Need help reverse engineering Timex Store Demonstrator ROM file

[XavSnap]

Issue 2.2:

[Paul]

Sockets are useless for the anything other than the ROM and only possible causes of problems.
the recom and the capacitor can be inserted on the Backside of the PCB.

[dessony]

XavSnap and the rest of you,

I hope that none of the components on the board hit the computer's case. How about the card edge connector's row spacing specification fixture?

Thank you very much in advance.

Regards,
DesSony

[XavSnap]

Hi,

Gerber_issue_22.zip

(185.02 KiB) Downloaded 260 times

The new connector 5.08 is ready !

[dessony]

All of you,

I placed a PCB fab order today. (11/1/'22)

Cheers,
DesSony

[XavSnap]

Thanks DesSony.


>> 11/23/22 !

[dessony]

XavSnap and the rest of you,

I received a T S Demo board yesterday (11/7/'22) from a carrier.

T S Demo V. 2.2

Direct connection. All components miss the computer's case. Go!

Edge card connector hole size. Go!

Edge card connector row spacing. Go!

I can use a triangle piece as a key tab for the edge card connector. I fixed the particular piece to fit within the connector. Go!

I read voltages off the board test points without chips in their places. 5+V and GND Go!

I need some time to test the board. I only saw a white screen at this time.

Best regards,
DeSony

[XavSnap]

Hi DesSony,

The /ROMCS seem to be active at the ROM startup.
Check the 78LS04 component/socket.

[dessony]

My apology about a very long delay! However, I finally found a bad PCB fabricator work on the Issue 2.2 board! The U6 donut pad #10 spread onto a trace coming from the hole #19. The U6 is a 27C64/28C64. The problem is the pin #10 hole and the #19 trace tied together on the Issue 2.2. It is wrong because A0 and D7 are connected to each other! I also checked the continuity test on the Issue 2.1 board with the same area and is indeed isolated! The Issue 2.1 board worked fine. The Issue 2.2 failed its test and showed only a white screen. I have not claimed a difficulty solved yet.

Donut pad touches track.

Cut between pad and track

[David G]

Good catch. Very interesting project

I love the fact that it is a BASIC program that autostarts from the ROM. Could make all sorts of demos with this. Is it small enough the fit inside the case, say with a flat cable going back to the edge connector?