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Trying to fix that old Lynx 1 from my childhood


battleman13

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Hello!

 

My name is Brandon, and although I've done a bit of lurking on the forums this is my first time posting!

 

 

So the Atari Lynx, what a thing of beauty. My grandfather owned two of them, bought them I suspect

very near the time they came out. Myself being born in 86, I did enjoy them but probably by the time

I really new what was going on, they were on the way out in the retail world. Still that didn't bother me

or my brother and my grandfather from having a blast with these things! He had a Lynx 1 and 2 and

about 20 or so random games.

 

Well these Lynx's are a little worse for the wear, the years haven't been good to them. I think the DC

jacks on both were damaged from the cord getting yanked on. They really weren't even thought about

for the past 10 years. However, I have recently started having another interest in not only playing, but

also fixing these things. Sadly, he took the Lynx 2 apart and "lost some things" and threw it away, so

he told me. The Lynx 1 survives, but doesn't work all that well. He tried batteries in it, I'm afraid as I've

read that's a no no on an old system like this. Basically some bits in the power circuitry could have

failed and let 9V flow through all the lovely 5V parts.

 

So I hacked the end off of a USB cable, plugged it into an old iphone charger (5V 1A) and using

alligator clips I fed that directly into C39 (the power cap on the Lnyx 1). Screen lights up, but I see

nothing on the screen. Tried a variety of games, and tried cleaning the games up a bit. Still no love

on the screen. I made sure to be careful not to short the legs of the cap together, and that I measured

the wires from the USB cable to be sure I had the ones for 5V and to verify the 5V (it was actually 5.05V)

 

After feeding 5V directly into the legs of power cap, is there any chance this lynx is still fixable? I've

seen some people mention the ribbon could be not making good contact? I'm not sure how to disconnect

and reconnect this LCD ribbon. The brightness dial also has no effect.

 

 

Would be pretty sweet to be able to fix this one, lots of memories with this unit in particular. Just wondering

if there are any things to check to be confident one way or another if this lynx can be saved.

 

 

Thanks in advance!

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Anyone? I'd really like to get this Lynx 1 working.

 

 

I did buy two of the Lynx 2 units off of eBay. I got the pair for $50 shipped,

hopefully I can get at least one of them running. I know one has a bad LCD

but if they both have functioning motherboards I can attempt a McWill LCD

in the one with the known bad LCD and maybe keep the other stock.

 

Would be sweet to be playing Lynx on the real deal hardware again all these

years later, and i know my grandfather would love to see his old Lynx running

again!

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If the lcd ribbon cable were the main problem I would think you would still be getting sound. Since you get neither with the 5v trick I have to think you have bad caps which is a somewhat uncommon issue on lynxes or damage to the custom chips/motherboard components due to unregulated 9v being supplied in the past

 

Did you try connecting headphone ground to battery minus terminal

http://www.retroisle.com/atari/lynx/Technical/Hardware/lynx_repair.php

.

Edited by sirlynxalot
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Hey sirlynxalot

 

 

Thank you for your input. I have tried the headphone jump trick... the interesting thing is that

if I short to ground on the headphone jack, it doesn't "power up" but if I short to the middle pin below

(again supplying exactly 5V) the screen lights up but nothing happens... no sound and no video.

 

 

I bought two "broken" Lynx 2 units on eBay.

 

One has signs of life, pumping 5V into the battery terminals and doing the headphone jump has both

video and sound playing... although the power LED seemed to be flashing?

 

The other doesn't seem to be working at all.... same test (with multiple games, and even no game) shows

just a plain black screen with the backlight. I'm curious to try pumping 5V directly into the power cap but

I don't think that will help. I think it's a dead board. The LCD in this unit was supposedly known to be faulty

BUT there should still be sound. The negative wire to the speaker was broken off, but I put in a pair of

earbuds and still didn't hear anything. I may swap motherboards and see if it makes any difference since

I know I have a functioning pair of motherboard / LCD.

Not sure what to do with the dead Lynx 1 or 2 systems.

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Yeah that doesn't sound too great. You could always keep the broken lynxes for spare parts, never know when you might need a replacement screen or rubber grip or speaker or something. You could also give a try at gutting one of the lynxes and using the case to house a raspberry pi. I've seen some cool mods along those lines even hooking up the original lynx buttons and speaker to make a substantial portable emulation machine.

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@sirlynxalot

 

Yeah, I might look into that. I was interested in building a raspberry pie retro / htpc "machine". I dunno that I want to put it into a lynx

but you never know!

 

 

@Karri

 

I was for sure thinking about offering up any "salvage" to the users here first. So If I do decide to get rid of anything, I'll be sure to PM

you with the information!

 

 

 

I might tinker with them a bit more tonight just to confirm the one is "dead". I might just wire a connection between headphone ground and

battery minus on the working lynx, and hook a USB cable directly up to the solder pads for the battery. This will allow me to plug it in and play

it. It would could still even be portable if I found a battery bank that put out 5V 1 A. I'm fine being plugged in either way. It will just be cool to

start enjoying the old games again :)

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  • 5 months later...

Old topic I know, but I've made a bit of progress.

 

I thought that at least the one "working" lynx 2 had a bad flex circuit. After tinkering some more I got it working perfectly.
I ended up cutting about 1/8th of an inch off of the top of the flex circuit ribbon as most of that "material" was scratched off.

 

Well now the buttons all work wonderfully, the LED is bright and strong and the lynx 2 plays great!

 

 

The other unit has a good flex circuit, good screen, but an apparently dead motherboard. I had a few USB cables that were

bought to power a cell phone charger, the ends were super cheap so I cut them off and soldered the positive and negative

wires directly to the solder blobs for the power solder pads by the battery holder. Makes the lynx 2 a little less portable, but

I don't care... It's a fairly long cord and I don't plan to play these "on the go". So anyway, one unit that I got off eBay is working

great and the other appears to be a dead board. I soldered its own usb wire directly to the solder pads for power and soldered

a jumper wire from battery minus to head phone middle pin. Nothing on the screen, no sound. I did swap the other motherboard

into this housing to confirm the screen was working and it is.

 

 

Anyone have any idea about what could be causing the "dead" board to be lifeless? SirLynxAlot suggested bad caps, any ideas

or should I just replace them all? Are there "commonly bad caps"?

 

Pumped to have at least one "working" unit! I'm quite happy having the hard wired direct 5V supply. I used a little extension cord

so that I can unplug to change games easily. Quite happy to be enjoying some of these classics I remember playing so many

many years ago as a very young boy. Just a bit sad I couldn't get any life out of the original lynx 1.... motherboard seems dead.

Probably from over volting. Maybe I can find a cheap parts unit with a good board.

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The Lynx board has several "islands" of electronics that can be separated from each other for finding which chip is bad. The power to the "islands" go through dummy zero ohm resistors. I did not find them in the schematics. But when you look at the PCB you notice that there is square "islands" of electronics and the power feed to the island goes through some dummy wires or components that have no function.

 

By cutting these wires I was able to measure the distance to ground of every island. If the power is shorted to ground through a blown up chip then it is possible to find where on the board that chip is.

 

If you then apply +5V to the PCB and start by observing the xtal. Does it provide a good clock.

 

Then you could buy a cheap 8 channel USB logic analyzer and connect pins to reset and cart OE pin to see if the CPU starts up at boot and tries to read from the cart. If you solder a wire between cart pins 31 and 33 then the Lynx should boot up with the message INSERT CART. So you do not need a cart for debugging.

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My old Lynx 1 used to show EMAG TRESNI =D Strangely enough I've not come across another one that does that - I think the Lynx 1 I have was corrected and shows INSERT GAME. Great tip from Karri there on seperating the VCC rails between components. You could also just see what gets hot (if anything). My guess is it probably went over voltage and more than one component could be dead. Certainly worth checking the XTAL - they can break from impacts. I've fixed numerous handheld systems with faulty crystals over the years.

Edited by GadgetUK
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How exactly do I check the XTAL?

 

I have a scope (never used before, but willing to try!) and from looking over the Lynx 2 schematic it seems there is mention of XTAL on the U2 chip? XTALI and XTALO. Is that right or no...

 

 

Just curious where to probe and what to look for. Not totally lost on this stuff, just not quite sure about how to check this.

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XTALO sounds like Output. This is the heartbeat that takes care of the timing of everything.

 

You need to put the scope into auto trigger mode. Put the ground clip of the probe to the ground of the Lynx. Could be headphone ground. Then the tip should touch the XTALO and you should see a nice square wave.

Edited by karri
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  • 1 year later...

Thinking of pulling the two older non working lynx units out and trying to get one or both of them going again....

So I do have the one lynx model 2 (that I got a pair of on ebay for $50) working fine. I almost want to convert it back to using batteries, remove that USB power mod, and fix the zenner and power jack to restore it to original condition.

 

I'm thinking perhaps the Lynx 1 may have issues with either the Mikey / Suzy / or RAM chips.... is there a good guide out there for testing these chips with a scope?

Is it possible to use those three chips from the Lynx 2 on the Lynx 1 board?

 

From what I remember, I think the non working lynx 2 has a good board but bad LCD. I don't want to take apart my working lynx 2 again more than necessary as the end on those flex circuits flake off easy and I don't want to have to keep trimming it... but if the board on the non working lynx 2 is good then I just might be able to get another screen for it (maybe even McWill!) or salvage those chips to fix the lynx 1.

I guess I'm wanting to confirm that the lynx 1 has damage to any of it's three most critical chips first, if there is good info out there on that. I did a bit of google searching, but nothing really came up other than it might be possible to buy the mikey / suzy chips from best electronics. Perhaps another option if I can confirm what ales the non working lnyx 1.

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Testing a Lynx I. The first thing I would do is to set 5V on the 220u cap poles to see what happens when you apply power. Does the Lynx start drawing a lot of amps. Does one of the RAM chips get very hot: Does the game start?

 

You should replace the 470u and the 220u caps before starting the test. They are always crap after all these years.

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  • 1 year later...

So another update:

I now have both of the two original Lynx 2 units I bought off ebay when I started this post. I also have my grandfathers broken lynx 1. Recently I bought another Lynx 1 and Lynx 2 as well as two spare Lynx 2 motherboards.

That gives me a total of 3 complete Lynx 2 units, two complete Lynx 1 units and two spare lynx 2 motherboards. I spent about an hour last night testing out hardware. Swapped motherboards into a lynx 2 shell, connecting headphone to battery negative, and soldering a USB lead to the legs of C41 and inserting 5V via an old iphone charger. I did hook up the speaker, LCD backlight and LCD video ribbon. I did not keep connecting the flex circuit. I didn't want to cause wear to the carbon traces.

Of that, I have two fully working Lynx 2 units. The remaining 3 lynx boards have some level of failures including, sound but no video (likely bad suzy?) one that displays no audio or video, and one that has rather glitchy audio and video. The original lynx 1 I had of my grandfathers still doesn't work. In the next few days I'll retest both of my complete Lynx 1 units. I suspect my grandfathers lynx 1 likely has a bad Mikey, but it's just a guess.

The one with no video, I'm optimistic I can fix with a new suzy. 


The one that's looking dead with no audio or video, I'm suspecting a new mikey

 

The one that's glitchy... I'm just not sure. I think I'll probably start with a full recap / power rebuild and then check and see if we get chips getting really hot. Could be anything and everything. Bad caps, cart slot issues, issues with mikey / suzy (not an expert on these.... but what I know is that Suzy is the GPU and basically Mikey does all else), ram issues. Best electronics has all the chips necessary. Unfortunately for the lynx 2, some of the chips are not cheap. Mikey's are $40 and Suzy's $30. The nice part is buying from them, it keeps from stealing parts for other units. Keeping from reducing the number of potentially workable lynx units from going down / motherboards getting thrown out potentially. 


My end goal is to get at least two fully working Lynx 2 units (which I technically have, would like a 3rd working) and the newer much better condition lynx 1 to be functional (didn't test it yet). I will be installing BennVenn screens into as many of the complete Lynx 2's as I can get working. If I can get the Lynx one going, it will eventually get that new screen treatment as well. I'd like to have a model 1 and model 2 for myself, and be able to give my grandfather back a working and refurbed model 2 with upgraded screen and a bennvenn flash cart. He's going to love it. I should be able to deliver that to him in the next few weeks. Just some ramblings of my attempt at lynx repair... who knows, maybe someday this might help someone else going down this same path.

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Progress!

I have the lynx 1 that I bought in good condition just a few months ago working!

 

C38 was leaking, and appeared almost like battery acid corrosion on a leg? Pretty much wore half the pad on the screen side of the board off. In a bit of a noob move, I continued to use a tip that was visibly shot because it was my favorite shape. I had thought I was responsible for ripping the rest of the pad off, but in reality, it was only on by a thread thanks to the leakage. I almost though all was for not, when I realized most of the through hole caps had little if any solder on the screen side of the board. So apparently, just having solder on the underside is good enough!

Replaced C38, C39... (the two biggest power caps) and resoldered the speaker as it was barely hanging on. Inserted a game cart, and "INSERT GAME" but boy was I happy! This means that Mikey and Suzy are fine! I removed and reinserted my chips challenge game about 10-15 times, and IT WORKS! The screen even looks really good for an original screen, no "zones" as is customary with random "thirds" of the screen being different levels of brightness / contrast.

Very awesome!


Although I had really bad luck with the Lynx 2 and spare boards, I think I can get at least one of the 3 boards going... maybe 2. I probably won't have the time for quite a while, but I can use my oscilloscope and my working lynx 1 to diagnose my broken lynx 1 (grandfathers really) by studying the mikey / suzy activity. I suspect a bad mikey. 

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  • 3 months later...

Finally got one of the lynx units fully finished, the one for my grandfather. Can't wait to deliver it to him sometime soon.


A lynx 2 that has full board refurb, benvenn screen upgrade, and a replacement speaker installed as well as a benvenn flashcart.

He has no idea new modern screens were adapted to be usable with the lynx, nor that throughout the years homebrew devs have

continued creating new content for the lynx. I imagine he will be thrilled!

That just leaves... a lot, on the to do list. Including finishing my own personal lnyx 2 as it still needs it's BV screen fitted, and my

very clean and nice looking model 1 lynx needs it's power circuit rebuilt and i'll probably keep it's stock screen as it's got to be one

of the best original screens I've ever seen.

Lastly, a few lynx 2 boards that I need to try to get at least one more working board out of. I have another empty lynx 2 shell that

is in nice shape. Might as well try to make another complete unit. I have a BV screen for that one as well, if I ever get it put together.

I posted pictures in the facebook atari fans group.

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