Macintosh IIcx PSU Problems

[CompuNurd]

Let's take a better look at this:

I read what unity said in the forum above, and it looks like I put the cap polarity in the same as the others. I reverted it, same result. If you take all load off, such as floppy and hard drive, it stays on if you are holding the power button. Once you plug something to the graphics card or add a hard drive, it dies. Hold the power again and it ticks, chimes, ticks, chimes...

I do have a Q700 coming next month, so I will see what happens if I swap PSUs.

 

[CompuNurd]

Before I get the Q700, does anyone have an idea as to what is wrong with the IIcx?

 

[CompuNurd]

No one?

 

[unity]

Lets recap this recap. You recapped the motherboard and power supply?

 

[CompuNurd]

Only the motherboard was recapped.

 

[unity]

Do you have any other power supplies? Like one from an SE or SE/30, etc? Just to rule it out. I modified the pin-outs on an SE supply to power up a IIcx. Worked great and told me that the motherboard was indeed the issue.

Or wait for the Q700.

Or take another look at the mobo. Keep in mind on a IIcx not all caps share the same polarity direction.

 

[Ferrix97]

My IIci also had the ticking problem when i got it, but when I recapped the logic board it came back to life.

I think you should replace the "big" axial caps on the logic board

 

[CompuNurd]

I did replace the axials with the rest of the capacitors. I will double check polarity and orientation on the weekend.

 

[CompuNurd]

Well, I finally got some time today to take a look at it, and I had a spare IIvx PSU that fits the IIcx. I hit the power button, and the board powered up, but I had a rapidly repeating startup chime. I held the power button for a little longer and it looked like it started up. I then hooked it to a monitor, to which it immediately died and did nothing at startup. Is the video card the issue? Motherboard issue? Maybe two bad PSUs in a row? I am clueless right now.

 

[Ferrix97]

try powering it from the keyboard.

also, try removing the HDD and the FD drive

Are you using an Apple CRT display?, maybe you need a monitor/adapter that understands Sync on Green (SoG).

 

[CompuNurd]

It appears to die right as I plug a monitor in. It's a VGA adapter I am using to a flat screen monitor. I will try to power it from the keyboard and see what happens.

 

[Ferrix97]

I think that your card requires a SoG compatible monitor, like a Dell 1907FP.

Or maybe the adapter is not compatible, is it one of those models with a few DIP switches on it?

 

[Elfen]

It's been a while since I heard from this. Any luck?

For the card to work, the monitor should do 640X480 256 colors with Horz & Vert Sync on and Composite Video on in the adapter you are using. I find that if you set it to work with a LC/LC II, it should work with the Mac II Video Cards.

EDIT: Also - check the caps on the Video Board. They need to be recapped too if they are as old as the IIcx.