Author: synthchaser

In my latest video, I finish a recap of an ARP Omni 2 for a customer, and find some burned up parts resulting from shorted tantalum capacitors.  Getting the tantalum capacitors out of your ARP synths should be considered mandatory maintenance, and can save you from expensive, out-of-production chips getting damaged, like the top octave generator in this video.

Capacitor kit available at:
http://synthchaser.com/product/arp-omni-2-capacitor-replacement-kit-with-4075-vcf-rebuild-kit/

 

I know what you’re thinking, but really, I do repair other brands of vintage synths other than ARPs!

In this video I rebuild the power supply and repair some other problems like tuning issues, broken trimmer pots, and hiss, noise and static in the output.

I recently restored and repaired a pair of ARP Pro Soloists that used to belong to Bernie Worrell and made some videos along the way.

In this first part, I take a look at the two keyboards, come up with a plan of attack to restore them, and begin disassembly.

In this second part, I troubleshoot the first of the two ARP Pro Soloists.  There’s a rather interesting problem, the notes are getting lower as you move up the keyboard!  Also touch sensor effects are dead and I get to the bottom of that.

In the third part, I repair some broken welds on one of the Pro Soloist cases with a two part epoxy.

In the fourth part, I disassemble and recap the second of the two Pro Soloists.  We fire it up, but we’re not as lucky as with the first one, so we troubleshoot and get to the bottom of the problem.

In this fifth part I repair the Voltage Controlled Filter.  The second Pro Soloist has a dead 4034 VCF submodule (the Moog patent infringing type), which unfortunately is sealed up.  We cut it open, excavate it out, troubleshoot and repair it.

In the last part of this video series I show you the final product–two Pro Soloists working great and ready to start making some funky music again!

 

I have the pleasure of being able to restore and offer for sale this early ARP 2600.  A true collector’s piece, this is one of approximately 35 produced “Grey Meanie” ARP 2600’s and is extremely rare!  It comes with the matching 3604 keyboard (not pictured).  If you have been looking for this rare piece of synthesizer history, please contact me while I am able to customize the restoration plan with your input.

I made this video which shows how to test the power supply of an ARP Synthesizer.  It was intended for someone with an ARP 2600, but I’m demonstrating with the power supply of a Pro Soloist, and the method shown can be used to test the power supplies in all models of ARP synths.  To do this test you just need a multimeter, the intended audience doesn’t need to be electronics wizards or even know how to use the multimeter.  If your power supply tests bad, I can repair it or supply a modern, upgraded replacement.

 

Finally, a MIDI interface for the ARP Omni 1 & 2 synthesizers!  This MIDI adapter is user installable and requires no soldering or permanent modifications to the synthesizer to install (other than perhaps a hole to mount a MIDI jack).  Provides MIDI In and Through capabilities on Channel 1-16.  Easy channel selection with the push of a button and the press of a key.  Easy to configure on which key the Omni notes start on your MIDI controller.

Order now!

Synthchaser MIDI Adapter for ARP Omni 1 & 2

I’ve made a video series chronicling a restoration I just did on one of the ARP Pro/DGX synthesizers I have for sale.  In the first part, I show what’s wrong with this keyboard and come up with a plan of attack:

 

In the second part, I give a technical overview of how the ARP Pro Soloist and Pro/DGX works:

In this part, I install the Synthchaser LED slider kit:

In this part I recap the keyboard and fix some of its issues.

In this part, I rebuild the Pratt Read keyboard and install a new aftertouch sensor, and get all keys working and feeling great. No more clacking keys!

In this part, I troubleshoot and repair the remaining issues in the keyboard.  Even after replacing the aftertouch sensor, some aftertouch effects weren’t working.  And some of the voices didn’t sound right.  So I whip out my oscilloscope and get to the bottom of it.

In the last part, I give a demonstration of the finished product working nicely, and show the features and settings of the Pro/DGX as well as run through the preset voices.

I received an ARP Omni 2 “for parts” that literally was in parts!  It came to me as a pile of boards.

Since it was complete, I decided to restore it slowly as time permits, recapping each board, inspecting for damage, etc…  This morning I got around to the Upper Voicing Board.  Someone had tried to fix a problem (likely a “stuck” note, caused by a shorted tantalum capacitor), but they lifted some solder pads and destroyed a trace while changing some diodes.

To correct the damaged trace between the diode and the resistor network, they soldered a 1W resistor to the board…  ARP PCBs are extremely easy to damage without proper soldering techniques.  They are not plated through hole, so it’s easy to lift solder pads, and more difficult to solder a component with traces on the component side of the board.  With some flux, and good soldering and desoldering skills, it is possible to work on these delicate ARP boards and have them looking pro when you’re done with them.

Here’s the same board with the 1W resistor hack removed, the board recapped (using the Synthchaser capacitor kit–pardon the shameless self promotion), and the diodes the previous person tinkered with also replaced.  Notice on the capacitors the smooth solder fillets on the component side of the board.  Because the boards aren’t plated through hole, it’s important that the solder joints on both sides of the board be solid!