Hi Andrew, Well, I'm not sure where the problem is at the moment, I don't recall this happening in the past so indeed it could be my 8080 pod that is part of the problem... I did find one cute trick - I have the Kurz Kash fixture and cards for Sea Wolf and while it does allow you to test all the functions the LED lights are difficult to get to light up to make sure that all the driver transistors work. So I put the 8080 pod into Learn mode for 10000h - 1000FFh which is the I/O port for the 8080 and the lights all turn on - at least the lights for the transistors that work...Cute. Otherwise you have to load the the I/O data with 0F or F0 at the correct !/O port address which I haven't gotten around to figuring out yet. Still can't get the high end FFs at addresses FF0h to FFFh to be stable though... Any chance of sharing your Midway 9100 script with the group? John :-#)# On 06/27/2014 3:56 AM, Andrew Welburn wrote:
John, there is no trick to Fluking 8080 Pcbs, they work as normal, no fudging necessary. I use a 9100 however, ymmv.
Are you perhaps using a device that isn't strapped properly on the myriad of jumpers? I think I may have seen what you describe happen before, and it was due to something like having a 2716 EPROM in, but the Pcb was strapped for 9316 roms..
Andrew Welburn (mobile) www.andys-arcade.com
On 26 Jun 2014, at 21:42, John Robertson <jrr@flippers.com> wrote:
Anyone remember what is needed to get valid memory reads on the 8080 boards? I seem to recall one has to set the gates to a state prior to doing a ROM test, but can't recall the process...perhaps someone has a script they can share?
At the moment the RAM test works fine, however any ROM space that has FF in it - on the high memory area (FFXh) gets random garbage inserted from the injection of some clock info on the data buss. The valid data locations in the ROM dont' appear to be affected. Tried adding a pullup resistor bank, no change. No ROMs, no change...
Thanks!
John :-#)#
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