#turbokit — Public Fediverse posts

With all the AI slop and advertisements that fill everything, we often forget how wonderful Internet still is. I could easily get in touch with one of the original developers of the #GEM #S2 #synthesizer, to which I sent my blog post about the #Turbokit replica. He kindly replied and seemed happy to learn that someone was still interested in a 30 year old instrument!

I finished proofreading the blog post on my webpage: http://davbucci.chez-alice.fr/index.php?argument=elettronica/gem_s2/gem_s2.inc I hope you'll enjoy! #Turbokit #GEM #Generalmusic #S2 #S3 #electronics #diy #synthdiy

By the way, I managed to have the Ramdisk working reliably. Look at that whopping 2048KB free! #turbokit #GEM #S2 #Generalmusic

I wrote a (lengthy) article for my blog about the #GEM #S2 #Turbokit. I still have to proofread it, so it is still a little rough around the edges, but if you want to give a peek here it is: http://davbucci.chez-alice.fr/index.php?argument=elettronica/gem_s2/gem_s2.inc #music #homepage #blog #generalmusic #electronics #DIYelectronics #diy #diysynth

This is amazing, I am so happy it works. It was my first 4-layer PCB I designed from scratch on #KiCad! #GEM #S2 #turbokit #replica

Big win! I installed the #Turbokit on the #GEM #S2 and after some fiddling IT WORKS! I waited this moment since 1996 🥰 The #PCB was correct and the components were perfect, but it took a while to fix all the bad solder joints. Gosh, those 0402x8 resistor networks are SMALL and it took a while to learn to solder them properly (hot air and flux are your friends). Now, I only have to install the NiMh battery in a safe way. #electronics #sinthdiy #diy #music #Generalmusic #S3

The #Turbokit replica for the #GEM #S2 is complete. I will check it again and then install it on my synthesiser. I hope it will work! It is a little heavy because of the EPROMs, so if the board works I will 3D print a support bracket. #electronics #synth

I started assembling the #Turbokit replica for my #GEM S2. I had some troubles soldering the tiny 8-resistor networks but I managed to do it in a reasonable amount of time. I just ordered a 4-resistor network in the wrong package and some connectors and the EPROMs are still missing. A nice board, I like it, I hope it will work 😅

I received a few days ago the 4-layer board I designed for the #Generalmusic #S2 #Turbokit replica. It looks very nice, let’s hope it works 🙂 I will assemble it in the next few weeks, then I will try to install it on my keyboard.

In the meanwhile, I sent the order both for the components that remain to be sourced and the PCB. Now, I just have to wait. #Turbokit #Generalmusic

I corrected some errors and I think I reached what I think it will be the v1.0 design of the #PCB. I hope it will work! #Generalmusic #Turbokit #electronics #DIY #Synth

@brouhaha The S2 already uses a WD37C65. The #Turbokit upgrade specifically requires to swap it with a uPD72064. I think the newer software in EPROM (to be installed in the external board) explicitly requires some of its advanced features. I tried to source one, I will check it when I will try to install the upgrade. Let's hope it is not a fake!

I'm not very experienced with the routing of a 4-layer PCB but it is fun. The different copper layers are starting to look nice! #Turbokit #Generalmusic #Electronics #Diy

I created a GitHub project for the #Turbokit replica for the #Generalmusic #S2. It is not a project for the faint of heart, however, at it will require to modify the original boards of the #synth. It is still pretty much an ongoing project: https://github.com/DarwinNE/GEM_turbokit #openhardware #electronics #diy

I realized I swapped the position of the left and right connectors that will be connected in the original EPROMs sockets in the #GEM #S2. I'm glad I checked, that would have been an expensive mistake to fix... #electronics #DIY #PCB #Turbokit

I resumed working on the #Turbokit replica for the #Generalmusic #S2. I tweaked a little the 4-layer PCB and got a quote from a well-known company: the estimated cost is US $81.87 for 5 PCB's. 2-layer boards would have been less expensive, but the circuit was too complex and I couldn't route it. #electronics #diy #synth

After a few iterations, I could slightly shrink the #Turbokit card. Now it should fit. Or at least I hope so, there are a few capacitors below the upper part of the board that can create problems. I may try to print a test on paper to see how it would fit on the real thing. #DIYelectronics #Generalmusic #S2

In the last few weeks I did a first tentative design for the Turbokit replica to be installed in my #Generalmusic S2 keyboard. I had to adjust the position of a few connectors as I originally planned them under the keybed and there is no place there. This second iteration is much better, but still does not work because it interferes with the connector on the right. #S2 #Turbokit. #DIYelectronics #Elka

I received the order and the first impression is very good. Everything was properly packaged in antistatic bags. The most difficult to source chip seems OK, but we will know only when installed in the keyboard. It would be amazing to build a #Turbokit replica for my #Generalmusic #S2. It is a massively underrated synth from 1992, a project started by #Elka!

Work is of course still far from complete. I think I will probably use larger resistive networks as I will have to hand-solder the circuit and those I selected are quite small. I then have to pour copper for at least a large GND plane as 3 copper layers are used for the connections. Before doing this I will have to check for the routing of the most important signals. The final PCB will be much nicer than this. But at least I know the PCB is routable. #GEM S2 #turbokit

Since I still don't have my #GEM S2 close and I cannot do tests, I am continuing planning what I can. I begun to route the #turbokit PCB. It took a while as I do not have a lot of experience with digital circuits. I mainly wanted to see if the circuit was routable and the Freerouting Kicad plugin was very useful. The result is far from optimal, but it confirms the board can be done in a 120 mm x 120 mm size. I still have to see how to keep it firmly in place, maybe with a 3D-printed bracket.

Now I would like to install a #Turbokit on my #GEM #S2, but it unobtanium. I discovered this very interesting project, relatively recent (2021), but it does not seem to be available for order: https://www.hackster.io/DitroniX/gem-generalmusic-s2-s3-series-synth-retrofit-turbokit-c30f63