Rabbit Punch PCB Problem

[mastercello]

Got a Rabbit Punch PCB of ebay, seller sold as working board.
Unfortunatly i got it in the following state:

- All moving sprites are the same, changing the type of the object constantly.
- Background is perfect, also the bullets are shown normal.

Here are a few pictures of it:





What i've done already:
- Checked voltages, all fine with +5 and +12V
- Cleaned up the boards (2 Layer pcb)
- Reseated all socket EROMS and cleaned the sockets
- Reseated the connections between the boards
- Checked for bent pins
- Checked for visual cuted pins

When i run my fingers around two of the RAM IC's (HD74LS273) the pattern is stop moving from one to another object and stays in the same object.

Do i have a bad RAM?
How can i check this?
Do i have another problem?

Thanks for any advices :!:

[grantspain]

maybe you have a poor contact on the 74ls ic legs,try putting pressure on the top on the ic

[mastercello]

Thanks grant, there is nothing happen when i do this.

The objects stop changing only when i touch the solder pins of the 74LS ic's.
These are RAMs right?

[grantspain]

no not rams,
These monolithic, positive-edge-triggered flipflops
utilize TTL circuitry to implement D-type
flip-flop logic with a direct clear input.
Information at the D inputs meeting the setup time
requirements is transferred to the Q outputs on the
positive-going edge of the clock pulse. Clock
triggering occurs at a particular voltage level and
is not directly related to the transition time of the
positive-going pulse. When the clock input is at
either the high or low level, the D input signal has
no effect ar the output.
These flip-flops are guaranteed to respond to
clock frequencies ranging form 0 to 30 megahertz
while maximum clock frequency is typically 40
megahertz. Typical power dissipation is 39
milliwatts per flip-flop for the 4273 and 10 milliwatts

[richy13]

have you looked for broken traces marcel??

richard

[mastercello]

have you looked for broken traces marcel??

Yes Richard, there are a few scratches, but i dont think that any of them is broken - thanks for the input.

@Grant - so these Flipflops aren't my problem i guess?

[grantspain]

dunno,doubt it more likely some video processor
i just copied that description before anyone thinks that i know what i am talking about

[mastercello]

For me it seems like the sprite ram doesnt know what pattern to put where and when.
Or is this completly impossible?

[grantspain]

going into some real complex logic realms now,something is mapping completely wrong
if no amount of physical manipulation affects the graphics then its certain that ic failure has taken place

which ic is the question and that question is beyong my technical know how i am afraid

do you have an ic test in the service settings?

[mastercello]

When i touch the pins of this 74LSXYZ flipflops,
then the sprite stops changing and just stays at the same sprite pattern.

Unfortunatly there is no test menu and also no RAM/ROM check at startup.

[grantspain]

what processor is on that board,a z80?

[mastercello]

Yes it's a Z80 :!:

Here is the manual with 6 pages schematics of both boards:

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http://pdf.textfiles.com/manuals/ARCADE/K-R/Rabbit%20Punch%20[Uni.%20Field%20Conv.%20Kit]%20[English].pdf

[grantspain]

whats ic10 part number

[mastercello]

Seems a sprite related ic :!:

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NEC JAPAN / D65012CW217 / 8737KX001