I troubleshoot and repair a dead Roland TR-808, and convert it from 220V operation to 110V operation.
Analog synthesizer repair, parts, sales, and innovation. I buy broken synthesizers!
I troubleshoot and repair a dead Roland TR-808, and convert it from 220V operation to 110V operation.
CEM and SSM chips are analog integrated circuits (commonly called “chips”) used in many synthesizers.
Founded by Doug Curtis in 1979, CEM developed a family of signal processing products for electronic music synthesizers and audio equipment. In 1988, Doug migrated the company to become OnChip Systems. In 2016, it was announced that the CEM3340 VCO had been remanufactured by OnChip using the original design, the CEM3340 RevG. Other manufacturers manufactured copies of the Curtis Chips as well since the patents had expired. Cool Audio produces the V3340 and the V3320. AS ALFA RPAR released the AS3310, AS3320, AS3330, AS3340, AS3345 and AS3360 in DIP and SMD packages.
Solid State Music, later known as Solid State Microtechnology for Music or simply “SSM,” was founded by Ron Dow and John Burgoon in 1974, with assistance by Dave Rossum of E-MU Systems. The company originally produced synthesizer chip sets, and provided bare boards for the hobbyist to experiment with early SSM chips. In an unusual pairing, they also produced S-100 bus computer cards, including a Sound Synthesizer Card. SSM was acquired by Precision Monolithics in 1988, who was in turn acquired by Analog Devices in 1990. New SSM-badged IC’s continue to be introduced by Analog Devices, but bear little resemblance to the original SSM line. Several early members of the SSM team reformed in 2017 as Sound Semiconductor to develop audio IC’s in the spirit of early SSM products.
This vintage Roland TB-303 bass synthesizer has difficult to trigger and double-triggering pushbuttons, and in this video I show how to replace the pushbutton switches. Switches are available at the link below, and installation services are available.
In this video we troubleshoot and repair a dead Juno 106, that powers on but either the LEDs flicker or the display reads “8” and the synth is non-operational. The theory I touch on and process I use can easily be applied to any other microprocessor based system that isn’t booting.
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!
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.
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!
Synthchaser Precision LED Slider Upgrade Kit for ARP Odyssey
Check out the photo album on my Facebook page with pictures inside the world’s worst Juno 106.
https://www.facebook.com/media/set/?set=a.680775182290559.1073741829.544327069268705&type=3
I couldn’t pass up the opportunity to repair this rare and interesting early sequencer made by Roland. Very few of them were made and even fewer still exist today. But there’s no service manual or schematics!
So we have a look around inside and see what makes it tick, and I show you an approach I use for tracking down problems I don’t know I’m looking for. And after it’s fixed we take a peek at it in action. It’s hugely different from other sequencers of its time.