External Cards

Card edge interface

The weakest link in the Z88 is the connector between the Z88 and the cards. The card edge interface has a long and successful history: for example, in PCI and ISA. Gold is normally used to make sure that it is a reliable connector, but for a number of reasons, this was not used on the Z88 cards. This gives a range of problems including

• Solder contamination
• Corrosion effects
• Physical damage

These effects may be reduced by not removing the cards often. This is now possible as RAM cards should not be removed and Flash cards are erased in the Z88 itself.

Mechanical Failure

There are two sorts of mechanical failure that make the Z88 behave badly.

The first sort gives you unexplained "Memory stack overflow" or FAIL messages at the top of the screen. The most common fault that causes this is when the RAM or Flash card physically comes apart. You will notice this when removing the card from the Z88. It may be a loose fit. What you should find is that the RAM card is made up of two halves and these are coming apart.

You can repair this by

1. Pressing the RAM or Flash card together and wrap a strip clear sticky tape (one inch wide) around the outside the pack, near the connector. This should force the card together and will make better contact with the Z88 when plugged in again.
2. If this works, consider using `SuperGlue' around the edge of the card and squeezing it shut.
   If this method is used, bear in mind that it will not be possible to do any future repairs without breaking the card case apart.
   Remember not to get your fingers stuck, as these are not required with the card.

The second sort is that the Device just stops working due to the 'gold' contacts becoming dirty. 

The easiest way of doing this is by sliding the card in and out of the connector a few times. If this doesn't improve its performance use a very soft pencil rubber and clean both the connector in the Z88 and the 'gold' contacts.

Be careful though, There is not a lot of 'gold' used on the connector, it is only 'mechanical gold' and you might find that you can clean it off altogether!

Testing RAM Cards

Another type of failure is when part of the memory doesn't act like memory. This leads to inconsistent results when checking the size of the Ram with ( CARD). For example, you may have a 512K RAM card in your Z88 but ( CARD) reports that you only have 128K. See Check Z88 Cards.

This program tests 32K, 128K 512K and 1MB RAM cards.

Main Prerequisites

Items Required	Description
	A blank 32K EPROM Card to store the applications or files.
	(Optional) EPROM Eraser to erase the EPROM card (if required).
	Connecting the Z88 to the Desktop to transfer the programs to the Z88. See Computer Links for more details

Download Memtest

Memtest, consists of four files.

• 30aug 1988.z88 - the original instructions which reads as follows:-

             |Procedure;
 30 AUG 1988 | 1) -Insert EPROM into slot 3, RESET Z88.
             | 2) -RESET Z88, when the screen prompts for the size of 
    RAM TEST | card to be tested 32,128 ( 512, works ). Open the 
             | flap and insert RAM card into slot 1.
             | 3) -Press the SPACE bar to start. To test again

 (2)

• the boot.CLI file 
• RAMCARD.BAS - the memory test software 
• RAMTEST.CLI - a copy of boot.cli

from here, unzip and transfer them to your Z88 with a transfer program

There are two ways you can use this program.

1. Just running the BBC BASIC program (Ramcard.bas)
2. Before using the program, save "RAMTEST.BAS," 30aug 1988.z88 and BOOT.CLI to an EPROM.

#F
|EF
RAMTEST.BAS~E~E
#B
CHAIN
"RAMTEST.BAS"~E

Memory test

do the following:-

1. Back-up all your files.
2. Take out the RAM pack.
3. Put in the EPROM with the three files BOOT.CLI, RAMTEST.BAS and 30aug 1988.z88 in it.
4. Do a Hard Reset.
5. When you get the Command line "Size of card to test? (in KBytes, Eg. 32, 128 etc.)"
    
6. Type in the number of K the RAM card is.
   
   
7. Put the RAM card in Slot 1.
    
8. Press the key until you get the "Testing . . . " message.
    
   whilst the program is running, `tapping' the RAM card underneath may expose any mechanical fault.
9. When the test is finished,
    
10. Remove the EPROM pack and
11. Do another Hard Reset.

Soft Memory Errors

The other sort of memory failure is where certain bits of memory suffer amnesia when you are not reading or writing to the memory.

This is like when you are just storing files in the RAM.

This fault can be found with any program, (zCheck, Zip, Unzip (Z88 Forever) or SqueeZ~88 (Rakewell)) that uses checksums on files. To use it you should:-

1. Run the program initially so that the checksums of the files are calculated. If you are using SqueeZ~88 or Zip, squeeze/Zip a load of big files.
2. Turn off the Z88 and leave it alone for about three to five days.
3. Re-run the program to see if the checksums of the files are different or unsqueeze/Unzip all the files again. If they are, then the RAM where the file was stored is faulty.

Test RAM with big file

A quick way to check the memory is to load a large file and see if it is readable.

The example here is using

• a standard British Z88.  
• a 512K/512K Flash/RAM card with OZ 4.5 B4 is in Slot 1. 
• flash.txt file that is supplied on and with the Flash cards.

The procedure is as follows:-

Select Flashstore  J

Move the cursor over the flash.txt file name. Press the  key.

The following screen appears, Press the  key.

Use the directed keys to exit the application.

Reading a file in Pipedream

Select PipeDream  P

 FL (File Load)

Select Filer  F
Move the cursor over the flash.txt file name if you are testing the memory
Press the  key to mark it.

Or move the cursor over the eprlog file name if you are using the Flashtest file
Press the  key to mark it.

Press the  key to return to Pipedream's file load page. Notice that :RAM.1/flash.txt or eprlog has been entered from the Filer.
Move the cursor down to 'Load as plain text'
Change it to 'Y' 

Press the  key to Load the file into Pipedream.

Select   to display the bottom of the file

Select   to display the top of the file again. If this all works, it is looking good.

Testing Flash Cards

Introduction

When Flash cards are assembled, they need to be tested to ensure that all the connections are made and chips are working correctly. Flashtest has been designed to test four different types of flash cards in the Z88. These are:-

• 1M INTEL
• 1M AMD
• 512K AMD
• 512K AMIC

If the RAM is detected in the 512K cards, a RAM test is also run.

Blowing Flashtest

A 32K EPROM card is being used to store two applications that are 16K each. These are Flashstore and Flashtest.

Prerequisites

These are the same as the Main Prerequisites as above.

Download Flashtest 32

Unzip Flashtest 32, the file and transfer the five files to the Z88.

The Z88 needs to have the following cards as a minimum configuration.

• Slot 1 needs to have at least 128K
• Slot 3 has a blank 32K EPROM card to blow the two applications.

Slot 2 may have another Flash card with the Computer Link in it.

The files are shown here displayed in the Filer are:-

• FLASHEPROM.62 &.63 - These are the image files for Flashtest and Flashstore.
• Romcombiner.bas, .bin & RomUtil.bas - These files are required to blow the image to the EPROM card.

Running RomCombiner

To run the program, do the following:-

• Select BBC BASIC B. Type
• RUN "ROMCOMBINER.BAS"

The following screen is displayed.

EPROMs can only be programmed in Slot 3.

Verify EPROM banks properly erased

Press V. followed by

• F
• 32

If the EPROM is properly erased the following screen is displayed.

If an error message is displayed, the EPROM should be removed and erased again with the EPROM Eraser until it passes this test.

Blow image files to blank EPROM

From the main screen, Select

• B
• 3 and then the Card name
• FLASHEPROM
• F

The screen will flash a few times until the following screen is displayed. If any programming errors are given, the EPROM will need to be erased and this procedure needs to be repeated from Verify EPROM banks properly erased.

• Select
• Open the Card Flap
• Remove the 32K EPROM card from slot 3
• Close the Card Flap
• Open the Card Flap
• Insert the 32K EPROM in slot 2
• Close the Card Flap
• Press the key to display the two new applications at the bottom of the list

Running FlashTest

Configuration RAM ROM FLASH

• Flashtest needs an expanded Z88. There needs to be at least 128K RAM in slot 1 in s standard machine,
• The Flashtest and Flashstore Applications are in the 32K EPROM card in slot 2.
• The Flash card under test is in Slot 3.

Starting Flashtest

Flashtest is either selected from the INDEX screen it in the APPLICATIONS window, or use ZT to start it directly.

otherwise the stating screen will be displayed.

Testing 1M Flash

Depending on the size and type of Flashcard is being tested, different start screens will be displayed. This happens too quickly to screen capture but at the end of the test a summary is displayed. This is for the 1M INTEL card.

This is for the newer AMD card.

To view the full report, which has been saved in a file can be viewed using Pipedeam.

The top part of the report, followed by

the end of the report.

Testing 512K/512K Flash/RAM

When testing this size, it is done in two parts. First the Flash chip, followed by a choice on whether to test the RAM.

Testing the RAM takes some time, but eventually the summary page will be displayed.

To view the full report, which again has been saved in a file can be viewed using Pipedeam.

The top part of the report, followed by

the end of the report.

Faulty Card?

You can contact Rakewell and see if it can be repaired.