deadl0ck Posted August 24, 2020 Share Posted August 24, 2020 Hi all, I picked up a broken Lynx 2 for cheap (15 Euro) and I hoped to repair it. It's my first Lynx so this is all new to me, so please bear with me.. So I've taken it apart and cleaned and I've recapped it fully, and replaced the MOSFET but still no power. I then tried the power trick with the wire from battery -ive to the headphone jack +ive. The screen lights up but that's it (even with a game inserted). I had lightly soldered the wire to the headphone +ive and it fell off, so I tried it again just to see for sure if anything was on the screen and it actually turned on once and the game started (so it's not totally dead) Here's the strange bit: when it played I took the wire away to cut out the bypass and it stayed playing. I've tried it a few times more but the game won't start again, however, it seems I can turn on the Lynx and it lights the screen if I just touch the wire to the headphone +ive and then remove - it does not need to have a constant connection. The one thing I did NOT do was clean the little power switch as it was kind of glued to that plastic wire loom, but I'm going to disassemble again and and remove it and give it a clean, that's all I can think of - any advice or suggestion would be great. Thanks all! Another thing that occurred to me was maybe the copper RF shield that I had to partially lift up to get at C3 was touching something, so I may make sure C3 pins are properly insulated with some kapton tape. Here's what I bought (this is the seller pic - I should have take a before pic): Here's the WIP: Quote Link to comment Share on other sites More sharing options...
+karri Posted August 24, 2020 Share Posted August 24, 2020 As the game started up at least once it means that most chips are ok. I would probably connect +5 V from a lab power supply directly to the +5V trace and GND on the Lynx PCB to see that it works. If it does, then the fault is in the power on/off circuitry. Quote Link to comment Share on other sites More sharing options...
Nop90 Posted August 24, 2020 Share Posted August 24, 2020 Grounding the headphone jack vwith 9v is the worst thing you could do. If the zener is gone the 9V fries one or more of the chips. If the lynx doesn't start anymore that's what probably happened. Try again powering with only 5v and check if there is a chip getting hot (you have to remove the metal shield on a lynx 2), this is a hint that the chip is dead. Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted August 24, 2020 Author Share Posted August 24, 2020 Thanks @karri - I'll have to see what I have that can output 5V - I don't have a lab power supply Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted August 24, 2020 Author Share Posted August 24, 2020 It's still starts @Nop90 - but just a white lit screen. Game only started once Quote Link to comment Share on other sites More sharing options...
Nop90 Posted August 24, 2020 Share Posted August 24, 2020 The lcd blacklight turns on, but the systens doesn't start anymore according to your description. I bet on a burned chip. Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted August 24, 2020 Author Share Posted August 24, 2020 Yeah - but at the beginning it only gave a white screen, and then once for some reason it started - then white again after that Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted August 24, 2020 Author Share Posted August 24, 2020 Out of curiosity - is the Copper RF shield really necessary ? Quote Link to comment Share on other sites More sharing options...
Nop90 Posted August 24, 2020 Share Posted August 24, 2020 Avoid 9v and maybe you could be so lucky to find the problem and fix it without changing the chips. First thing is to clean the pcb with isopropyl alcohol. There could be short circuits for dirty or acid from the capacitors. Also clean the cart and cart connector contacts. A bad cart connection could cause a hame not to start. You can do the cart trick (two pins of the vart connector to short) to make the lynx turn on without a cart, that should show the Insert cart message on the screen of a working lynx. If the cart trick has no duccess start checking the single components. The power on circuit is probably broken, but for the moment you can power the circuit with 5v after the ppwer circuit. Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted August 24, 2020 Author Share Posted August 24, 2020 Hmm... So this is what was under the power buttons - broken traces - similar on the other side also - am I screwed ? Quote Link to comment Share on other sites More sharing options...
+karri Posted August 24, 2020 Share Posted August 24, 2020 You could wash the traces with isopropyl alcohol and put a coat of tin on them. If some trace is completely broken solder a wire to get it connected. Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted August 24, 2020 Author Share Posted August 24, 2020 I have some very old conductive paint that might work actually. it's in a little bottle like nail polish, I'll need to check it. Any maybe some type of stencil for very thin lines...I'll see what I can come up with Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted August 24, 2020 Author Share Posted August 24, 2020 Would bad traces with occasional connection explain the behaviour especially since it booted once? - i.e. if there were connections sometimes and not others ? Quote Link to comment Share on other sites More sharing options...
+karri Posted August 24, 2020 Share Posted August 24, 2020 In my opinion - yes. For testing I would solder in a wire between the pins 31 and 33 on the cart connector. Then you don't need to have a cart when starting it up. There is also another solder in some other thread that short circuits the Power On button so that the Lynx starts when you apply power. Then you don't have to mess around with buttons. You just need the main board. Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted August 24, 2020 Author Share Posted August 24, 2020 OK - Great. So I just need to find what other solder for power on and then the buttons are irrelevant for testing if they lynx powers up. If it powers up then I know the issue is with the membrane. Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted September 5, 2020 Author Share Posted September 5, 2020 OK - I need to get back to this as I was busy for the last while and left it. Here's the Lynx II schematic off Console5's website ( https://console5.com/wiki/File:Atari-Lynx-II-Schematic-(Hayato)-C104247-6-29-90.png ) Basically this part: Do I need to connect +5 to power to try and turn it on without a flex/membrane circuit ? Thx ! Quote Link to comment Share on other sites More sharing options...
+Stephen Moss Posted September 7, 2020 Share Posted September 7, 2020 Personally, I would be inclined to use a small piece of wire and touch it between pins 14 & 11 of U6 to switch on and between pins 7 & 11 to switch off, that always works for me. I think the Power connections shown in that image are for supplying to the flex circuit not for powering the Lynx on/off. Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted September 7, 2020 Author Share Posted September 7, 2020 (edited) Thanks so much @Stephen Moss - that's just what I was looking for. Just to be sure - Have I numbered the pins correctly here? : Edited September 7, 2020 by deadl0ck Typo Quote Link to comment Share on other sites More sharing options...
+Stephen Moss Posted September 8, 2020 Share Posted September 8, 2020 No, those pin numbers are incorrect... Pin1 is Top Left Pin 7 Bottom Left Pin 8 Bottom Right Pin 14 Top Right Often there is a little indentation in the top of the case near one corner or the centre of one end and pin 1 is locate to the left of that, if you cannot see one then on rectangular device with the text horizontal and reading left to right pin 1 should be the bottom left corner and the pin numbers increase in a counterclockwise direction. 1 Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted September 8, 2020 Author Share Posted September 8, 2020 Thanks @Stephen Moss ! I was looking for a notch and couldn't find one - just as well I asked !! You the man !! Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted January 6, 2021 Author Share Posted January 6, 2021 HI - I eventually got back to looking at my Lynx II today. I have the flex cable totally disconnected as there are so many bad traces on it I can power it on by touching pins 14 & 11 of U6 with a piece of wire, as you suggested @Stephen Moss but all I get is a lit up screen with no game starting. Could the wire from battery -ive to the headphone jack +ive that I did at the start have killed something ? Where can I go from here ? Thanks ! Quote Link to comment Share on other sites More sharing options...
+Stephen Moss Posted January 7, 2021 Share Posted January 7, 2021 Unless something is getting very hot it is difficult to know that horrid headphone hack has damaged something or not. If you have a DMM locate MOSFET Q12 set your DMM to the 20V DC range, the G as S pins should be Marked on the PCB place the com lead of your Meter on the S pin and the other of the large tab on the opposite side to the G and S pins, if using batteries I would expect an reading of 1-2 volts. with an external power source I would expect a reading of about 4 volts, it does not necessarily relate to the nothing happing issue but I does establish if the Zenner is functioning. I do not recall ever powering up my Lynx without the flex circuit connected and so do not know if that would prevent a game running or not, I would think it unlikely but my Lynx is at work and we are under a national Covid lockdown so it will be at least 8 weeks before I can get to it to verify if that is an issue or not. You say your flex circuit have many bad traces, are you basing that on just appearance or have you confirmed via continuity testing? If you have confirmed you can get pens with conductive ink that you could use to try to repair it. Alternatively, you may still be able to purchase a replacement, you might want to try a forums search for a retailer as the question of where to get a replacment has come up before but off the top of my head I think Best Electronics sell them. If you look the the top left corner of the schematic, your will see R1, D1 C3 and TP1, this holds the reset pins of Hayato and Suzy low for a short period of time after power up while the power to stabilizes. If my Lynx was powering up but nothing was happening the first two things I would check are that Suzy and Hayato are getting the correct voltage to their power pins and that the reset circuit is operating correctly. If you can locate and get easy access to TP1 and have a DMM then set it to the 20V DC range, place the Com lead on either the S pin of Q12 or pin 7 of U6 and the V/Ohm lead to TP1. If you are powering the Lynx from batteries then I would expect you to get a reading of about 6 volts, if powering it form an external supply then I would expect that to be about 9V. Assuming you have a cartridge inserted and that having the flex circuit being disconnected is not an factor. If you are not getting those voltages then depending on what the voltage is it is possible that Hayato and Suzy are being held in reset which would prevent anything from happening. The Lynx II schematic I have is drawing number C104247, but it indicates that is sheet 1 of 2, if anyone knows where I can find a copy of sheet 2 let me know. 1 Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted January 7, 2021 Author Share Posted January 7, 2021 (edited) Thanks so much for the detailed reply @Stephen Moss I have a DMM so it's time to start tracing stuff - it's a right pain trying to keep the batteries in the holder when it's taken apart (I don't have a power adapter) - time for some sticky tape I think..... Thanks again - I really appreciate it - we're back in total lockdown here too (Ireland) - stay safe ! Edited January 7, 2021 by deadl0ck added my location Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted January 7, 2021 Share Posted January 7, 2021 If you just want to test the main logics of the lynx you can use a bench power supply or other +5v 1A source to directly power the lynx and essentially bypass the power stage. Solder wires to the leads of capacitor C41 in the upper left of the board. Attach your +5 source to those leads (Paying attention to the polarity of the power supply or adapter you are using and matching them to the polarity of the capacitor!). If you have a game inserted, then as soon as you plug in the adapter, the Lynx will power on and hopefully start the game you inserted. If not, then it it likely one of the main IC chips at that point. If it does power on and work, then you know you can isolate your troubleshooting within the power stage section. On the Lynx 1 is is C39 near the speaker to do the same thing. 1 Quote Link to comment Share on other sites More sharing options...
deadl0ck Posted January 7, 2021 Author Share Posted January 7, 2021 Thanks @-^CrossBow^- And you reckon I don't need to have the flex circuit attached at all ? Quote Link to comment Share on other sites More sharing options...
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