Time flies, it’s been one and a half year since I started this project and progress is slow. Though there is progress!
Battery change, service V8.3 upgrade
In March I discovered a battery leak in the PPG Wave 2 and decided to send that board to Virtual Music for repair. I also did the same with corresponding 2.2 board. Since the V8.3 firmware upgrade goes on the same board I sent the chips as well. Besides the battery change, the 2.2 also got a little service.
Today, nine months later, I decided to put the card back in the 2.2 and it started right up! Great success on that and I feel that the hardware is now serviced. Focus will now be on the racking process.
A year ago I also purchased a rack chassis. I bought a 6U rack with the widest inner width I could find. The inner width is 434 mm and the outer width is 436 mm.
I’ve also done a lot of measurements of the PPG and rack, and right now I’m feeling very hopeful. There were two main obstacles, both having to do with the width.
The first one was the fact that the original LCD and the “button board” simply wouldn’t fit. With the newer LCD, that will not be a problem. The board is around 240 mm and the lcd is 182 mm. That means more than 10 mm margin.
The second one, and this still needs to be solved, is the 2.2 motherboard. The width is 435 mm which is 1 mm wider than the inner width. I see two ways of solving this:
Use washers or some other kind of spacer on each side to move the side panels a few millimeter outwards. According to my measurements I could probably gain 6-8 mm by doing this
Shave off the motherboards right edge – from what I can tell it’s probably possible to shave off around 2-4 mm of the motherboard. In a way, I feel this is kind of risky, but on the other hand the rack case will be properly assembled.
No matter what route I take, there’s one thing that also has to be modified. On the motherboard’s other edge, there are two pin headers that have a 90 degree angle. They need to be desoldered and straightened up, otherwise the connectors will hit the side panel. They can’t be bent when soldered to the board since they’re very thick.
I think the best thing to do next is to simply test fit the board in the case and actually see how many mm that are missing!
Yesterday I got my new display and digital board back from Alexander at Virtual Music in Vienna. The old display had to be changed to a newer one for two reasons, even though the old one still worked.
First of all, the old one would never fit a 19″ rack since it’s too wide. The new one is 182 mm, so it will fit.
Secondly the old one was very hard to read, especially if you were not straight in front of it. Since the PPG Wave 2.2 is supposed to sit in a rack, sideways visibility is crucial.
As you can see on the pictures it’s not just a matter of swapping the old display for a new one – serious modifications must be made to the so called digital board. The digital board contains the driver for the display and the two keypads. All work was very professionally done by Alexander! I plugged it in and it worked instantly!
The encoder for the contrast was also replaced since the old one was kind of intermittent.
Virtual Music also happens to be the reseller of the newer V8.3 firmware that adds a lot of sysex and fixes bugs. V8.3 was ordered as well as new battery kit. I tried to change the eproms, but the old ones were really stuck and impossible to remove without using brutal force, which I didn’t want to. I will have to install V8.3 when the board is removed from the chassis.
The next step is to order a new 6U 19″ rack chassis.
I just upgraded the firmware in my newly bought MKS-70 from 1.03 to 1.08. I’m not actually sure what the differences are, but since I have the possibility to program EPROMs there was no reason not to.
However, the engineers at Roland decided to put the EPROM in a position that makes it impossible to pull it straight out. The EPROM is located at the mainboard in the bottom of the MKS-70 and marked with an A. The two voice cards (same as used for the JX-10) are stacked upon that. It is possible to fold away those cards, but a lot of cables has to be detached. I should mention that there each voice card also has an EPROM, these are didn’t have to be upgraded.
The TOP853 couldn’t burn the TC57256D-20 EPROM that are used in the MKS-70 and JX-10. My advice is not to buy the TOP853 if your’re going to use it for programming. The GQ-4X did it after I added a custom line to a new text file called customdevices.txt
I know it’s a bit insane, but I got a very good deal and bought an MKS-70. The MKS-70 is the rack version of JX-10. The JX-10 contains two JX-8P. So at the moment, I have a total of five JX-8P engines!
It seems to be fully working, has a few scratches on top and the front panel looks very nice. However, when booting it and pressing the VALUE button the screen read “Ver 1.03 FINAL JX”, which is not the last version of the firmware. Regarding “FINAL JX”, it’s kind of strange because it was not the last JX synth produced (JX-1 was the last one, though it’s not analog) and it was not the last firmware version either. Just like on the JX-10, the firmware was very buggy on the MKS-70, but they got it all sorted out with version 1.08. I’ll have to open the MKS-70 and check what kind of EPROM it uses.