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Give your Roland SH-101 a little TLC

Recently, one of my regular customers put his Roland MPG-80 up for sale, having acquired a Retrtoaktiv MPG-8X. I’ve always, always wanted a MPG-80 to (obviously) go with my MKS-80 but I’ve never seen one in the kind of condition I’d like. Dan’s MPG-80 however, was pristine so I made him an offer which he conditionally accepted, the condition being that I provide him with a Roland SH-101 service.

Dan told me that he’d picked it up at a knock-down price but although cosmetically things seemed okay, some sliders weren’t working properly, some keys were intermittent as well as similar problems with power. Hmm… Okay, let’s have a look.

Well, when I took this thing apart, I was shocked to see the dust and grime within. On top of that, it had sustained fluid damage and from what I could tell, twice!

This SH-101 was completely full of crap! It was clear that this poor ol’ gal had been kept in a smoker’s environment. The pads that cover the switches, just crumbled. That’s right. Tobacco smoke doesn’t just discolour, it reacts with certain materials, making them stiff and brittle.

Roland SH-101 serviced at Plasma Music
The dust covers underneath the Portamento and transpose switch levers, just crumbled. Difficult to see in this picture but I managed to replace them with some of my black magic thingy!!!

It was no surprise then, to suss out why some keys were intermittent and why some sliders had quite poor performance. Dan, this is a little more than a standard Roland SH-101 service, mate!

I stripped the whole machine so as to wash the knobs, buttons, slider caps, keys and even the plastic top-case. With the afore mentioned exposure to smoke, I was very concerned that the keyboard contact strips would break as I removed them but I got lucky.

Roland SH-101 keyboard bed after decades of neglect
Roland SH-101 keyboard bed after decades of neglect and being kept in a smoker's environment.
Keyboard contact strip after decades of neglect
Same with the keyboard contact strip. Looks absolutely awful.
Roland SH-101 keyboard bed and contact strips after cleaning
Before and... after. I got lucky with this one. After such a long time (and especially after long-term exposure to tobacco smoke), it's quite common for the contact strips to tear when removing them from the keyboard bed.

There were a few dry joints which were to be expected and some of the sliders couldn’t be cleaned and therefore required replacement.

While I was at, I also cleaned the sockets hoping that they would be okay. Dan supplied me with a power switch which I fitted but I also changed the DC input jack as the original seemed lose and let’s face it, after thirty-something years, why not?

After a gruelling seven hours, Dan’s SH-101 was back together again, so time to fire up. The machine switched on first time. Playing around the the DC input, power now was stable. Although I had sound, the HOLD function was stuck on. This is a relatively common problem and is often caused by the HOLD jack socket being stuck open. I’d already checked the sockets and quickly traced the source of the issue to a dry-joint that I had missed.

After an extensive testing of all functions, it was time to flip the machine over and recalibrate. As it turned out, things were quite good and I ended up not doing too much at all.

It’s unfortunate that the plastic pillars used to secure the metal bottom-case to the top-case, are so fragile. During my thirty years of fixing SH-101s, I haven’t yet found a way to cost-effectively and reliably repair these. Fortunately, so long the majority  of them are intact, it’s not too much of a problem.

A sadly familiar sight to many Roland SH-101 owners - a broken screw post
A sadly familiar sight to many Roland SH-101 owners - a broken screw post.

One of the pillars that secures the metal bottom case to the keyboard chassis was missing and the other had an incorrect self-tapping screw rammed into it at some point in its life, which has completely ruined it. The original pillars are very hard to come by and with a couple of the internal plastic pillars broken, it was important to ensure that the bottom-case is properly secured. I therefore fitted brand new M3 PCB spacers to the keyboard chassis, in place of the original pillars. Of course, I also had to dig out a couple of nice, shiny black M3 machine screws. It all ended up very secure and looking very tidy.

Replacement M3 pillar on Roland SH-101 keyboard chassis
Here's one of the two replacement M3 support pillars that I fitted on to the keyboard chassis. Two non-self-tapping screws, pass through the metal bottom-case and into these pillars.

Kept near a heat source at some time, the battery compartment cover had warped slightly. The deformation was subtle but resulted in the cover sitting ever so slightly proud of the top of the top-case. Not too big a deal, in fact it’s hardly noticeable. I was tempted to gently heat the cover to see if I could make it straight again but these things are so fragile, I decided against it.

Roland SH-101 serviced at Plasma Music
Dan's Roland SH-101 almost looking like new again and definitely feeling and sounding a lot better than when it came in.

There’s a lot of talk on-line about the infamous Roland SH-101 discolouring. The SH-101 was released in three colours; red, blue and grey. ALL versions discolour and no one really knows why. Exposure to ultraviolet (sun) light seems to be the most common opinion but my own SH-101 has been kept in an artificially lit, smoke-free environment for most of its life and is now more pink than red! I can understand why people blame UV, however. Removing the battery compartment cover reveals  the ‘original’ colour of your SH-101 suggesting that everywhere else which is of course exposed, will be discoloured by ambient UV. Oh well, just one of those weird mysteries of life, eh!

Nice shiny looking and smooth feeling keys
WOW! Nice shiny looking and smooth feeling keys.

Another slightly annoying issue with the SH-101 is that it's very GROOVY!!!!! Yes, that's right. Those nicely aesthetic lines cut into the top-case add to the SH-101's cool look but they also gather all sorts of dust and crap over the years. Even if kept in a nice, clean environment, the grooves in the SH-101's top case do get dirty and getting it out can make a Roland SH-101 service a little longer than anticipated. 🙁

The brittle plastic, the weird decolourisation and the dirt gathering grooves in the top case don't of course detract from the SH-101's attributes. That classic analogue, mono-synth sound and the pure ease with which it can be manipulated, are what the SH-101 is really all about and perhaps decades after its launch, the niggles now simply add to its cute character.

Anyway, at long last, this Roland SH-101 now looks, feels and sounds fantastic. Nice and shiny, smooth and responsive controls and a solid keyboard, it's almost like new! It's always really exciting for me, when customers come over to collect their gear and I know Dan's busting to check out his refurbished Roland SH-101. 🙂

Launched in 1983, the humble but amazingly well-known and popular Roland SH-101 is pre-MIDI not that many seem to care! Being equipped with CV however, means that the SH-101 can be controlled by another source and as many of my customers will know, my favourite MIDI gadget / upgrade manufacturer, Kenton Electronics, offers a couple of options to to get your SH-101 controllable via MIDI. The SH-101 MIDI CV kit for example, is installed into your SH-101 and although requiring holes to be cut into the case for MIDI sockets, it does mean that you won't have another box floating around.

Kenton Pro Solo Mk 3
One of several gadgets made by Kenton Electronics that'll get your Roland SH-101 connected to your MIDI studio, the Pro Solo Mk 3 stand-alone MIDI / CV converter, is fast and accurate.

Kenton also makes a range of stand-alone CV / MIDI converters like the USB Solo, Pro Solo Mk 3 and Pro 2000 Mk 2. These gadgets are very fast and accurate and  don't require any modifications to your synth's case. I've already mentioned that I've always been a big fan of Kenton's products, so if you do want to get your SH-101 connected, then I strongly suggest you check out their MIDI / CV converters, here.

As well as owning a SH-101 myself, I've worked on hundreds of them over the years and know this Roland classic, inside-out, so if you've got one that's in need of a service or if it just needs a little TLC, please don't hesitate to get in touch. 🙂

Read more about the Roland SH-101 here:

Vintage Synth Explorer - Roland SH-101

Roland Icon Series - SH-101

"Hang on a minute. What happened to the MPG-80?" I hear you ask. Well I'm lovin' it but... I now had a template for my RE-MPG-80 replacement rack ears. YAY!!!! You can read about them here.

RE-MPG-80 replacement rack ears for the Roland MPG-80
My RE-MPG-80 replacement rack ears for the Roland MPG-80, mounted to my new MPG-80!

Roland MKS-70 repair at Plasma Music

Recently, this gorgeous vintage Roland MKS-70 synth module came in for repair.

The MKS-70 is basically the rack version of the Roland JX-10 keyboard synthesiser, which itself is essentially two JX-8Ps. Also known as the Super-JX, the JX-10 and the MKS-70 are famous even today for their rich, analogue tone and pristine sound quality. At this point I need to make something clear; the Super-JX is not actually 100% analogue unlike for example, one of it's well known predecessors, the MKS-80. The oscillators are in-fact, digital. So when I refer to 'analogue' tone, I'm referring to just that, the tone.

Check out more details and some sounds here and here.

Anyway, the customer said that it wasn't powering up properly with just a flash briefly appearing on the display and then nothing. Well, let's see if we can get this ol' girl singing again..

Apart from being a giant classic, the MKS-70 like the MKS-80, has hinged circuit boards which means that it opens up quite nicely. Having said that, if you need to get at the 'CPU' board (the service notes refer to this as the Assigner board, for some reason), you really do need to disconnect and remove the lower analogue voice board.

Checking voltages before anything else, I realised very quickly that I had a major problem. The voltages on the power supply were all about 25% more than what they should be. Eek! Hope no serious damage has been done.

I'll keep you posted on this fix but please bear in mind that I'm respecting the COVID-19 lock-down so it may be a while before I'm back.

UPDATE - 2nd April 2020

The power supply is a really clever and well thought out design for the time but I don't think the Roland R & D team had any idea that their machines would still be making music over thirty years after their conception. There's a small voltage monitor chip on the power supply which, when it fails, sends the +/-15 V rails to like +/-22 V. Unfortunately the +5 V rail for the digital stuff has a dependency on the +15 V rail so if that freaks out, then so does the +5 V supply.

I decided to change all the major components on the PSU including transistors, capacitors, bridge rectifiers and of course that frigin' voltage controller IC. Okay, so now power is good.

UPDATE - 14th April 2020

Well the voice-boards turned out to be fine but the CPU or assigner-board, was seriously not happy. The code was trying to run but not getting anywhere. My worst fears an' all that... This was not going to be a straight-forward Roland MKS-70 repair!

Vecoven Flash Module Installed In Roland MKS-70
Using Fred Vecoven's Super-JX flash upgrade module meant that the assigner-board could be tested without having the voice-boards connected. Wow!

I'll get back as soon as I get somewhere... or not 🙁

UPDATE - 14th January 2021

The assigner board on this Roland MKS-70 is indeed kaput. Having got to know Guy Wilkinson of SuperSynthProjects over lock-down 2020, Guy came over when things calmed down and we both agreed that although laborious, one coarse of action would be to swap out all of the ICs but... as many will know, there's one IC that can't be replaced too easily and that's IC2, the 63H149 propriotory Roland gate array.

MB63H149 extracted from Roland MKS-70 Service Notes
The proprietary 63H149 gate array IC found in many 80's Roland synths and modules is impossible to replace now-a-days.

The 63H149 is used in a lot of Roland keyboards and modules, right up to the S-10 and the D-50. In many machines, including the keyboard version of the MKS-70, the JX-10 the 63H149 is mainly used as the keyboard scanner but unfortunately, it's also quite connected to other devices in the MKS-70.

Guy came up with an idea and is currently in the process of designing a 'replacement' for the 63H149. This isn't going to be a drop-in 80-pin device like the 62H149 itself but something that will kind of 'bypass' the chip's functions and fool the MKS-70 into thinking that the gate array is there and functioning normally. If we can do this, it'll be quite a break-through and will potentially save a lot of MKS-70s.

An exciting but time-consuming project, it's going to take a while but be sure that I'll definitely keep you posted.

Please don't hesitate to contact me if you have a sick Roland MKS-70 or any other vintage synth.