Another Lynx I needs repair

[Nop90]

I was very lucky buying two months ago a not working Lynx II. It had only dirty contacts on all the 4 carts coming with it and a dpad stuck on right direction (still have to fix it, but sould be only a dirty contact).

 

Some days ago bought a Lynx I for 30 € and this time there is something broken (already tryed to short the battery minus with the audio jack mass).

 

Probing the circuit, the +5V point and the mass are in short circuit (measured it at the ends of D14). The zener diode and the mosfet, tested without desoldering them, seems ok.

 

Now I should start desoldering components in the hope that there is a fault component before mickey os suzie. Or I could connect the power supply and check if there is a transistor or IC heating.

 

But before doing anything I'd like to know if someone else experienced such an issue, what are the most common points of failure and how to check them.

 

 

[+karri]

I had a RAM chio that worked as a fuse. Replacing it fixed my Lynx.

[+Stephen Moss]

Some days ago bought a Lynx I for 30 € and this time there is something broken (already tryed to short the battery minus with the audio jack mass).

Connecting what should and thus could be at 4V to 0V is not a good idea!

 

 

Probing the circuit, the +5V point and the mass are in short circuit (measured it at the ends of D14). The zener diode and the mosfet, tested without desoldering them, seems ok.

 

 

Not quite sure what you mean by "the mass".

When you say D14 is that D14 from the the schematic diagram on AA or have you transposed the component reference to that of the AA schematic because I am sure that schematic is for a Lynx 1, D14 on a Lynx 2 has nothing to do with the power stage at all. On the Lynx 2 D12 is the diode drawn immediately to the right of the MOSFET connected across the 5V power rails.

 

There have been many posts here regarding Lynx's that do not turn on/off, I suggest using the search facility to find them as they will at least get you started.

[Nop90]

Not quite sure what you mean by "the mass".

Wrong translation from an ialin term Read "ground"

 

 

When you say D14 is that D14 from the the schematic diagram on AA or have you transposed the component reference to that of the AA schematic because I am sure that schematic is for a Lynx 1

 

I'm using the schematics on AA for the Lynx 1 (the one not working) where D14 is drawn just after the MOSFET and is good poiint for testing the voltage.

 

Anyway already found some broken components. First one is the L15 at the power supply input. The MOSFET too seems gone. I'll continue probing.

[Nop90]

After some small fixing I can power the circuit with 4 batteries.

 

Zener and MOSFET are gone. Bypassing the MOSFET the LCD backlight turns on, but there is no other sign of life.

Edited March 4, 2019 by Nop90

[Nop90]

In the end found that powering the circuit the two ram modules became very hot.

 

Now I'll try replacing he MOSFET, the zener, the capacitors and the two ram modules.

 

This will take some time.

[Nop90]

Still waiting for the parts to fix the first Linx,but yesterday bought for 20€ onother Linx I not working that resulted being working.

 

The owner bought it for parts 15 years ago, but never touched it. He tested it only with batteries.

 

After disassembling it and testing most common points of failure, found nothing wrong (it's already recapped ) , so tested the lynx with a wall power supply and it turned on with the Insert Game screen, but after cleaning the cartridge connector contacts it worked fine.

 

The problem with the batteries seems to be the spring of the power connector to be stuck in the "plug inserted" position. Before trying to replace it, is there something I can do to try to fix it without desoldering the connector?

Edited April 29, 2019 by Nop90

[+karri]

Console 5 sells these connectors in lots of 5. I have already changed 2 Lynx Is.

[Nop90]

Instead of opening another thread I use this to ask advice on aother Lynx, a model II this time , I'm trying to repair.

 

The Mosfet is gone, an probably the zener too, but poweing it with 5V and shortening source and drain it turns on.

 

The problem is that the images on the screen are messed. The CPU is ok because judging from the sound and from how the images moves, everithing is running fine in backgrounds.

 

Here is what I can see on the screen using a cart of my game Xump:

 

 

while it should show this

 

 

The scrolltext moves correctly, but the letters are not clear.

 

What do you think could be the problem: the LCD, the ribbon cable os Suzy?

 

 

[+karri]

My guess is the ribbon cable

[Nop90]

I hope this. Probably can't fix it but the console is in perfect aesthetic conditions so is a perfect candidate for a Lcd mod.

[Nop90]

According to this http://atariage.com/forums/topic/256036-lynx-ii-repair-scrambled-video/ probably it's Suzy.

 

Yesterday bought other 3 Lynx II for parts. Two of them doesn't start with batteries, but are ok with a power supply.

 

The third shows humidity stains on the outside and misses the battery cover: inside it I found a dead spider of about 3 cm and the pcb and the back of the screen was covered by a thick net. Bad place to make a nest.

 

After cleaning everything, it turns on but shows a fast flickering Insert game screen: there must be oxidation on the cart connector, but there is something wrong with screen or Suzy too. I'llclean everything again.

 

Now that I have 4 working lynxs I'm satisfied because I have what I need to test multiplayer code, but still hope to save at least the Linx I of the OP. I received all the replacement parts so next week I'll try to fix the zener, the mosfet and the two ram chips.

[Nop90]

Update: the lynx with the broken suzy has all the pins of the connetor to keys at 5V, that is not good.

 

So I cleaned the second pcb (the one where I found the spider) and its cart connector, put it in the case of the first one and it now is almost full working: only the turn on key works, the other not, but everything else is fine. The situation is much better, and probably cleaning the keys contact will solve everything.