I Need Help (Fixing an Intellivision 2609 Motherboard)

[Humblejack]

Hi,

Is there anyone out there who has the patience to help me repair a motherboard off of a 2609.

 

All it does is show a black screen. I put another motherboard in the unit and it works so I know the problem is in this MB.

 

I can do most checks with a mulitmeter but don't know exactly what to look for.

 

So, I need someone who if we were a little closer so to speak, will hold my hand and walk me through the process of finding the problem and fixing it one step at a time.

 

I can send pics as needed.

 

Please have patience with me, I am an old man and very feeble in the brain department.

 

Please PM me and we will get started. This will be at your speed but please allow time for me to work your instructions.

 

As soon as I find someone willing I will post here that we are on our way.

 

Thanks all you smart AA people.

[HunterZero]

Well if you swapped in another motherboard and it works, then the power supply is probably good, but it's worthwhile checking the voltages coming out of the 5 pin ribbon connector all the same. I replace the blue capacitors and 3 pin 5V and 12V regulators on these with modern equivalents as a matter of course for preventative maintenance.

 

Does the console flash when you press reset?

 

Check the 5 pin ribbon cable and the blue wire from the 2 pin connector for continuity and verify that both are making good connection. Breaks in the 5 pin flat cable are common and can result in black screen.

 

To go further you will need to desolder the RF shielding.

 

Inspect the board for any obviously burnt or broken components, eg the little glass capacitors and black diodes.

 

Carefully remove socketed chips, clean the sockets and chip legs with deoxit, and place them back in. Do them one at a time, and take note of the direction.

 

Easy thing to check first are the two 2N3906 transistors Q1 and Q2 next to the CPU, or just replace them as they are a cheap part.

 

Otherwise if you have a known working board, you can try swapping the STIC, SRAM and CPU chips to rule out faults with these commonly failing logic chips.

 

- J

[Humblejack]

Well if you swapped in another motherboard and it works, then the power supply is probably good, but it's worthwhile checking the voltages coming out of the 5 pin ribbon connector all the same. I replace the blue capacitors and 3 pin 5V and 12V regulators on these with modern equivalents as a matter of course for preventative maintenance.

 

Does the console flash when you press reset?

 

Check the 5 pin ribbon cable and the blue wire from the 2 pin connector for continuity and verify that both are making good connection. Breaks in the 5 pin flat cable are common and can result in black screen.

 

To go further you will need to desolder the RF shielding.

 

Inspect the board for any obviously burnt or broken components, eg the little glass capacitors and black diodes.

 

Carefully remove socketed chips, clean the sockets and chip legs with deoxit, and place them back in. Do them one at a time, and take note of the direction.

 

Easy thing to check first are the two 2N3906 transistors Q1 and Q2 next to the CPU, or just replace them as they are a cheap part.

 

Otherwise if you have a known working board, you can try swapping the STIC, SRAM and CPU chips to rule out faults with these commonly failing logic chips.

 

- J

 

Thanks, I will start the process tonight. One step at a time.