Topic: Raiden DX Arcade PCB Repair  (Read 12097 times)

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Offline ifkz

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Re: Raiden DX Arcade PCB Repair
« Reply #15 on: November 09, 2009, 07:53:55 PM »
Hi everyone,

This is only my second post here!  I am a member of several other arcade forums: KLOV, arcadecontrols, digitpress, etc.  I just found out about RCM through a Google search about repairing my Raiden DX board.  Here's hoping I can get it going!  I've been collecting for about two years now, and my local buddies have gotten me a number of arcade machines.  So far my repairs have actually fixed some problems.  I'm getting into more advanced board repair now, it seems.  Here's my VAPS entry for those that are interested:
http://www.klov.com/members/member_detail.php?member_id=387525

Offline Womble

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Re: Raiden DX Arcade PCB Repair
« Reply #16 on: November 09, 2009, 08:27:24 PM »
Hiya, am afraid the shotgun approach isn't likely to do you much good, especially as raidens can suffer from track rot, you could replace every chip and it would still do the same.

If you are into arcade repairs then I reckon now is the time to get yerself a logic probe, you can get them for about 5 quid. Also you will need a multimeter with a continuity beeper function to test tracks. I can help you out with how to use the probe, and also where to start based on your fault. Will post more when I am at a real keyboard and not on a tiny phone screen.

You might also like to take a look at aussiearcade.com.au , lots of arcade heads on there and loads of repairlogs. A few Brits on there, me included, but is probably the best site I have found for an arcade community.
Sic Transit Gloria Atari

Offline ifkz

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Re: Raiden DX Arcade PCB Repair
« Reply #17 on: November 09, 2009, 08:35:05 PM »
I'll try to post a pic later.  Any legend for the PCB picture you posted here?

Offline Womble

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Re: Raiden DX Arcade PCB Repair
« Reply #18 on: November 09, 2009, 08:50:37 PM »
You mean schematic? None that I know of, you rarely need them. Oh you mean the key to what is ringed and labelled, no sorry, it's not my photo and there was no key. I know which bits are the sprite ram and roms, but my money is on the control logic, or a rotten track.

OK, the Sprite and Object ROMs are the 4 fat chips below the yellow ring number 3, the 42 pins ones. As you have lost all sprite and object data it is very unlikely that these chips are bad, ROMs fail by losing one or two data lines, you would need some catastrophic event to kill the chips dead, and as your board works that is ruled out.

The three chips in the yellow 3 ring are the sprite static RAM chips, again its not likely these are dead for the same reasons as the ROM. The surface mount custom chip in the Red ring #8 is the sprite controller chip - if this is damaged the board is pretty much scrap unless you can find someone locally to replace that chip. You need specialised equipment to replace surface mount chips so its not something you can do with a normal soldering iron.

The most likely cause for your total loss of all sprites and objects is that either the sprite ROMs or sprite RAM is disabled. This is where you need a logic probe, you need to see what pins 11 and 13 are doing on all 4 sprite roms.

Pin 11 is CE  (chip enable), or actually it is inverse logic so its chip "not enable", if this line is logic level 0 then the chip "not enable" = "no", therefore the chip is active, if this line is logic level 1 then the chip is basically in standby mode and it will never output any data = total loss of all objects and sprites in that ROM. All 4 ROMs will have their CE lines connected together, and probably tied to the 5V line anyway so they may always be active, but you need to check this.

Pin 13 is OE (output enable) again with inverse logic. All 4 ROMs share the same data lines and address lines, therefore there needs to be a system to ensure that only one ROM can talk on the data bus at any given time, if they all talk you will get corrupt data - which will result in totally corrupted sprites, not missing sprites. This is what OE is for, at any given time 3 of the 4 ROMs will have their OE pin held at logic level 1, so they will not talk, only one will have its OE pin at logic level 0 and this one will be talking on the bus. If none of the chips have any activity on their OE pin and it always stays at logic level 1 then none of the chips will talk, therefore you will get no sprite or object data and nothing will be displayed.

The same goes for the SRAM, you need to poke a logic probe at the SRAM CE and OE pins (I will find out the pin numbers later tonight).

Once you know if the sprite system is actually active then you can work out where to go next. It is possible that you have lost an address decoder chip (therefore all OEs are silent), or you have lost a track on the board that goes to the CE lines, leaving the chips in standby mode.

« Last Edit: November 09, 2009, 10:29:46 PM by Womble »
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Offline EQUITES

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Re: Raiden DX Arcade PCB Repair
« Reply #19 on: October 25, 2012, 01:33:17 AM »
I'd just like to add that I recently picked up a faulty Raiden DX PCB with the exact same problem with the sprites.

I checked the same MASK ROM and found that pin 36 (A13) was floating, so using kynar wire I created a path as Womble did to the upper 373 logic to 1D pin (Pin 3) too (Womble said D0 but I'm sure he meant 1D).



Fixed!

What are the chances the same exact problem with track rot could occur?  Like Womble, I could not see where the break was either.

Offline porchy

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Re: Raiden DX Arcade PCB Repair
« Reply #20 on: October 25, 2012, 06:12:25 AM »
Very odd indeed but clearly not impossible.

Oh, welcome.to RCM too

Offline Womble

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Re: Raiden DX Arcade PCB Repair
« Reply #21 on: October 27, 2012, 03:28:22 AM »
Good work, the odds of having track rot on that board is pretty likely, the odds of having the exact same track  out of all the hundreds on there that's bad is very very unlikely - good fix tho!

(Womble said D0 but I'm sure he meant 1D)

The naming of pins tends to vary on manufacturer and therefore from datasheet to datasheet. Some manufactures label their pins D0 to D7, other use D1- to D8, an others flip it to be 1D ;)
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Offline EQUITES

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Re: Raiden DX Arcade PCB Repair
« Reply #22 on: October 29, 2012, 02:36:26 AM »
Thanks guys for the welcome - will be posting some repair logs very soon.