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HELP! Regulator mod gone wrong!


GTretro87

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Hey all

 

Ok so, I just got myself a nice mint working Lynx II and I attempted the regulator mod which included cutting the battery positive trace on the board

 

Didn't turn on, so I put everything back to how it was and now it doesn't turn on. I soldered a wire from the battery positive point to the positive side of C 41. Still nothing

 

Then I replace that 3055 transistor and the system turned on but then I turned it off.. And when I tried to Turn it back on it did not turn on

 

 

So I don't want to be screwed now. I will show pics tonight to see what everybody thinks

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When I assembled the stock parts together, I'm not sure if L14 was placed back together correctly or not..

 

I supposed that since the battery positive trace was cut, I might as well retry the mod since I realized now that I forgot to remove a few more parts like D13 and Q8...

 

I really REAAALLY hope I didn't screw this one up, and this is not my first mod at all.. But a finicky one for sure

 

 

In addition, I'm not sure if this matter but the regulator I used was a RECOM R785.0-1.0 and I had soldered it onto D9 and D11 accordingly (and yes correctly), and then had a wire soldered from the battery positive to the input leg of the regulator

 

I will just redo everything and post my results

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Ok so here are some pics... I did not remove Q8 or D13 still (I forgot what each does, I think D13 is for the LED right?), but I re-performed the German 5v mod with one of the diodes on L14 (as shown below in the pics)... I decided to place the regulator right on the board - connecting a wire from Battery + to the input leg which is also soldered right on D9..

 

I need to poke around and see what kind of readings I get throughout the board - but before I do, should I have a cart in the slot? Or should I jump cart pins 31 and 33, and then start measuring?? This I need to confirm before I progress

 

 

However, when I connected the plugs and ribbons, and put a cart in the slot.. even though the system did not turn on, I did measure some 5v readings from the regulator output leg, the battery +, and I forgot what else.. I will write down my readings when I have some more time, possibly tomorrow or day after.. but nonetheless, at least the regulator is outputting 5.05v!!

 

 

but when I plug in this Nakitek or whatever power supply (for lynx, GG and express with a 6v and 9v switch), with the 6v switch on, I don't get a 5.05v reading from the regulator output leg....... it's pretty much ground, and the input leg (and battery +) is reading like 3.4v..

 

 

 

In all honestly... I wish I just installed McWill's LCD screen and just been happy like that..... anyway, here are pics

 

 

post-40678-0-16493300-1431758343_thumb.jpeg

 

post-40678-0-26757500-1431758346_thumb.jpeg

 

post-40678-0-28018000-1431758349_thumb.jpeg

 

post-40678-0-43284800-1431758352_thumb.jpeg

 

post-40678-0-84611300-1431758354_thumb.jpeg

 

post-40678-0-07311700-1431758357_thumb.jpeg

 

post-40678-0-09946900-1431758361_thumb.jpeg

 

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One thing to mention, on L14 where the diode was placed.. I had first placed a copper jumper wire there, and accidentally a solder pad pretty much (90%) came off from the other end -- and that's when I realized that I diode was supposed to go there.. and thats what happens when you're in a rush..

 

But anyway, I have to measure if any voltage is picked up there when the PSU is plugged in - if not, I'll eventually find out where it's supposed to connect to and then jump it

 

 

Please let me know what you're thoughts are --- if it was working before, it HAS to work again (I hope)

 

 

Thank you guys so much

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Ok so update.

 

The lynx powers on with the headphone ground to battery ground jump... But without there's still no turn on

 

I put a new MOSFET in Q12... STILL no turn on without the wire jump

 

I looked at the edge of the flex circuit and some of the trace has come off the bottom. So I applied a circuit pen to complete the trace to the edge.. Nothing

 

I cut off a small portion of the edge so that the trace meets the connector directly... STILL nothing

 

 

So is this my flex connector? Or perhaps something else?

 

 

I still have yet to install McWill's LCD screen.. I wonder if that would make a difference considering some parts will be removed ...

 

 

I need your thoughts people please!!

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I have ordered a new flex circuit and silicon pads from Best Electronics to see if maybe this will help solve my issue.. I've read an article here where the actual orientation of the flex circuit cable and the battery holder both in place can affect how the flex circuit works.. and for some reason, I feel that I've discovered this over 10 years ago when I last had my Lynx....

 

 

Anyway, that's an idea I'm going to try.. however if the power doesn't work, but the rest of the buttons on the circuit works -- I'll just make my own power on toggle switch

 

 

This is why I can't wait to get my Lynx I, add a regulator (without having to cut any traces) and LCD screen .. and be done with it, while without dealing with a flex circuit

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Search for posts by me in this forum. This is a common problem with Lynx 2. New flexi should fix it but more important is how you put the system back together. I ran into the same issue you have and through trial and error discovered that stress on the flexi causes the system to not power on.

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I have no idea what could be wrong with your Lynx, but I wish you the best of luck and I hope you get it working again.

EDIT: have you been trying both batteries and external power?

 

Yes I've tried both batteries and power supply, but the power supply I have is currently outputting 6v (with a switch that can turn to 9v alternatively).. and the regulator can only start working once it receives at least 6.5v (in order to output 5v, otherwise it won't work)... So I will have to test it with 9v..

 

 

However without the flex circuit working properly (should everything else be working, especially the MOSFET).. then nothing will work at all..

 

 

 

Search for posts by me in this forum. This is a common problem with Lynx 2. New flexi should fix it but more important is how you put the system back together. I ran into the same issue you have and through trial and error discovered that stress on the flexi causes the system to not power on.

 

 

I have found them and that's what led me to believe that how the flex circuit is inserted and placed in the case WITH the battery case affects how the system powers on and off...

 

like I said earlier, I think I've done this about 10 some odd years ago... so that just might be the culprit! Only time will tell until I get my new flex circuit and test it out

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Update...

 

 

So I re-did the mod.. Now it still works fine (as long as I jump batt ground and headphone ground).

 

I traced everything out, mounted the regulator out back with double sides tape instead of on the solder pads, used the zeners on D10 and one on L14, removed D13 and Q8. I initially tested with a 7805 just to make sure that the PCB wasn't fried from replacing the zener diodes with standard diodes (don't ask..).. and then again with the R785 which definitely does the job (runs A LOT cooler than a 7805, of course).

 

It plays great so far, LED light works.. Just the damn Power On, Off and Backlight don't work.. However, option 1, pause, and option 2 (and restart and flip) all work.. So with the right side buttons working and the left side now, it must be the flex circuit.. I hope...

 

The MOSFET on Q12 is outputting about +5v through the legs.. So it can't be the MOSFET, I mean it's brand new too! And the two others I swapped from were an old and new MOSFET and still had to jump battery and headphone grounds to boot it up

 

 

I've tried adjusting the ribbon cable but so far no luck... Probably after having cut a small (probably big) portion of the ribbon cable (again because the trace was eaten off some how from the edge).. The small amount of length is probably very crucial

 

 

 

So.. Until the new flex circuit comes in (tomorrow probably).. We shall see.. If it isn't that, then I'll have to develop some sort of DPDT power switch where one side will help jump the system on and the other side will power down - if that's possible

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