Toki Repair

[Womble]

Board landed on my desk with a couple of faults, firstly it had no sound, secondly the game would freeze semi randomly.

 

Random crash problem was a dry joint on the crystal, someone had attempted to resolder all 4 joints but hadnt done a very good job. Removed all old solder with desolder station and resoldered the lot. Board was then solid as a rock.

 

Sound problem was slightly trickier, the amp on board was fine, touching its pins gave a buzzing noise and the volume pot worked too. Made up an audio probe and fed the output of the DAC chip into an external amplifier - I had sound, well the FM sounds, not the samples. The only thing between the DAC output and the AMP chip input was a custom SIP package, over a dozen pins, its looks like a small PCB covered in black plastic, you can see the component bulges in one face of this board. Luckily the owner had another Toki that had more serious issues, including no sound. On that board the DAC was dead so I chanced my luck, desoldered the SIP package and moved it to the other board. Flipped the power on and all sounds and samples were restored. I dont know what this little SIP board does, but I suspect its some form of audio mixer circuit. The FM sounds and samples come from separate parts of the audio section and come together at this chip before the merged audio hits the amp.

 

Problem fixed tho! Mad game too!

Edited June 13, 2008 by Womble

[KAISERSIGMAX3]

Toki pcb randomly freezing!!!!!!!

 

Hello to all of you arcade dreamers like me.

I have a Toki PCB that boots ok, plays ok, sounds ok, but lately something is REALLY BUGGING ME.

I'm experiencing RANDOM FREEZES of a strange kind.

The game suddenly stops! The screen gets static, the music continues playing normally and the game accepts more coins if I press the coin button (I can even hear the insert coin effect).

I removed and resoldered the 20 Mhz oscillator and nothing changed.

By inspecting, I can say the solder joints are OK.

All I can say is I love this game and I would really be grateful for any help.

Please help-me!!!!!:(

Edited April 27, 2015 by KAISERSIGMAX3

[Womble]

Measure the 5v rail at the pcb, not the power supply.

 

Then remove and reseat every socketed chip on the board.

[felixthadog]

Hello to all of you arcade dreamers like me.

I have a Toki PCB that boots ok, plays ok, sounds ok, but lately something is REALLY BUGGING ME.

I'm experimenting RANDOM FREEZES of a strange kind.

The game suddenly stops! The screen gets static, the music continues playing normally and the game accepts more coins if I press the coin button (I can even hear the insert coin effect).

I removed and resoldered the 20 Mhz oscillator and nothing changed.

By inspecting, I can say the solder joints are OK.

All I can say is I love this game and I would really be grateful for any help.

Please help-me!!!!!:(

 

Welcome to Aussie Arcade :D

 

Cheers,

Matthew

[KAISERSIGMAX3]

Thanks, Matthew! I'm feeling at home...:)

[KAISERSIGMAX3]

Oh, Womble...

I measured the 5V rail before a coffee break and I've seen it falls to 4.83V ~ 4.86V. I'm worried because if Im having this voltage in the JAMMA connector, maybe I'm having even less in farther regions of the PCB. Maybe all the logic is being underfed..

 

This is the supergun I built myself with audio attenuation, odd sync pulse fixer, composite and component video out, and a PC power supply.

 

 

To the right is the power supply. I used four wires for +5V and 4 wires for GND to ensure sufficient power.

 

When I was in a test phase, I did not experience any trouble maybe because I used all +5V wires coming from the power supply (at least 8 red wires) tied together.

Before I install the PS in the supergun case I tried to make it clean by removing all unused wires.

 

I'll make some tests.

 

Thank you very much...

Alex

Edited April 26, 2015 by KAISERSIGMAX3
pics in wrong place

[KAISERSIGMAX3]

So I reinforced the +5V and GND soldering in the power supply to enlarge the conductive surface and corrected a mistake I made when I removed the PS metallic shell. Basically the shell shortens some points and all I made was join them again. Now I'm reading 5V instead of 4.86 (when connected to Toki)

I'm with a sense of dread because when I read the output voltages before this correction, it was like the PS gone mad! In the +5V line, the voltmeter was going up and down from 0,54V to 4,7V like mad, almost in fixed intervals. Same for the 12V line. The -5V line was normal. I found strange when I inverted the voltmeter tips. I was reading now fixed -5V in the +5V line without the mentioned oscillation and -12V in the 12V line.

Even with these fixes, the PCB was still freezing.

 

Then I removed every socketed chip in the board, cleaned the pins plus sockets and reseated them all. I always use antistatic wrist strap to perform such a task.

Tried again and..... PCB STILL FREEZING!!!!

 

Below is a video I made that shows what actually happens.

https://www.youtube.com/watch?v=YJXRLywWjfs

 

 

Any help would be welcome.

My wife told me to forget about it for a while, but I really want to see this thing working as it should....

[KAISERSIGMAX3]

I measured the voltage directly in the chips pins near the jamma connector and I got 4.98V. In distant places 4.88 ~ 4.90V.

I powered on the PCB and left it running alone (the presetation and demonstration screens) for about 2 hours and went to do other things. When I returned, the PCB was still running fine. So I decided to play once again.

I played for about 15 minutes from beginning to Bashtar (stage 5 boss) and then the game froze again.

It seems the freezing issue happens only if there's someone actually playing the game. Any clues?

Do you think this alone discards a power supply issue?

[aaablettt]

I would play it until it freezes again. I would then get freezing spray and systematically cool segments of the board until you can get the game to start again. Then see if you can repeat this until you can isolate the fault. You have a thermal issue that appears when the game is active. One of the chips is getting stuck once it warms up through game play.

 

 

Jimmy D

[Zedmaniac]

Hello to all of you arcade dreamers like me.

I have a Toki PCB that boots ok, plays ok, sounds ok, but lately something is REALLY BUGGING ME.

I'm experiencing RANDOM FREEZES of a strange kind.

The game suddenly stops! The screen gets static, the music continues playing normally and the game accepts more coins if I press the coin button (I can even hear the insert coin effect).

I removed and resoldered the 20 Mhz oscillator and nothing changed.

By inspecting, I can say the solder joints are OK.

All I can say is I love this game and I would really be grateful for any help.

Please help-me!!!!!:(

Those epoxy encapsulated packages can be serviced. The trick is to remove the outer coating by soaking it in acetone. It takes about a day for it to become pliable and is easily removed with a sharp blade. Vintage synths use the same type of packages.

Z

Board landed on my desk with a couple of faults, firstly it had no sound, secondly the game would freeze semi randomly.

 

Random crash problem was a dry joint on the crystal, someone had attempted to resolder all 4 joints but hadnt done a very good job. Removed all old solder with desolder station and resoldered the lot. Board was then solid as a rock.

 

Sound problem was slightly trickier, the amp on board was fine, touching its pins gave a buzzing noise and the volume pot worked too. Made up an audio probe and fed the output of the DAC chip into an external amplifier - I had sound, well the FM sounds, not the samples. The only thing between the DAC output and the AMP chip input was a custom SIP package, over a dozen pins, its looks like a small PCB covered in black plastic, you can see the component bulges in one face of this board. Luckily the owner had another Toki that had more serious issues, including no sound. On that board the DAC was dead so I chanced my luck, desoldered the SIP package and moved it to the other board. Flipped the power on and all sounds and samples were restored. I dont know what this little SIP board does, but I suspect its some form of audio mixer circuit. The FM sounds and samples come from separate parts of the audio section and come together at this chip before the merged audio hits the amp.

 

Problem fixed tho! Mad game too!

[Womble]

Depends on what potting compound was used. Acetone only works sometimes, have had others soak for over two weeks and be totally unchanged.

[Zedmaniac]

Depends on what potting compound was used. Acetone only works sometimes, have had others soak for over two weeks and be totally unchanged.

Hot Dang they musta turned the goop up a notch for them ones! I've never seen that.

Edited May 24, 2015 by Zedmaniac

[KAISERSIGMAX3]

Thanks a lot, Jimmy.

I'll search for the freezing spray and try the tip.

I've dumped all roms, sent to romident and all of them are fine. No bad roms.

[KAISERSIGMAX3]

Hi Jimmy.

It's been a while since I tried the freezing spray without any discoveries or clues.

Today I discovered one thing about this Toki PCB I would like to share with you all.

First of all, My setup consists of a supergun that powers the board using an arcade PS that can deliver up to 15A through well dimensioned wires. So no power problem!

And............... I use the Tototek adapter to connect PSX pads. I have some of these pads here with me and I picked up one of them that was damaged and then refurbished and I decided to use it specially to play fighting games and it ended up being the main pad for my supergun. Newer PSX pads have a plastic limiter in the form of a X that sits on the D-pad not allowing more than 2 directions (diagonals) pressed at the same time. I replaced my pad's broken limiter with a piece of hard rubber just to be able to use the D-pad again. The problem is that in the heat of the moment, if you press the D-pad a bit more you'll end up pressing more than 2 directions. Maybe 3 or the 4 directions pressed at the same time.

TOKI seems to not like it. I can reproduce the freezing issue now when I please. I made it 5 times in a row in the first stage's first screen by pressing these many buttons.

This now explains why the PCB will not crash when left powered on for a long while alone without someone playing it.

This discards the overheating possibility too.

I tried the game with another PSX pad (now perfect) and it played fine.

I never knew in my entire gaming life of a game that crashed by receiving many inputs. I wonder what happens internally to cause such an annoying problem.

I have another perfect TOKI pcb here and I'll test later to see if the same issues happen by receiving these many inputs.

Until next time.

[Womble]

Wow, that's a weird one, thanks for reporting back, glad you got it sorted out.