Nintendo Popeye pcb repair - graphic glitches

I see.. 😅


LS20 on 5D is checked with a logic probe.. all inputs and outputs are toggling. But no logic analyzer used..

I'm trying to swap the NAND Gate on 1D first before i looking for other possible issues
 
No changes after swapping 8F.. but the ic is showing good now

7J also an LS139 is also showing good


3 x 74Ls367 has bad outputs..

Those testers are useless on chips like 367's that have tri-state busses.
They're not smart enough to only compare when the DUT is enabled.

but also piggybacking had no effect.. is it normal? I thought piggybacking of a good ic "overrides" the bad ic

Piggybacking is almost never useful -- it can only "override" the bad IC if the bad IC isn't driving its outouts at all.
 
I see.. 😅


LS20 on 5D is checked with a logic probe.. all inputs and outputs are toggling. But no logic analyzer used..

I'm trying to swap the NAND Gate on 1D first before i looking for other possible issues

If you have spare LS20 and LS02 chips spare it couldn't hurt to piggyback them while you wait for the other chips.
It might not make any difference but it's worth a try.
 
1D swapped but no changes.. 8D looks also suspect.. swapped.. but no chamges

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Now i'm on 8C a 74LS139 the 2nd decoder inputs looks strange. Half signals overlapping other signals.. Pin 15 -> Enable, Pin 14 -> Input A, Pin 13 -> Input B

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Have to look in the schematics where the inputs come from

But still same issue:

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Hmm.. the 2nd decoder is for the enable line for the roms.

IMG_1520.jpeg

The roms are checked all fine. So the decoder have to work well.. right? But strange that the inputs looks strange



Update: I guess the floating signal is correct. The address lines comes directly from the z80 and the address bus isn't pulled high or low.. so when no address is set the output is floating
 
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I see.. 😅


LS20 on 5D is checked with a logic probe.. all inputs and outputs are toggling. But no logic analyzer used..

Even though the outputs are toggling the logic probe won't tell you if those are the correct outputs.
I still think your graphics are coming out correct,just not being displayed at the correct times hence why I'm guessing it's the end of the video output circuit that has issues.
 
Even though the outputs are toggling the logic probe won't tell you if those are the correct outputs.
I still think your graphics are coming out correct,just not being displayed at the correct times hence why I'm guessing it's the end of the video output circuit that has issues.
Have to order ls20 and ls02 to check 5D and 5E.. games works, sounds is well.. Highscore screen looks correct. The combination with background and sprites screw up
 
Update: I guess the floating signal is correct. The address lines comes directly from the z80 and the address bus isn't pulled high or low.. so when no address is set the output is floating

The address bus is controlled by a bank of PLAs for both the CPU and the DMA address counter, and there is a delay between the ~BUSACK when the the CPU releases the address bus and when the DMA takes over (and likely between when the DMA is done and ~BUSREQ is released).
 
Ah,I see.

Also on that page :
The hardware doesn't use any other interrupts, only the NMI.
The NMI vector is the same for all Z80 program and starts at address $66 in ROM.
It is triggered essentially by the /VBLANK signal and during this time all the on screen background and sprites are updated.

So now I wonder if the NMI is being triggered at the wrong times?
Might be worth checking out the chips leading to the NMI input of the CPU.
 
I checked earlier all LS74 with the HP comparator.. no one looks bad.. in the NMI circuit are three LS74 involved
 
Gameplay and sound seems working well.. so I guess adress bus and data bus musst be working well.. I double checked all LS74 and LS02.. all are good compared with the HP Comperator.. glitches are also present when all proms are removed from pcb (5A, 5B, 4A))..

Update:

LS00 on 1B, 1D and 4L are also checked fine
LS161 on 2L, 1F, 2F, 2E checked good
LS139 on 8C and 8F checked good

IMG_1579.jpeg
IMG_1580.jpeg

IMG_1582.jpeg
Not many options anymore… LS367 maybe or LS138?
 
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Update: swapped 3H LS367 no changes, 2H is checked good, 3J LS08 checked good with the HP comparator.. 3N LS14 looks right withered logic probe
 
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