Pixelated Characters = A Ram Issue?

kmssd

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When I have my game on for a while, like when I was adjusting the monitor yesterday, the characters start to get choppy. Eventually it gets to the point seen below in the pictures. Yesterday it took about an hour to get there but it was clear when I turned the machine on today. Anything that moves on screen gets distorted. Could the ram be bad even though they are soldered in?
 

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When I have my game on for a while, like when I was adjusting the monitor yesterday, the characters start to get choppy. Eventually it gets to the point seen below in the pictures. Yesterday it took about an hour to get there but it was clear when I turned the machine on today. Anything that moves on screen gets distorted. Could the ram be bad even though they are soldered in?

Yes, the ram can be bad!

I am not so sure that is your problem, What are the voltage when this happens?

The first thing would be to locate about where the problem is on the board with freeze spray, When you have the described problem freeze spray parts of the board until there is a change.

The problem is probably a connection with a socked chip, a feed though, or voltages.
 
Yes, the ram can be bad!

I am not so sure that is your problem, What are the voltage when this happens?

The first thing would be to locate about where the problem is on the board with freeze spray, When you have the described problem freeze spray parts of the board until there is a change.

The problem is probably a connection with a socked chip, a feed though, or voltages.

I was told to check the voltage but I haven't done it yet (at a 470uf cap), should I be testing the voltage coming from the power supply?

For that freeze spray, I have to pick some up but does that cool a component down like it was overheating?
 
The video RAM dictates what characters/sprites get displayed to the screen and where. Address to the video RAM = sprite location. Data written to the video RAM = which sprite to display.

But the sprites themselves are blitted in real-time. The data from the sprite ROM gets serialized and sent out to the display. So based on your images.. I'd say the RAM is prob fine (I can see that the sprite types are correct and general location is correct as well). I think it's an issue in the sprite ROM datapath.
 
I was told to check the voltage but I haven't done it yet (at a 470uf cap), should I be testing the voltage coming from the power supply?

For that freeze spray, I have to pick some up but does that cool a component down like it was overheating?

You should be testing the voltage at the board. Testing from the supply is a good idea to get the voltages to a general safe level (4.9 to 5.15) but the +5 should be fine tuned at the caps or chips (better) for actual voltages.
 
@ajcrm125, is the sprite ROM datapath something in the chips I recently bought to return this to DKJr?

@kb0jjn, could I test the voltages on chips legs via a pinout guide on Braze's site?
 
@ajcrm125, is the sprite ROM datapath something in the chips I recently bought to return this to DKJr?

@kb0jjn, could I test the voltages on chips legs via a pinout guide on Braze's site?

You can test the voltage on the chips. Just about any 74lsxx chip at the bottom left side (ground) to the top right (vcc, or +5 volts dc).
 
@ajcrm125, is the sprite ROM datapath something in the chips I recently bought to return this to DKJr?

@kb0jjn, could I test the voltages on chips legs via a pinout guide on Braze's site?

Technically the sprite ROMs are part of that logic, yes. If/when you switch it back does the problem still exist?
 
Technically the sprite ROMs are part of that logic, yes. If/when you switch it back does the problem still exist?

I believe the problem does exist when it was Special Forces. I didn't have it on for the same amount of the I had it on as DKJr, but there were times when it started to happened. On SP it would make a black horizontal line appear across screen when the main character stood in a certain position.

@kb0jjn, there are alot of 74LSxx chips, is there a few in question, or will it be an all or nothing testing?
 
I believe the problem does exist when it was Special Forces. I didn't have it on for the same amount of the I had it on as DKJr, but there were times when it started to happened. On SP it would make a black horizontal line appear across screen when the main character stood in a certain position.

@kb0jjn, there are alot of 74LSxx chips, is there a few in question, or will it be an all or nothing testing?

Just about most 74 series chips are like that but I tend to start out with the 16 pin 74lsxx type chips as I usually look at the input/outputs also.
 
I got my board back from a fellow KLOVer who tested out my board and verifed that the board works ok for him. Which falls back to my setup having a problem with voltage or a loose connection in one of the wires.

So I ran it to see what happened and the problem returned. First before playing I tested the 5 volts at the power supply (those board plugs are a pain to get into) and read 5.24v. When the glitches appeared I measured again and got 5.71 that slowly rose to 5.74 until I removed the meter.

Am I heading for a PS recap?
 
I got my board back from a fellow KLOVer who tested out my board and verifed that the board works ok for him. Which falls back to my setup having a problem with voltage or a loose connection in one of the wires.

So I ran it to see what happened and the problem returned. First before playing I tested the 5 volts at the power supply (those board plugs are a pain to get into) and read 5.24v. When the glitches appeared I measured again and got 5.71 that slowly rose to 5.74 until I removed the meter.

Am I heading for a PS recap?

Something is very wrong with either the power supply or the meter. Try replacing the battery in the meter or try a different meter.

WITH THAT VOLTAGE YOU WILL FRY CHIPS!!!
 
Something is very wrong with either the power supply or the meter. Try replacing the battery in the meter or try a different meter.

WITH THAT VOLTAGE YOU WILL FRY CHIPS!!!

I got these measurements at the power supply, I don't know if that would explain the high number. I will also check the battery and see if I can use another meter.
 
This board was tested on my bench and ran great. I let it burn in for a full day and it never missed a beat. It almost has to be a voltage or connection issue in the cab. At first glance it looks like a monitor sync issue but you can see some of the picture is clear.
Yeah, I dont reccomend running that thing too long with 5.7v ....wont last long.
Your power supply may need to be recapped or the pot is flaky and is starting to drift. You know, im not even positive they have a 5v adjust on them but I think they do.



I got my board back from a fellow KLOVer who tested out my board and verifed that the board works ok for him. Which falls back to my setup having a problem with voltage or a loose connection in one of the wires.

So I ran it to see what happened and the problem returned. First before playing I tested the 5 volts at the power supply (those board plugs are a pain to get into) and read 5.24v. When the glitches appeared I measured again and got 5.71 that slowly rose to 5.74 until I removed the meter.

Am I heading for a PS recap?
 
This board was tested on my bench and ran great. I let it burn in for a full day and it never missed a beat. It almost has to be a voltage or connection issue in the cab. At first glance it looks like a monitor sync issue but you can see some of the picture is clear.
Yeah, I dont reccomend running that thing too long with 5.7v ....wont last long.
Your power supply may need to be recapped or the pot is flaky and is starting to drift. You know, im not even positive they have a 5v adjust on them but I think they do.

The PS does have a 5v adjust, in fact it has 4 pots. I did break the glue free, rotated it to knock off any grime and gave it a shot of contact cleaner. Adjusted the pot to 5.03V. At startup I got 4.96 @ PS and 4.83 @ chip 1K (74LSxx chip). Right after that I turned off the game, in case that voltage range is too low.

@kb0jjn, I did change the batteries, they were probably the original batteries from Amprobe...
 
Low voltage wont hurt anything. Worse case is the board wont boot or it will have random resets or graphic issues. No damage can be done to it if the voltage is too low. Its when they are too high that you need to worry.
So is the game working correctly now?
 
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