The T5200 has 2MB of memory soldered on board and an expansion SIMM board with 6 and a half SIMM slots but uses proprietary 40 pin SIMMs.
Here are details on a mod to add 8MB of RAM using a standard 72 pin 8MB Parity SIMM. (Requires at least 2MB of proprietary SIMMs already fitted)
Use this info at your own risk, don't blame me if you damage your T5200!
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The above shows both empty and fully populated boards with the proprietary SIMMs
The SIMM slots are numbered from left to right IS17 (A & B), IS16 (A & B), IS15 (A & B) and IS14 (parity)
SIMMs must be fitted in pairs as they are only 16 bits wide and the processor is 32 bits wide. Each pair of SIMMs gives a 2MB expansion so the memory can be expanded by 2, 4 & 6MB (2 + 2 + 2) however the centre pair of SIMMs can take a larger SIMM pair of 8MB giving a total of 14MB memory (2 + 8 + 2 of SIMMs plus 2MB on board). The RAM chips on the 8MB SIMMs are larger than those on the 2MB SIMMs and there was insufficient room for the Parity chips so they are fitted separately on the 30pin SIMM (IS14). Note although this is a 30pin SIMM it is a proprietary pinout.
The memory size is detected in order left to right, so you must have a 2MB pair of SIMMs fitted before you can fit the 8MB pair + parity.
This means you must already have 2MB of standard SIMMs fitted in order to do the 8MB mod described below.
If you don't have any additional memory you can still mod your system but it will be more complicated and will be discussed in another post.
First you need to obtain a standard 72 pin 8MB Parity Fast Page Mode (FPM) SIMM and some 40 way ribbon cable (e.g. an old IDE cable)
Then use hot melt glue to stick this SIMM to the edge of the parity socket (IS14) making sure no electrical contact is made:
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Note the above board already has the required 2MB of standard SIMMs fitted as mentioned above. (You could optionally fit another 2MB in IS15 as well to give the maximum 14MB after this mod.)
Before proceeding any further, make sure there is enough clearance to fit the board back in the T5200. (You will almost certainly need to dismantle the T5200 completely to fit it back in)
Rip the ribbon cable back to 36 ways and cut into two strips approx 15cm (6in) long. Then using a ruler and sharp knife, score a line about 2mm from the end of one of the ribbon cables and do the same on the other side (not the other end) then pull the 2mm strip of insulation off using a pair of blunt nosed pliers. This should leave 36 wires exposed on the end of the ribbon.
Solder the exposed wires to pins 1-36 of the SIMM and then repeat this for the other ribbon, soldering to pins 37-72.
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Then turn the board over and solder the ribbon wires to the centre connector (IS16) according to the following table:
(I suggest wiring all the data lines first as they are all straight with no wires crossing)
Wire 1 to Pin 8 (Ground)
Wire 2 to Pin 2B (Data 0)
Wire 3 to Pin 2A (Data 16)
Wire 4 to Pin 3B (Data 1)
Wire 5 to Pin 3A (Data 17)
Wire 6 to Pin 4B (Data 2)
Wire 7 to Pin 4A (Data 18)
Wire 8 to Pin 5B (Data 3)
Wire 9 to Pin 5A (Data 19)
Wire 10 to Pin 1 (+5 VDC)
Wire 11 Not connected
Wire 12 to Pin 6 (Address 0)
Wire 13 to Pin 7 (Address 1)
Wire 14 to Pin 13 (Address 2)
Wire 15 to Pin 14 (Address 3)
Wire 16 to Pin 24 (Address 4)
Wire 17 to Pin 25 (Address 5)
Wire 18 to Pin 31 (Address 6)
Wire 19 Not connected
Wire 20 to Pin 9B (Data 4)
Wire 21 to Pin 9A (Data 20)
Wire 22 to Pin 10B (Data 5)
Wire 23 to Pin 10A (Data 21)
Wire 24 to Pin 11B (Data 6)
Wire 25 to Pin 11A (Data 22)
Wire 26 to Pin 12B (Data 7)
Wire 27 to Pin 12A (Data 23)
Wire 28 to Pin 32 (Address 7)
Wire 29 Not connected
Wire 30 to Pin 1 (+5 VDC)
Wire 31 to Pin 33 (Address 8 )
Wire 32 to Pin 34 (Address 9)
Wire 33 to Pin 20B (Row Address Strobe 3)
Wire 34 to Pin 17B (Row Address Strobe 2)
Wire 35 to Pin 22A (Parity bit 3 - bits 16-23)
Wire 36 to Pin 22B (Parity bit 1 - bits 0-7)
Wire 37 to Pin 18B (Parity bit 2 - bits 8-15)
Wire 38 to Pin 18A (Parity bit 4 - bits 24-31)
Wire 39 to Pin 23 (Ground)
Wire 40 to Pin 16B (Column Address Strobe 0)
Wire 41 to Pin 16A (Column Address Strobe 2)
Wire 42 to Pin 21A (Column Address Strobe 3)
Wire 43 to Pin 21B (Column Address Strobe 1)
Wire 44 to Pin 17A (Row Address Strobe 0)
Wire 45 to Pin 20A (Row Address Strobe 1)
Wire 46 Not connected
Wire 47 to Pin 19 (Read/Write)
Wire 48 Not connected
Wire 49 to Pin 26B (Data 8 )
Wire 50 to Pin 26A (Data 24)
Wire 51 to Pin 27B (Data 9)
Wire 52 to Pin 27A (Data 25)
Wire 53 to Pin 28B (Data 10)
Wire 54 to Pin 28A (Data 26)
Wire 55 to Pin 29B (Data 11)
Wire 56 to Pin 29A (Data 27)
Wire 57 to Pin 36B (Data 12)
Wire 58 to Pin 36A (Data 28)
Wire 59 to Pin 40 (+5 VDC)
Wire 60 to Pin 37A (Data 29)
Wire 61 to Pin 37B (Data 13)
Wire 62 to Pin 38A (Data 30)
Wire 63 to Pin 38B (Data 14)
Wire 64 to Pin 39A (Data 31)
Wire 65 to Pin 39B (Data 15)
Wire 66 Not connected
Wire 67 Not connected
Wire 68 Not connected
Wire 69 Not connected
Wire 70 Not connected
Wire 71 Not connected
Wire 72 to Pin 35 (Ground)
Note if a pin has "A" on the end it has to be soldered to the "A" side of IS16 and "B" means soldered to the "B" side of IS16
If no "A" or "B" is mentioned then either side can be used as they have the same signals, however note that the "A" and "B" sides have independent drivers so they are not connected together electrically. (The "A" side is the one closest to PJ1 - see second photo below)
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Note that wires 1 & 72 in this picture are connected to alternate ground points, not the pins detailed above.
Another view showing "A" and "B" rows :
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After finishing, double check your wiring and if you have a multimeter, do the following tests:
First make sure +5v and ground aren't shorted together, then check continuity between +5v on the pcb (e.g. the + side of the electrolytic capacitor) and the wires going to the 8MB SIMM listed above as +5v. Do the same for the ground lines.
Finally connect the board up, power up and hopefully your BIOS will detect the extra RAM.