PCjr cartridge PCB for single 64K or 32K ROM

PCB for making your own IBM PCjr computer cartridge.

  •  PCB Component side
  •  PCB Solder side
  •  Configuration
  •  Bevel and finish
  •  Fits in original cartridge cases
  •  Example use with a 32K EEPROM
  •  Example use with a 64K EPROM
  •  Packaging (front)
  •  Packaging (reverse)
  •  Schematic
  •  In-use on a PCjr

Description

This is a PCB for making your own cartridges for the IBM PCjr computer! Perfect for development, making reproductions or publishing your own game. The PCBs accepts a single 32K or 64K (E)EPROM and are configured using solder blobs. To use a 64K EPROM, a 74LS08 AND gate is also required.

The edge of the board with the contacts is beveled at a 30° for smooth insertion and the surface finish is ENIG (Immersion Gold). While not as good as hard gold, it is arguably superior to HASL (Hot Air Solder Leveling).

Design note: Many similar PCBs use two 32K ROMs instead of a single 64K ROM as this one does. The rational behind this design choice is that there are less pins to solder in total (saves assembly time) and the fact that a new 64K OTP EPROM actually cost less than a pair of 32K EPROMs! Saving money and time is good right?

Supported chips:

Tested chips include:
  • Atmel AT27C512R (64K OTP EPROM)
  • Atmel AT27C256R (32K OTP EPROM)
  • Winbond W27E257-12 (32K EEPROM)
  • ST M27C512 (64K UV-erasable EPROM)
  • NM27C512 (64K UV-erasable EPROM)
Naturally, many other chips will work too! According to the PCjr technical reference manual, the access time must be of 250ns or less. You will also need to make sure your EPROM programmer can program the chip you will use..

Non-included parts:

At the moment we only sell the PCBs. We do not provide EPROMs, capacitors or other chips. Besides your own (E)EPROM chip, you will also need to provide:

  • 0.1 µF Ceramic capacitors. Suggestion: AVX SR205C104KAR (Digikey 478-3187-ND)
  • 10 µF Electrolytic capacitor. Suggestion: Nichicon UVR1C100MDD1TD (Digikey 493-12763-1-ND)
  • 7408 AND Gate. Suggestion: Texas Instruments SN74ALS08N (Digikey 296-1484-5-ND) Only if a 64K ROM is used
  • 28 PIN DIP IC Socket. Optional, for developement

This is an implementation of the following raphnet.net project: PCjr cartridge

Ordering

Buy here

In stock : Ships within 5 business days unless noted otherwise (out of stock, pre-order, holidays, etc).
The raphnet online store is temporarily closed for 5 weeks, from February 10 (2025) to March 17.

New orders will be accepted from March 10 but shipping will only resume on March 17.

Item #PCJR-64K-CART-PCB
DescriptionPCjr cartridge PCB for single 64K or 32K ROM
Price
1...2$7.99 Each
3...4$6.39 Each (20% OFF)
5...9$5.99 Each (25% OFF)
10...24$5.59 Each (30% OFF)
25+$4.00 Each (50% OFF)

We normally ship within 5 days (excluding week-ends and holidays) after payment.
Prices are in US dollars and are subject to change without notice.

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