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Sothius' Home-Museum- AMIGA-Amiga 500 Plus-additional pictures

Amiga 500 Plus
Additional pictures. Note that loading the page could take a while...
(pictures copyright by M.A.Grundke)

A500 Plus serial number (27 KBytes)
C= COMMODORE
MODEL A500PLUS
SERIAL NO. 213404
A500+ MA 0105291363642002114508


A500 Plus board overview (70 KBytes)
A500 Plus REV 8A board-overview:
On first sight (and in most other cases also on second), this is an 'ordinary' A500-board (which normally is completely shielded, of course). Let's go through from left to right. There, you can see the machine's 85 pin expansion slot, and the CPU (U1) to its right. Above them is Denise (U4) with some video output logic. Next to the CPU is the Kickstart ROM (U6), and the RAM bank's left side below it (8 pcs. 256Kx4, U16-U23). Following the RAM bank further to the right, we're under a board-inscription (A500+), with Fat Agnus (U2) above it. Moving further up, there are Paula (U3) and one of the CIAs above her ('ODD CIA A' at U7). Right from that is the 'EVEN CIA (B)' at U8, with Gary (U5) below it. Between the two CIAs, by the way, are the Motorola MC1488 & MC1489 (U38, U39) responsible for serial communications (RS232). Now below Gary is one of the above-mentioned differences to the 'standard A500': a battery backed-up clock (just above the internal expansion port). On the board's right side are two silkscreenings and two stickers. That's were the internal floppy disk drive resides normally , that is, if some maniac hadn't removed it :-D


A500 Plus board-info part 1 (46 KBytes)
board silkscreening, part 1:
C=A500 +


A500 Plus board-info part 2 (20 KBytes)
board silkscreening, part 2 (below floppy drive):
ARTWORK 312815
PCB FAB 312814
SCHEMATIC 312813
PCB ASSY 312812
© COPYRIGHT --
1991 COMMODORE


A500 Plus board-info part 3 (36 KBytes)
board silkscreening, part 3:
B52/ ROCK LOBSTER
GRR/ JSP/ FISH/ NINES
RVW/ VFA/ DCA/ WILSON
AJM/ CJW/ TC/ SMK/ BCN
ITOH/ PRY/ F+F/ LOLLI
C=A500+ REV 8A


MC68000 & expansion port (41 KBytes)
The Motorola 68000. When the A500 Plus was announced, it was rumored it'll have a faster CPU (MC68010 or MC68020), but it didn't come true... Behind it, however, the 85 pin expansion-port


CSG 8375 Fat Agnus (45 KBytes)
The CSG 8375 is the same as the MOS 8372B which is used in the Amiga 3000's ECS. It allows the A500 Plus to have 2 MBytes ChipRAM onboard


RAM bank (51 KBytes)
The A500 Plus' RAM bank, which is another difference from a 'standard A500', since it consists of 8 pcs. 256Kx4-RAMs for a total of 1 MByte. Earlier A500 and the A500 REV.8 which used the same board like this A500 Plus, came with 4 pcs. 256Kx4 only (probably there were also machines with 8 pcs. 128Kx4). Now the difference is that you could expand these older A500 by just soldering in these additional RAMs, but then you couldn't use an internal memory expansion (like the A501) anymore. Now the A500 Plus can! With the A501+ expansion, ChipMem grows to the full 2 MBytes the 8375 can handle


Kickstart v35.175 (31 KBytes)
This is the Kickstart 2.04-ROM C390979-01, v37.175. With 512 KBytes it's twice the size of Kickstart 1.2/1.3, and has lots of useful enhancements like ECS-support a 3D-look GUI and many others. v37.175 was also used in the Amiga 3000. Interesting in this context is that the Amiga 600 had Version 37.300, which was slightly modified for the A600's PCMCIA-capability


CBM 6570 (32 KBytes)
Another 'standard-IC' in the Amiga-series is the CBM 6570, which most of them use as keyboard-controller. In the A1200, however, this chip is replaced by the so-called 'keyboard-MPU' which resides directly on the motherboard (the 6570 was always with the keyboard)


CSG 8373 ECS Denise (47 KBytes)
CSG 8373 is the ECS-version of MOS 8362 'Denise', with video output circuitry before it. Denise introduced some new resolutions such as Productivity (640x480, 640x960) and SuperHiRes (1280x256, 1280x512), and was introduced with the Amiga 3000


CSG 8364 Paula (34 KBytes)
CSG 8364 ('Paula') has never changed in the whole Amiga-family, it was even found in the latest machines (Amiga 4000(T), CD³²)


CSG 8520PD CIA (40 KBytes)
The same for the 8520 CIA: all Amigas have two of them for I/O (although in the CD³² they're integrated in 'AKIKO'). The ones found here are called 'CSG 8520PD'. Below this one here, the machines' floppy connector


CSG 5719 Gary (36 KBytes)
CSG 5719, 'Gary', is present in all OCS/ ECS-machines (in the A3000 as 'Fat Gary') and handles some logical operations. It also controls the floppy-motor (e.g. stepping control)


A500 Plus clock (45 KBytes)
Clock-circuits and battery found on the A500 Plus' board. In the older A500s, the A501 memory expansion contained battery-backed up clock and clock circuits. On the lower right you can see part of the internal expansion port (e.g. for A501+ memory expansion)


Sothius' Home-Museum- AMIGA-Amiga 500 Plus-additional pictures