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TheSolderMonger

Explosive Fairchild Channel F problems

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my channel f stopped working correctly, it only outputs a blank screen to channel 3 and nothing to 4, I'll get back to you once I figure out what is wrong with mine

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Drat, well that rules out the PSU. I'm looking at doing a recap of the main logic board or a MUCH closer look at the soldering to rule out cold/broken joints and another 12 regulator replacement. Could it be possible for you to measure the 12 volt regulator INPUT voltage? If so I could reverse the path of the traces to a possible malfunctioning component.

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On my machine, the eject button pops off (like a lego brick) , not held in by screws/glue and the RF shielding pops off easily, just leaf spring metal pressure. I still recommend caution on your machine since mine was slightly disassembled when I bought it.

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post-65010-0-31160600-1534462598_thumb.jpg

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Could you check the 1000 uf capacitor and see if it's outputting 23 volts? It could be that the cap is bad. Also, I checked 2 caps on the logic board close to the regulators and they are getting 12 and 5 volts, but I check the other end and my probe gets nothing. Could that be a sign of a faulty capacitor?

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I have a channel f that's doing the exact same thing yours is doing. I already swapped all the caps and both voltage regulators with no change. When the system is cold it runs alright for a min or so but then the screen goes blank. The 7812 has 24v coming in and 12v coming out and the 7805 has 12v in and 5v out. Have you been able to identify the problem yours is having? My though it something ahead of the 7812 is the source of the issue.

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I managed to kind of sort of identify the problem area in my channel f that's doing the same thing yours is. I went over the board while it was turned on with freeze spray and it seems that the fcm9101/n chip is the culprit. As soon as the screen went all crazy I hit that chip with the freeze spray and it went right back to normal. Unfortunately none if the solder joints are suspect and u can't seem to find any shorts going into that chip, so my guess is that the chip itself has gone bad and needs to be replaced.

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On 9/1/2018 at 5:18 PM, Jerilock said:

I managed to kind of sort of identify the problem area in my channel f that's doing the same thing yours is. I went over the board while it was turned on with freeze spray and it seems that the fcm9101/n chip is the culprit. As soon as the screen went all crazy I hit that chip with the freeze spray and it went right back to normal. Unfortunately none if the solder joints are suspect and u can't seem to find any shorts going into that chip, so my guess is that the chip itself has gone bad and needs to be replaced.

I am ressurrecting this topic because this is precisely my issue. My series 1 Channel F would come up fine at first but over about a minute the picture would slowly degrade until it finally went black. I opened it up, hit the board with freeze spray, waited (this time took several minutes because it was cold) and when it started to go wonky I hit the fcm9101n chip with the spray and it went back to normal. My bother and I looked all over the board and nothing seems to be wrong with any of the soldering or anything, no obvious burnt out caps or whatnot. I have tried shielding all around the chip when spraying it so only the chip is getting the freeze spray. Fixes it every time.

 

Dumb question, but that means I have to find another of those chips right? And the only way to do that would be to find a Channel F for parts? I'm pretty sure it would have to be the series 1 kind to work with mine.

 

In addition...I'm not actually sure how to remove the motherboard completely from the aluminum bottom. There's something next to the controller ports holding it in place I'm afraid to force. If anybody knows how to get it apart I'd appreciate it. Obviously if I have to do any soldering I have to get to the underside. (We lifted it up as much as we could so we could see and again it looked fine.)

fcm9101n.jpg

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Amazingly I just got one of these units and am experiencing the same issue, plugged it in, powered it up and after about 5 min loses power. If I wait a few minutes i can turn it back on and play again. If any of the other members that had this problem and fixed it please post how/what you did. 

NeitherSparky: I saw this on another site earlier and might be what you are talking about, look like there are 2 clips you have to pry at.

20200616_223556.jpg

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17 hours ago, mistermarc said:

Amazingly I just got one of these units and am experiencing the same issue, plugged it in, powered it up and after about 5 min loses power. If I wait a few minutes i can turn it back on and play again. If any of the other members that had this problem and fixed it please post how/what you did. 

NeitherSparky: I saw this on another site earlier and might be what you are talking about, look like there are 2 clips you have to pry at.

20200616_223556.jpg

Thank you but no, I got the top and bottom cases apart, the problem is the motherboard is attached underneath to the bottom case by something I can't see so I'm afraid to try and rip the motherboard away.

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