Xevious ...PCB problem :-(

[Darth Nuno]

Hi There,

I'm a proud owner of a Xevious Cab' 

See all the roadtrip here : http://www.dragonslairfans.com/phpBB2/viewtopic.php?t=63

Now, here's my problem...

The game doesn't work 

Each time I power on the game, a get an error :



RAM 8

...and time to time, i got the message :

RAM 7

According the documentation :



I suppose I have to change the chip at the 2S location on the video PCB ?!

No luck, the elecronic shop near my place can't order the 2S chip here :



but I was able to buy chip 1H ( for the RAM 7 error message )

OK, the  RAM 7 error seems fixed, but now I got :

RAM 8

...and time to time, i got the message :

RAM B

Jesus Christ, what happens ? WHat could be the problem ?

Thanks for your help

[2600]

This should be in Arcade misc.

I would think typically the problems may be:

Power Supply - Does this have the typical Atari Power Supplys? they seem to always cause weird problems, especially the Big Blue Cap.

Have you tested the voltages near the Chips?  Or Capacitors?

[Darth Nuno]

Opsss, sorry for posting in a bad section....  Maybe an admin can move this message...

Here's the view of the power supply :



WHat can I check on it ?

Do you think it's the first thing to check ?

Thanks for your advices.

[2600]

Don't worry about posting in the wrong section, I just wanted you to get more exposure from people more knowledgeable on repairs.

Usually on Atari's the power supply is the first thing to check.  I think I see the big capacitor on the other side of that transformer.  You should also check to see what kind of voltages you are getting out of the power supply.

[RayB]

Check that your fuses haven't been replaced with tin foil.

Measure your voltages coming off the AR-II board (it should have test points labelled with various AC and DC voltages) and test the AC voltage coming into the AR-II.

On the power supply itself, not much to check. Personally I had a hard time finding where power was outputting from on that thing...

It's usually a safe bet to just rebuild the AR-II with a kit from Bob Roberts and also replace the BIG BLUE capacitor on the power supply. This usually clears up power problems and ensures you're good for a number of years to come.

[Brunnen-G]

Definately rebuild the power supply and replace the big blue cap.  It will save you tons of trouble down the road even if it doesn't fix this particular problem. 

You should be able to find the RAM you need from Bob Roberts as well.  If not from him, try www.arcadeshop.com.  Whenever one chip of RAM dies, the others seem to follow in short order, so you might want to go ahead and swap all of them out at once so you won't be pulling the board out every other week to replace the chip that just went out. 

[RayB]

**WAIT**
Unless the RAM is cheap, don't buy it. My hunch is the errors are due to power problems. The fact that it's never the same error twice makes me feel a bit confident about this. Sounds like not enough juice (or fluctuating juice).

Step one: Measure voltages.

[2600]

I'm with RayB.  Do the power supply first before replacing anything else.

[Darth Nuno]

Thanks for your precious help 

Is it the BIG capacitor you're talking about on this picture ? the BIG red one ? :



I've other arcade cab. Can I take the Power Supply from another games and only use the 5V for the PCB Xevious card ?

[Brunnen-G]

The big blue cap is the one just to the left of the main power transformer in that picture.  It's bolted into the power chassis, and has leads screwed into the terminals on the underside.

[RayB]

I don't know WHAT that red thing is.
 

[2600]

Get a closer picture.  I can't tell what that bright red thing is, but I believe the big cylindrical shape thing to the left of the transformer and above the fuses should be the Big Atari Cap.

We usually call it the Big Blue Cap, but we are thinking Atari USA.  Atari Ireland may not of used the exact same Cap or yours may have been replaced at one time.

[D_Zoot]

Just to add some info to this thread....

Your local electronics shop likely had no luck ordering that ram chip using the part number off the chip (MSM2128RS is the manufacturers part number, not a common trade number).

[Rocky]

I would guess that those are 2128 ram chips.

[Darth Nuno]

OK, I need to know what exaclty is the 'Atari Big Cap' 

So, here's pictures :



or



The Big cap is on picture 1 or 2 ? How can I check it ?

Thanks for helping a 'newbie' in electronic 

[RayB]

Picture 1. The black one. Originally they were blue. Looks like yours may have been replaced at some time.

That red thing also looks like a cap. I have no idea why it's there and "loose" like that. Looks like that thing and the fuse are NOT original. They were hacked in. Which I could figure out why.

[2600]

Like Rayb said the black one.  I still wonder since your overseas if Atari Ireland actually used the blue ones, but that doesn't matter just curious.

No clue why that red one is there and why it is hanging, I wouldn't think that that is a good thing.  You should probably put the fuse back in the holder.

Also, the Atari Regulator board, ARII?, is inside of that enclosure just so you know in case you have to get in there to replace anything.  (Is that correct?, RayB)

[Brunnen-G]

I ended up with one of the Ireland built Tempest machines.  It had a big blue that was actually, well, blue.  It might have been simply what they had on hand, or someone could have replaced it in the past.

[Darth Nuno]

Ok, I've found a picture of a Xevious cab with the famous 'BigBlueCap' :



What is the purpose of that component ? Is it common to found it in the shops nowadays ?

Something I don't understand : How is it possible the monitor works if the power supply has a failure ? Can I use a common 5V alimentation from another arcade game to test the pcb ?

Thanks for help 

[RayB]

Something I don't understand : How is it possible the monitor works if the power supply has a failure ? Can I use a common 5V alimentation from another arcade game to test the pcb ?

Monitors typically run on 110v, which is what comes out your wall socket. The power supply would have a fuse on that line but other than that, power is probably direct to your monitor. It's the OTHER PARTS of the power supply that do other conversions and output lower voltages to the AR-II board (for further conversion). I don't know if it is standard, but in my Missile Command, it outputs 36v to the AR-II. Then the AR-II converts to DC and outputs 5v and 12v to the game board.

The Big Blue *I think* is suppsed to keep the voltage "clean" and steady. If it gets so old and doesn't function right, then the voltages will vary, be too low or be too high or spike. Basically, wrecking the AR-II board. (but the point is, your monitor voltage isn't affected by this cap).

Bob Roberts has replacements to Big Blue and rebuild kits for the AR-II. It's best to do both at the same time.

But before you do any of that, hopefully you've bought yourself a digital multimeter over the week.

[Darth Nuno]

Thanks for the explication RayB.

So the purpose of the AR2 board is not only sound ? but it also make a output conversion.

Here's pictures of the AR2 :



Closer ...




On the back of the board, I notice this :




WHat can I check on it ?

What is the url of Bob Roberts website ?

Oh, for information my Xevious is an EURO version. And I'm still not able to identity the PCB... this is not written Namco or Atari, except on the AR2 boad...

[RayB]

OK I am not familiar with Euro boards, so take what I say with caution...

Your AR-II looks really clean. Almost as if it has already been rebuilt. Once again, your capacitors look like modern ones instead of the blue style I usually see on those. Could be because it's a built in Ireland one or could be that whoever you bought it from has already rebuilt it and it still didn't fix the problem so they gave up and sold it to you!

[Rocky]

Wow, that really is a nice clean ARII

[Darth Nuno]

Thanks for the procedures 

OK, before take mesure, I need to know which Xevious PCB I have 

There's nothing written on the PCB 

Can you help me to identify it ?

Here's the CPU pcb :



and the VIDEO pcb :



...there's no ATARI or NAMCO indication 

I've found on a website this :

 "Xevious" (Atari, 1983)
------------------------

P20: 44-pin edge connector

        component side        solder side
        --------------        -----------
                   GND  A  1  GND
                   +5V  B  2  +5V
                        C  3
                        D  4
       +10.3 VDC UNREG  E  5
               AUDIO 2  F  6  AUDIO 1
           COIN CNTR R  H  7  COIN CNTR L
              COIN AUX  J  8  TEST
                COIN L  K  9  COIN R
               START 1  L 10  START 2
                ZAPPER  M 11
                  LEFT  N 12
                  DOWN  P 13
                 RIGHT  R 14
                    UP  S 15
                        T 16  BLASTER
          START 2 LAMP  U 17  START 1 LAMP
                        V 18
                        W 19
                        X 20
                   +5V  Y 21  +SENSE (+5V)
(to control panel) GND  Z 22  -SENSE (GND)

but according my harness :




...it doesn't seems to fit the documentation... So I presume it's a Namco pcb... and I'm not able to find pinout description for the Namco pcb 

OK, so I decide to check what I can... and I try to found the +5V

The power come in wires from AR2 in two places :

- On this connector :



- and on the main harness.


A strange thing... When I remove this cable...



... and I power on the game, there is a bad smell and some smoke seems to come from the AR2 

What do you suggest ?

I would like to know which PCB version I have, in order to get the right pin out, and check at least the voltage 

[RayB]

Wow. OK, it could be a bootleg...

[dabone]

A bootleg board wouldn't bother with a ar2 or use the original custom namco chips.

I looks to be similar to a galaga boardset pinout wise.


From klov
s
The game uses three Z80 microprocessors and a Namco 3-channel PSG for sounds. The original Namco boardset uses the "Namco Galaga" pinout while the Atari boardset has a unique pinout.

The seperate video connector leads me to believe its a namco.

Pinout are here.

http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=pinout&page=Galaga.html

            

           
GND    A    1    GND
Speaker +    B    2    Speaker -
Lockout Solenoid    C    3    Coin Counter 1
P1 Start Lamp    D    4    P2 Start Lamp
+12 VDC    E    5    +12 VDC
+5 VDC    F    6    +5 VDC
GND    H    7    GND
Service    J    8    Test
Coin 1    K    9    Coin 2
P1 Start    L    10    P2 Start
P1 Fire/Jump    M    11    P2 Fire/Jump
P1 Left    N    12    P2 Left
P1 Down2    P    13    2P Down2
P1 Right    R    14    P2 Right
P1 Up2    S    15    2P Up2
   T    16    
   U    17    
   V    18    
   W    19    
   X    20    
Coin Counter 2    Y    21    Table1
 GND    Z    22    GND

6P Plug        

   1. Video Red
   2. Video Green
   3. Video Blue
   4. Video Sync
   5. Video Ground
   6. N/C

3P Plug
# +12VDC
# GND
# +5VDC

Hope that helps.

Btw, smoke from the ar2 is BAD!!

Later,
dabone

[RayB]

Well there's your starting point. (that last pinout).

Start with the 3 prong plug. (power!). Keep everything connected so there is a proper load (though DON'T keep the power on if the AR2 smokes again!) You should be able to jam the voltmeter probes down into the plug. The middle one is ground, so just measure each of the other ones.

[Rocky]

That is definitely not the Atari version.

[dabone]

Also all of the custom namco chips on that board have a known problem with corrosion on the legs.

I usually remove the chips from the sockets and GENTLY!! use a brass wire brush to remove the corrosion. Be very careful as these chips are very, very fragile.
And there are no modern replacements for them.


look here for an example.

http://www.arcadeshop.com/galaga/galaga.htm

look for the description Example of dirty and clean chip.


and most of all, good luck and have patience.

Later,
dabone

[Darth Nuno]

Thanks for all that precious informations 

Ok, so like to suggest me, a get some mesure on the pcb.

First on this connector :

3P Plug
# +12VDC          -> 29.1 on my digital Multimeter
# GND
# +5VDC            -> 10.3 on my digital Multimeter

How can I get so HUGE value

See on pictures :





When I got these values, everything was plug ON and powered.

I'm not sure my Xevious PCB has the same pinout than the Galaga...

Here's some value I got on the PCB :

no value   A  1     no value
14.5         B   2    13
1.4           C   3    30.1
1.4           D   4    1.4
no cable   E   5    no cable
11            F    6    10.8
no value  H    7    no value
10.8         J    8    10.5
10.8         K   9    10.5
10.8         L  10   10.5
10.8         M 11   no cable
10.8         N 12   no cable
10.8         P 13   no cable
10.8         R 14   no cable
10.8         S 15   no cable
no cable   T 16   no cable
no cable   U 17   no cable
no cable   V 18   no cable
10.8        W 19   no cable
no value   X 20   no cable
no value   Y 21   no value
no value   Z 22   no value

Can I use an other power supply for output correct +5V and +12V ?

What do you suggest me at this time ? 

Thanks a lot

[RayB]

WOW. What I want to know is why your board is still working and not just frying up.

Actually, you CAN use another power supply. You will probably also need an amplifier for your sound output.

But on the other hand... Why not keep it original? Do you have a power supply lying around? A rebuild kit and big blue cost about the same or less than a new power supply.

[Darth Nuno]

I've ordered a new modern alimentation. Hope it will solve the problem 
Thanks for your help 

[Darth Nuno]

Do you think modern alimentation can produce the correct voltage for that board ?

[fredster]

That's not an atari Xevious board. They look like centipedes and Asteroids boards. I've sold two of them on ebay.