User: Default Corporation - Piemonte, Italy
Volume up and enjoy!
This is a fan site for a great Synth! For the Roland JD-800 and of course, the JD-990 sound module. (coming back from Geocities)
By Merlin, of AmiBay, English Amiga Board and Vintage Computer Forums (among others)
How to deal with the “not-so-mellow yellow” of old computers and consoles
“The problem was finally cracked in late July 2008 with a mixture of hydrogen peroxide, a small amount of an “Oxy” laundry booster as a catalyst and a UV lamp; we believed that this could do the job in hours instead of days. Proof of this concept was demonstrated on EAB by Tonyyeb from Hull, UK, Chiark from Leeds, UK and myself. The original test I did as proof of concept took two hours, as opposed to up to the five days it took for the original tests at CBM and a1k.org. We were on to something!!
|Image from the DVD 'CLASSICAL WAKEMAN'|
Vol. 1- Live in Lugano
|Master Rick Wakeman is an English keyboard player, composer, and songwriter
best known as the keyboardist for progressive rock group Yes.
This is a Mod to the JD-800 circuit. Do it at your own risk.
|Photo: Gwydion Elderwyn|
A 270 kOhm resistor across R27 will make it possible to use full range of aftertouch without straining your fingers.
|R27 position. |
Photo: Gwydion Elderwyn
I poked around with a multimeter on the aftertouch circuit today. The pressure
ribbon starts out at 150 kOhm and by full pressure it is around 1 kOhm...
Shunting the ribbon will make it possible to move the threshold to make it start
earlier but will not make it more sensitive.
This is a modification you can do inside the JD if you are comfortable with a soldering iron that makes the aftertouch much more responsive.
This mod might require to unsolder a SMD resistor ... not something for people with ten thumbs.
For sure you can ask an electronics technician to perform this modification.
Removing all screws may do your internal components fall.
You must remove only the screws AROUND the bottom and two screws in the center line, they are at 1/4 from side, and may be you can see a few bigger hole where thy fit to.
Sometimes the bottm have some "dust" acting like glue to.
|Photo: Gwydion Elderwyn|
|How to remove the panel. |
JD-800 Manual. (click to enlarge)
Source: Roland Co.
|Image by: Preben Friis|
What I'd like to do instead on this mod is replace the resistor by a lower value, cut the trace next to it and connect a 500Kohm trimmer pot with modding wire (26-28Awg) and have it adjustable.I imagine not every aftertouch ribbon has exactly the same value, so this would make it tweekable. Nice thing is if the value of the ribbon changes in time, all you have to do it open it up and adjust it a little. The fixed resistor is there as safeguard so the value doesnt go below a safe value and draws too much current.
Also, I would not connect a pot in parallel with the current value. The response of the pot would not be linear at all, and hard to adjust.
|Foto: Yuri Alfons Peeters Charlotte|
This is a fan-page.
JD-800 and JD-990 are @ copyright by Roland Corp.
I found all material (pictures, etc) at internet and sometimes I have not find the original sources to give credits.
If you own the copyrights of any material or information shown here and I miss your link OR you don´t agree with it´s use here, just send me a message and I will correct it.