▲ 11 r/synthesizers
Blast from the past - full restoration of Yamaha DX27
Hey everyone! By day, I work as an electronics engineer at a Polish space startup, but my other massive passion is music. Because of that, I spend a lot of my free time fixing up vintage toys.
Originally, I wanted to restore a Yamaha DX7. You see them pop up on eBay sometimes missing knobs, cracked side panels, "no sound, MIDI works" which usually means internal battery was discharged. Those are minor issues you can easily fix if you have a 3D printer and MIDI cable, and it keeps the buying price super low. I actually made that dream come true and bought a broken DX7 from Japan, but it's going to take a while to finally arrive in Poland.
To kill some time, I checked a local marketplace and found a guy selling a broken DX27 for about 80 bucks. The synth powered on, but the wheels were bent, the slider caps were gone, the keys were covered in glue, and the whole chassis was so sticky I honestly felt gross just touching it.
Opening it up was like busting open a full vacuum cleaner bag. It was packed with dust, dead spiders, and literally pine needles. I had to blast it with compressed air outside before I even dared to bring it into my apartment.
I kicked things off by replacing the battery on the motherboard. The nice thing here is that, unlike the DX7 or DX9, you don't need to reload all the patches via MIDI afterwards. You just hold down a specific key combo when you power it back on. The PCB substrate is crappy, you can't heat it too long with soldering iron or it will delaminate.
After sorting the battery, I tackled the dead keys. The culprit was incredibly mundane: sand had just found its way under the rubber contacts. A quick wash was all it took to get the keyboard working perfectly again.
I fully expected to have to replace the tiny tact switches under the green buttons. Surprisingly, giving the board a good scrub with isopropyl alcohol and lubricating the switches with a little vaseline oil brought them right back to life.
As for the pitch and mod wheels, they were scraping against the top of the case simply because their internal metal brackets had gotten bent over the years. I just unscrewed them, straightened them out with some pliers, and popped them back in.
I also went ahead and tested the capacitors. It's usually the tiny ones that cause headaches after so many years; they dry out way faster than the big ones near the voltage regulators. Sure enough, a few were completely bone dry, so I swapped them out for fresh ones.
Once I got the keyboard put back together, the last step was dealing with a bunch of Pokemon (or similar) stickers plastered all over it. I used kerosene to take them off since it dissolves the adhesive but doesn't react with the paint on the metal casing.
Since I didn't have the original slider caps, I hunted down a 3D model online to print replacements. I totally forgot to swap out the filament in my printer for black, so I ended up printing red ones by mistake. I decided to keep them, though—I think they look awesome and really make the whole synth pop.
So, how does it actually sound? Most of the factory presets are terribly flat, but that doesn't mean you can't dial in some really cool tones. Programming it isn't exactly a breeze, though. Being an engineer, I don't really mind menu-diving and punching in parameters with the buttons, but I completely understand why a musician without a technical background would find the workflow to be an absolute nightmare.
Overall, I had a blast bringing this thing back from the dead!
u/Reasonable_Quail_425 — 30 days ago
▲ 19 r/Polska
Naprawiłem ciekawy polski zasilacz z lat 70.
Hej,
Część osób zapewne już mnie zna dlatego, że lubię pogrzebać w polskim sprzęcie i pisać o tym w internecie.
Ostatnio zrobiłem nowy setup pod filmy na YT, więc postanowiłem nakręcić film pokazujący zmagania z zasilaczem laboratoryjnym Unitra Unima ZT-980-4M.
Czemu ten zasilacz jest taki ciekawy?
- ZT-980-4M oraz ZT-980-4 to dwa różne zasilacze. Zwykle jest tak, że urządzenie z literką w nazwie na końcu i bez literki różni się kilkoma drobnostkami, a tutaj to zupełnie różne urządzenia
- Ma preregulator tyrystorowy. Co to znaczy? Taki klasyczny zasilacz w uproszczeniu działa w ten sposób, że różnica między napięciem na wyjściu a na wejściu jest wytracana w postaci ciepła przez tranzystor. Tutaj też tak jest, ale prostownik jest zrobiony na tyrystorach i dzięki temu napięcie jest wstępnie ograniczone w zależności od zakresu. Wydziela się mniej ciepła i można użyć tańszych elementów.
- Ma sensing. Chodzi o to, że na długich kablach pojawiają się spadki napięć. Ten zasilacz jak podepnie się jeszcze dwa przewody bez problemu sobie skompensuje te różnice.
- Można je ze sobą łączyć w szereg, równolegle i sterować zdalnie.
- W środku nie ma bałaganu w kablach co jest dość nietypowe dla Unitry
Zachęcam do obejrzenia filmiku w którym pokazuje wszystkie prace krok po kroku: https://youtu.be/MEtwE8mmAGA?si=BkOTP2pamCVwtboJ
u/Reasonable_Quail_425 — 2 months ago
▲ 3 r/Guitar
Restoring a "Cat-Damaged" LTD EC-200
Hey everyone. You know the drill—projects don’t exactly grow legs and run away, so I took my sweet time with this one.
Back in late 2025, I scored a dirt-cheap LTD EC-200. The catch? The guitar was no longer a single, continuous object. The previous owner claimed their cat knocked it off a guitar stand.
Let's look at the casualty list, shall we?
- Completely snapped headstock
- Chunks of wood missing from the back of the body
- Destroyed bridge
- Snapped pot shaft
- Missing nut
- Busted pickup selector switch
A buddy and I tackled the headstock first. We glued the break, routed out channels across the joint, and glued in some solid oak splines for reinforcement. Short of a nuclear blast, that headstock is never snapping in that spot again.
Naturally, after such intense and grueling labor, the guitar spent the next six months chilling in my closet. But spring is finally here, the weather is gorgeous, and I decided it was time to finish what I started.
Here is how the restoration has gone down over the last couple 2 weeks:
- I filled the craters in the back with an epoxy-based filler and sanded the entire instrument down to 600 grit.
- I carefully taped off the top & fretboard to keep it clean.
- Sprayed the back with two coats of black automotive primer. Once it dried, I sanded it nice and smooth up to 1000 grit.
- Hit it with two coats of black automotive paint.
I finally got the clear coat on the front and back. The good news? Thanks to some obsessive dust management, I only ended up with two tiny dust nibs near the pickups. I could buff them out, but let's be real—my pick is going to scratch that area up within a few weeks of playing anyway.
The bad news? I caused some nasty runs on the sides. It is what it is! I'm going to sand out the drips, do a quick repaint on the sides, and the whole project should be wrapped up by next week.
Right now, I'm just waiting for the mailman to drop off a new Graph Tech nut.
u/Reasonable_Quail_425 — 2 months ago
▲ 22 r/Polska
Cześć! Od pewnego czasu zacząłem się zastanawiać, czy da się co nieco usprawnić poczciwą Śnieżkę R-206 która grała u mnie w warsztacie. W głośniku było słychać głośny przydźwięk, a stacje radiowe nakładały się na siebie.
Rozwiązałem oba problemy, podniosłem selektywność dzięki autorskiej przeróbce. Opublikowałem artykuł na Elektrodzie gdzie opisałem szczegóły modyfikacji.
Tym sposobem pamiątka z PRL stała się użytecznym dodatkiem :)
u/Reasonable_Quail_425 — 2 months ago