Lynx 1: blank screen with root cause found but...

[+Apocalypse]

Hi all,

I got my hands on a pristine Lynx 1.

I bought it faulty, I don't remember if the seller mentioned the exact problem.

Anyway it does power up and plays blind (sound works so as controls), screen remains blank, brightness/contrast wheel has no effect.

By quickly probing few signals I found I had only 3.9V on TP12 where there should be 20V.

I went back and found the root cause lies in the small daughterboard used to generate the backlight power (which works fine ~100VAC).

One of the coils of the transformer is cut but I'm having the most difficulties sourcing a replacement part.

I've googled the 2 references on the PCB (PCU-575 and KU-3294V-O) and the reference of the transformer (CXA-0072 from TDK) with no luck.

Is this issue that rare?

Does anyone know a cross reference that could be used for this transformer?

I want to keep the machine 100% OG so no LED or LCD mod for me.

 

Thanks.

 

P.S.: By isolating TP12 and injecting 20V from an external source with ground in common with the Lynx everything works fine.

[+karri]

I can send you this daughterboard as I have some extras.

[+Apocalypse]

Thanks for your help. YGPM!

[+Apocalypse]

Hi karri,

I've received the daughterboard, thanks a lot.

As expected brightness/contrast now works perfectly, however screen has horizontal bars:

 

 

Of course I've reflowed the 2 flat cables but no dice. Should I consider the screen dead or can a capkit help in this case (I've read similar problems have been solved this way but I'm a bit doubtful).

[+karri]

A cap-kit is a must on any Lynx I today. The caps dry out due to age. You should consider it a miracle to get the cart to boot on a Lynx I at all without changing the 470u and the 220u caps. There may also be some other smaller caps that are essential for correct operations. Here is the ultimate manual for changing the caps:

https://console5.com/wiki/Atari_Lynx

[+Apocalypse]

I've replaced all electrolytic (polarised) caps but saw no improvement.

However if I gently tap the screen some lines disappear and others appear so I think the driver chips on the screen have started to lose their connections.

Not much I can do about that I guess...

[CasetheCorvetteMan]

Hi karri,

I've received the daughterboard, thanks a lot.

As expected brightness/contrast now works perfectly, however screen has horizontal bars:

 

 

Of course I've reflowed the 2 flat cables but no dice. Should I consider the screen dead or can a capkit help in this case (I've read similar problems have been solved this way but I'm a bit doubtful).

That is certainly capacitors, ill second that. Got a few here that do the same.

 

You should look at doing the McWill screen, sounds as though youve got the skills, and its actually not too hard to do anyway.

 

The only thing you're gonna regret is not doing the mod sooner.

 

Here is a couple videos i took last week of mine:

 

https://m.youtube.com/watch?v=XwsfgJ5WuuM

 

https://m.youtube.com/watch?v=9Y9MD0GTyhg