal es de 10
The troubleshooting of the TZXduino is much more interesting than only showing it working. Again a very good video!
Thanks! Yes, I guess I should have known it would be better. But since the video in my mind was going to be about something else, all of this was stuff getting in the way! But lesson learned: Keep all this stuff in because it makes for interesting videos, failures and all.
When you started testing on the scope and you played the tape my brain went "THAT'S AN AMSTRAD!"
I'll never forget those tapes. Nice video!
Thanks! Yes, those sounds are engraved in our brains, aren't they? I can still tell what kind of data is being loaded by the sound of it (code, data, or a loading screen). Kind of crazy!
I love when videos about DIY hardware show the mistakes too; reminds me that no-one is a super-human, and we all make mistakes, and it's all part of the process to make something nice, to go through those mistakes, whether you are just starting out or already creating stuff. Not failing means not doing anything, and it's important (and interesting) to see others make mistakes too, as not only do you learn from your own mistakes, you learn from others' mistakes too!
So true! Glad you liked it!
Ah don't ever take that diagnostic part out. It's one of the best things about the channel. C O N T E N T!!!!
Sounds good. The only reason I thought of cutting it is because this was not the video I had in my mind I was going to make. But I should know by now that sometimes those end up being even better 😃
Good troubleshooting Noel. Great video. Yes. It was interesting to see the problems.
Good to hear. Thanks for the feedback!
great video, and the delivery of the package was awesome !
I agree, it was very Scott Pilgrim.
Yhar, good call, definitely more compelling, educational, and valuable seeing the skirmish with the problems.
Cool. Glad that was interesting that way.
The troubleshooting process is the most important part! When I build things, something always goes wrong. I'm pretty basic at the investigation, so I learn a lot from watching someone experienced like you.
I love your videos!
TZXDuino Reloaded was already updated with these changes and the fixes to the board so it's even easier to build! That was fast!! Thank you Edu Arana! github.com/arananet/TzxDuino-Reloaded
@Mr Guru Please do not take this as an insult:
You know how it looks, taking free cookies, complaining about that there is no free milk? :)
And why did you talk about a reverse engineered schematic instead of making one? :P
Just to think about what you demand. One can have the completely opposite opinion.
You're right, it is interesting to see you work on unexpected problems.
Thanks! Glad you enjoyed it.
I don't have an SVI328, nor desire to have one - so your video is so much more interesting for the sake of diagnosing a fault; I'm glad you kept that in.
Me alegro mucho que no hayas cortado la parte del debugging del sistema Arduino. Excelente video. Muchas gracias!
I totally agree, please keep the trouble shooting part in the videos!
Really got the urge to get one of these now!!! :)
Do it. I love how reliable they are!
Cool device. I love this kind of devices that give live to old computers. Great video, I'm subbed now.
Thanks! Glad you enjoyed it and welcome on board!
Thanks for another great video. I like to see you work out fixes for things. Very handy skills to have.😁
Thanks! Glad you liked it!
The delivery segment was awesome, even the dubbing :D
Thanks! 😃
Another great vid Noel. By coincidence I've been playing with an Arduino to pipe programs into my 1978 Science of Cambridge (Sinclair) MK14 replica computer with some good results, so I appreciate how frustrating this must have been and how great it felt when it finally worked!
Very cool! I'm glad it worked. What kind of source data did you start from? Did you convert original sound files to something like a CAS format and then play it back from the Arduino? Or were those files already available? The more rare the computers, the less stuff there is out there already ready to use.
@@NoelsRetroLab Well the MK14s cassette interface was an optional extra so I just connected the arduino directly to the serial in pin and generated the pulses directly. The MK14 has only 640 bytes of memory fully expanded so programs are usually just hex listings! Its an extremely primative computer, with a 20 key keypad and a 8 digit 7 segment display. Its built in monitor routine is only 512 bytes long but does have cassette routines to support the optional interface. Its not TTL serial, its a combination of 4mS and 16mS pulses for 0 or 1 respectively. The MK14 is quite rare but there is a surprising amount of info out there, a couple of years ago I designed a replica and built it, and several other people have built my replicas too. The only hard part was getting the 50 year old memory and processor chips.....
I've not got much on the net about it other than this livejournal entry. I suppose I should get on that :) ianrolfe.livejournal.com/40720.html
Yes, I've designed boards and found glitches afterwards that required cutting traces and adding jumpers. Sometimes things work great in the breadboard stage but suffer in the copper layout stage. Especially things like shielding.
Like your videos but the only "game" computers I ever had were the Radio Shack color computer and the Atari 2600. Glad to see you using the 'scope to analyse things. I've done a ton of logic design and the 'scope is the most valuable tool for troubleshooting logic flow.
Yes, that happens. I'm starting to do some hardware design myself now, so I'm sure I'll run into that as well.
Do you ever use logic analyzers? They seem really useful in theory for more data, but I find that you need at least 24-32 channels to really get anything useful out of them (certainly not the puny 8 channels of the one I have!).
Glad you helped the project, no project is perfect from the very beginning. What my opinion is the TZXDuino don't have to be that small, make the trouble shooting and building hard, even SMD have large size component.
I'll have to call to PCBWay and make a complaint, their couriers use child labour!
In China, that's common, we can only pray that the child got a fair salary.
at that age would have loved having a courier job (did paper route instead - but those are nearly extinct now). There wasn't nearly so much of creeps that prey on children back then as there is now
@@TheSulross there were, but it Wasnt so publicly known.
Oh, yeah, thanks very much fot nice mood, keep smile at its full!)
I am impressed. Thanks for the video.
Glad you liked it!
Cool video to finish a stressing day at work. Thank you for not cutting parts of it: showing mistakes naturally is the magic of your channel !!!. I guess Iĺl make one of those, as it will be useful for Sinclairs and perhaps C64s. Cheers mate
Glad you liked it. Make sure you get a version with amplifier for the ZX Spectrum.
Noel you use a tip, ring and ground stereo plug and cable. Old cassette players were MONO so you only need tip and ground. You may be shorting out the ring to ground. It is not needed so I would suggest you remove the red ring wire from the connector on the computer. That is how I load Spectrum games. I hope that helps. Best wishes from France.
Right, I knew that about the ZX Spectrum. In this case it doesn't matter because the SVI 328 has its own adaptor, so there's no potential confusion there (and the audio jack in the TZXDuino is stereo).
I didn't know that there were these assortments of smd USB-connectors available - had to order one immediately!
TZXDuino is a great piece of work. So is MaxDuino, which is a spinoff (kinda) project from TZXDuino. I prefer MaxDuino with my ZX Spectrum because the code is constantly updated with new features and optimizations. I've contacted RC Molina, and he was more than helpful with some problems I had. I know some Arduino, I am not a programmer with any definition of the word, but I can write some code for my needs and I can understand (mostly) how other people's codes work. The only criticism I have about the MaxDuino code is it is always like a development copy rather than a release version. All the changes made from the beginning are commented out but still there, this makes it very hard to follow and makes heads and tails of it. MaxDuino is a multiplatform software, meaning, it can be run on different MCU's, using different types displays, can decode different types of file formats for different 8bit computers, with different kind of settings for each. But, everything is integrated into one piece of firmware. Anybody with a decent level of coding knowledge can work with this, but for the novice level it can become very complicated and frustrating. The firmware barely fits into an Atmega328 because of all these different options. Granted, if you know what you are doing and manage to comment out the parts you do not need for your specific hardware (MCU, display) and the 8bit computer you intend to use it with, not everything is compiled and the firmware gets considerably smaller. I wish dear Mr. Molina came up with a version that is cleaned out of unnecessary old code, with better comments that explain how to tweak (or set up) the options optimally for its use. A user manual explaining the menu settings etc would have been great too. With each new version I spend hours reading the code and cleaning it from everything that I do not need to come up with the smallest code I can do. Oh, by the way, you can add a buzzer to the output pin with a series resistor (470 ohm to 1K works best) if you want to hear the loading. With ZX Spectrum this is not needed but apparently SVI needs it.
I have looked at the GithubV directory. Unfortunately, there is no circuit diagram there yet. This makes improvements difficult. In the layout, I can see optimisation possibilities in the pictures.
Continuous ground plane on top, avoid islands.
The space is there to also use CH1206 designs for passive components.
Holes for spacer bolts for the display.
Mounting holes on the PCB.
Optional push-buttons for operation from above.
GND via stiching.
I agree with you. The author prefers not to share the circuit schematics unfortunately. On the other hand, it's probably simple enough to start your own project (especially if you avoid the amplifier). You seem to have a lot of good ideas of where to take it. Do it! 😃
The way you shorted the potentiometer, you actually shorted the audio signal to GND... that's why it plays very quiet in "amplifier ON" mode (the switch is labelled correctly). Two bottom pads are GND and signal IN, the top pad is signal OUT.
When, the first time or the second time? I don't think the potentiometer was connected to the audio signal, but to the gain signal on the amplifier (first time I left it unconnected).
@@NoelsRetroLab For the first time. I wasn't aware of the circuit at first, but now I found the old v1.4 project and there was a bug in the circuit design, the left bottom pin of the potentiometer, should not be connected to anything, but it was connected to GND (so you've connected one side of C4 to GND, and pin 1 - unconnected). The potentiometer is indeed in the GAIN control loop, not in the audio path. The right bottom pin goes to the C4, and then to pin 8, the top pin goes to R5 and to pin 1. Pins 1 and 8 should be either not connected at all, or connected via a capacitor and a resistor in series.
2:20 It's Narnia delivery services! The coolest way to send parcels! =)
Noel the correct contacts for the cassette connector is Molex 08-50-0106. You can obtain these from RS Components Part# 173-3284.
Thanks! Any idea how they're supposed to stay in place inside the 3D-printed connector? I can't visualize what would hold them in place.
@@NoelsRetroLab They slot in and have a barb on the bottom to lock them in place. The slots at the front of the connector allow you to lift the barb if you need to extract a contact.
Who cares about the games? The best part is what you showed us!
Haha, good to know! 👍
You made the right call, I really enjoy the debugging stuff regardless of the system! I should see if there is a tape player for the STM32 blue pill as got one for Xmas and would like a convenient way to load to my speccy
Ah, looks like it might be, cool new project time! hackaday.io/project/169311-sildenafile
Thanks! Good to hear that feedback. The STM32 should compile just about the same things as Arduino, right? With some pin interface differences but mostly the same. I noticed that MAXDuino even has options for multiple microprocessors so I bet you can get it to work on the STM32.
You can program Blue Pills directly from the Arduino IDE by changing a few options:
idyl.io/arduino/how-to/program-stm32-blue-pill-stm32f103c8t6/
(I have one of the £2 STLinkV2 adaptors off ebay and find it to be 100% reliable.)
Excellent video, recently found your channel and I am thoroughly enjoying watching these retro-tech based videos. Greetings from the Netherlands.
Las videocomputadoras Spectravideo son sistemas interesantes! The tape edge connector is similar to the C64 one. I had a dedicated SV tapedeck at some point but gave that away to a friend. The joys of proprietary connectors.
BTW: if you have some fine (gauge) wire, you could run it from the board to a regular size 10k potentiometer (such as one salvaged from a dead transistor radio).
Right. That was plan B until I noticed that the whole amplifier part was not working as intended, even with the correct resistance, and that the unamplified part worked fine on this computer 😃
Nice video. The SVI328-mkII was my first computer back in de eighties. I still have several Spectravideo machines including my first 328 (albeit "slightly" modded) that I still use today. With respect to turbo tape loading, SVI328 machines do not support turbo tape modes, the firmware only supports 1800 baud plus-minus tape jitter corrections. Later MSX machines do have dual tape baud rates, default 1200 baud and a 2400 baud turbo tape mode, the earlier SVI328 does not support this turbo feature.
Oh I didn't know that. Thanks for the info!
What kind of mods do you have in your 328 BTW?
@@NoelsRetroLab Machine has a Z80B at 6Mhz (mkII machines work fine at 6Mhz) switchable to 3.5Mhz original. Other mods are in the attached SVI605 super expander, floppy controller is modified to work with 80 track drives, made my own memory boards with a memory pager also supporting the native bank switching, flash storage board emulating an ATA harddrive, 68000 coprocessor board, GPIB board for interfacing with my test equipment. Most of that stuff was developed many many moons ago. I am a software developer by trade. Today I mostly use the 328s for running CP/M natively and for occasional vintage gaming.
BTW. SVI328 machines can run MSX-1 games and MSX Basic 1.0 software unless the software directly addresses the MSX hardware (hardware is identical, IO map differs from MSX) using a software MSX-1 emulator that runs a modified MSX-1 ROM bank switched to bank 0 page 01 replacing the 328 ROM at runtime. There is also a hardware MSX-1 SVI606 adapter accepting MSX cartridges similar to the SVI603 Celeco adapter, unfortunately the hardware MSX adapter is ultra rare and considered a holy grail. Several MSX-1 Konami games run fine with the software 328 MSX ROM.
Thanks for the vid. I had a 328 growing up. It died and I didn't know how to fix or troubleshoot it at the time. I wish I still had it.
You're welcome! It's never too late to get a 328 again! 😃
Great video. The lag on the microscope would drive me insane though.. =)
Ok, if I know anything about Op amps. You need some resistance to get amplification. If you simply drop 0 ohms across a op amp feed back loop you will get unity output or no gain. Try using a SMD resistor across those points instead of that jumper.
That chip footprint Noel showed looks like its an LM386 power amplifier rather than an operational amplifier, that has a gain select on Pin 1. Thats usually got a capacitor between it and pin 8 to set the gain. I think if you just short it it to pin 8 it moves the gain up to ~200x which would explain why it was picking up the 150kHz interference signal and amplifying it!
@@IanSlothieRolfe YEah I noticed that after I made the comment. Not sure why he used an amplifier when an Op amp would have been fine.
yep i remember of that blistering sound it made when came to downloading the
game off the cassette thanks sinclaire spectrum zx .
It seems to be that PCBWay have nice people for very fast delivering. LOL
Hi Noel, thanks to your videos I was able to bring my SVI 328 back to life. I am missing a key as well, where did you get your replacement? Thanks in advance
It looks like the power and activity LEDs are installed upside down, so they shine into the board. Was that done on purpose?
Haha, good eyes! No, I noticed that afterwards but decided to leave them in place since they were bright enough anyway 😃
Hi Noel, I have an original SVI-328 MKII in case you ever need to see how it looks like without any alterations
Thank you! I actually got an MKII and an MKI recently, so I'm all set in that regard. But much appreciated. I have some more SVI 328 content planned in a couple of months from now too! 😃
@@NoelsRetroLab I also have a Super Expander and a original tape recorder. My SVI328 is currently not turning on and you motivated me to start working on it. Thanks!!
I don't want to worry you, but PCBWay appear to have an elf hiding out in your closet...
🤣🤣
That Sony tape player is way cool!
It is, isn't it? 😃👍
Is there a tzxduino already pre-built?
You can order them from hobbyretro.com/tienda for example. They don't have any right now but they have the new boards ordered and should get them in soon.
Also look on Etsy and Ebay.
@@rog2224 thanks!
Also, I noticed that - while you were soldering the Arduino Pro Mini PCB to the main board - you forgot to solder some of the pins on the bottom of the main board; though it’s possible that these are just unused GPIO pins for this application.
I think I just left that part out of the video (too many cuts for something not crucial). They're all soldered and in place.
@ 20:47 - Seems like somebody that proggramed it used a PWM to efectively reduce the overal amplitude of the signal but PWM carrier should be filtered out. But the author probably assumed that the supported computers probably do not have enough bandwidth or have their own input filters so they will not see this carrier. Not so elegant sollution but what did you expect from arduino based project ;)
Hey Noel, I was just wondering, when you were building the board, you used a LOT of flux, and I saw it melt and make pools all over the place. At the end of the day, how do you clean all that off to make the board look professional and neat?
Didn't I show the cleaning process here? Sometimes I cut it to make videos shorter. I apply isopropyl alcohol over the board, brush with well, and then, before it dries, put a rag on top, and brush over the rag. That soaks in the alcohol with the flux and takes it away from the board. I'm sure you'll see it in some of my other videos. Works like a treat!
Thanks Noel
Noel did you try ZXDuino with ZX spectrum?
I did not. I will at some point in the near future when I test ZX Spectrum loading devices though. I believe there it does need the amplifier.
Thumbs up for VERY cheese dingdong yokes!
24:20 it looks like lower left 2 pins on the switch are bridged.
Yes, that's one of the "fixes" you had to do to that revision of the board. I skipped over it, but it was listed in the project page.
Absolutely the right call to leave the debugging bit in. It is both interesting and satisfying to see the problems being fixed. BTW, why do you keep your daughter in a cupboard? Are you concerned she might get a place at Hogwarts?
Hi. I had the svi 728 msx. It had given me 6 years of joy untill it had gotten stolen in 1992.
Bummer! And seriously, who would steal a 728 in 1992??!?!? Hopefully you can get another one not very expensive now. So much fun to be had with these machines!
@@NoelsRetroLab I had played Moon Lander & Jump Jet on mine, and other games. Plus I learned Basic programming on mine
Well the next computer my dad had purchase was a IBM 286 with 1 meg ram 256 VGA grafix card 20 meg hard drive and Super VGA screen.
I think the graphic on the screen, when loading this game was normal, not 100% sure (so long ago).
Cload only work if you have a basic program header first.
Bload was for binary file (machine codes files)
Load was also for basic program, but slower (can't remember if it also could load machine code programs)
Cload"",r load basic program and run it
You could also write something like run"" it was the same as the load command but it also automatically start after loading
But I think you should try to read up on
Load, run
Bload "filename"
Cload "filename"
Right. I saw there were games that loaded with CLOAD and some with BLOAD. I did find two other games with an identical loading pattern loading data onto screen memory, so I think you're right and that was the way it was intended.
@@NoelsRetroLab I know that the game you tested also ran on a sv-318, that computer only had 16kb of memory, so maybe they used the video memory as a loading buffer, but I don't know about that.
But it's good to see you got the sv-328 up and running 😁👍
Strange that they didn't specify an exact part number from a major manufacturer for that USB connector in their required bill of materials. They should. octopart.com could then be used to find a source or suitable replacement. That would save time for builders.
If you look at the BOM there's a number there, but since I wasn't ordering components from a major vendor (didn't have 50€ to buy to avoid huge shipping) I ended up buying it from Ali and there the number was pretty useless.
Nice video, keep it up. Greetings from Karachi, Pakistan.
Thank you!
would 300 Baud have worked as it appears to be the default baud rate that the MTX512 uses and is why CRAIDERS takes so long to load.
I liked the microscope work. I looked at one of these, but what put me off is that you can't save to them. Keep debugging and fixing. :)
What do you mean you can't save to them? This one has an SD card and you can take pics and take videos of what you're doing. Or do you mean something else?
@@NoelsRetroLab Ah, I'm so sorry. I was reffering to the TZX SD card not the Microscope in the second sentence. If you write a program, you can't save it to the SD Card. It can only load. I typed it in my head, but it obviously did'nt reach my fingers. LOL.
WOuld this also work with Amstrad CPC?
It should, it supports CDT
Yes, absolutely!
Computer: 3.58 MHz. "Cassette": 16 MHz. :D
Yes, it always feels weird to use a piece of technology like this for something like this or even as a coprocessor or add-on, realizing it's so much more powerful than the original hardware.
I don't know why they add an amplifier to this cassette player emulators. The 5v output of the Arduino is more than enough.
I think it's for the ZX Spectrum.
@@NoelsRetroLab No amp needed for the Spectrum.
I've just built one of these and can confirm this.
@22:40 You bypassed the copy protection on the Amstrad? Only for scientific purposes I assume ;-)
Suuuuuuuuure 😃
I would love to solder a number of SMD circuits but they are just so tiny and that puts me off. 😠😖😞🥺🥺
I totally get it. I was put off/scared by SMD as well, but it's just a matter of getting used to it (and maybe having some kind of magnification, even if it's just a magnifying glass). I recommend starting with some of those SMD learning soldering kits from Ali or Ebay.
👍 👍 👍 👍 👍 👍 👍 🍀
Next time use solder paste with the metal and the flux 2x1 and an "air iron" for soldering.
I'm planning on doing some SMD soldering with stencil and paste next time. Should be fun.
Can i use this with a commodore 64 ?
I don't think the MaxDuino firmware works with Commodore 64, but I'm sure there's a similar device out there somewhere that works with C64.
another great video....... (i will tell u my secret i dont use flux at all......) i use a small soldering tip and small diameter solder lol
Thanks! I used to use very little or no flux, but it makes things so much easier... 😃
@@NoelsRetroLab you know better!!!!
nice vid :-)
It looked the same for me on my original SVI 328.
What a coincidence SVI *328* and ATmega *328*
A normal tape drive wouldn't have worked in any case. The svi tape drive wasn't a normal audio tape drive.
Oh really??? I didn't realize that! Was it a different speed than normal, or was there something different about the reading mechanism itself?
Ah this is what happens when software people try analogue electronics :-) I'm about to build a version to use on the Spectrum.
It's a shame the shipping is 4 times the cost of the PCB. Not PCBWay's fault...just the way things are. But on the bright side, those PCB's would have cost thousands only a few years ago.
huh, are you sure you shorted the regulation well ??? you rather shorted it like this (I see you noticed ...)
THE BIGGER THE GLOB THE BETTER THE JOB!
Noel. You also mentioned the MSX cartridge slot, that is not compatible. Just I've found some info about a guy that has a solution for this. I suppose that there could be built some kind of cartridge adaptor circuit, that enables de cartridge port for standard MSX cartridges: hansotten.file-hunter.com/uploads/files/svi728cart.txt
Neat. There are still some significant differences between the 328 and MSX, so even with that a lot of things wouldn't work. I'll get into that in a bit of detail next video actually.
@@NoelsRetroLab But I've seen already some developments to improve the MSX compatibility for SVI-328, 728 and 738. It may be interesting to see some of them.
Hi there, thanks for the vid, i’m Building one for my amstrad 6128, i’m Working on it slowly, be great if you can build one for yours and post it 👍
I will probably build the updated version and test it on an Amstrad CPC 464 with the audio jack mod. But it's going to be a few weeks. I can confirm it works great on the Amstrad and without the amplifier. Good luck with it!
I will build mine without the amp first and see how it works, thanks again for the great work.
There's a new (1.5) version that corrects these issues
Yes, he released it within a day of me reporting those changes. I'll be building one of those new PCBs in the next couple of weeks. It looks great!
Oh, and you need to complain to DHL. Their delivery person wasn't wearing a mask. LMAO!
Nicely done! If you would like to make a few cartridges (like on the picture) feel free to use this repository: github.com/Wierzbowsky/SVI-328_Cartridge
Thanks! Maybe I will for a future video 😃
no never heard of it but im drunk so go on
the video was better to show all the board debugging - there are tons of retro video that looks at games
Thanks! Glad you thought so 👍
If you've got to solder smd components on to the pcb ANYWAY... it seems so wasteful and over complicated to solder a pro mini on the board too... it would be so much simpler to just put an ATMega on the board instead.
Would it? I haven't used an ATMega by itself before. Would you program it the same way you do an Arduino? Which type of ATMega microcontroller would you recommend for something like this?
So you don't install a potentiometer and run into problems. Shocking. Variable gain. Can't run Full gain and not expect problems.