🚀 go-pugleaf

Dieter Lohrstraeter (lohrst@quantum.de) schrieb:

> Nun hoerte ich dass es beim B2000 Rev 4.x Timingprobleme gegeben hat,
> die mit einem Rework zu beheben sein sollen.

Im folgenden das 4.x -> 4.5 Rework, dass Du auf eigene Gefahr an Deinem
A2000 ausfuehren kannst. Ferner gibt es noch ein 6.x -> 6.2 Rework,
das in Teilen auch fuer Rev 4 Platinen anwendbar ist (habe ich nicht
greifbar im Moment). Viel Erfolg!

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This is certainly not the latest, but it is about upgrading older A2000
motherboards.  do all the mods described here at your own risk.

 
From "An Update for the Service Technician"  Issue 25 (Apr/May/Jun '89)
by Commodore-Amiga. 
 
25/3-1.1 A2000 PCB FIELD UPGRADE TO REVISION LEVEL 4.5 
 
The following instructions detail the changes which must be implemented
to upgrade a U.S. manufactured A2000 PCB from revision 4.0 (or higher) to  
revision 4.5. Field upgrades are NOT recommended on rev. 3.X PCBs. 

1) The following components will either not be installed, or will be
   removed if installed. 
   R901, C917, C902 (should not be installed, located left of CN601, last 
                     expansion connector on Amiga bus, near pin 1.) 
   C910, C911       (fix for Hytek keyboards, located off keyboard
                     connector, CN300.) 
   C905, C908       (C908 located above crystal X1, C905 located below
                     Gary pin 20.) 
   C230, C240       (located above U204, U303, the two ICs between the
                     34 pin drive connector and the 8520 U301.) 
 
2) 1.2 Kickstart ROM is replaced with 1.3 Kickstart ROM (1.3 ROM is
   P/N # 315093-02). 
 
3) Install RP904, RP905, RP906 only if U205 and U206 are 74HC244 type
   ICs (resistor pack is 4.7K ohm X 5, 6 pin, P/N # 902441-31). Do NOT
   install if U205 and U206 are HCT type 244. RP905 is located between
   U205 and U206, RP906 is located between Paula and Denise, RP904 is
   located to the right of Denise. 
 
4) Add .01 uF capacitor on J300. Add this capacitor on solder side of
   PCB, from pin 2 (middle pin on connector) to ground (use either of
   the ground pads located, on the solder side, down and to the right,
   above Paula between pins 46 and 48). 
 
5) Add 3.3K ohm resistor to U605, from pin 11 to pin 20. 
 
6) Add 470 ohm resistor to D800, cathode side, to the second pad from
   the left, under CN605. (D800 is located to the left of the real time
   clock IC at U801). 
   NOTE: On rev. 4.3 and above this resistor is on PCB as R1000,
         located to the left of Q302. 
 
7) If R5719 is not present (located off pin 1 of CN400, power connector),
   add a 470 ohm resistor between VCC and CPU side of R106. (Use pad
   located to the right of U100, the 68000, between pins 11 and 12, and
   the pad on the ground trace which runs under pin 14 of the 68000). 
 
8) Replace Gary IC, the 5719, at U102, with a MOS manufactured type, if
   it is a Toshiba manufactured type. Part number for Gary is 318072-01. 

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-- 
| Ciao!   /// Niels Knoop ///  e-mail:
  niels@rbg.informatik.th-darmstadt.de |
                                      --