NEC PC-9821Na7
Jump to navigation
Jump to search
- For more information, see this article's corresponding Wikipedia page: https://en.wikipedia.org/wiki/PC-98.
| This device is in the WorkNeeded:OriginalParts category because it was flagged as missing information on the original parts. It may have replacement parts listed but those cannot be assumed to be identical to the originals. If you have a list of the original parts, please feel free to add them by copying the relevant table from EditorsToolbox:Tables | 
|
| This device is in the WorkNeeded:ReplacementParts category because it was flagged as missing information on replacement parts. If it has the original parts listed you may be able to search for replacements using the parametric searches available from parts distributors. If you have or make a list of replacement parts, please feel free to add them by copying the relevant table from EditorsToolbox:Tables | 
|
| This device is in the WorkNeeded:General category because it was flagged as missing general information about the device. The information may be incomplete, using default text, or inaccurate and should be verified with external sources if possible. If you can add or correct information on this page, please feel free to edit it and do so. | 
|
NEC PC-9821NA7
| Preliminary Information | |
|---|---|
| Release Year | 1980 |
| Leak Risk | Medium |
| Batteries | None |
| Mounting Technology | Through Hole, SMD, BGA, Sockets |
| Capacitor Types | Aluminum Electrolytic, Tantalum, Ceramic, Polymer |
| Destructive Entry | No |
NEC PC-9821 series notebook.
Known Issues
Only powers on intermittently.
Causes
- Bad PSU, bad caps, leaking battery.
Solutions
- Unknown at this stage.
Battery leakage near memory socket.
The Ni-Cd battery for the RTC and settings can leak after time. Leakage can wick up the wires to the socket, and contaminate the memory socket.
The memory socket is a Hirose SX1BA-72S-0.635SH, but they are no longer available.
Disassembly Notes
Disassembly video: https://www.youtube.com/watch?v=VlzsPEkEGVc
Being old and brittle plastic, it's easy to snap the small clips when unhooking the sides and front.
Original Parts
Mezzanine board EMMM1 94V-0 / PDU66 / EHMDD955-4.
Soldered to the lower board.
| RefDes | Qty | Capacitance | Voltage | Mount | Diameter/Size | Height | Lead Spacing | Temp | Type | Brand | Series |
|---|---|---|---|---|---|---|---|---|---|---|---|
| C01?, C02 | 2 | 180 µF | 16V | TH | 6mm | 14mm | 2.54mm | 105 °C | Electrolytic | Panasonic | HFQ |
| C16, C18, C26 | 3 | 470 µF | 10V | TH | 8mm | 16mm | 4mm | 105 °C | Electrolytic | Panasonic | HFQ |
Lower board G8TXT Z C5B
PCB on the base of the computer, with the drive connectors.
All caps not listed here are SMD ceramic or tantalum.
| RefDes | Qty | Capacitance | Voltage | Mount | Diameter/Size | Height | Lead Spacing | Temp | Type | Brand | Series |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Unlabelled?
7K2 and 8K1 above it. |
1 | 220 µF | 6V | SMD | 8mm | Electrolytic | Nichicon |
Replacement Parts
Basic PCB Name
| RefDes | Qty | Compatible Part Number | Order Links |
|---|---|---|---|
| C01?, C02 | 2 | EEU-FC1E181BJ | Digikey Mouser LCSC |
| C16, C18, C26 | 3 | EKZE160ETD471MH15D / UPW1C471MPD6 | Digikey Mouser LCSC |
If parts are not available or different selection is preferred, you can use the values in the Original Parts section to perform a parametric search.
Kits
- Digikey BOM: https://www.digikey.com/