kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 It's still 22.3v 1 minute ago, ChildOfCv said: Yeah, that's it. Leave the logic board ribbon cable unplugged, and get a voltage reading with black and red on opposite legs of the capacitor. Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 4, 2020 Share Posted May 4, 2020 2 minutes ago, kevincondrick@gmail.com said: It's still 22.3v Sorry for missing your voltage reading. I edited my last post. Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 4, 2020 Share Posted May 4, 2020 Oh, and put the 7407 you have back in. Let's really draw some power from the board. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 4 minutes ago, ChildOfCv said: Oh, and put the 7407 you have back in. Let's really draw some power from the board. With everything together it's about 20.6 Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 4, 2020 Share Posted May 4, 2020 2 minutes ago, kevincondrick@gmail.com said: With everything together it's about 20.6 That's back where we started isn't it? Is the test resistor bridge still connected? Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 Yah there still connected they get really hot tho. Also what about the c5 missing you think that's a problem Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 4, 2020 Share Posted May 4, 2020 6 minutes ago, kevincondrick@gmail.com said: Yah there still connected they get really hot tho. Also what about the c5 missing you think that's a problem Could you switch to AC mode and check the voltage at the same point? It's hard to read the labels on this low-res scan of the service manual. If C5 is the blob that's on the negative voltage supply though, it's not a current concern. You could look at the solder side of the board though, and look for evidence that there may have once been a capacitor there once. Actually a good high-res picture of the solder side would help to match components to the schematic anyway. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 I did try that it goes up to about 14 then 0s out and dose it again. Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 4, 2020 Share Posted May 4, 2020 It cycles between 14 and 0 volts? And that's without you moving the probes? Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 I did resolder some of the things but I don't think there ever was a cap in there Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 2 minutes ago, ChildOfCv said: It cycles between 14 and 0 volts? And that's without you moving the probes? Yah it jumps around but it seams like 14 is the highest Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 4, 2020 Share Posted May 4, 2020 1 minute ago, kevincondrick@gmail.com said: Yah it jumps around but it seams like 14 is the highest Then it sounds like the capacitor isn't making a good connection. It could be the opposite of the usual problem (internal short/leakage) and instead the wire is broken inside. Did you already replace the 2200? Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 Just now, ChildOfCv said: Then it sounds like the capacitor isn't making a good connection. It could be the opposite of the usual problem (internal short/leakage) and instead the wire is broken inside. Did you already replace the 2200? I have not but I did replace the smaller caps the .1uf and the 100uf. Also I know I blow out that one voltage 12.v regulator wile testing ? so that might be a problem I plan on getting a new one of them. Also I also planed on getting new caps for the 2 main. So if you think that's the problem we can check it all again when I replaced them Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 4, 2020 Share Posted May 4, 2020 Just now, kevincondrick@gmail.com said: I have not but I did replace the smaller caps the .1uf and the 100uf. Also I know I blow out that one voltage 12.v regulator wile testing ? so that might be a problem I plan on getting a new one of them. Also I also planed on getting new caps for the 2 main. So if you think that's the problem we can check it all again when I replaced them Yeah there's definitely something weird going on with the 2200 if you get such crazy readings. It's as if it connects for a little bit, then due to temperature changes or whatever, it disconnects and then repeats. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 Just now, ChildOfCv said: Yeah there's definitely something weird going on with the 2200 if you get such crazy readings. It's as if it connects for a little bit, then due to temperature changes or whatever, it disconnects and then repeats. Yah those resistors were real hot that on there to I didn't know if that was normal or not. Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 4, 2020 Share Posted May 4, 2020 2 minutes ago, kevincondrick@gmail.com said: Yah those resistors were real hot that on there to I didn't know if that was normal or not. They were draining a lot of power straight to ground, so yeah they were going to get hot. It's possible that they are quarter-watt resistors too, and in my head I was thinking of half-watt resistors to do the job. Basically they have to handle 2W of power. So definitely not a permanent solution, but I only wanted to know if they would ease the suffering of the logic board. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 1 minute ago, ChildOfCv said: They were draining a lot of power straight to ground, so yeah they were going to get hot. It's possible that they are quarter-watt resistors too, and in my head I was thinking of half-watt resistors to do the job. Basically they have to handle 2W of power. So definitely not a permanent solution, but I only wanted to know if they would ease the suffering of the logic board. I mean it did seam to help alittl you think if I were to add more resistors it could get back down to were it needs ? Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 4, 2020 Share Posted May 4, 2020 5 minutes ago, kevincondrick@gmail.com said: I mean it did seam to help alittl you think if I were to add more resistors it could get back down to were it needs ? Possibly, but it's not the best solution. Just a convenient test. Here's another question: With everything still hooked up, test in AC mode, between the two blue points. Then between the two red points. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 9 minutes ago, ChildOfCv said: Possibly, but it's not the best solution. Just a convenient test. Here's another question: With everything still hooked up, test in AC mode, between the two blue points. Then between the two red points. I'll test it tomorrow i don't have time now Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 4, 2020 Author Share Posted May 4, 2020 18 hours ago, ChildOfCv said: Possibly, but it's not the best solution. Just a convenient test. Here's another question: With everything still hooked up, test in AC mode, between the two blue points. Then between the two red points. I got 10.6 on both Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 6, 2020 Share Posted May 6, 2020 For future reference, here's a cleaned up schematic and PCB for the power board. I don't know if I got all the labels right (blobs are just hard to read, after all), but I'll refer to these labels since they're readable. IntellivisionPower.zip Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 6, 2020 Author Share Posted May 6, 2020 1 hour ago, ChildOfCv said: For future reference, here's a cleaned up schematic and PCB for the power board. I don't know if I got all the labels right (blobs are just hard to read, after all), but I'll refer to these labels since they're readable. IntellivisionPower.zip 108.73 kB · 1 download Ok thanks ? Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 6, 2020 Author Share Posted May 6, 2020 11 hours ago, ChildOfCv said: For future reference, here's a cleaned up schematic and PCB for the power board. I don't know if I got all the labels right (blobs are just hard to read, after all), but I'll refer to these labels since they're readable. IntellivisionPower.zip 108.73 kB · 2 downloads Do you know what the k means on the diodes Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted May 6, 2020 Share Posted May 6, 2020 5 hours ago, kevincondrick@gmail.com said: Do you know what the k means on the diodes That's just how they mark the c(k)athode. It's equivalent to the vertical line indicating polarity. Quote Link to comment Share on other sites More sharing options...
kevincondrick@gmail.com Posted May 6, 2020 Author Share Posted May 6, 2020 Ah I see Quote Link to comment Share on other sites More sharing options...
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