32K EPROM to 512K Flash Card

Owned by Vic Gerhardi
Last updated: Mar 09, 2017
4 min read

https://tinyurl.com/hz4xuph

Introduction

EPROM cards are becoming useless as they do not offer much storage.

Benny Boogaert has modified several 32K EPROM cards to 512K Flash cards.

Components used

ComponentManufacturer Part NoOrder CodePriceMin Qty

AMIC - A29040C-55F - MEMORY, CMOS, 4MBIT, DIP-32

A29040C-55F

Farnell2.76
1

0,2 or 0,25mm Kynar wire





Bison polyurethane professional





Pattex Ethylcyanoacrylaat



This is what he did.

Modification to card



Instructions


Pull off the lid


round off the 4 plastic pins


cut some space around the pins


  • Drill 2 holes - 0.3 mm each
  • Strip the wire long enough to
    • push it from the bottom to the top,
    • bend it back
    • push it in the hole and then
    • into the copper strip.
  • Make it as flat as possible, applying a tiny bit of solder.

This is a very strong connection, which does not damage the copper track on the motherboard.


Connect the wires to the chip
and edge connector,
Only use a small amount of solder, leaving
as much of the gold connector as possible.
Make space for the little wires,
not too much as the plastic has
to push the PCB leading wires
around the holes.

Edge ConnectorWireChipSignal
37Green1A18
36Yellow30A17
22Blue31WE#
hole under
pin 30 		Blank32VCC
2Black3A15
1White2A16
Existing connection160v



Flatten the 32 pins and clean up copper.
They go through the pcb too far preventing
the cover to sit tight in it's place.


2 pieces of sellotape were used to keep the
top and bottom of the case tight to start with


one layer up front and one in back,
Tape should be tight and flat


Unfortunately, the tape loosened, causing bad contacts.

Solution - the following steps were taken

Glue the assembly with a small drop of polyurethane on

  1. the 4 plastic points (original holding points)
  2. the 2 sides that slip around the PCB connector
    of the Z88 slot with fast glue. Then
  3. let it dry under some weight for several hours.

The card worked super after that.


For the 4 black pins Bison polyurethane professional was used.
It has the tendency to expand (swell up).
Only a tiny droplet was used applied using a tooth-stick.
The case was kept under pressure of 1- 5kg/cm2 for 4 hours.
That made sure that it remained in the correct position.


For the side flaps, a quick glue, official name is ethylcyaanoacrylaat is recommended.

Patex was used but there are a dozen other brands.

This glue sticks within a few seconds and has to be applied at the last instance before pressing the plastic box together.


Here is the flash card being used for files.

Conclusion

Benny Boogaert has shown that it is relatively easy to build your own 512K Flash card for very little money. The difficult bit is getting the extra wires to connect to the gold connector without contaminating it with solder. Not an easy task.

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