Paperboy Graphic Issue

Superully

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my paperboy has recently developed a graphic issue: the sprites are alright, but there are vertical lines running through some of the objects (e.g. the houses and the road on the right). let me show you some pics:

5100369606_26d86a9367_b_d.jpg


5100369222_2c4b25f78f_b_d.jpg


any idea what that could be and what i could do? btw, no error is being displayed in test mode!!!
 
you have a bad 6116 RAM, run the RAM test in test mode or do the touch test the bad RAM will probably be hot to the touch
 
you have a bad 6116 RAM, run the RAM test in test mode or do the touch test the bad RAM will probably be hot to the touch

the ram/rom test should come up with the test switch in ON position. when i do so, the screen comes on with the processor test, no ram/rom test is being displayed. does that mean that the games passes the ram/rom test without reporting an error?

as for the touch test: some of the chips are slightly warm, but none of them is hot to the touch. i've had the game turned on for about an hour!

any suggestions?
 
There is a procedure to get into the RAM test, it is in the manual. I do not recall the procedure off of the top of my head.

here's what the manual says: "the game must be turned off, the self-test switch turned on, and the game power turned on again to start the self-test with the RAM/Interrupt/ROM test." [...] "If the RAM/Interrupt/ROM test passes, the display will advance to the 6502 Processor test."

i'm doing exactly as described in the manual, a RAM/Interrupt/ROM test does not appear on the screen, the tests start with the 6502 processor SOUND test automatically. does that mean that it passes the RAM/Interrupt/ROM test?
 
From what I recall, you have to start with the game on. Put it into test, and leave it in test. Turn the game off, and back on and you should have the RAM test.
 
From what I recall, you have to start with the game on. Put it into test, and leave it in test. Turn the game off, and back on and you should have the RAM test.

ok, i start the game with test switch OFF. during gameplay or attract mode, i turn the test switch ON, the accounting information comes up on the screen. from that screen, i turn the game off (test switch still ON though), turn the game back on again (test switch STILL ON), 6502 yamaha sound processor test is the first thing i see - RAM/Interrupt/ROM test nowhere to be found :(
 
Use the throw buttons to cycle through the tests

i know, i know, but a RAM/ROM test doesn't come up. the sequence is as follows:

6502 processor test
control test
alphanumeric test
scrolling playfield test
motion object test
motion object height test
color bar test
color purity test
convergence test
accounting information
switch settings

then it starts all over again ...

i'm at a loss here!
 
Locate all of the 6116 RAM and start moving them to see which one is at fault. IIRC there is something like 3 different locations where they are located.
 
Check that none are getting stinking hot first, hot as in burn-your-finger-hot, thats often a give away sign.
 
what do you mean by "start moving them"? exchange their position? if something should change then, how should i know which one is faulty?

Take the one at 2A on the video board, and swap it with the one at 2 B/C. If the problem moves, it is one of those two. If the problem remains, swap 2 B/C with 2 C/D, then 2 C/D with 2 E, then 2 E with 3 A, etc. Basically you will be moving one RAM chip (2A) to every RAM position to identify the bad one.

The 6116 RAM Locations on the video board are...
2A
2B/C
2C/D
2E
3A
3B/c
3C/D
3E
3N
3P/R
3R/S
3T

The 6116 RAM on the main board are not causing the issue, but are at locations...
1A
1B/C
7K
7P
 
Yes, each RAM chip will be involved in something on the screen, try to avoid swapping any RAM that is obviously part of a pair with its partner. If you do the subtle change in the fault may not be obvious. Most of the ones you swap will have no impact on the fault, when you find the bad one you will see the background fault vanish and a fault affecting the sprites or the colours will appear, coz the bad chip is now at a different location.
 
ok, i did it a little differently, here's what went down:

i took the 2A RAM from another SPARE paperboy board i have (which has another issue) and exchanged it for the 2A RAM on the board in the cabinet - error stayed the same. then i moved that RAM through all the other RAM positions. unfortunately, the error did not go away.

after that, i exchanged the entire 12 RAM set with the one from my spare paperboy board - erorr is still there :( nothing has changed at all! :(

questions:

- is it possible that the error is being caused by the two big blues i'm still running on the power supply?
- is it possible that the error is being caused somehow by the monitor? my chassis has two LED lights on it, a green one and an orange one. when i turn on the game, the green LED comes on first, then there's a click and a sound, the green LED goes off and the orange one comes on. for pictures see here:
http://forums.arcade-museum.com/showthread.php?t=155490&highlight=paperboy+monitor
 
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