brojamfootball Posted December 11, 2009 Share Posted December 11, 2009 Just had a 7800 a couple of months now. When I first got it, I plugged it up and played just a bit to make sure it worked, but am just now really starting to use it. Seems every time I put in a cart and turn it on, the first powerup never works. Turn it off and back on and it always works the second time. If I quickly power cycle it more it works every time, but if I turn it off and wait a few seconds it requires two powerups to work again. Anybody else have this going on? Quote Link to comment Share on other sites More sharing options...
+Mitch Posted December 11, 2009 Share Posted December 11, 2009 Voltage regulator going out, perhaps? Mitch Quote Link to comment Share on other sites More sharing options...
Kurisu Posted December 11, 2009 Share Posted December 11, 2009 I know my buttons are a little jumpy, but I do not have the same issue you describe, just the occasional pop on or off when I press the button the wrong way. Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 11, 2009 Author Share Posted December 11, 2009 I know my buttons are a little jumpy, but I do not have the same issue you describe, just the occasional pop on or off when I press the button the wrong way. On first power on, the system does turn on: LED lights and up TV reacts, just with a black screen or occasionally some garden variety Atari gobbledy gook. Everything is clean as a mofo by now as I've been cleaning, cleaning, and then doing a bit more cleaning in effort to make a 2600 Frogger II cart work on this machine. Quote Link to comment Share on other sites More sharing options...
Kurisu Posted December 12, 2009 Share Posted December 12, 2009 I'ma go with what mitch said: this seems to be something deeper in the system than just a funky button. I feel for you, and best of luck. This could very well be connected with your cart issues. Quote Link to comment Share on other sites More sharing options...
gdement Posted December 12, 2009 Share Posted December 12, 2009 Not sure what the cause is, but if I was to guess I'd try replacing the voltage regulator and the capacitors and see if that helps. Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 12, 2009 Author Share Posted December 12, 2009 I'ma go with what mitch said: this seems to be something deeper in the system than just a funky button. I feel for you, and best of luck. This could very well be connected with your cart issues. Aside from 2600 Frogger II, all carts work, and it's definitely not the power button. I'm kinda leaning towards the power regulator angle or something related. Changing the power regulator is not that big a deal, but I hate trial and error with no results(or maybe bad results), especially when the system basically works, just with this weird turn-in-on-twice requirement. Still crossing my fingers, hoping someone around here has seen this before and has the magic answer... Quote Link to comment Share on other sites More sharing options...
Curt Vendel Posted December 12, 2009 Share Posted December 12, 2009 Could be the 7805, might be the big capacitor as well from what he is describing. Curt Voltage regulator going out, perhaps? Mitch Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 14, 2009 Author Share Posted December 14, 2009 Could be the 7805, might be the big capacitor as well from what he is describing. Curt Voltage regulator going out, perhaps? Mitch Changed out the 7805 voltage regulator today, and...problem still exists. Dang. At least it was easy. I was pretty sure I could find one in one of my boxes/piles/stacks/closetfuls of shtuff, but ended up buying one for $1.59 at Radio Shack. They didn't have a capacitor that matched the biggie so that's the next thing to find and try. Anybody with more electronics knowledge than me know if there's playroom on the value/voltage of that capacitor? Or anybody have one laying around they'd care to send me? I have a mangled 7805 to trade Quote Link to comment Share on other sites More sharing options...
+Mitch Posted December 14, 2009 Share Posted December 14, 2009 Changed out the 7805 voltage regulator today, and...problem still exists. Dang. At least it was easy. I was pretty sure I could find one in one of my boxes/piles/stacks/closetfuls of shtuff, but ended up buying one for $1.59 at Radio Shack. They didn't have a capacitor that matched the biggie so that's the next thing to find and try. Anybody with more electronics knowledge than me know if there's playroom on the value/voltage of that capacitor? Or anybody have one laying around they'd care to send me? I have a mangled 7805 to trade Sorry to hear it wasn't the regulator. For the cap you can go up in voltage but not down and the value should be the same. Mitch Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 14, 2009 Author Share Posted December 14, 2009 Changed out the 7805 voltage regulator today, and...problem still exists. Dang. At least it was easy. I was pretty sure I could find one in one of my boxes/piles/stacks/closetfuls of shtuff, but ended up buying one for $1.59 at Radio Shack. They didn't have a capacitor that matched the biggie so that's the next thing to find and try. Anybody with more electronics knowledge than me know if there's playroom on the value/voltage of that capacitor? Or anybody have one laying around they'd care to send me? I have a mangled 7805 to trade Sorry to hear it wasn't the regulator. For the cap you can go up in voltage but not down and the value should be the same. Mitch Thank you, sir! Hope to have a reply on the result of this next step tomorrow. Cross your fingers for me. I CAN say that on visual inspection all caps look fine, but we'll see. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted December 14, 2009 Share Posted December 14, 2009 Electrolytic caps rarely look bad on the outside (unless they blew up), they usually dry out on the inside. Mitch Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 14, 2009 Author Share Posted December 14, 2009 (edited) Electrolytic caps rarely look bad on the outside (unless they blew up), they usually dry out on the inside. Mitch Hey, thanks again for the attention and input. Yeah, was just throwing in more info as I went along my merry way. Obviously, I'm less than an electronics guru--more like a brave guy with a soldering iron, although some of my electronics-shy friends would believe otherwise. At least I haven't made anything worse so far Info on 'big' capacitor replacement forthcoming here in a few hours. Edit: gonna be a few days before work moves forward. An awesome atariage member is sending me a few caps in the mail--apparently good ones that won't waste my time or need more attention later. Edited December 14, 2009 by brojamfootball Quote Link to comment Share on other sites More sharing options...
Bruce Tomlin Posted December 14, 2009 Share Posted December 14, 2009 Seems every time I put in a cart and turn it on, the first powerup never works. Turn it off and back on and it always works the second time. If I quickly power cycle it more it works every time, but if I turn it off and wait a few seconds it requires two powerups to work again. In which way does it "never work"? Does it not stay on the first time? Does it not seem to start running? (The latter might indicate that the reset circuit isn't working right.) Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 14, 2009 Author Share Posted December 14, 2009 Seems every time I put in a cart and turn it on, the first powerup never works. Turn it off and back on and it always works the second time. If I quickly power cycle it more it works every time, but if I turn it off and wait a few seconds it requires two powerups to work again. In which way does it "never work"? Does it not stay on the first time? Does it not seem to start running? (The latter might indicate that the reset circuit isn't working right.) LED light comes on and power stays on, but output is black screen. Off and on again, then it's golden. In a way I'm being bitchy 'cause the system does work, just not on first button press. Quick power cycles always come back good, but if I leave it off for a minute or two pondering what the next game to play is, we're back to square one needing to turn it on and off twice to make it go. It's like there's a capacitor or other electronic component that needs to get charged up to work or something? Reset circuit--hmmm, that's an interesting tidbit. Initial powerup gives black screen that seems similar to what is seen if reset button is held down--I gotta go back to the machine and look at that. Got any ideas what a guy would do if that circuit is screwy? Eliminate the reset button from signal path? Replace the reset button with whatever cheesy switch I can find? Pour gasoline all over it and light a match? Quote Link to comment Share on other sites More sharing options...
Bruce Tomlin Posted December 15, 2009 Share Posted December 15, 2009 (edited) Reset circuit--hmmm, that's an interesting tidbit. Initial powerup gives black screen that seems similar to what is seen if reset button is held down--I gotta go back to the machine and look at that. Got any ideas what a guy would do if that circuit is screwy? Eliminate the reset button from signal path? Replace the reset button with whatever cheesy switch I can find? Pour gasoline all over it and light a match? The button with the word "RESET" on it has nothing to do with the CPU reset, which seems to be your problem. EDIT: the reset circuit seems to be C53 (.1uf), R46 (2.2M), and U10 (4013). I doubt it's the chip, but it is CMOS, so who knows. Edited December 15, 2009 by Bruce Tomlin Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 16, 2009 Author Share Posted December 16, 2009 Reset circuit--hmmm, that's an interesting tidbit. Initial powerup gives black screen that seems similar to what is seen if reset button is held down--I gotta go back to the machine and look at that. Got any ideas what a guy would do if that circuit is screwy? Eliminate the reset button from signal path? Replace the reset button with whatever cheesy switch I can find? Pour gasoline all over it and light a match? The button with the word "RESET" on it has nothing to do with the CPU reset, which seems to be your problem. EDIT: the reset circuit seems to be C53 (.1uf), R46 (2.2M), and U10 (4013). I doubt it's the chip, but it is CMOS, so who knows. Well, guess I obviously didn't know what reset you were talking about. There's more stuff to try changing out there--thanks for the info. Gonna be a couple of days before anything else gets done. Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 20, 2009 Author Share Posted December 20, 2009 (edited) Replaced the 'big' capacitor and no improvement. Moving on to the reset circuit. Edit: Having quite a tough time locating the spots on the board for reset circuit using schematics in AtariAge archives. I may be about to give up and just live with it. It does work, after all. Edited December 20, 2009 by brojamfootball Quote Link to comment Share on other sites More sharing options...
thebiggw Posted December 20, 2009 Share Posted December 20, 2009 I had the same problem with a 7800 as well and it ended up being CD4013 chip? Anyway I called best electronics at that time and he told me it is real common on 7800's they also called it the flip-flop circuit. Not sure on that chip number but it is near the upper right hand side of the board, near the power port. I am not an engineer but they walked me through what the problem could be, and I bought the chip and some other goodies from them and it all worked out!! Now I am just waiting on my mod kit from L.E. Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 20, 2009 Author Share Posted December 20, 2009 (edited) I had the same problem with a 7800 as well and it ended up being CD4013 chip? Anyway I called best electronics at that time and he told me it is real common on 7800's they also called it the flip-flop circuit. Not sure on that chip number but it is near the upper right hand side of the board, near the power port. I am not an engineer but they walked me through what the problem could be, and I bought the chip and some other goodies from them and it all worked out!! Now I am just waiting on my mod kit from L.E. Far as I can the the chip you're referring to is the one labeled: Toshiba 8818HB TC4013BP Japan Sound right? Anyway, thanks so much for the info. First I've heard of someone else with the same problem. I gotta try and call Best Electronics and see if I can make a repeat of your experience. EDIT: Actually, now comparing your info and Bruce Tomlin's, it seems you're both on the same track and probably right. So it appears there's light at the end of the tunnel after all! Edited December 20, 2009 by brojamfootball Quote Link to comment Share on other sites More sharing options...
+Mitch Posted December 20, 2009 Share Posted December 20, 2009 Here's a scan of a blank 7800 system board. It might help you track down part numbers from the schematic. It sounds like you have a handle on it though. Mitch 1 Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 20, 2009 Author Share Posted December 20, 2009 (edited) Here's a scan of a blank 7800 system board. It might help you track down part numbers from the schematic. It sounds like you have a handle on it though. Mitch Nice! That's very helpful. That should allow me to more easily follow Bruce Tomlin's info and try replacing the other components he mentioned before I worry about the chip, which frankly I don't like the idea of replacing--tight connections without much clearance, just dying to have me accidentally bridge something, the kind of thing I'm likely to fry with too much heat, etc. Thank you! Edit: Just to let anyone know who might be reading, I forgot to mention that I also replaced the two other largest capacitors at C22 and C61 and problem not solved. Edited December 20, 2009 by brojamfootball Quote Link to comment Share on other sites More sharing options...
brojamfootball Posted December 21, 2009 Author Share Posted December 21, 2009 (edited) Update: Just changed out the .1uf capacitor at C53 and, you guessed it, the problem is still there. I'm on the quest to find the 2.2M resistor for R46 that was mentioned above. I'll change that out, then if it isn't fixed(which I'm guessing it won't be)it's on to chip-changing town, via Best Electronics. Edited December 21, 2009 by brojamfootball Quote Link to comment Share on other sites More sharing options...
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