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The Memotech MTX Series

Memotech Compact Flash System

MAGROM - Special Fit

 

Courtesy of David Kimberlin-Wyer

 

Introduction

I wanted to put the MAGROM inside the case of my MTX500, but as it already had Andy's MTX Memory Card, a few modifications were needed to accomplish this. Dave had already managed to connect the memory card with the CFX ( http://primrosebank.net/computers/mtx/projects/cfx/cfx_special.htm ) so this paved the way for my modification.

As with Dave's modification, I used the same 2 row, 64 pin DIN 41612 connectors, which he very kindly shipped over to me as I had trouble locating them over here in the US.

 

The first task is to remove the right hand edge connector of the memory board. I cut just on the right angle which leaves enough of the metal pin behind for removal.

This was repeated along the first row.
Cutting as close to the edge connector as possible, I removed the remaining bits of metal. This makes accessing the pin using long nose pliers a lot easier.
This is my new soldering station - a Hakko FX-888D.

I cannot recommend it enough. It has transformed my soldering skills immensely. No more horrible looking "blobs".
To remove the pin, I heated the solder joint until it melted and gently removed it using the long nose pliers.
As one hand was holding the camera, I can't show the soldering iron melting the solder at the same time the pin was removed. You get the idea.  

This was repeated for the remaining cut pins.
The second row was a bit tricky to cut, but I was able to twist the edge connector up slightly to allow me to cut the pins as close to the connector as possible.
Connector removed. I started cutting the pins too close to the board which made them a bit tricky to remove before I twisted the connector as shown here.
My Rolson Helping Hand makes extracting the pins a breeze as it keeps the memory card steady and the magnifying glass allows me to see what I'm doing!
All pins removed.

Next job was to clean up the solder holes so that the new connector pins can be installed.
I placed a small bead of flux on each of the filled holes as it helps in the removal of the excess solder.
Using a solder wick, I went over each hole in turn.

The wick acts like a sponge soaking up the excess solder and clearing the hole
With all the solder removed, the board was almost ready for the new connector, but the burnt flux had to be removed first using isopropyl alcohol, available from most good chemists.
Looking good!

(Ed. Good as new in fact -well done David)
The 64 pin DIN connector has 4 extra pins that need to be removed and after checking, double checking and triple checking that the right ones were selected, they were cut off.
All four pins removed.
This procedure was mirrored for the other connector, once again, checking , double checking and triple checking the correct ones were selected as I didn't have spares if a mistake was made.
Four pins removed from the other connector.

New connector soldered into place.
As with Dave's modification, three patches R0 to R2 had to be soldered between the edge connectors.

Also, during testing it was found that another patch between pins 30, the GROM, was also required.
The second edge connector soldered into place onto the MAGROM.
Underside of the two boards.
Connected together.......
It's worth noting that the edge connector needs slots cut out from each end to make it fit over the board on the inside.

(Ed. with the slots cut, it is important that the slot key in position 5 is present to prevent misalignment when fitting the board !)
...... and fitted neatly inside the MTX500.
Up and running!

 

 

 

References:

1 Andy Key's Memotech Hardware page

2 Que Publishing, Upgrading and Repairing PCs, 21st Edition, ISBN-13: 978-0-7897-5000-6. Sample Chapter : The ATA/IDE Interface

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