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Quick repair for Dead ARP Omni? – Synthchaser #142

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.

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ARP Pro Soloist Dead Presets Repair – Synthchaser #140

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.

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Tom Oberheim SEM Pro Repair – Synthchaser #139

In this video we have a look around inside the new Marion Systems Tom Oberheim SEM Pro. And thanks to the kindness and generosity of Tom Oberheim himself, we’re able to repair a problem this one is having with an envelope randomly getting stuck “on”. The birds in my area love Oberheims (remember the OB-Xa Hummingbird?), and a Red-Tailed Hawk comes to check out the repair job.

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Roland Jupiter 4 JP-4 Repair – Synthchaser #138

In this video we have a look around inside the mighty Roland JP-4 synthesizer and see how it works. Then we troubleshoot and repair this dead Jupiter 4.

00:39 – The Problem: No Output

01:28 – Tour Inside / Technical Overview

06:10 – Power Suppy Check

07:04 – CPU Check

11:56 – Key Assigner Board Check

13:30 – Main Motherboard Check

16:07 – DAC Troubleshooting

20:25 – Making The Repair

22:46 – Jupiter 4 Repaired!

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Designing Roland TR-808 Mods for Doctor Mix – Synthchaser #136

Claudio from Doctor Mix has been busy repairing and modding his Roland TR-808 drum machine and asked if I could help design some mods for the hand claps. In this video I show you my approach to designing mods, and give a little introduction to RC time constants, which are used in all analog synthesis circuits.

See and hear the mods I came up with in action in the new Doctor Mix video here, and be sure to subscribe to the awesome Doctor Mix channel!

Here are the instructions for the TR-808 Hand Clap mods I designed.  I’ll keep this up to date with any feedback received.

Click to access Synthchaser-TR-808-Hand-Clap-Mods.pdf

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Synthchaser Update May 2021


NEW VIDEOS: I’ve got a new video finished up, and I’ll be making a brief appearance on another YouTube channel that’s much more exciting than my own.  Both videos go live Friday May 7, will post links then.  For now, this screen grab is the only clue.

ARP QUADRA MIDI:  Over the last couple of months I’ve spent a lot of time developing a really awesome MIDI adapter for the ARP Quadra.  Unfortunately now that the design is done and the prototype has been perfected, we find ourselves in a global microchip shortage and I can’t get it produced!  If you’re interested please be sure to let me know.  When microcontrollers become available, I’ll try to grab enough for those on the waiting list.

SUPPLY CHAIN ISSUES:  Besides the Quadra MIDI, the microchip shortage has put my ARP Omni MIDI adapter out of production.  I have 1 unit left and no ETA when they can resume production.  Also, our replica slide potentiometer manufacturer is having manufacturing delays due to COVID, and we are backordered 2 months on replica ARP sliders.

LED SLIDERS FOR MORE SYNTHESIZERS: Because I’m backordered on regular sliders, I’ve made LED slider sets available for more synthesizers, including the ARP Odyssey and ARP Avatar.  These come pre-assembled for less than the cost of “Lumina” which comes unassembled.  There are multiple sliders on each assembly so your sliders come out straight and parallel, as opposed to some fiddly hard-to-assemble adapters people have been using.

ARP QUADRA WITH MIDI FOR SALE: I’ve got a very nice, restored ARP Quadra for sale on my website.  Besides being meticulously restored by yours truly, it’s equipped with the prototype MIDI adapter, so it may be the only ARP Quadra in the world with MIDI!  While at one point not too long ago I had 5 ARP Quadras, this is the last one I’ve got.  So if you had been considering a Synthchaser ARP Quadra for your studio–this is your last chance!

Restored ARP Quadra Synthesizer Keyboard with MIDI

Synthchaser Precision LED Slider Upgrade Kit for ARP Odyssey

Synthchaser MIDI Adapter for ARP Omni 1 & 2