Lynx II - Odd power issue.

[cristalmine]

Hi there

 

I've done some research online but I've ran out of ideas on what to do next for a faulty Lynx II I purchased.

 

Symptoms are:

- It powers on automatically as soon as it gets power, batteries or power adapter.

- It shows video and plays sound and seems to work OK, every buttons does what it should, except if you press D-PAD right, it turns off.

- After this it won't turn back on with power button. If you disconnect the power, you have to wait 30 seconds or so before plugging it back in for it to turn on by itself again.

 

Work done so far:

- I ordered a "Atari Lynx 1 & 2 Voltage Regulator Rebuild / Refresh Tune-Up Kit with Power Jack" from console5.com. The symptoms above were happening before I opened the Lynx, but it had a broken power jack.

- I opened the lynx and found that it had some modification to the power section already, with an added resistor going from one place to another. I removed that and replaced the Zener diode, MOSFET IC, Two 3906 transistors and the Power jack.

- I inspected the circuit board for any splashed solder or other shorts from the last persons repair but couldn't find anything.

- I inspected the button flexible circuit board for any issues. The carbon contacts where it plugs into the motherboard looked a bit patchy when held up to the light, so I trimmed off the edge a little.

 

None of the work done has changed it's behaviour in any way (other than being able to use the power adapter after the replacing the socket).

 

Any suggestions? Thanks in advance.

[+karri]

I had a Lynx that also started automatically. By changing the hex inverter chip U6 things got back to normal.

[bdoi]

I had a Lynx that also started automatically. By changing the hex inverter chip U6 things got back to normal.

Karri, do you have a part number for this hex inverter u6?

thanks:)

[cristalmine]

Another test I remember doing, was that leaving the controls unplugged, it wouldn't turn itself on (based on the screen backlight). Should the lynx operate "normally" without the buttons connected? Obviously you would need to work out a way to turn it on without the power button if it did work normally without the buttons connected (though turning on automatically is one of this units symptoms).

 

I merged the scanned schematics into one file in case that's useful to anyone.

 

 

[+Stephen Moss]

Check to see if someone has done that horrid hack of connecting the speaker ground to the supply ground (thereby bypassing the FET) and if so remove it, although I would not expect ti to turn off if that were the it is definitely worth checking for and removing as all the 5V parts of the system will be running at 9V with it in.

 

Not sure about the D-pad turning it off perhaps when it was previously taken apart the flex circuit was not correctly re-installed resulting the the D-pad contact making a connection somewhere it should not thereby creating the same effect as pressing the power off button - so check it appears to be correctly positioned and for any possible bad repairs to it.

 

FYI that schematic looks like the one already hear on AA which is for a Lynx 1, it is basically the same circuit but some of the component references are different, I would have attached the correct one but it is not working for me.

Edited October 24, 2018 by Stephen Moss

[cristalmine]

Thanks for the suggestions. No evidence of any hacks other than the resistor that I already removed.

 

Didn't realise that was a Lynx 1 schematic, and indeed it was downloaded from here but in 4 parts.