J.E.Lawrie HINTS-26. OZ4 Operating Chip. Before production of the Z88 was stopped it had been intended that the OZ3 chip would be replaced by an OZ4. This probably never happened but the chip was made available through the Z88 Users' Club (now defunct) at about £25. The chip could only be fitted in place of the OZ3 if that was plugged in to a 32-pin socket, not a 28-pin, unless one was very brave and very expert in soldering a 32-pin chip on to a printed circuit board ! Everyone I have spoken to, who has tried the OZ4, has been very happy with it. I have tried FOUR, two on each of two Z88s and I got more trouble in two days than I had had in two years so I'm not a great believer. This is what the OZ4 does - Prevents "in use" errors in the Filer It is possible with the OZ3 to insert and remove ROMs with the machine off - this is not good. Now it wakes the machine as the card slot is opened. Updating the PrinterEd will not cause a FAIL. There is a third page to the PrinterEd which gives a further twenty-eight translations. Since even the nine on page two is four too many for normal use on British machines this ain't much of an improvement. Files left in RAM.- will not cause any problems. A machine is "expanded" no matter where a RAM larger than 32k is located. On previous versions of the machine a larger RAM on the main PCB did not make it "expanded" - a minimum 128k in slot 1 was still required. Ah! how does one know which version of the Z88 they have? Go to INDEX and press the HELP key, then the left arrow key and look at the top line. Faulty Cartridges We have probably all seen the two covers of RAMs and EPROMs coming apart, especially the latter as they get more handling. One may think that a little looseness here is of no consequence but it can prevent good contact between the strips on the cartridge and the wire connecters inside the slot. In the case of an EPROM ( I've never had trouble with a RAM ) it might well be the cause of it failing to be recognised or failing to accept files and causing an error message. So you could go on repeating erasures without ever getting acceptance and yet it has been successfully erased. So, if you get a loose case on a cartridge, glue it. Doesn't take more than a tiny bit in each corner but it doesn't matter if it can't be opened again as there's little chance of finding/repairing a fault if there really is one END Back to HINTS-INDEX