Lynx 2 - replaced everything - but still not working

[damaci]

Hi Guys,

 

I am confused.

A couple of month ago I got two Lynx 2 consoles.

But this one on the picture makes me confused.

I already spent hours on it trying to get it alive again. It powers on and off, but has no sound and picture.

It has a stable 5 volt supply and a lot of new parts.

What I replaced so far:

- 5 Volt Mod with Recom

- new ram modules

- new C301719-001 (Hayato)

- new C302284-001 (Suzy)

- new 16mhz resonator

- new resistor R10 (10Mohm according to schematic)

- new capacitors

- reheat nearly every solder joints

 

The first Lynx 2 had same replacements and mod, and is working fine again.

But the second doesn't want to work.

 

Now I have no further ideas what to do anymore, so maybe some of you have additional hints. I would appreciate them.

 

Regards

Daniel

 

 

 

[+karri]

Once you power it on you could measure signals.

 

The first is the clock. Is the clock ok.

 

Does the RESET signal generate a proper startup RESET.

 

Then you could look at the read strobe OE to the cart. Does the CPU try to access the cart at all?

 

Then you could look at the data bus. Is there clearly different states like '0' and '1' on the D0..D7 pins.

 

There may also be conductive acid on the PCB surface. If you measure resistance of the green fiberglass does it conduct electricity? If it does get some Isopropanol to clean it away.

 

There is also a lot of components missing on the PCB like transistors, capacitors, diodes... I assume removing them has been intentional.

[damaci]

Hi Karri,

 

thanks for your reply.

 

Yes, the mentioned parts were removed on purpose. They were part of the original power supply, which I replaced by the Recom dc dc converter.

Measuring data signals is currently not possible for me, I have no oscilloscope at hand ?.

Conductive acid on the surface can be excluded, checked that already.