#technology 3.1

This was a very long and drawn out process that provided many challenges but ended unsatisfactorily, due to a number of factors that will be detailed here. Despite this, I did learn a lot and my practical electronics skills have increased exponentially, so it did not end in complete failure.

From the outset of the process, it appeared that this would be very challenging. It contained two aspects, both of which needed to be completed: the repair of two of our client's Juno-106 synthesizers and the construction and modification of two PAiA audio electronics circuits. Although both aspects would have a fairly straightforward process of building and testing, the sheer magnitude of the combined jobs was daunting. I resolved to set aside three of my many free periods a week to commit to this project and tried to divide work between the two evenly.

As mentioned, the process was very straightforward. For the Juno-106s, the client's problem was a common fault that had been well documented on the internet; because of this, we had plenty of resources to draw on for the repair. It was a case of removing the chips, stripping the plastic coating via acetone and then soldering the chips back in, all of which was completed in a relatively short amount of time. The problem came with the calibration of the units: after we had re-installed the chips, we put aside this part of the project to focus on the construction of the PAiA circuits. Various factors prevented us from returning to the calibration, mainly the absence of either Tom or myself, or the possibility of more important work. Our teacher Terry had predicted the calibration would not take that long and we would only need to set aside a double period to complete it; at the time, this seemed like a realistic prediction and I agreed.

When we actually came to calibrating the units, the task was far more difficult than we had originally thought. It required many, many precise tweaks through the use of an oscilloscope; this was a very long and laborious part of the process. By now, it was close to the end of Term Three and we did not have enough time to complete both the PAiA circuits and fully calibrate the synthesizers. Therefore we decided to end this part of the process; admittedly, we did not fully satisfy the client's request, but the client did not provide us with a strict timeframe nor did they seem disappointed at the length of the process. With a less liberal-minded client, the incompletion of the calibration would have been a terrible problem.

The second part of the project was in some respects harder, and suffered more than the synthesizers. Again, the process looked to be, for the beginning at least, very straightforward: follow the instructions in the manual to build and test. Both Tom and I got to pick which circuit we wanted to construct; he picked the VCF and I picked the VCO. As we built, the process was simple enough but very time-consuming. I spent many weeks just soldering in the resistors. 

We originally intended to modify the circuit so that the unit's potentiometers were controlled by an Arduino-based microcontroller, and we would design a GUI for use with this - very high-tech stuff. However, as the weeks became months, the possibility of creating a conceptual design and doing the actual modifications slipped further and further away. Again, our problem was time - we simply did not have enough to complete a project of such magnitude. The other time-related problem was that, as the assessment was not part of a regular class period, there were inconsistencies with how much time was devoted to the project itself. Furthermore, as it was not connected to any actual classwork, there was less of a drive for me to finish it, and at times where I was very busy more important work would take precedence.

Ultimately, even though we set aside almost an entire year for the completion of this project, time was the biggest contributor to its half-finished stated. I was simply too busy to maintain such a long side-commitment. That being said, such an extensive period spent working on practical electronics has really improved my precision and skill - so I did manage to achieve one of the goals set out in the brief. Additionally, we did meet many of the points set out in the brief, it was just the conceptual design and its implementation for the PAiA circuits and the calibration for the Juno-106s that could not be facilitated.

This project is a practical, electronics-based project with two sections to be completed:

1. The client, an acquaintance of our teacher Terry Hawkings, has contacted us with a request to repair two Roland Juno-106 synthesizers that he owns. The synthesizers are broken due to a common fault, wherein the voice chips that create the unit's sound and polyphony have ceased to function properly. These chips must be removed from the unit, stripped of their plastic covering and reinstalled. The chips then require further manual calibration.

2. Two circuits have been ordered from the audio electronics retailer PAiA Corporation: a voltage controlled filter (9730K VCF Electronics Kit) and a voltage controlled oscillator (9720K VCO Electronics Kit). These two circuits will be modified to have their potentiometers controlled via a computer using an Arduino microcontroller. The circuits must be built and tested for functionality before modification. The modification will require the drafting of a conceptual design.

For both projects, frequent evidence must be provided in the form of screenshots and photographs that track the progress of the build. These will be posted on the student's Tumblr blog. The project will take place outside of regular class time, so approximately three periods must be put aside each week to work on it. The entire year has been set aside for this project to be finished, and it must be completed by the end of Term 4.

Written work must be completed alongside the practical work and evidence of process. This includes writing a project brief, a key factors chart and a final evaluation. This is to be completed by the end of Term 4 and posted on the student's Tumblr blog.

The finished product for part one of the project will be returned to the client; the finished product for part two of the project may be taken home upon completion. The first project must meet the client's requirements, and will be judged on how well it does so. Both pieces will be judged on the consistency and detail of the process and the quality of the paperwork. The student will either receive one of three passing grades: Achieved (A), Merit (M) or Excellence (E).

Points:

To repair the aforementioned common fault with the client's Juno-106 synthesizers

To calibrate the Juno-106 synthesizers after the repairs

To satisfy the client with the final repairs and calibration

To build and test one of the PAiA Corporation circuits

To create a conceptual design for the modified PAiA Corporation circuits

Frequent posting of screenshots and photographs that document the process

To address all key factors and elements of the brief

Goals

To improve my practical electronics skills and precision

There is not much to detail in this week's reflection: work on the circuit is trudging forward, ever so slowly. It is taking a long while to solder the many, many, many resistors in. For the coming week, work will continue as like this. The solder must flow.

Terry, Tom and I are going to have our meeting on Thursday; this meeting regards the other project required for this standard, the Juno-106 synthesizers we worked on earlier this year. We replaced the broken voice chips in these units, but we have still not calibrated them. Once we have calibrated the Juno (a relatively simple task), that part of the project will be over and we can focus solely on the building and modding of the PAiA circuits. Photos of last week's progress will follow.

After an unfortunate extended break, we are now launching back into work for the 3.2 assessment with all our proverbial guns blazing. Our teacher Terry has called for weekly planning sessions, where we will check up on what we have done and plan for the weeks that follow. This was something we did not do last term, and I believe it will give us a clear sense of direction and time management.

We had our first meeting today, albeit a brief one, which was devoted to creating a prospective timetable for the work that needs to be done, of which there is quite a bit. We will be building a pre-ordered PAiA circuit - which we will then need to test it to see if it operates - and modifying the circuit's potentiometers to work automatically, with code written using an Arduino microcontroller. Not an easy task, especially given the tight time frame.

Work on the construction of the circuit began this week, and photos of the process made will be posted after this. I am devoting three periods a week to this assessment, one on Monday and a double period on Thursday; our weekly meetings will take place at the start of the Monday period.

Tom and I began scholarship work today; the first stage of which involves working with Roland's fabled Juno-106 synthesizer.

Our first client, a collector of old synthesizers, has brought in a faulty Juno which needs to be fixed. As our teacher Terry explained, the fault - a common one - had been traced to two of the Juno's 80017A VCF/VCA modules, i.e. the synth's voice chips. These voice chips, as I discovered during background research, are prone to failure due to a resin coating which somehow disrupts the circuitry of the ICs. This coating must be removed for the module to function normally again, which can be done by bathing the voice chips in acetone for a minimum of twelve hours.

When work began today, the chips had already been desoldered, removed from the board and stripped of their coating; Tom and I had the rather simple job of (precisely) soldering the chips back into the board and testing the results. Unfortunately, time ran out before we got to the testing stage, but we did manage to finish all the soldering; this will need to go under a magnifying glass, as Terry says there are minor touch ups to be done.

Later in the day I did some research on the Juno-106, the faulty modules and the acetone bathing process. My main sources of information were Wikipedia's entry on the Juno-106, the synth's page on the Vintage Synth Explorer (a very useful database for this type of work) and this handy FAQ.

These videos detail the acetone bath process (note that in the second video a Juno HS-60 is used instead of a Juno-106; the two synths are practically identical).

Here are .pdfs of the 106's user manual and its service manual.

Listening:

The Hollies - King Midas in Reverse

Tim Rose - Maman

Pulp - F.E.E.L.I.N.G.C.A.L.L.E.D.L.O.V.E.

2Pac - Holla At Me