For your viewing pleasure, I present Synthchaser #069 and #070… A 2 part video series where I repair an OB-Xa for Matrix of Matrixsynth.com.
One voice card is dead, and others are failing autotune and sounding really inconsistent from voice to voice. In the first video we take a look at the state of the synth, and troubleshoot and repair the dead voice card.
In the second half, I continue the repair by rebuilding the power supply and voice cards, and get the synth in tune and sounding consistent from voice card to voice card. I also show you a common defect with the voice cards that prevents proper calibration. Lots of time lapse soldering with looping music.
For my next few videos I’ll be showing the restoration & repair of a Sequential Circuits Prophet 5 (revision 3). While in pretty good cosmetic condition, except for a broken pot, the synth doesn’t work (all LEDs light up, “88” shows on the 7 segment display, and no output or response from any controls). As I release the videos I’ll add them to this post. Be sure to subscribe to my Youtube channel to be notified when new videos are added.
We peek at the insides of a Sequential Circuits Prophet 5 that we will be restoring.
Part 2 – Power Supply Rebuild
I show you how to remove, test, rebuild & calibrate the power supply of your Sequential Circuits Prophet 5 synthesizer. We also stumble across evidence of a really good reason why you will want to do this to your Prophet 5.
Part 3 – Capacitors, Battery, Switches & Pots
We recap the remaining circuit boards of the synthesizer. I show you how to test and replace the battery, clean the switches, and clean and replace the potentiometers.
Part 4 – “Dead” CPU Repair
We troubleshoot and repair the dead Prophet which is non-responsive and stuck with all LEDs on and “88” on the display.
Part 5 – Keybed Refurbishment
We yank out the Pratt Read keybed, and I show you how to change the key bushings to get a nice quiet action to the keyboard, and we clean the buss bar and adjust the key contacts to fix dead/re-triggering keys.
Be sure to pick up my Prophet 5 capacitor kit, and a new set of key bushings!
The pedal is for sale if you are interested, please contact me.
It’s not just your vintage synths that need love from time to time, it’s also their accessories. I service a Rhodes Chroma dual footswitch by replacing the damaged plug, cleaning the switches, recapping the switch, and polishing the brass. Result is a pedal someone will be proud to plug into their Rhodes Chroma.
All the Oberheim OB series power supply and voice board kits are back in stock. Click the shop menu above and navigate to your synth to view the selection of DIY service kits I have available.
In the previous video we installed the Synthchaser OB-8 Voice Board Rebuild kit, which replaces the dried up electrolytic capacitors, dodgy trimmer pots and noisy resistors that can prevent an OB-8 from autotuning and sounding consistent from voice to voice.
In this video I show you how to perform a full calibration of the OB-8 and demo some of the sounds of the completed synth.
We install the Synthchaser OB-8 Voice Board Rebuild kit, which replaces the dried up electrolytic capacitors, dodgy trimmer pots and noisy resistors that can prevent an OB-8 from autotuning and sounding consistent from voice to voice.
I show you around the inside of an Oberheim OB-8, and we take a look at a dead oscillator which is causing autotune to fail for one of the voices. Then, I install my power supply rebuild kit, which replaces the power supply capacitors and beefs up the bridge rectifiers.
I repair an ARP Pro/DGX Mk I with a bad slider and certain voices that sustain indefinitely. And experiment with video editing and speeding up the video so you can see me solder!
Pulled another Polymoog 203a synthesizer out of storage and have started making it ready for a new owner. DM me if you're interested! ... See MoreSee Less
