Weird Lynx-II repair. Has anyone seen this before?

[greenmonkeyking]

Hi everyone, I picked up 2 lynx-II units off ebay. One of them has a strange repair. I'd like to remove it but I need to ask the experts 1st "What are they trying to do here?

 

Thanks for your help.

 

[+karri]

It is a pull-up by which someone tries to force the Lynx to "on".

 

My guess is that either U6 (hex inverter) is broken or D13 (transistor) is broken. I have seen both go bad.

 

The resistor forces the Lynx to be "on" all the time.

[greenmonkeyking]

Thanks River, I'll check it again. I had 2 on the bench at once, but I thought they both powered on and off. Still, I need to check again.

 

As a side note: I've heard of another issue where the 5V is too low. Replacing ​R74: 30 Ohm replacement resistor, This increases regulator circuit voltage slightly for picky Lynx units that need a few more tenths of a volt to work.

 

I have to check and see if this is some odd way of doing the same thing.

 

 

 

I hope your right. That's an easy fix to set it right.

Edited April 30, 2018 by greenmonkeyking

[+karri]

I was looking at Lynx I schematics, sorry. In Lynx II the resistor is really in the front end of the voltage regulator. So it may really be an attempt to increase the voltage.

[bdoi]

Hi everyone, I picked up 2 lynx-II units off ebay. One of them has a strange repair. I'd like to remove it but I need to ask the experts 1st "What are they trying to do here?

 

Thanks for your help.

 

Hi greenmonkeyking,

do you know this resistor value? it 's hard to sse color on your pics.

[greenmonkeyking]

The resistor is hard to read due to the color of the resistor itself. I measured it in circuit and it was 13K so it has to be at least that much.

[greenmonkeyking]

Hi Everyone, the color pattern appears to be brown - yellow- blue - red. which makes it a weird resistor since typical resistors only have 3 bands.

[greenmonkeyking]

Hi Everyone: New question... Is there a common component failure that causes no video/no audio aka game not booting yet everything else works fine ? I've been searching the threads but no luck so far?

 

I've got a Lynx picked up off ebay from Techbabe that has no game boot issue. Just looking for a starting point or common parts that fail causing the no-game-boot issue.

[+Stephen Moss]

Hi Everyone: New question... Is there a common component failure that causes no video/no audio aka game not booting yet everything else works fine ? I've been searching the threads but no luck so far?

 

I am not aware of any common part that is particularly prone to going and causing this problem but trying the tests I mentioned here may help.

 

I am not sure about those resistor colours although on some metal file resistors (which can be 5 band, 4 for value and one for tolerance and opposed to 4 bands) sometimes it can be hard to distinguish between Red, Brown and Orange, the only way to clearly identify it would be to de-solder one end and measure it.

Edited May 8, 2018 by Stephen Moss

[7800fan]

Hi Everyone, the color pattern appears to be brown - yellow- blue - red. which makes it a weird resistor since typical resistors only have 3 bands.

 

Typical resistors have 4 bands with the 4th being tolerance. There's 5 band resistors that have higher precision but it's not commonly used in consumer goods.

 

Assuming the red band is for tolerance, 2% then brown-yellow-blue would be 14Mohm. But if the tolerance band is brown (1%) then red-blue-yellow is 260k

 

You will need to desolder one leg to properly measure it.