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TMNT Turtles In Time horizontal stripes

nassekova

nassekova

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I have a TiT board which have had these weird horizontal stripes from the beginning. At first it took some time for them to appear, but now they come straight from the start. See the video to get a good idea of the problem. Game itself plays fine.

View: https://youtu.be/6QRoZYrTnP0


What have I done so far:
  • re-capped the whole board (electrolytic capacitors).
  • re-seated all EPROMs
  • cleaned the board and gave it good look to see if there was anything that would have caught in eye (nothing so far).
  • re-flowed one component.
The board
IMG_0315.jpeg


This weird "comp" had one leg reflowed before I got it so I reflowd all the legs. No difference.
IMG_0317.jpeg


What is this jump resistor here? Some kind of "pull the color" fix? Could it be this one to cause those stripes?
IMG_0316.jpeg


All the ideas are welcome! I have not played this through cause I wanted to fix it first. So PIZZA POWER waits but I'm getting out of ideas :/ I don't have scope to check the signals, but everything else should be doable.
 
ic3b4ll said:
My fault-sense is telling me to replace the IC with the resistor... I think it's connected to the 53251 custom and issues with that one would cause similar glitches.
Click to expand...
Yeah, definitely something shady going on on that chip, I think I'll follow your fault-sence and change that next! :thumbup:
 
PIZZA POWER!!!!!

Well I finally got around and replaced that SN7407N which @ic3b4ll suggested. I tried to be careful but still botched 3 pads while lifting that old chip.

IMG_0473.jpeg


Luckily it was only on this side of the board and one was clearly connected to that larger chip next to it, other was not connected on this side at all, so all I had to hunt down was that bottom left pad. Luckily it was connected to top right corner of the same chip so it was pretty easy fix. I happened to have a socket of this size so I just jump wired that socket from the bottom and it was all good to go.
IMG_0474.jpeg


Now it can be easier debugged too if I need to insert that old chip with the resistor back to test it again etc.

Luckily that wasn't the case since it now works perfectly! :thumbup:
IMG_0490.jpeg


New chip.
IMG_0492.jpeg


So thanks to @ic3b4ll s spider sense, this is now back in action! I played it 4 levels and left it to run about 40minutes. Before the fix that glitching started in 5minutes and it just got worse in time. Happy to finally have working TiT ^^
 
Happy you fixed it!

Curiously, do you have a BOM/parts list for the caps you replaced? Also, did you replace the pots on your board? The pots on mine look different, and they're a little crusty... trying to figure out replacement options.

Thanks!
 
kazuo said:
Happy you fixed it!

Curiously, do you have a BOM/parts list for the caps you replaced? Also, did you replace the pots on your board? The pots on mine look different, and they're a little crusty... trying to figure out replacement options.

Thanks!
Click to expand...

Here is a capmap of all the electrolyte capacitors! I didn't touch the pots they seemed to work fine.
 
nassekova said:
Here is a capmap of all the electrolyte capacitors! I didn't touch the pots they seemed to work fine.
Click to expand...

Thanks! I got around to ordering these on Mouser (I'll post a BOM sooner or later) and everything was perfect.

One thing I noticed was that a couple of the caps (I think the 4.7uF 50V caps) looked a little... funny on my board, and I noticed there is another similar-looking component labeled "C1", near the custom sound IC and the crystal:
7h0vbkL.png

Any idea if this also should be replaced with an electrolytic? Is it also one of the 4.7uF 50V caps?

Thanks again for your help!
 
kazuo said:
Thanks! I got around to ordering these on Mouser (I'll post a BOM sooner or later) and everything was perfect.

One thing I noticed was that a couple of the caps (I think the 4.7uF 50V caps) looked a little... funny on my board, and I noticed there is another similar-looking component labeled "C1", near the custom sound IC and the crystal:
7h0vbkL.png

Any idea if this also should be replaced with an electrolytic? Is it also one of the 4.7uF 50V caps?

Thanks again for your help!
Click to expand...
Those are ceramic capacitors and usually do not need to be changed. They don't dry out or leak like electrolytic do, so I would just leave them as they are. Of course if one of those looks like it's damaged you can take it out and measure it and replace with a new of the same kind.
 
It's a tantalum, not a ceramic. Most ceramics are non polarised, tantalums are polarised and will explode if installed the wrong way around - don't mix them up. Tantalum capacitors are generally highly reliable - they don't wear out and when they rarely fail it's a complete failure. It's the correct component for the board, don't replace it unless it fails or is physically damaged.
 
Finally I had some time to play this and I but it on my Tekken cabinet to play it with my friends. It ran there 10minutes just fine but after that those damn graphical glitches came back (see the video on first post) :cursing:

So I guess my earlier "fix" did not work after all, I just tested it too small amount of time after that. I need to dig in to the service manual and try to see where does video signal go, but it's almost like it does not appear when the PCB is "cold" and when it starts to warm up those glitches come every now and then. Almost like dried out capacitor, but I changed all of those...

If anyone has pointers what to look or have had something similar (with any game) let me know!
 
nassekova said:
Finally I had some time to play this and I but it on my Tekken cabinet to play it with my friends. It ran there 10minutes just fine but after that those damn graphical glitches came back (see the video on first post) :cursing:

So I guess my earlier "fix" did not work after all, I just tested it too small amount of time after that. I need to dig in to the service manual and try to see where does video signal go, but it's almost like it does not appear when the PCB is "cold" and when it starts to warm up those glitches come every now and then. Almost like dried out capacitor, but I changed all of those...

If anyone has pointers what to look or have had something similar (with any game) let me know!
Click to expand...
It could also be cold solder joints on the big custom QFPs.

I recently sold a TIT conversion that, when I tested it, I noticed a weird 'snow' effect in the background layer that would appear after the board was on for a few minutes. I took a shotgun approach and reflowed all of the customs and the problem went away.
 
benime said:
It could also be cold solder joints on the big custom QFPs.

I recently sold a TIT conversion that, when I tested it, I noticed a weird 'snow' effect in the background layer that would appear after the board was on for a few minutes. I took a shotgun approach and reflowed all of the customs and the problem went away.
Click to expand...

Need to test this next, thanks! I tried to eyeball all those chip legs but if it's something tiny better to just go them through.
 
Ok so I reflowed all those custom QFPs and after that I was missing red color
IMG_3386.jpeg


I then checked what parts of the components are responsible for red and found this from the schemantics.

IMG_3389.jpeg


I then reflowed U25 (red) and two other colors on those 052535.
IMG_3390.jpeg


After that I got all the colors and no glitches, but I knew this sonofabitch has fooled me earlier so I left it to run for 40minutes. And like I suspected after 40 minutes I went to check it and this time it was lacking BLUE X/

So I guess it's somewhere further down on the line where RGB colors are handled, since it's not just one colour that has issues...
 
Well finally it's working :thumbsup:

My friend tipped me off that I should measure the voltages of those 7407 chips, since if some of those drop under 5v it might affect this.

IMG_3390.jpeg


So I started to measure them while the game was playing and sure enough 2 of them at first gave me 4.something which was moving all the time, but when I pushed the multimeter head harder to the leg (and in the same time pushed the leg to the VIA wall so it takes better contact) all the problems went away :thumbup:
IMG_3461.jpeg


After that I re-flowed all those five chip legs with fresh solder and flux. Then I ran it about 2 hours and 0 glitches on graphics! FINALLY I get to play this game :)

Although I think I have had my fare share of "PIZZA POWEEEER!" song while this thing has been running to test it for multiple days now...
 
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