Screwed up big time....... MCR Stack

I think that test only checks the ROM/RAM on the SSIO board. I think, not 100% on that. Since the ROMs were coming up bad perhaps the sockets are bad?

You can boot that stack with the SSIO removed. You wont have sound and cant control anything but at least you can see if the rest of the stack works.
 
I will try that and see what happens.
BTW, I did replace the sockets and even cleaned the work area, unlike the .156" headers that I re-flowed!;)
Pics to follow......
 
One more....
With regards to the vbatt connection, does that have to be +3.6vdc or is it OK to use +5vdc?
I have researched this and come up with +5vdc is OK and voltage MUST be applied to this circuit or the game will not boot?

Thanks
Jeff
 
One more....
With regards to the vbatt connection, does that have to be +3.6vdc or is it OK to use +5vdc?
I have researched this and come up with +5vdc is OK and voltage MUST be applied to this circuit or the game will not boot?

Thanks
Jeff

Some boards will boot without V.Batt connected and some wont, its a crap shoot.

But it is OK to hook it up to +5.

Might also be worth taking a look at the reset line from the power supply (or did you already do that?).
 
Thanks for that info...

I tried another known good P/S to no avail so if appears that the fault lies on the PCB somewhere....
 
Ye Gods, you were up all night!

> Originally the game "kinda" played, with various issues, especially the soundtrack (but that seems to be another problem all together).

The music comes from the cheap squeak deluxe board and it is an entirely different beast. It's possible to have a good board stack and bad CSD board or vice versa.
 
I'll sleep when I am dead!

Just for the record, here are pics of A7 / A8 / A9 socket replacement - cleaner than the header job.......
 

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BTW, I tested the board set with and without the SSIO connected and get the same display.
The first pic is "running" and the second pic is in "reset", both are static and there is no animation of the display characters.......
 

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Also, I probed around the Z80's while the SSIO was connected and there is activity on the Z80 located on the SSIO but the Z80 on the CPU PCB has no activity at the address lines, all low. I tried some spare Z80's but the same results.
I do get pulsing at the clock pin.
I will post detailed readings in a few.
Jeff
 
Hi,
Thanks for that suggestion.
I checked and I think I found something but are not sure....
Checking 4F (LS244) I compared the inputs to the outputs using the reset to toggle low to high and all is as it should be (AFAIK).
Then checking 5F (LS244), on 5F-8/11/13/15/17 (all inputs) they are low but when I depress the test switch, instead of going high, I get nothing (no high - no low - nothing) BUT the outputs toggle as they should.

I am not exactly sure how to test the LS245 but that might a possible culprit as the Z80 is doing nothing, no code running even though it is getting the clock.....

I am going to check the select lines on the EPROMs 7/8/9/10/11D and see what I see...

BTW, if the SSIO shows ROM errors, would that just be on the SSIO or could that indicate ROM errors elsewhere?

Thanks
Jeff
 
check cpu_reset @ pin 26 of the z80. It should be high with power applied. (actually, it should start low when powered on, then go high. Its really hard to catch that transition though).
 
Thanks for that suggestion.
What I did was place a momentary button from GND to RESET and when I depress the button, pin 26 goes low and when released it goes high and remains so but there is still no action on the address lines.

I did find a bad S163 @ 8A but after replacing did not make a difference.

Checking the EPROMs, D6-22 is low and D7 through D11-22 is high.

Pulled and chksum D6 and verified.

Need to verify pin 20 (forgot) on the EPROMs....

One more thing, although I am still a nubie with the Fluke, I thought I would give it a try and although the Fluke and the POD both pass self tests, once connected to the CPU PCB, the Fluke displays: "Pod timeout - attempting reset"
Does that ring a bell to anyone?

Thanks
Jeff
 
Did some research and it seems that with no clock, that would be the error received on the Fluke.

Now that I think of it, I used the logic probe and received pulses and assumed the clock was there but now I need to hook up a scope and verify............

mmmmmmm,
 
Verified clock present at the Z80 (with scope).

So back to, what would cause the Z80 POD to give that error - "Pod timeout - attempting reset" - when connected to the set?

BTW, I am now testing with the SSIO disconnected from the CPU PCB.....

Thanks
Jeff
 
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