City Connection PCB dead, Help!

[CHRIS-F]

Hi Guys,

I put my City Connection (bootleg) PCB in my cabinet today and it's not working, it was working a couple of years back and has been in a box untouched since then, I re capped the board before putting it away and it worked fine then, the only thing i did since then was replace the 3 big caps again as i previously used radials with bent legs, i changed them for axial's, I don't remember if I checked it after changing those 3 caps, but like i say it's sat in a box indoors since then.

Where do i start to diagnose the fault? I'm not even familiar with the MC6809 CPU so don't know what i'm looking for.

What I know so far;

It is doing something because once i plug it in the screen goes black.
The CPU is getting warm and the second CPU is also getting warm.
Pin 7 of the MC6809 CPU is getting 4.78V (is this enough?)

Thanks in advance,
Chris.

[Mike A]

Did you try turning up the +5V?

[CHRIS-F]

Hi Mike,

No, I haven't tried turning it up, I just assumed that if other games worked, then it should be fine for this game too, do some games need a bit more juice? if so what is a safe upper limit don't want to over do it and kill something, also doesn't it increase the 12V line too, is it best to measure at the IC's on the board or at the PSU?

I was trying to fault find yesterday, I know i have a reset signal it goes high after power on and stays high, and I think i have a clock signal, my multimeter set to HZ shows activity, i think it only goes up to the khz scale  so can't measure it for 8mhz but at least it shows there is some kind of signal there, I'll turn the 5V up a bit and see what happens.

Thanks,
Chris.

[Zebidee]

Mike's suggestion is good. Many PCBs are fussy about voltage supply.

Try tweaking the 5v line up to 5.1v minimum. Measure voltage at the PCB.

I did a quick search and looks like you've had issues with this PCB (& PSU?) before?

http://forum.arcadecontrols.com/index.php?topic=138541.0

[CHRIS-F]

Mike's suggestion is good. Many PCBs are fussy about voltage supply.

Try tweaking the 5v line up to 5.1v minimum. Measure voltage at the PCB.

I did a quick search and looks like you've had issues with this PCB (& PSU?) before?

http://forum.arcadecontrols.com/index.php?topic=138541.0

Yeh, I did have a few problems with my machine a while back, but I re capped the PSU with some low ESR caps as suggested by Shawn and Ed If i think and it's been fine since, it powers other game boards fine, I do have a vauge memory of having some graphical glitches with City Connection also, and remembered now they disappeared when i turned the voltage up a bit.

This board had been working fine until I put it away in a box a while back, I even tested it after re capping it, I had a sound issue that was fixed by replacing the few electrolytic caps, so i change all the electrolytic's at the same time, I only had radials though so the three big caps were radials with the legs bent and heatshrink tubing over the legs, what I can't remember is if I checked it again when the axial caps arived and I changed them.

I turned the 5v up yesterday and it didn't make a difference, the screen is mostly black, as I turned the voltage up i disconnected the board and connected it again, I think I went as far as 5.6V and the 12V was as high as 13V, as I was unpluging the board and connecting it again, different things happened sometimes it plays a few sound samples, sometimes a garbled screen like the attachment but mostly just a black screen. the CPU and Co CPU amongst other things seem to be getting fairly warm too, not sure if they used to or not.

Where do I go from here? I have a Multimeter that does logic and frequency, although the frequency only goes up to the khz range so not sure what good that will be.

Regards,
Chris.

[Zebidee]

I also have a theoretically "working" City Connection PCB, and last time I tested it (last year), it didn't work and I didn't take it further. So you are not alone and I am interested.

I'd guess your caps are probably fine if you changed them 8 years ago and minimal use. However, as seasons change from hot to cold, PCB components can go through thermal expansion and contraction, becoming loose. Seated ROMs etc. can become unseated, so make sure they are in firmly and connections sound. Rust is a real problem too, corrosion on parts and traces, especially in a humid climate, even if you keep your PCBs "dry" otherwise.

It won't hurt to buy/try a new PSU, they are like $10 give or take, nice to have a couple handy, to ensure that is not an issue.

DISCLAIMER: While I have soldering/troubleshooting skills, not much direct experience in game PCB repair. Mostly my modest collection of PCBs live in bubble-wrap for 10 years at a time, and I play the game on MAME.

[Mike A]

You should read 5V at the chips. Don't go much over that. 5.1 maybe.

If the PCB is dirty at all, clean it. Wash it off in the sink and use an air compressor to make sure you dry it out completely.

Clean the edge connector. Pull all of the socketed chips. Clean the legs. Then paint the sockets with Deoxit and reseat the chips.

Reflow the solder joints for any connectors.

Use a magnifier to check for cut traces, cold solder joints, etc.

You need to get that out of the way before you try probing around.

[CHRIS-F]

I have checked and can't see any trace damage and have also checked and cleaned the IC legs for the CPU and EPROMS.

I set the voltage so it read 5.1 volts at the CPU and other IC's, (other PCBS's are wqorking fine so the PSU looks good)
Not sure how accurate my Multimeter is but I checked pin 38 on the main CPU MC6809 and my meter shows 2.50Mhz so I assume I have a clock signal, original should be 2.048Mhz but this is a bootleg so could vary. the xtal pin 39 is connected to GND as it should be according to the datasheet when using an external clock signal.

I traced the reset circuit and when the board is not connected to the JAMMA loom the reset pin 37 is open, when I connect it to the harness it is showing low with my meter set to logic and at power on the pin goes high to 5V so it looks like the reset circuit is working.

I have read the EPROM's and 12 out of the 13 are a perfect match to the ROMset 'citycon' in MAME, but my IC 11 (which I think is the main game program code) is way different to the MAME ROM and the bootleg ROM, I don't know if it's somehow got corrupted or if it is just a different bootleg ROM, I have ordered a new 27C256 EPROM an I will burn a Bootleg ROM onto it when it arrives and see what happens.

The screen is mostly black manually shorting the reset pin to GND gives a few lines here and there on screen briefly but no difference, turning the voltage up sometimes gives a garbled screen, and occasionally a few sound samples, I hope I didn't turn it up too far 5.6V, I've lowered it back to 5.1V now.

with my Multimeter set to logic, the data pins and address pins show both low and high at the same time so I think there is data being sent.

Thanks for your help so far guys, but where do i go from here, what can I check next?
Chris.

[CHRIS-F]

Update:

As the contents of my IC11 seemed way different to anything in MAME, I ordered a replacement 27256 Eprom and burned a bootleg IC11 that i found online. It actually boots up now and runs, the only problem is I'm missing sound and apart from the Menu all the colours are wrong and some gfx issues.

Where do I go from here?

I know all the EPROM's are correct as I dumped them and they match MAME perfectly, I know the reset circuit is working as a manual short to GND resets the machine and have 5.1V at the IC's, could it be that the bootleg IC11 I found online is just the wrong code for my bootleg version? what else could be wrong?

Could I have damaged anything when I turned the voltage up to 5.6V when it wouldn't power up? what is a maximum safe voltage for future reference?

Any suggestions are most welcome :-)

[Zebidee]

Missing colors suggests ROM issues 

I recall the the original City Connection cabs had a custom sound setup.

I loved the game in an original cab (when I was around 10-12 years old), and a big part of that was the music.

I distinctly recall being on holiday with the fam, playing CC at some cafe on a generic cabinet, and while the sound was "OK", it sucked compared to the original cab I was used too.

[CHRIS-F]

Missing colors suggests ROM issues 

I recall the the original City Connection cabs had a custom sound setup.

I loved the game in an original cab (when I was around 10-12 years old), and a big part of that was the music.

I distinctly recall being on holiday with the fam, playing CC at some cafe on a generic cabinet, and while the sound was "OK", it sucked compared to the original cab I was used too.

Yeh! It was the sound I remember most about this game myself, I remember being on Holiday in Rhyl, Wales UK, I was around 11 myself and I guess that's why they call it attract mode, I distinctly remember hearing the music and then the bit where you hit the cat, I followed my ears and found the game, played it a lot while I was there, Ah! the memories :-)

Any Ideas what I can check next? I know all the EPROM's are good, I checked them against MAME with the exception of C11, but I know that's good also as I'v only just burned the bootleg c11 and verified it. I guess the sockets may be dirty, I will check continuity of the sockets next but other than that I'm clueless what to try next.

Chris.

[Zebidee]

I'm no expert in game PCB repairs, but...

Often it comes down to ROMs not being seated properly, corrosion, poor contacts. So close inspection, cleaning, reseating.

Try carefully pressing down on the ROMS while the game is running, see if anything happens.

[Mike A]

As already stated by Zebidee and me,

If the PCB is dirty at all, clean it. Wash it off in the sink and use an air compressor to make sure you dry it out completely.

Clean the edge connector. Pull all of the socketed chips. Clean the legs. Then paint the sockets with Deoxit and reseat the chips.

Reflow the solder joints for any connectors.

Use a magnifier to check for cut traces, cold solder joints, etc.

You need to get that out of the way before you try probing around.