Atari Lynx II -- What's that smell?

[TechCowboy]

I had just done a McWill update and everything was working great.

 

It ran fine for a few hours and a few on/off cycles, then I couldn't turn the Lynx on.

I assumed the MOSFET has failed, ordered a couple, put it in and then POP, TP18 blew up real good!

 

Perhaps I didn't purchase the right MOSFET, or just a coincidence?

 

This is the MOSFET I ordered from Digikey:

NDT2955CT-ND NDT2955 MOSFET P-CH 60V 2.5A SOT-223-4

 

Assuming nothing else blew and I have the right part, I've heard there was a zener diode I should be replacing as well, but I don't know which one or it's value.

 

I, of course, need to replace TP18 -- what part is that?

 

Thanks in advance to you all.

[+Stephen Moss]

Anything labled TP is a test point- a hole/pad on the PCB provided for the convenient measurement of key voltages/signals in the circuit and so cannot blow up. From the image it looks like a transistor, possibly labled Q8, but being at home this week I cannot check as both my Lynx II and circuit diagram are at work.

 

The MOSFET/Zenner and equivalent replacements have been discussed here many times, a search of the forum should provide the answer you need.

[Lynxman]

I hope nothing else damaged...

You should install a 5V Mod to avoid such issues...

[Igor]

I hope nothing else damaged...

You should install a 5V Mod to avoid such issues...

 

 

Are you talking about this? http://atariage.com/forums/topic/245901-usb-to-lynx-powerac-connector/

I tried to look for a definitive guide on how to do a 5V mod, but couldn't find it, can you share please?

[+-^CrossBow^-]

 

I had just done a McWill update and everything was working great.

 

It ran fine for a few hours and a few on/off cycles, then I couldn't turn the Lynx on.

I assumed the MOSFET has failed, ordered a couple, put it in and then POP, TP18 blew up real good!

 

Perhaps I didn't purchase the right MOSFET, or just a coincidence?

 

This is the MOSFET I ordered from Digikey:

NDT2955CT-ND NDT2955 MOSFET P-CH 60V 2.5A SOT-223-4

 

Assuming nothing else blew and I have the right part, I've heard there was a zener diode I should be replacing as well, but I don't know which one or it's value.

 

I, of course, need to replace TP18 -- what part is that?

 

Thanks in advance to you all.

 

Look like Q8 is what went out. The Diode is directly above where it is labeled as D13 in your pic.

 

I always advise that before installing the McWill on your Lynx that you always go and replace the parts that come in this kit to be sure the power regulation is good for a long while more:

 

https://console5.com/store/atari-lynx-1-2-voltage-regulator-rebuild-refresh-kit-with-power-jack.html

[Lynxman]

Are you talking about this? http://atariage.com/forums/topic/245901-usb-to-lynx-powerac-connector/

I tried to look for a definitive guide on how to do a 5V mod, but couldn't find it, can you share please?

http://atariage.com/forums/topic/236279-what-are-the-5v-regulator-mod/

[Igor]

http://atariage.com/forums/topic/236279-what-are-the-5v-regulator-mod/

 

 

Thanks. There's a lot of discussion on that thread but no final step by step guide on how to do it. Looks like different people took slightly different approaches. I might have to write up a guide at some point after trying it out myself.