Roland Juno-106 restoration/repair, nice update parts are now available

Posted on May 15, 2017 by Chris Hewitt

When quoting restoration/repair of the Juno-106 I often describe it as a money pit because of the amount of work it requires, and high parts price. If it is in physically nice condition and you want to keep it then it is worth investing in as it is a nice sounding synth. I just want folks to know what they are getting into up front and that it is not a quick and cheap fix as if the voice modules have not been dealt with then they need to be.

We all know about the voice module issues on the Juno-106. If the module has not failed the chances are it will so I recommend changing all 6 80017a modules. If you have the original 80017 modules then you need to change them as a set as Roland warns your in the Service Notes that the timbre is different on the “a” variant. A common belief is that it is the epoxy coating becoming conductive over the years that is causing the failures (dead, crackling, failing the various tests in Test Mode) and that the acetone strip method was a cure. Long term the acetone strip method was not holding up and I had a couple of units in for rework that had been to the xxxxSpa. Looking at these with a microscope I saw incomplete material removal between the pins of the chips, and pins on the chips and the chips pins going cold-soldered. This leads to the belief that it is not the epoxy becoming conductive, but more it is the that the epoxy was pushing against the chips and as the temperature fluctuates, it expands and contracts which eventually lifts legs off the pads on the PCB. I re-flow the solder on all the pins on my re-work solder station under a microscope, then coat the module with silicone conformal coating to seal the moisture out and protect them. This will not cure a bad chip but has recovered a far greater percentage of modules with far less fallout. I also see failures of the Wave modules but the acetone strip (if the epoxy comes off with this method) does not seem to help as there is a red coating of “other stuff” over the actual chips that I have not tried to remove so cannot re-flow the soldering. This coating is much softer than epoxy so the epoxy is not applying any leverage on the chips.

I still do some acetone strips but prefer folks to order the complete package of 6 voice and 3 wave modules from Analog Renaissance in Belgium (Analogue Renaissance voice and wave module package ) and bring/send them with the synth. They have a buy 5, get 6 pricing on the voice modules. These are really nice and a much better solution than acetone stripping. Shipping is a bit slow and the price is something like $350 depending on the exchange rate but I so much prefer installing them as I know I can just put them in and they set-up easily and work. Syntaur also carries the modules but do not offer a complete package price.

I change the battery and reload the factory patches on a service, plus clean the unit inside and out. There is a factory FCO for early battery fail that was later incorporated. Check that pins 4&5 of IC4 which is near the battery.

On the modulation panel it is common for the mod lever and/or LFO bend plate to be broken. Syntaur carries these. I also see failures of the sliders. When I service a mod panel with the old crumbling gaskets still in place I remove the old gasket and fit a new new laser cut gaskets (foam or fiber) which I have had made.

The final area of concern, and one which many initially come in for is the front panel. Bad sliders cause it to constantly drop into edit mode (you can see bad ones wittering on the MIDI Out stream). The gaskets over the sliders crumble and fall into the slider impacting its smooth travel so things get worse and worse with the shaft breaking when you move a tight one. The switches behind the buttons become sticky and intermittent (they can’t be cleaned).

For a front panel service we:

Clean the panel removing all the old gasket material
Clean (or replace the sliders… I’m recommending these really nice ones from
LASynth that the slider caps are a correct fit on. These work and feel perfect: LA Synth Juno-106 Slider set )
Fit new laser cut gaskets (foam or fiber) which I glue to the front panel. This looks
really nice and works well
Replace all of the button switches if they are original/any are failing.

One final item folks like is to have the original 2 pin power connector replaced with a standard IEC grounded cable connector

As you can see there is a lot of work to do in order to get a tired Juno-106 back to a nice operating condition. Contact me if you would like yours restored.

CHD MIDI Upgrade for the Roland TR-808

Posted on April 6, 2014 by Chris Hewitt

When writing about the MTG TurboCPU upgrade I promised to put a blog entry up for a really nice and non-intrusive MIDI mod for the Roland TR-808, and here it is. The thing I really like about this implementation is the degree to which they went to make in non-intrusive (i.e. drilling holes!).

It comes complete with a printed manual of step-by-step instructions, and supporting CD.

For the MIDI connector the existing Din-Sync connector is removed, along with its In/Out switch. A new connector that includes MIDI In/Out is fitted (a special adapter cable is supplied. The switch is replaced by a 3 way one, In/MIDI/Out.

The “umbilical cord” for triggers and power is socketed at the controller end, so for service it can be unplugged and the TR-808 will still work (so this is not a CPU upgrade/replacement like TurboCPU).

Only one hole needs to be drilled, and it is for a MIDI active Led and sits in the Start/Stop switch, under the yellow label. Awkwardness here is that they specify a metric drill, and for accuracy a woodworking one is probably best. I’m sure you could get by with a slightly larger US drill and use a band of shrink-wrap tubing or some-such to tighten the fit. Of course you could ignore this step and just know that center switch is MIDI on!

Be sure to keep the parts removed such that the TR-808 can be put back to standard if need be. Here is a link to the CHD TR-808 MIDI kit. I may well contact CHD and offer to distribute this in the USA.

March of the Juno-106

Posted on March 21, 2013 by Chris Hewitt

I do not know why, but March saw a stream of Roland Juno-106’s. Voice module failures were a common failure item, and I spent a lot of time running modules through the acetone bath. The acetone bath method is not a cure all, as once a chip is damaged by the epoxy coating shorting it, then it is bad of course. The acetone strip method is a good preventative maintenance item though. I have been suggesting that customers look at services such as the synthspa as they say they will replace bad modules as part of their stripping process, and I cannot compete with that as I’m having to purchase reclaimed modules for repair.

One unit had been dropped which resulted in a lot of broken keys, and a distorted panel. Another unit suffered a broken pitch bend lever, and another the plastic push “spring” for VCO modulation (both of these parts are available from Sam at www.syntaur.com).

Loss of patches due to battery failure was seen on 2 units, so I’m recommending replacing the battery now even if the voltage is good. The bad side of this though is that the patch loading tool for the Juno-106 only does a patch at a time (no sysex load/dump capability), so you have to do the tedious patch edit and save for all 128 patches.

Two units were highly touch sensitive, and this was due to multiple bad sliders. One issue leading to this is oxidization due to a bad storage environment, another is the crumbling gasket Roland used falling into the slider. The cure is to remove, open and clean all sliders, remove old gasket material, and make a gasket from stiffened felt. While I have been in this area I have also been replacing intermittent patch etc. switches, and really they should all be done if one fails as dust getting into the switch is the culprit.

A final issue seen is with the bubble contact strips failing and giving intermittent keys. On the Juno I seem to be seeing other factors such as a liquid spill (on the Korg Poly6/61/MonoPoly they just plain fail).

All of this is leading me to making the standard service for the Juno-106 include front panel switch replacement, slider removal, open, clean, and lube, gasket removal and replacement, battery change, and optional module acetone strip. This is all labor intensive so not cheap, but it would get the keyboard running nicely again, and last another 20 years.

Roland System 100 Model 101

Posted on February 18, 2013 by Chris Hewitt

This unit shipped in and per the customers description, had a dead keyboard and lots of slider issues. The sliders in here are rare, and the worst one was a dual slider type that could not be found anywhere. All sliders were found to be gummed up with old grease, dust, hair, and other debris. The unit had to be deep cleaned, and all sliders opened, cleaned, and lubricated.

The keyboard was giving a large negative CV out, so off the audible scale. The customer said it worked until he tried to clean the contacts due to a few bad keys. What he had done was to over aggressively clean it such that a lot of the CV contacts were dis-formed and resting on the gate bus-bar. These were straightened out, but the majority of keys were then intermittent and badly triggering. Closer investigation revealed that the contact wire that is welded onto the key spring was either missing, or broken at one end such that a consistent on and off point for the trigger and gate could not be achieved. Contact sites were rare and expensive, so it was a case of using the good trigger contacts from some of the contact assemblies to make complete good ones, then salvaging assemblies from my spares RS-09 (fewer keys) to fully populate the 101. This was a LOT of work, but the keyboard is fully functional now and the owner is delighted.

One other note here is that if someone uses the wrong tool on a ferrite oscillator coil slug as a previous repairer did on this one it will crack and not be adjustable in the future.

Roland TR-808 Step Switches

Posted on February 11, 2013 by Chris Hewitt

I have found a source of the correct original type of step switch used in the Roland TR-808, and put them in the Parts section of my main site. You have to be really careful on how you remove the switch actuator so as not to break it, and the ribbon cable to the panel is very fragile leading to intermittent/no step button operation. The originals get gummed up and dusty inside, and they cannot be cleaned. I stock 2 types, the original, and a sealed variant (which has a different action). If you replace a switch I would suggest doing them all.

Rack-mount Synths

Posted on January 23, 2013 by Chris Hewitt

I often get asked to work on rack-mounted synths. Unless they are very early units I have to turn them away as without factory extension cables (which I do not have for any model) you can’t get the crammed in cards out on the bench in order to work on them. I this post you can see the amount of stuff that has to come out in order to perform a simple battery change on a Roland MKS-70.

Roland VP-330 Service

Posted on December 30, 2012 by Chris Hewitt

Roland VP-330

This Roland VP-330 came in for general service. As is common with Roland synths, the gasket material had crumbled and a lot of debris was in the slider controls and needed to be removed. Its amazing that something that was designed to stop dust entering the sliders ends up doing damage (this makes me shudder because of the hours spent cleaning off the foam turned to goo on the Moog Opus 3, Rogue, and MG-1).

I cleaned out the sliders, disassembling a number of them, and lubricated them. The old gasket material was removed, and I used double-sided tape to attach stiffened black felt (from Michaels), which I cut slots in for the shafts. The end result is nice, and certainly improves over the look of the gaping slider slots. The felt will shed a bit of course, but the cure is better than leaving it the way it was.

I have applied felt to a number of Juno-106’s using variations of the attach method (double-sided tape, glue, attaching to underside of case, or to the top of the sliders). I would be interested to hear of any better materials (neoprene?), along with supplier.

Roland Juno 60

Posted on November 11, 2012 by Chris Hewitt

This unit needed a deep cleaning session and service.It was disassembled and cleaned-up, with fluff etc vacuumed away. The sliders and volume control had switch cleaner applied to cure the crackles, and key contacts were cleaned. One bank switch was not working, so I removed, opened it, and cleaned it. The battery was replaced, and FCO applied for dropping into manual mode (I have never had one come in that had this dealer applied; it addresses the fact that the power to the front panels goes through a couple of small connector pins, and this was insufficient, so direct power connections are added). Patches re-loaded, and unit put on burn-in test for a week.

Roland Space Echo RE-201

Posted on June 20, 2012 by Chris Hewitt

RE-201 with Tape Jam issues and no control over motor speed

I have had many requests to service Space Echo’s in the past and have repaired a few. I had decided not to do any more as I needed to purchase a number of service items to service them properly, and I was finding a dire lack of parts such as heads, bearings, and motors. One of my regulars managed to squeeze one in, and then I got a request to service one that was in dire straights after it had been to another repairer that specializes in them.

My next move was to scout and purchase a head de-magnetizer, splicer, splicing tape, and the correct type of 1/4″ tape for these units (must be lubricated tape). The first unit was simple enough, just needing a full service. The one that had been to another repairer was a different story.

The capstan was barely moving, and the motor shaft had a significant amount of play in it such that you had to push down on the shaft with your finger to get things moving. I removed the motor, and did a lot of research on line re replacing motor bearings. After a struggle I got the motor shaft out and measured the upper bearing race, eventually finding a replacement type. The lower bearing could also have done with being replaced, but this is a press-fit sleeve bearing and I could only find one on Ebay, shipped from Australia.

Cleaning the old grease from the motor and capstan shafts/bearings, and replacing the upper motor bearing restored operation and the speed control now worked. The tape loop was crumpled, so I made a new one and fitted it. I then found that the tape was not flowing smoothly in the cassette area. I cleaned a lot of old oxide and sticky stuff from the cassette chamber, and found that a big piece of felt had been glued in the chamber exit path (checked with the customer and the previous repairer had done this, perhaps trying to address the motor issues (the unit was sent to him due to the motor barely turning)). The felt was removed, along with the glue residue. The tape then rang for 6 hours without jamming at various settings of the speed control.

The final work was to glue the front panel back on where it was lifting, clean the tape path, tighten jack nuts, and clean the controls after which it was working nicely. Another 6 hours of test and I will return it to the customer!

Roland Juno 106

Posted on March 23, 2012 by Chris Hewitt

Roland Juno-106 800017a board with chip removed

A number of these have come into the shop and for most of them it is a 80017a voice module issue. Roland put 3 chips (including the 3109) and supporting components onto a module, then covered it with a moisture sealing epoxy coating. There is a belief that the coating was required in order to protect surface mounted resistors from humidity change in order to stabilize their value, and/or protect their IP. This coating is thought to become conductive after 20 years or so. The only source of replacement parts is through chip pulls from scrap machines, and they are rare so costly. A typical symptom is a hanging voice, and/or crackling. I recently invested in a de-soldering station in order to get these chips out cleanly. The keyboard here was purchased on Craigslist by the customer for a good price but when he got it home he found it crackled badly, and a voice was hanging (you can isolate which of the 6 voices it is by putting the keyboard in test mode). For this unit it was not obvious which chip it was but careful testing showed it, and it could be verified with an oscilloscope. A replacement was obtained and fitted; all seemed well. After 3 hours of just sitting warming on the bench another chip started to crackle and had to be replaced. Speaking with the chip vendor this scenario is not unusual. The keyboard was not such a deal now that the cost of two replacement chips is factored in but the customer loves it and will get good use from it.

I have been using the acetone strip method to try and re-use a bad module before scouting a replacement. It takes 3 days of soaking and careful work to get residue out from between the chip pins. I silicone seal the module after washing it in order to seal the above mentioned resistors from humidity. This method has been pretty successful with crackly modules, but has not been good for completely dead ones, or where the VCF is drifting as we are looking at chip failures in those cases. It is a sad fact that all of these 800017a modules will eventually fail, and one unit eventually did have all 6 replaced. I have not tried the aftermarket replacements for the 800017a, but would advise folks to consider that. Also there are places that you can send the card and they will acetone strip all 6 modules; I’m not sure what the deal is when the strip does not work on a module though.

The bottom line is that if you are thinking of buying a Juno-106 then be aware of its issues and that they are not cheap to repair.

via This Old Synth – Vintage Analog Synthesizer Repair Portfolio Page.

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