Category: ARP

We kick off the New Year on the Synthchaser channel with troubleshooting and repair of this ARP Pro/DGX Mk I, which is the same as the ARP Pro Soloist with the exception of having pushbutton switches for voice selection instead of toggle switches. This Pro/DGX has no output at all, so together we troubleshoot and repair it, and in the process I explain how one of the least understood circuit boards in the synthesizer works.

We continue the repair of Don Lewis’ original Model 2700 ARP Soloist. Among other challenges, we run into a big problem–the 4030 Violin voice submodule is dead. It’s encased in epoxy and no schematic is available, but will that stop Synthchaser? I think not…

• The Ballad Of Don Lewis DVD: https://amzn.to/3t2Nbw9
• My multimeter: https://amzn.to/3Ltgqi3
• My oscilloscope: https://amzn.to/3rm6b8d

My friend Don Lewis was a brilliant musician and engineer. Before he built his LEO (Live Electronic Orchestra) system, he used the original, Model 2700 ARP Soloist for leads. His ARP Soloist has been sitting unused since the 1970’s and in this video I begin to repair it so it can be donated to a cause Don was a part of. If there is enough interest, I will continue this video series.

The Ballad Of Don Lewis DVD: https://amzn.to/3t2Nbw9

My multimeter: https://amzn.to/3Ltgqi3

My oscilloscope: https://amzn.to/3rm6b8d

A brief, off-the-cuff run through that shows the features and sounds of the ARP Explorer I. No planning or editing because I think the ARP Explorer I is so obscure that this will be one of my least viewed videos. Prove me right or wrong.

The ARP Explorer I (Model 2900) was ARP’s first non-preset single oscillator synthesizer, pre-dating the Axxe and the Solus. It includes the same 4027-1 Voltage Controlled Oscillator module found in the ARP 2600, and the same 4034 Moog Ladder Filter Voltage Controlled Filter module found in the ARP Pro Soloist.

I’ve got 3 broken ARP Explorer I synthesizers, and I show you my approach to repairing and restoring them. The ARP Explorer I (Model 2900) was ARP’s first non-preset single oscillator synthesizer, pre-dating the Axxe and the Solus. It includes the same 4027-1 Voltage Controlled Oscillator module found in the ARP 2600, and the same 4034 Moog Ladder Filter Voltage Controlled Filter module found in the ARP Pro Soloist.

• Strain Relief Bushing Pulling Tool: https://amzn.to/3EE74fy
• My desoldering tool: https://amzn.to/3PikaEf
• Deoxit needle applicator: https://amzn.to/3PgiAT5
• Deoxit pot cleaner: https://amzn.to/3sUGX1r
• My oscilloscope: https://amzn.to/3rm6b8d

00:00 Intro to the Explorer I

05:10 Look Inside / Disassembly

12:13 Keybeds

13:35 Circuit Boards Depopulating & Cleaning

16:38 Cleaning Switches & Rotary Pots

21:24 Capacitors, ICs & Sliders

27:37 Bench Testing, Repair & Calibration

Supply chain issues are finally easing up and I’m able to produce another run of the MIDI Adapter I designed for the ARP Quadra back in 2021. It is the first and only MIDI interface for the ARP Quadra synthesizer! This MIDI adapter is user installable and requires no soldering or permanent modifications to the synthesizer to install (other than perhaps holes to mount MIDI jacks). Simply replaces the existing keyboard electronics board. Provides MIDI In, Out and Through capabilities! Supports aftertouch In and Out (via MIDI In, aftertouch will be applied to the full 5 octaves of lead synth instead of just the upper 3 octaves as limited by the original hardware). Supports duophony in the lead synth section and is compatible with the Quadra’s internal sequencer/arpeggiator.

In this video I show how easy it is to install, and how it allows you to interface with all 4 sections of the Quadra.

Synthchaser MIDI Adapter for ARP Quadra

 

A customer brought in his ARP 2600 that started smoking while he was using it. I show you how I quickly locate the offending component and what I’m going to do to help his synthesizer kick its dirty smoking habit.

I have yet another dead ARP Omni in for repair and decided to take a moment to dispel some myths I see, primarily perpetuated by people trying to sell their broken ARP synthesizers (“powers on, no sound”, “power supply issue”, “probably a quick and easy fix”). So we try to fix this Omni the “quick and easy” way, and in doing so, hopefully demonstrate why there is such a huge price difference between a restored ARP Omni and a parts/repair ARP Omni.

It’s very common for some of the presets on the ARP Pro Soloist (and Pro/DGX) to be dead or just not sound like they should. It’s also common for people to blame these problems on the Pro Soloist’s ROMs, when they are rarely, if ever, what really has failed. In this video we track down and repair 4 dead/incorrect voices including the ubiquitous Fuzz Guitar I so the customer can get his Tony Banks back on.