Combatribes Arcade PCB repair

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Combatribes Arcade PCB repair

Рет қаралды 2,492

Күн бұрын

This time we are trying to fix a Combatribes PCB - a beat em up arcade game by Technos Japan made in 1990.
There is a graphical issue with the board - there are white horizontal lines all over the screen.
This time even without the help of circuit schematics we manage to track down the problem mainly using the continuity tester, oscilloscope and logic analyzer.
Enjoy!

Пікірлер: 36

@PhilBennett3D 6 жыл бұрын

It's refreshing to see an 'engineer's approach' to fault finding as opposed to yet another video of somebody randomly shotgunning a bunch of ICs or replacing all the capacitors at the first hint of an audio fault. I'd recommend purchasing some DIP test-clips for hooking up your logic analyzer leads though; they're a massive time saver :)

@christophzett 6 жыл бұрын

Actually I will do that! Just found some on ebay. And yes right - I had so many pcbs with audio problems because of a problem with the sound cpu, sound cpu's roms or rams which were pre-recapped and had replaced audio amps etc. for no reason... :-)

@leonkiriliuk 6 жыл бұрын

Thank you for your video. Your ability to show how tools and your brain can come together to deduce what the problem is and show the solution is priceless! Subscribed!

@christophzett 6 жыл бұрын

Thank you very much!

@splugereport Жыл бұрын

Super awesome to learn your logic on these. Wish me luck on these seattle boards :)

@pledg 5 ай бұрын

Thanks for the video. I have a couple of boards with missing sprite/object data so im going to trace them back using this method.

@Maxxarcade 6 жыл бұрын

This is a perfect example of why a logic analyzer is very useful vs. a simple logic probe. With RAM chips, the outputs may be pulsing, but the probe won't tell you if the data is actually correct at a given point in time. I really need to get one of these, but there are a lot of choices on the market, and I don't know how powerful it needs to be for this job.

@christophzett 6 жыл бұрын

imo you would need a logic analyzer with at least 32 channels - 64 would be better. 1GHz sampling rate would be great. I really can recommend the Tektronix TLA715 with a TLA 7N3 2 GHz sampling module and 2x P6417 probes for 64 channels. Overall a reasonable priced setup I think. Theres cheaper USB devices but they usually don't offer the amount of channels you really need.

@5976575 5 жыл бұрын

I can recommend Sigrok software, it's Open Source. They also has list of supported devices sigrok.org/wiki/Supported_hardware

@trentjackson4816 3 жыл бұрын

You ramble on, drag things out and sometimes talk some shit, but you are a very, very good electronics technician. 5☆

@christophzett 2 жыл бұрын

Thanks man! ;-)

@lustfulvengance 6 жыл бұрын

You know whats crazy is that everything that is on that board now takes place in a very small corner of ONE chip in modern electronics!! Crazy to think about how far we have come in a few decades!

@christophzett 6 жыл бұрын

Yes that's true! ...and I think it's a blessing and a curse. Modern electronics are unrepairable.

@nicolaslacoste9367 6 жыл бұрын

Very well explain. Thank very much for all yours videos

@christophzett 6 жыл бұрын

You are welcome!

@snesfan8935 5 жыл бұрын

Yey! it works again!!!! It's alive, it's alive!!!!!

@RayR 6 жыл бұрын

Thanks my friend. Your a talented teacher.

@christophzett 6 жыл бұрын

Thank you very much!

@azariayehezkel9064 6 жыл бұрын

Raymond Rivera Why you dont use clamp for logic analyzer aligator clip? There is different size for ttl chip

@azariayehezkel9064 6 жыл бұрын

Its hard understand for beginners I a sub engineer and 10 years and hard for me And need expensive tool for this

@christophzett 6 жыл бұрын

Yes, you are right. My videos probably appeal mostly to people with some experience with electronics and especially ttl circuit design. Expensive tools like the logic analyzer are not really required - it was just used in this vid to confirm our hypothesis about the dead ram chip. But that was not really necessary - we could just have replaced it to comfirm it. The tools you do need are the multimeter, the logic probe and sometimes an oscilloscope (which is not too expensive, any used 20-40 MHz 2 channel device should do) .

@christophzett 6 жыл бұрын

I have to get one of those ic test clips :-)

@JasonPullara 6 жыл бұрын

awesome. liked before i even watched.

@christophzett 6 жыл бұрын

Thank you for your blind trust ;-)

@casaborg 17 күн бұрын

hi buddy i have the same board, but not sound at all, i changed capacitors, the amp, is working, its hot...this board uses ram sound?

@sandorrozsa6148 5 жыл бұрын

Thank you for this great video. Good to see that it works again. Subscribed. I'm electrical engineer, but unfortunately i couldn't spend time on arcade or PCBs earlier. Is the test board (connection to CRT TV) your construction? Or can i purchase such board? Possibly with VGA (LCD) monitor connection?

@christophzett 5 жыл бұрын

Sándor Rózsa Thank you very much for the positive feedback and for subscribing. And, yes the test pcb hes been made by myself some years ago and I still use it on my test bench. Its perfect for an easy hookup of psu, monotor and test controllers. Try searching the e bay for „mak jamma“ and you should be able to find something similar! I wish you all the best for your future repairs!

@sandorrozsa6148 5 жыл бұрын

@@christophzett Okay, i try this. Thank you for your reply and for your kind help.

@sandorrozsa6148 5 жыл бұрын

@@christophzett Could i ask you this Combatribes PCB version contains a free play mode? Or only coin insertion mode?

@christophzett 5 жыл бұрын

@@sandorrozsa6148 Yes it does!

@sandorrozsa6148 5 жыл бұрын

@@christophzett Thanks.