Pure Electronics Repair 2: Part 2 Learn Methodical Fault Finding Techniques To Fix Almost Anything

[@alexguvera4137]

I'm a business advisor and binge watch your videos. In-depth explanation and so much to learn. Love from Pune, India. 🇮🇳

[@Iceking007]

Eagerly awaiting part 3!!! 😁 Who else was pointing at the screen and vigorously shouting "Ground Wire - Ground Wire - Ground Wire!" haha Great stuff, thanks Richard; I'm a subscriber now, please keep it coming.

[@Chipset53]

New to your channel. Have dabbled with electronics and watched many u-tube channels. I find your approach in explaining troubleshooting extremely informative. Thanks. Looking forward to catching up on all your videos to date.

[@wherami]

watching your video at 1.5 speed works pretty well . anything higher than that the speech becomes garbled. i have had a lot of people tell me of late they only watch videos on2x.

[@budgiefish]

Looks like a pretty standard data bus/addressing setup there - the 573 will be used to select devices to read (chip enable) and will connect those devices bits to the data bus (you can see there's one per DIP switch), one for EPROM sockets... They're essentially parallel switches - in a normal (inactive) state the CPU will have nothing connected to the data bus (but will be connected to all the 573s in parallel), and the microcontroller will enable 573 chip 1 to connect all the data lines through to read the bits (1 or 0) from the 1st DIP switch, chip 2 to read bits from DIP switch 2, so on and the EPROM will be read similarly (but also with separate addressing lines) through another 573. A live running diagnostic may be better, you can then firstly check for any stuck logic on the data bus (cpu side) as that will cause undeterminable problems :)

[@hernancoronel]

I totally back this approach! In some sense it is like using the machine to fault find itself rather than testing everything, thank you for the video Richard!

[@hernancoronel]

Adrian from Adrian’s Digital Basement uses deoxit in sockets and other electronics with great success maybe you could try some of that stuff. You are an inspiration, thank you for your very educational videos Richard and keep up the great work!

[@Dutch-linux]

it is a voice rec/play chip ISD2560P VOICE REC/PLAY youtube wont let me post the link to the chip but you can do a search for that

[@LearnElectronicsRepair]

Thank you

[@speedbeagle6498]

I recently tried to replace tracks on a CRT TV chassis that had been folded in half. I spent a few days in my spare time working on it, but in the end I got no love from it. Only reason I did it was because it was a 19" CRT and they're hard to find for arcades I build. It was a good exercise though I'm not sure I'd bother with it again. When something is this far gone I'm just not convinced it's worth the time.

[@jonnyduncan7056]

You have the patience of a saint.

[@josherickson7404]

ISD1760PY-ND is the substituted part number. IC VOICE REC/PLAY 120SEC 28DIP. Hope this helps.

[@LearnElectronicsRepair]

Thank you I know some guys here would know what that was

[@josherickson7404]

@@LearnElectronicsRepair Hi, no problems. if you search it up you can also get a 5V Arduino Voice record/Play module to play/program it. Might possibly work with the originals. Thanks for the reply.

[@KB1UIF]

Rich, those chips look awfully like the common 28pin 27256 EPROM to me. I should say the EEPROM or write once PROM equivalents of the 27256 windowed version. But looking it up they do appear to be the Voice Record / Playback chip ISD2560P. So based on that, maybe the one version speaks Spanish and the other speaks USA English.

[@LearnElectronicsRepair]

Si, claro 😄

[@Iceking007]

Genius!

[@orion310591RS]

Boards this dirty should not even be measured, 10 second cleaning with contact cleaner and good brush can/will save hours of troubleshooting in wrong directions. Its good to have some habits and checklist what steps to do in which order to be good troubleshooter. 23:35 35:30 - DIP switches are on different positions while you were measuring. Could be unrelated, but could be related. Some multimeters, in diode mode, bleep because they charge capacitors. Are you sure that this is not your case? My method of checking multiple IC chips is following: First locate pin on board which is ground. Then use diode mode and red probe on that pin on IC, while IC is out of circuit. Then touch each pin of IC with black probe and write a chart. Then repeat for second IC, while both of them are out of circuit. Difference is easily spotted. IF and only IF, board revisions are the same, this can be repeated for board slots for IC legs. Then investigate difference. 50:00 - Lemon acid can help to remove rust and battery leaks. Dont use strong chemicals they can ruin board even more. Regarding the chip, I just googled "isd2560 circuit" and found circuit and pdf datasheet, I believe its what you need. Use website alldatasheet [dot) com and search part number ISD2560P.

[@LearnElectronicsRepair]

@orion 310591 I changed the DIP switch settings (mentioned in the video) to make sure that was not causing the difference, maybe you didn't see that? Anyway it wasn't the DIP switches. I did try to find the datasheet (on alldatasheet.com and elsewhere) but was searching for 2560P so didn't find it. Well done for going one step further 😉 I think your method of probing is similar to mine that I used in this video. I just did it from what I thought was the eprom (was audio samples which I suppose is a kinda ROM really, and I also mentioned that possibility in the video) and I built up a map of connections that way. I guess we all have different methods to achieve pretty much the same thing. Regards the Fluke 79, when in diode test mode it gives one short bleep for a semiconductor junction and a continuous bleep for a short. In continuity (low ohms) mode it does not bleep at all on semiconductor junctions but still give continuous bleep on short (and also as you say bleeps for a short time while a capacitor is charging) I was getting too many false positives in diode mode so later in the video switched to continuity ohms mode. PS thanks for keeping me on my toes and raising these issues 🙂

[@jeremylaidman6525]

These boards must cost a small fortune to replace, to make it worthwhile you spending so much time on them, with no guarantee of success. Great for us viewers though. I appreciate the time you're putting in.

[@LearnElectronicsRepair]

Yes he has a number of these machines and only one working PCB. He has at least four bad ones and they are very expensive to replace

[@BjornV78]

Keep in mind that those red DIP switches are known to fail over time, even when they are not used often or even long periods of time in the same position. This can gives strange results, because you don't expect that they can fail. I seems that the contacts become oxydized over time and the resistance goes way up.

[@LearnElectronicsRepair]

Yeah I did mention that possibility in the video also. As I don't believe he ever changes the settings I could check with him and possibly just remove the switches and put some wire links in where needed

[@budgiefish]

@@LearnElectronicsRepair A resistance check will pretty much show anything failing there, it'll be logic 1 or 0 at +5V TTL logic level I expect so would have to be pretty high resistance to be a problem, in the Megs I guess, particularly as next to no current flow?

[@davet3804]

Fascinating, better than most detective thrillers on Netflix! I still need to know why the 5.6v regulator was getting so hot . 🤔

[@reacey]

Looking forward to the follow up vid

[@davesdigitaldomain]

after watching most of your videos it seems to me that a lot of the electronics in the Canary Islands seem to suffer with corrosion,

[@LearnElectronicsRepair]

Definitely!

[@benhumphrys1656]

@@LearnElectronicsRepair hmm corrosion acts when there are dissimilar metals in contact in the presence of moisture. On the video it looked as though the copper tracks under the solder mask were intact. So maybe the exposed copper/ solder had corroded. How about brushing some lacquer over the soldered contacts, to improve protection a little bit in humid environments?

[@ralphj4012]

Interesting. Personally, I would not reconnect the original board (marked O). Re my previous comment, and unless there is a motor configuration I am not familiar with, you cannot connect 'both motors' to one of those stepper controller ICs. There is (probably) only one two phase stepper (which is odd for just a blower motor) which requires both ICs to drive it. it is no surprise the fuse went bang and I suspect some of the 24V supply and both controller ICs are damaged (which could further damage the motor). Recommend the purchase of a grinding pen, if available in your location.

[@LearnElectronicsRepair]

I'm not sure those motor controllers are the blowers actually - they may be something to do with releasing the puck when you start a game. It's possible the blowers are switched by the two relays. I suspect that motor driver modification/botch worked for some time but it needs putting right. The next step I think is to determine if the micro-controllers are good. I ordered 20 of those HC573 so I can just change them all. Other than that, if I can determine the micro-controllers are good, I may also just replace all the remaining ICs (motor controllers, Audio Amps, and the glue logic as well. Since publishing this video I also spotted a 24LC01B near the voltage regulators and green LED. I can check that to see if the processor is trying to access it When I had all the boards powered up on the machine I checked the voltage rails (5V, 12V) and they were good. A lot now also depends on how much the owner wants to pay to get these fixed.

[@ralphj4012]

@@LearnElectronicsRepair Yes, something to do with pucks etc. makes more sense. I would still check the motor type and controller datasheet carefully before reconnecting. 2 IC's are required to drive a single 2 phase stepper. I would hate to see the motor being damaged. There may be a 24V supply which has been damaged, not sure. Good luck (Neeson style ho, ho).

[@keithking1985]

Another one for a save file. 😉👍🇮🇪

[@barrymerridan5891]

The dip switches are set different on both boards, surely they should be the same.

[@felipehernandezhernandez5533]

La memoria eeprom nunca vi una dañada siempre capacitores y relays y dip swcth sucios por el polvo en algunas ocaciones el controlador del motor de C A , saludos desde mexico

[@noddyspuncture]

Where is Pt3 please...? I wanna see the verdict..!

[@Dutch_off_grid_homesteading]

Heya, that is a lot of work have to see P3

[@darkdepth1991]

Maybe give the boards an ultrasonic clean before troubleshooting that dirty boards.

[@chocomochino]

Professor! (That's how i refer about you to my wife) i was just waching this series, what happened to the Arcade game? they worked?? is there another video in these series? greetings from mexico

[@63mrl]

A pencil eraser works great to clean chip pins

[@jamescoon9950]

Change the sockets Joes arcade repair always replaces them.

[@johnparker787]

turned pin skts. unless green with corrosion, they last for ever. I've watched joe's stuff, weeeeeell - lets just say ..... non professional.

[@carlos040256]

seems to be a Winbond voice record IC

[@LearnElectronicsRepair]

Thanks 🙂

[@techquirks707]

Nice content 👍 Subscribed!

[@computersrepaircotesaint-l7407]

Great video. thx

[@featurelessrecordings9588]

Where's part 3...Was it fixed..??

[@bjorntheviking6745]

Bud that is not an eprom, I am sure it is a voice record play IC

[@bjorntheviking6745]

Should have read the comments first y’all already told him

[@andywebber8749]

I work in this industry these board are 15 pounds to buy

[@hoobsgroove]

look in meme, that's what everybody dumps eeprom codes for arcade