On Mon, 13 May 2024 06:05:37 -0700 John Robertson via Techtoolslist <techtoolslist@flippers.com> wrote:
On 2024/05/12 8:34 p.m., David Gersic wrote:
On Fri, 10 May 2024 11:30:25 -0700 John Robertson via Techtoolslist <techtoolslist@flippers.com> wrote:
I've had this adapter sitting on a shelf since 2004 and just found a use for it when working on a Zaccaria pinball MPU. The problem is it doesn't work and it looks like the 2650 CPU has to drive INTACK, but it ties low in the original article on pages 9 &10 of TroubleshooterV1-1983-combined-searchable.pdf (on ftp list under Fluke/9XXX/Fluke Troubleshooter Magazine).
Anyone else use this adapter or made one that works for Zac. games? I sent you that one. I never got it to work correctly, though. I had a thread here on it back in 2017.
Right, I have the correspondence but forgot about it. Must be getting older...
I also only brought out the two Zac pins in the last few months, didn't have a customer in 2022 for them. Now I do, so getting them all cleaned up - finally.
I did find that the INTACK wasn't grounded as shown in the original Fluke Troubleshooter - it was floating, so I shall try tying it high to disable the Data Bus read - that may be my problem. It really looks like it should work.
Interesting. I just looked back at the original article, and it should have INTACK tied to Ground. If Mike's adapter has it floating, that could explain the weird random data reads. Looking at the board schematic, INTACK puts 0x40 on the data bus. It does look like it should work. If you get it working, I'll have to get another one. I'm not sure I'd use it, but it would be nice to have.