lynx battery upgrade

[haightc]

I didn't see any dedicated post to this, it looks like some who upgraded the LCD screen also switch to two rechargable lithium ion batteries, then used a step up converter to raise the voltage.

 

I have been thinking about putting in 3 or 4 then using a step down converter. How many people have down this, initially there appears to be room for it. Looking at the lynx schematic though it looks the lynx it's runs off 5v.

 

I think I have seen posts where the remove a zenor diode or convert it to run at 5v volts but I wasn't able to flush anything solid out of the forum search. I seem to recall reading though the mod results in parasitic battery drain. Hopefully someone can clarify this for me as well.

 

My lynx died a little while back, so I have purchased a cap kit, replacement mosfet and LCD upgrade. That had me thinking this would be the opportune time for upgrading the battery as well.

[+af0l]

I have modded one of mine, where the power section on pcb failed in a good way, meaning that the 9v did not wreak havoc on the chips. Basicaly I have removed everything that has to do with getting 9v to 5v, and powered the lynx off an USB charger. Then I put a charger board with lipo batteries inside (ok still waiting for the batteries that would actually fit inside to arrive from China). McWilled it too. It is amaizing now.

 

Sitll have to solve two problems - the power on/off buttons do not work, obviously. I have "developed" a simple circuit to fix that. The other is where to mount the micro usb breakout so I don't have to take the thing apart to charge it...

[cowdog360]

Some day I need to get around to properly implementing this setup with a LIPO pack and a pushbutton controller IC for the ON/OFF.

 

A note though, don't run Lithium batteries in series unless you're planning on removing them to properly charge them, or build in a balanced charger circuit. It can be dangerous.

[+af0l]

Some day I need to get around to properly implementing this setup with a LIPO pack and a pushbutton controller IC for the ON/OFF.

 

 

I had Linear send me samples of those IC's that Level42 used. It was a work of minutes - I managed to burn off the legs from all of them (4)

 

Level42 is a soldering ninja, I guess.

 

Anyway, I did not like the idea of having the inner workings of the IC forced on me (delay, no off button). So I snatched a design from somewhere, to implement the EN signal proprely, with human solderable components.

 

 

It works with a LED, I have enlited my father (who acually designs this stuff for a living) and he's leaning towards using an optocoupler. There's enough space inside al Lynx II, I guess...

[haightc]

Does anyone know how much lose is incurred by the existing lynx circuitry, I think the user in the previous example estimate about 70% efficiency?

I am kind of skeptical about the true output, I have purchased high capacity batteries before and turn out to be the same or lower. In theory a single 5000mAh should be equivalent to 4 AA alkaline batteries. In the previous example the use stepped up the current current to 9v from the ~7 volts and reported about 5 hours of run time using two batteries. Eliminating the lynx 9v to 5v circuit and stepping down from ~7.4v to 5V should in theory be much more efficient, I would guess greater than 96%.

 

When the lynx first came out, NiMH wasn't common available and using NiCd batteries left a lot to be desired. I remember the screen always being a lot dimmer and lasting less than half as long. NiMH the screen was a bit better, but my batteries would always be dead if I hadn't played the lynx in a while. Really the only way to play the lynx was plugged into the wall, I never sprang the big battery pack because I felt it was more silly carry a huge battery pack than to be tethered to an outlet.

 

I just stumbled upon these while browsing amazon on my lunch break.

https://www.amazon.com/Bleiou-2800mWh-Li-polymer-rechargeable-flashlight/dp/B00SXV9Z4U

It looks like they now have rechargeable Lithium Ion batteries that output 1.5v. I am half way tempted to try these, I wonder if the as susceptible to parasitic drain as nickle based batteries. Theoretically all rechargeable batteries will, it's just a matter of to what extent. I theory the self discharge rate should be less, and there would be a greater chance of the lynx not being dead when it comes time to fire it up again.

[Level42]

Here's what I did: works brilliantly....extremely long play on 1 charge...

 

http://atariage.com/forums/topic/255254-the-perfect-lynx/?hl=%20lynx%20%20ultimate

[haightc]

Interesting, I might try to get some base numbers before I swap to the lithium batteries. I picked up some 18500s and 14500s, the 14500s are the same size as double AA. The 18500 are a bit larger but in theory have twice the capacity. Initially the if looks like I could fit the 18500 case in the case, we'll find out though.

[haightc]

So last week I finally got around to recapping my lynx, still no luck powering it on. The the cap for sure had failed, also replaced the mosfet but at this point I suspect the zener as I measure -8.3v at Q13. My diode just showed up today, I was hope to get a run time reference before I tried doing a battery upgrade.

[FlyingForStatus]

Sorry to revive a year-old topic, but I wanted to post my experience with a Lynx battery mod and this post seemed on-point.

I went to Walmart and purchased an ONN power bank for $4.88 and purchased push button power switches from Amazon for $4.98 and then got some switch caps to make it pretty from Digikey for $0.15. Used lots of hot glue for mounting after using a dremel for the power bank circuit board (to trim around the MicroUSB connector). Total cost: $10.01.

Since I did the McWill screen mod, I took the brightness wheel out which was a perfect spot for a microUSB jack (hot-glued in the circuit board from the ONN power bank). I desoldered the original Lynx power jack and replaced it with a push button power switch from Amazon. Once that power is switched on, the ONN power bank circuit board sends 5V to capacitor C41 and the Lynx comes to life. After removing the plastic battery tray in the Lynx and the foam from the inside of the battery door, the ONN power bank's lone 18650 (I think) Lithium cell fits there perfectly.

Not sure how much playing time I'll get but I've been gaming for almost 3 hours so far and still going. I know this may not be perfect and you guys might have done better mods but this was certainly cheap and pretty easy so I wanted to share details in case others want to attempt.

Thanks!

[Igor]

That's a nice way of modding it and cool use of the original power jack for the button. I've not taken a Lynx apart in a while, but would it have been possible to cut the traces to the original power button and reuse that to turn the power bank on instead of having a separate switch?

[ninsei]

Seems like a great mod. I just ordered that power bank and the switch. The picture you posted helps. I assume I'll be able to figure out how to wire up the power wires from the inside of the power bank once I open up the power bank....

[FlyingForStatus]

Hi ninsei,

 

necrocia reached out and offered that I should do a guide or howto on Atari Gamer but I havent had the time to respond much less create the guide.

 

To help you with your mod, the advice Id give is:

 

1. Wiring and placement - when you disassemble the ONN power bank, separate the battery from the board. The battery needs to fit under the screen in the old battery compartment area and the board should be glued/mounted/affixed at the top of the Lynx mothernboard. I ran wires throughout that connected the ONN board, Lynx, battery, and switch. Sorry no diagram here.

2. Getting power from ONN board - remove/desolder the big USB Type A port from the ONN board. Thats where You get the 5V output to shoot to the C41 point (via power switch). Look at a USB Type A pinout or use multimeter to see correct points.

3. Dremel use - shave away on the ONN board around the Micro USB port so that it protrudes enough to be easily accessible through brightness wheel hole. Also, you may or may not need to slightly enlarge hole with power button. Depends on if you use a switch cap and if so, how big it is.

4. Switch cap - I had a hard time getting it to fit onto the switch (tight). Eventually, I had to trim the switchs nib down and I added a tiny dot of glue just in case.

 

Good luck!! Its been working well for me. Let us know you experience and if you can improve on this mod!!!

Edited January 13, 2019 by FlyingForStatus

[ninsei]

Thank you so much.

[Igor]

Thanks for the update!

[ninsei]

Started this project but am now stuck: I took apart the ONN power pack and desoldered the large USB type A port. But I only get 2 volts from the +/- points on the board where the old type A port was unless I press the switch on the ONN board. When I press that little switch (the one you can see in the pic of the ONN in the Walmart link earlier in this thread) I get the 5 volts needed. The LEDs on the board also go on when I press that little switch.

 

My original plan was to just run wires from the two pins on the old type A USB port to C41 (through the new push button power switch from Amazon) but I don't see how that will work now. Do I have to wire in that little switch on the ONN board somehow? Any help is appreciated.

[ninsei]

Nevermind. i feel silly. It just works: as soon as I actually connect the wires from type A USB to C41, Lynx powers on nicely. I guess the multimeter didn't draw enough current to turn on the full 5 volts.

[ninsei]

Thought I had it working but now I get the following behavior:

 

Connect 5v from a transformer to C41 and Lynx 2 powers on nicely.

 

ONN Battery is charged but if I hook up the type A usb +/- pins to C41 right after pressing ONN button, the LEDs on ONN immediately turn off and the lynx screen does not power on.

 

But if I disconnect ONN type A USB wires from Lynx C41 and press ONN button (ONN LEDs turn on) and test tyoe A USB +/- with multimeter, I do get 5v.

 

Seems like whenever the Lynx2 draws current from ONN, the ONN shuts down.

 

Still tinkering ...

[FlyingForStatus]

Im sorry youre having trouble - Im sorry I didnt do a proper guide or add more photos or a schematic. Ill try to post something more.

 

To be more clear, I didnt do anything with the power button on the ONN circuit board itself. My ONN battery pack seems to automatically turn on as soon as it senses a draw from the USB Type A port. I believe the power switch I mounted in the Power hole in the Lynx case sits between the C41 positive post and the positive 5V output line of the USB Type A port. The power button I purchased to install in the Lynx (linked above) is a true on/off switch - you press and it clicks on, press again and it clicks off. It isnt a momentary switch.

[ninsei]

Thanks for confirming. Thats what I thought and thats how I have it wired. I swore it worked once but now it doesnt (battery is charged). Maybe I damaged the ONN board during install. Ill keep trouble shooting.

[ninsei]

ok so I tried this mod again all the way from the beginning and I made some progress but am still stuck. Now I get the following behavior: If I press the button on the ONN or I plug and unplug a charger to the ONN (E.g. anything to get the ONN LEDs on) everything works. But if the ONN sits idle for a minute or so (LEDs turn off), and I connect C41 positive/negative, the Lynx 2 does not turn on. Lynx 2 only turns on if the ONN LEDs are already on.

 

BTW I'm sporting a Lynx2 with the MCwill screen mod.

[ninsei]

Ok here's my solution to my problem (keep in mind I don't care how the case of my Lynx looks): I dremeled out a half inch size hole in the case just to the left of the ONN board. Now I can access that little ONN button to "wake up" the ONN system, then I press the Amazon bought button to turn on the Lynx 2. So it doesn't look nice I have to manage dust getting inside the Lynx but now I have a Lion battery in my Lynx that can charge from any USB port.