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 :)
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... :-)
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!
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.
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.
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!
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) .
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?
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!
![The Combatribes Longplay (Arcade) [4K]](http://i.ytimg.com/vi/PoZukXtIhJY/mqdefault.jpg)
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 :)
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... :-)
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!
Thank you very much!
Super awesome to learn your logic on these. Wish me luck on these seattle boards :)
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.
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.
I can recommend Sigrok software, it's Open Source. They also has list of supported devices sigrok.org/wiki/Supported_hardware
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.
You ramble on, drag things out and sometimes talk some shit, but you are a very, very good electronics technician. 5☆
Thanks man! ;-)
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!
Yes that's true! ...and I think it's a blessing and a curse. Modern electronics are unrepairable.
Very well explain. Thank very much for all yours videos
You are welcome!
Thanks my friend. Your a talented teacher.
Thank you very much!
Raymond Rivera
Why you dont use clamp for logic analyzer aligator clip?
There is different size for ttl chip
Its hard understand for beginners
I a sub engineer and 10 years and hard for me
And need expensive tool for this
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) .
I have to get one of those ic test clips :-)
Yey! it works again!!!! It's alive, it's alive!!!!!
awesome. liked before i even watched.
Thank you for your blind trust ;-)
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?
Very good video. Danke!!
You are welcome!
Hi
I dont have any sound a all with my pcb combatribes..im looking for the shematic online and there is nothing
Can you help me please
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?
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!
@@christophzett Okay, i try this. Thank you for your reply and for your kind help.
@@christophzett Could i ask you this Combatribes PCB version contains a free play mode? Or only coin insertion mode?
@@sandorrozsa6148 Yes it does!
@@christophzett Thanks.