Sega Model 2C - Stuck on Garbage boot

[TheDeath]

I have poorly experience on repairing these boards, a part from checking proms on the sub-board.
I have a HouseOfTheDead Model2c, checked proms and changed 2 related to the game code, but the issue persist.
Looks like is kinda watchdogging but it's doing it "internally" and i don't see the typical screen reset (like loosing sync for example).
What should i check to begin with? Should i just try to change the i960 cpu? I've read that this is typical to a dead cpu but there are very scarse information about these being repaired, a part from a guy called ken wich does that as a job (but that leads to no free informations)
Any tips?

 

[truxpin]

Have you got the gun i/o board hooked up?
As house of the dead wont boot without a working gun i/o hooked up you will just get a frozen picture that looks a bit like a pastel colour rug

 

[Hydreigon]

Check voltages. Make sure the +5v and +3.3v are a bit above the tolerance (5.1v and 3.37v to be exact).

 

[biggestsonicfan]

I've read that this is typical to a dead cpu but there are very scarse information about these being repaired, a part from a guy called ken wich does that as a job (but that leads to no free informations)
Any tips?

Have you tried emaling Ken? He's given me info for free. Also had him repair traces on a board.

 

[AMS]

Hotd will boot with scramble and looks like dead video if the gun I/o is not connected! Look first if the gun I/o is working properly @TheDeath

 

[Hydreigon]

Just wait till TheDeath can confirm if its a voltage issue. I advised the same "voltage check" for an owner of a Gunblade NY cab as his pcb was booting to garbage too. The Gunblade NY PSU's 5v was set to 5.7v (from the previous owner thinking cranking the voltage will fix a previous issue).

Voltages are the #1 priority everyone should check on a pcb that has problems and I hate seeing posts that don't mention if voltages are spot on or not.

 

[TheDeath]

Yeah, sorry guys i fogot to add some details. Voltages are fine (crunking up/down and checked the voltage regulator on the pcb) and yes, i did plug in the I/O (hopefully in the right way)
This is the main screen and keeps doing that forever
All the LEDs are showing up exept the lone one nearby one of the asic/drams on the right bottom, also gun I/o led is showing up.
A also did the rgb passthrought on the board and i'm using an extron converter as i always use for 31/25khz boards (fully tested and working as always)
All eeproms/proms checked, changed 2 of them (the one with silver sticker on it)

 

[Hydreigon]

Odd. Under normal circumstances, this would happen if there were to be a voltage irregularity (at least from testing on my Namco System 23 pcbs if its missing a voltage line/wire). I almost confused this for Model 3 where those boards would use 5v and 3.3v to power the board. Model 2 only uses 5v to power the main board.

 

[TheDeath]

Odd. Under normal circumstances, this would happen if there were to be a voltage irregularity (at least from testing on my Namco System 23 pcbs if its missing a voltage line/wire). I almost confused this for Model 3 where those boards would use 5v and 3.3v to power the board. Model 2 only uses 5v to power the main board.

@irepairsega, I hope you have the time to explain the LED behavior on these Model 2C boards because Klov shut down and we are unable to access that info for now.

It does use 3.3v but it's regulated by a mosfet on the board, you do not plug it directly like a naomi, for example.
Anyway, i was pissed off by doing that but i just removed the working board from my cabinet and directly tryed this one. Game is working, there's some weird stuff going on with the green color but other than that the game is working.
So at this point, based also on your suggestions, the I/O is bad. I'll try to reflow it and see if those few ttls are bad, but it's defenetly that one.
Thank you all for the help