I just released a demo of a #Moog #Rogue #synthesizer that I modded while giving it a full overhaul. Now the LFO speed can be switched with some overlap. Schematic included. Have fun.

https://www.youtube.com/watch?v=JBErF9-iCq0

#synthrepair

Trying to find where a deceased synth software enthusiast checked for hashed-against-your-serial-number keys before allowing use of the revised software.
So of course I now have an interactive m68k disassembler/labeler/exploration tool.
If only I could figure out the load address. It isn't zero.
Maintenance manual hardware diagrams at least give me ROM and device address ranges.
Now I need automatic basic block extraction.
#synthrepair #reverseengineering

Now running a soak test on the reg board with no load

#synthrepair

Full re-cap of the power regulator board for the CS-10 after finding more leaky caps.

#synthrepair

I just fixed another #Roland #SH101. A lot of damage and since the oscillator (famous #CEM3340) was dead and needed replacement I ran into hi notes tuning issues once more. This time I addressed them by making a custom circuit with a dedicated hi end trimmer.

If you have the same issue, please drop me a note to see if there is demand for a small series production.

Read more about repairing various issues of this wonderful #synthesizer in my blog.

https://www.u-labor.de/repair-roland-sh-101

#synthrepair
@synths

Solina String Ensemble MkII issue tracking. A lot of work on top of the usual recapping because of the Bass Circuit board being populated with a blend of MkII and MkIII resistor values. A total mess and I guess the bass section stopped working in 1993 when the net voltage was raised from 220 to 230V. The #Solina #Strings have an unregulated PSU so the main point is to get voltages to spec or certain transistors will fail.

#SynthRepair #Eminent #Synthesizer #vintage

Last year I needed to repair the backlight of the display of my Roland D-550. I've chosen to replace it with an OLED.
Now I've created a short video with footage and pictures taken during my repair. More information to be found in the description of the video on Peertube.

https://makertube.net/w/fkdEfK8VmKNMRTishsyM7V

#synth #synthesizer #synthrepair #roland #d550

@flpvsk This sounds great! Thank you for spreading this initiative. I've started to progressively increase my skills in soldering and repairing my synths/fx gear.
Maybe I'm going to come along at a later date. Currently I don't have enough time to dive into a new maintenance project.

#Synthrepair #Repaircafe #Audiogear

Well, that escalated quickly. I discovered MakerTube today, liked it so much that I created an account and uploaded my first video in a rush. 😄
The video is already older and shows how I replaced an old LCD with a new OLED in my ESI-32 sampler:

https://makertube.net/w/eXkuEXxqjX4pZ5NCpDHzck

I'm planning to create more videos with and about my synths, but don't expect new content in this year. ⏳

#synthrepair #synthesizer #esi32 #sampler

„Guck, in der Chipstüte sind nur noch Krümel.“

#retrocomputing #synthrepair

Incidentally, this synth is *absolutely* not worth the effort.
But I have learned a ton about Z80 operation, serial register chains, discrete logic, ROM and RAM operation, and my scoping equipment. So even if the synth never comes back to life, I've sure learned enough to build useful mid-80's electronics!
#synthrepair #electronics #retrocomputing

The data lines only run to, oh, *every* device on the board, so finding the offending party will be difficult.
It's probably a bad capacitor next to one of them? Making a list to desolder and replace.
#synthrepair #electronics

This fool synth (psn-70) has been on the bench much longer than it should be. It's going to have to give up its space shortly, and probably won't be running.
And today I finally thought I'd scope the data lines *analog* instead of digital, and I find that all the ROMs and RAMs are responding, but not managing to raise the signal levels high enough - they choke out around 1V.
Is something shorting them to GND?
#synthrepair

Wired up, scope on the address lines, looking good. But the ~CS signal is never de-asserted. I swear I checked that one. At least it's easy to trace.
But that will mean putting my mitts back inside the case.
I kind of wish I'd put an interposer arround the Z80 as well. I can probably piggy-back a socket on top of it and drop in another 28 pin wire?
Or should I go the full de-solder and socket route?
It's not like its a *valuable* synth.
#synthrepair #electronics

Nice tidy desoldering job. Now I no longer need my mitts in the case!
#electronics #synthrepair

Looking for the service manual or circuit diagram for a Casio MT400V synth. Willing to spend $$.

I have the sm for the CT405, MT68, MT100, and some parts are applicable, but the power (supply and amplifier) board appears to be unique to the MT400V.

Any leads, and all reblog appreciated.

#diy #maker #repair #synthrepair #synthesizer #casio #mt400v #analogfilter #synthdiy #synthmaker #servicemanual

Saved from a Berlin trash container: Korg 900PS #synthesizer with missing top plate, from 1975. Functional basically, still a lot of issues need to be resolved. But this one will add some nice tone to the studio, literally, since 900PS translates to 900 horse power in German.

#synthrepair #synthwave #synthporn

Läuft.

#synthesizer #synthrepair #synthwave #korg #kpr77

That old humming Wurlitzer 200A e-piano is not doing hum/harm any longer. Since all the usual measures I took before did not bring down hum to an acceptable level I rebuilt the psu and that did the trick. Now make a proper pcb of that.

#wurlitzer #epiano #synthrepair #synthesizer #musodon #electronics

And it completes the format. It was a simple repair in this case. #synthdiy #synthrepair #maintenance #floppy #retro #music #midi #storage