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A Surgical Guide to the Amstrad Notepad Computer
By Hans Boehling
An extract from the full article on Hans Boehling's website
How to open the NC100
Before dis-assembling the Notepad you should save all your data! Then put your Notepad on the table face down. Remove the four AA batteries (if fitted), then unscrew the five screws (one under the battery cover).
In Figure 1 below they are marked with a '*' sign.
One screw fixes the cover of the firmware EPROM. Place the Notepad the right way up and lift off the upper part of the case. Be careful, because the display is still connected to the main-board via a folio-flat-cable and so is the speaker! Don't be nervous, the cables can be simply pulled out of their sockets. Now you can separate the covers.
What's inside?
Inside the NC100 is a SMD layout. I have a German NC100 and the plate is labelled Amstrad plc 4500-001P-1, NA999-32142, manual marked C (A-H) and 1 (1-8) . All IC's are SMD apart from IC303 which is on the backside of the NC100 (behind the firmware EPROM cover). On the drawing below I have labelled all IC's :
The table below gives a description of the IC's in the NC100 :
| IC-# | Label | Pins | Description |
|---|---|---|---|
| 301 | ZILOG Z84C0006FEC Z80 CPU |
4*11=44 PLCC 44 |
Z84C00 CMOS 6MHz Z80 compatible microprocessor |
| 302 | NEC Japan D65034GD093 |
4*34=136 PLCC 136 |
µPD 65034 ??? |
| 303 | NEC Japan D27C2001 |
2*16=32 DIL 32 |
27C001 CMOS EPROM 256K*8 bit Firmware EPROM |
| 304 | NEC Japan D43257AGU-10LL |
2*14=28 SO 28 |
µPD 43257 A = CMOS SRAM 32K*8 bit Memory layouted as an SO 32 (32 pin)! |
| 305 | NEC Japan D43257AGU-10LL |
2*14=28 SO 28 |
µPD 43257 A = CMOS SRAM 32K*8 bit |
| 307 | T 9224 HB 8521 AM |
2*10=20 SO20 |
TC8521 Real-Time-Clock |
| 308 | NEC Japan D71051 GU |
2*14=28 SO 28 |
µPD 71051 UART (parallel to serial converter) |
| 309 | NEC Japan D4711 AG |
2*10=20 SO 20 |
µPD 4711 RS232-driver (shift level to /- 10V) |
| 310 | Not placed | 2*7=14 SO 14 |
Labeled on the layout as HC08 (74HC08?) |
| 311 | D4584G | 2*7=14 SO 14 |
4584 CMOS-Logic 6xSchmitt-Trigger |
| 312 | C339 G | 2*7=14 SO 14 |
??? (Could be LM339 which is 4xComparator) |
| 313 | D4013G | 2*7=14 SO 14 |
4013 CMOS-Logic 2xD-Flip Flop with set and reset |
| 314 | D4584G | 2*7=14 SO 14 |
4584 CMOS-Logic 6xSchmitt-Trigger |
The final questions
- I have read out the firmware EPROM of my German NC100. I have version 1.06.
- Is this the last version? Who can send me the English firmware? (BIN or HEX file)
- Who knows something about IC302 (µPD 65034)?
Thanks... Hans Boehling
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You can send email to Hans Boehling at H-Boehling@gmx.de and visit his website at http://home.nexgo.de/h.boehling where you can find the full version of this article, plus more information on each of the IC's mentioned in the table above (including pin-outs).
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