PK87.10 The PK-88 EPROM should now be inserted in the socket and the board should be checked for any defects such as shorts, solder splashes or bent pins. The board can now be connected up and tested. If all is alright it will enter the auto baud routine and can be started as from cold. If there are no problems turn the link block on JP 1 so it links the pins, remove power and reassemble the unit. If you have problems with resets due to spikes on the 12 volt line, such as when you turn on a radio on the same power supply, either put a high value resistor in series with D 1 or just cut a leg of D 1. You should now have a PK-88 in false colours. If you have problems with overheating or unreliable operation I suggest you replace the Z8400A with a 6 MHz CMOS Z80 processor as the clock is beyond the rated speed of the Z8400A, the same can be done for the 8530A. With a CMOS EPROM and both CMOS Z80 and CMOS SCC the current consumption can be reduced to below 250 milliamps. 73 ADRIAN, GM1FML @ GB7MAC