JADE COMPUTER PRODUCTS
4901 W. ROSECRANS BLVD
HAWTHORNE. CALIF 90250
SUBJECT: ENGINEERING CHANGE NOTICE # 1.
PRODUCT: DOUBLE D DISK CONTROLLER.
REVISION: BAND C REVISION BOARDS.
DATE: AUGUST 4. 1980.
IT HAS BEEN REPORTED THAT INSERTION OF THE DOUBLE D DISK
CONTROLLER INTO OF SOME S100 SYSTEMS PREVENTS NORMAL OPERATION.
USUALLY ON THESE SYSTEMS THE COMMON CHARACTERISTIC IS THAT THEY
JUST WILL NOT OPERATE. PLEASE NOTE S100 BUS PINS #20, #53, AND
#70 ARE CONNECTED TO GROUND, AS PER S100 STANDARDS, IEEE TASK
696.1/D2. THESE PIN CONNECTIONS DO CAUSE INTERFERANCE WITH IMSAI
FRONT PANEL SYSTEMS OR CPU BOARDS DESIGNED TO OPERATE WITH FRONT
PANELS. IT IS PERMISSABLE TO CUT THE FOIL LINKS CONNECTING PINS
#20, 53, AND 70 TO THEIR RESPECTIVE PLATE-THRU-HOLES. PLEASE
VERIFY IN YOUR SYSTEM DOCUMENTATION THAT THESE PINS ARE CAUSING
INTERFERENCE BEFORE CUTTING.
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SUBJECT: ENGINEERING CHANGE NOTICE # 2.
PRODUCT: DOUBLE D DISK CONTROLLER.
REVISION: BAND C REVISION BOARDS.
DATE: AUGUST 4, 1980.
A REVIEW OF THE DOUBLE D 8" PHASE LOCKED LOOP HAS BEEN
COMPLETED. THIS HAS RESULTED IN A RESELECTION OF SOME COMPONENT
VALUES. ENHANCED OPERATION, PARTICULARLY IN DOUBLE DENSITY, WILL
BE REALIZED WITH THE FOLLOWING MODIFICATION. THIS MODIFICATION
WILL DOUBLE THE LOOP CAPTURE RANGE AND ALSO ELIMINATE A CAUSE OF
LOOP INSTABILITY.
WITH THE EXCEPTION OF Rl, JUST CHANGE THOSE RESISTORS LISTED
FOR THE NEW VALUES AS SHOWN IN THE LIST. Rl DOES HAVE A CHANGED
VALUE BUT ALSO MUST BE INSTALLED SO THAT IT WILL CONNECT TO +5
VOLTS REGULATED INSTEAD OF THE PREVIOUS CONNECTION TO VX. WITH
CAREFUL LEAD BENDING AND RESISTOR PLACEMENT, ONE LEAD CAN SOLDER
TO THE +5V FOIL RUNNING FROM PIN #16 OF IC lA TO PIN #16 OF IC
lB. IT WOULD HELP TO SCRAPE SOME OF THE SOLDER MASK AWAY BEFORE
SOLDERING Rl TO THIS FOIL. VX WILL NOW MEASURE ABOUT +5.0 VOLTS.
INSTALLATION OF THE MODIFICATION WILL REQUIRE RETUNING THE PLL.
Rl 6.8K 1/4W (TO +5V) R42 470K 1/4W
R3 12K 1/4W R43 2.7K 1/4W
R4 10K 1/4W R49 JUMPER
R38 20K 1/4W
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