Replace your Lynx’s power transistor ASAP or it could brick at any time! Lynx repair, recapping, and MOSFET replacement recommendations

[+jgkspsx]

@Igor and Ben Grimmet recently posted a PSA that Lynx MOSFET power transistor failure can not only cause your system to not power on, but it can also fry the irreplaceable  Mikey and Suzy custom chips. It affects both the Lynx I & II.
 

It is a simple job to replace one (AtariGamer has a mini kit for $3), but some people are not comfortable doing any soldering. I’m somewhat comfortable soldering in low criticality applicatipns but still a little afraid of destroying my Lynxes. Plus, it’s a good thing to do along with a full recap if not a screen replacement.
 

I started this thread to collect recommendations for people on as many continents as possible who can repair and recap Lynxes for those of us not comfortable doing it ourselves.

 

I have one old beat up Lynx where the power mosfet certainly fried and maybe the custom chips with it, and I would like to send that out for a quick look, along with one of my working models for recap and service, so I can play it with less fear of a sudden pop and an expensive paperweight.

 

So: is there anyone you recommend?  What country is the repair service in? Do you offer your own services? And so on

[Igor]

Thanks for starting this topic, I can of course do this repair, so to start the list off...

 

@Igor (atarigamer.com) - Australia

 

The repair job might SEEM scary and difficult at first, but it really isn't. I remember the first time I did this, my hands were all shaky, but if you have side cutters and some decent solder wick, and tweezers, it takes less than 5 mins to do. I will be posting a guide on this soon on out website.

[+sramirez2008]

Here in the USA, I would highly recommend @-^CrossBow^- He’s worked on both of my Lynx IIs as well as, several other consoles.  His work and customer service are…Legen…Wait for it…Dary!

[+Stephen Moss]

11 hours ago, jgkspsx said:

posted a PSA that Lynx MOSFET power transistor failure can not only cause your system to not power on, but it can also fry the irreplaceable  Mikey and Suzy custom chips. It affects both the Lynx I & II.

That and the title of this thread seems excessively alarmist to me.

 

If the MOSFET goes open circuit the Lynx will not turn on so I fail to see how that could damage them.

If it goes short circuit then, yes, there is the possibility (but not a certainty) that they could be damaged due to excessive power dissipation, depending on how long the lynx is used in that state. Although you should be able to tell if the MOSFET is shorted as the Lynx will power on as soon as the power is connected/not turn off until the power source is disconnected.

 

What is more likely to do it the transistor going open circuit and people then following the bad "quick fix" advice spread around the internet of headphone ground hack which connects two parts of the circuit that should never be connected, thereby bypassing the entire power stage and continually running the entire circuitry at excessive voltages & power over and over again, which is bad news for any components that should be running at 5V rather than 9V. 

[+-^CrossBow^-]

I've heard the zener can go bad in a way that essentially dead shorts causing higher voltage to travel on through the rest of the system as well?

 

All I will state is that I pretty much insist on replacing at least the power stage components when getting an LCD upgrade installed. I prefer to do the power stage, caps, and then the LCD in that order as I have had those zeners go out on me a few times just on initial testing systems that have come in for services although I've not had one short closed.

 

[laoo]

I have Lynx with McWill, but have not idea if these parts were replaced. Is it dangerous even if I use only batteries and never use power adapter?

 

[Igor]

As promised here's a guide - Replacing the MOSFET and zener diodes in an Atari Lynx

[Igor]

On 2/8/2022 at 2:14 AM, laoo said:

I have Lynx with McWill, but have not idea if these parts were replaced. Is it dangerous even if I use only batteries and never use power adapter?

 

Batteries go through the same power circuit so yes, the same applies.

[oski_98]

I'm not a professional, but I have "refreshed" the power circuit on four separate Lynx II units (replaced Q13, Q8, Q7, D13). The post on atarigamer.com is pretty good but I would suggest some additional details.

 

As mentioned in the atarigamer.com post, the power MOSFET is the easiest component to remove if you have a pair of good flush cutter and cut the two smaller legs. Then you can heat the larger pad until the solder melts and push or pull the component out of the way. Installing the replacement components is also easier, relatively speaking, because the pads and the component are larger. Just remember to apply LOTS of flux to the large pad before you solder down the smaller ones. You will need to more dwell time with the soldering iron on this pad, at least 2-3 seconds.

 

The easiest way to remove the other components (D13, Q8, Q7) is with a hot-air rework station, but it's not that much harder to do with a stick of low melt solder bridging all connections. I don't recommend the "gently lift one side" method for people with little experience soldering. Low melt solder is cheap and it doesn't take much to bridge all connections of the component (or just use regular 60/40 solder). Soldering these into place is a bit tricky because they are tiny, I recommend a 2mm chisel tip for the job. Remember that on the Lynx II the black stripe on the zener side should be on the side next to where the RF shield is. Also if you replace D13 and Q13, why not replace Q7 and Q8 too? They're super cheap.

 

Finally, if it's your first time, and you're at all worried about damaging surrounding components, just slap on a bit of kapton tape on top of the surrounding area to protect it. That way you don't have to accidentally worry about touching the the cap and inductor straddling the MOSFET with your soldering iron. They stick out a bit so it's easy to bump into them with your iron, but if you have some kapton tape protecting them you don't have to sweat it. If you don't want to splurge on kapton tape find some suitable alternative.

 

 

 

 

[haightc]

-looks at pile of dead lynx motherboard-    The OP is not alarmist to many lynx's have been killed from over volt.    You are likely safer if you are using rechargable NiMH AA batties as your peak voltage is lower.     Replacing the stock zener diodes and mosfet are high recommend, there are a number of thread heads on ways to completely bypass the issue and run at 5v and additional power protection mean.     I would guess most lynx owners these days would have already been burned and made those change outs already

 

[JagChris]

On 2/6/2022 at 12:59 PM, jgkspsx said:

@Igorthe irreplaceable  Mikey and Suzy custom chips.

This makes me unusually depressed for some reason that there's no way to replace these. 

 

Aren't they merely a variation on the 6502 processor?

 

[Igor]

Mikey is a custom 65SC02 and has audio and DMA on the same chip, so it's not just a 6502 variant. Suzy is a completely custom chip for the Lynx.

https://atarigamer.com/pages/atari-lynx

 

I think BestElec still sell them if you're ready to part ways with your bank account ?