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PS/1 - 2155A 81A/76C/86C/72E/82E/ 24M/74T/84T/88V System Information

Applicable to: United States

PS/1 - 2155A System Information

2155A System Architecture

Advisor	81A
Investor		88V
Consultant			24M
Processor	486SX / 25	486SX / 25	486SX / 33
Cache / Max	NA	NA	0 / 256KB
Video Chipset	CL-5424	CL-5424	CL-5428
VRAM / Max	512KB / 1 MB	1 MB / 1 MB	1 MB / 1 MB
Disk Drives	Combo*	Combo*	Combo*
Hard Drive	170 MB	340 MB	253 MB
Memory / Max	4MB / 64MB	4MB / 64MB	4MB / 64MB
CD-ROM	Matsushita	Matsushita	Matsushita
Sound Card	Soundblaster 16	Soundblaster 16	Soundblaster 16
Modem Speed	2400 bps	2400 bps	2400 bps
Fax Speed (s/r)	N/A	N/A	9600/4800

Consultant	76C	86C
Expert	74T	84T
Essential	72E	82E
Processor	486SX / 25	486SX / 25
Cache / Max	NA	NA
Video Chipset	CL-5424	CL-5424
VRAM / Max	1 MB / 1 MB	1 MB / 1 MB
Disk Drives	3.5"	Combo*
Hard Drive	170 MB	253 MB
Memory / Max	4MB / 64MB	4MB / 64MB
CD-ROM	Matsushita	Matsushita
Sound Card	Soundblaster 16	Soundblaster 16
Modem Speed	2400 bps	2400 bps
Fax Speed (s/r)	N/A	9600/4800

*The Combo drive integrates a 5.25" and a 3.5" diskette drive into a single 5.25" enclosure.
Cache denotes installed external cache, VRAM denotes installed video memory, Memory denotes installed system memory, Max denotes maximum expandability. Fax speed is listed only on machines whose modems have fax capabilities and are listed as (Send/Receive) bps.

Regular system memory is upgraded with 36-bit or 32-bit (parity or non-parity) industry standard 70ns 72-pin SIMM chips. If the machine has 2 SIMM sockets, it can handle up to a 32MB SIMM in each socket. If it has 4 SIMM sockets, it can handle up to a 16MB SIMM in each socket.

Video drivers for these machines are available on IBM's FTP site
You can download the Windows 3.1 driver for the CL-GD5424 chipset at ftp://ftp.pc.ibm.com/pub/pccbbs/ps1/c5422_24.exe
You can download the Windows 3.1 driver for the CL-GD5426 chipset is at
ftp://ftp.pc.ibm.com/pub/pccbbs/ps1/c5426_28.exe

To upgrade cache memory on machines that have that capability (see product matrix), you will need to add either 4 (in bank 1 for 128K) or 8 (in both banks for 256K) 28-pin 32K x 8, 25ns SRAM modules. You will also need to add the appropriate TAG chip (32K x 8, 20ns SRAM for 256K ; 8K x 8, 20ns SRAM for 128K). If you are adding 256K of cache, you will also need to move the cache jumpers as shown below.

All of these machines use a standard IDE controller. This interface should support any standard IDE device. Some Enhanced IDE (EIDE) devices (namely hard drives larger than 528MB) may be able to function with the use of disk overlay software, normally supplied by the drive manufacturer, but is not supported by IBM. Though EIDE CD-ROMs are not supported on these machines, a CD-ROM with it's own ISA interface controller should work. Any ISA card (CD-ROM controller, modem, SCSI card) added to these machines needs to be non-"Plug and Play" to help insure compatability.
Machines that are capable of video memory upgrades require a 40-pin ZIP DRAM module configured as 256K x 16, which gives an additional 512K of video memory.

Processor Upgrade Matrix

Model	CPU	Upgrade Processor	Installation Notes
2155 81A	SX25	487SX, P23T-50	J23: 1-2, J24: 1-2, J25: 2-3
2155 76C	SX25	487SX, P23T-50	J23: 1-2, J24: 1-2, J25: 2-3
2155 86C	SX25	487SX, P23T-50	J23: 1-2, J24: 1-2, J25: 2-3
2155 72E	SX25	487SX, P23T-50	J23: 1-2, J24: 1-2, J25: 2-3
2155 82E	SX25	487SX, P23T-50	J23: 1-2, J24: 1-2, J25: 2-3
2155 24M	SX33	487SX, P23T-66, P24T-83	J23: 1-2, J24: 1-2, J25: 2-3
2155 74T	SX25	487SX, P23T-50	J23: 1-2, J24: 1-2, J25: 2-3
2155 84T	SX25	487SX, P23T-50	J23: 1-2, J24: 1-2, J25: 2-3
2155 88V	SX25	487SX, P23T-50	J23: 1-2, J24: 1-2, J25: 2-3

The 487SX indicates the Intel 487SX math coprocessor. The P23T-50 or P23T-66 indicates the Intel 486 Overdrive Processor (50 or 66 Mhz). The P24T-63 or P24T-83 indicates the Intel Pentium Overdrive Processor (63 or 83 Mhz). If you are installing a Pentium Overdrive processor, an EPROM upgrade is needed. If your machine has 2 SIMM sockets, the EPROM FRU is 07H0993. If your machine has 4 SIMM sockets, the EPROM FRU is 07H1001. Under installation notes (Jxx: y-z), Jxx denotes a jumper and y-z denotes its position. Some machines do not have a J24 or J25, in these cases, only check J23's position. These are the only processor upgrades supported by IBM for these machines.

Phone Support for these machines is available from IBM on a fee basis over the IBM Club's 900# (1-900-555-2582). The first minute of this call is free, each additional minute is charged to your phone bill at a rate of $2.99/minute.

	Search Keywords	PS/1, 2155A
	Hint Category	System Boards, Processors, Jumper/Switch Settings, Technical Specifications
	Date Created	23-03-98
	Last Updated	19-02-99
	Revision Date	19-02-2000
	Brand	IBM Aptiva
	Product Family	PS/1
	Machine Type	2155
	Model	81A; 76C; 86C; 72E; 82E; 24M; 74T; 84T; 88V
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