SOS Macintosh Iicx won't shut down.

[toples50]

I have a Macintosh IIcx just recapped but now it won't shut down.In fact I've managed to shut down once.Is it a common problem with Iicx machines or have a problem?

 

[AwkwardPotato]

It's pretty common for II-series machines to have power-on/power-off issues. Has the logic board been thoroughly cleaned? Does the IIcx power off when the case power switch or keyboard power switch is pressed?

 

[toples50]

The board recapped by a friend who is professional.As for power switch I tried everything.Still nothing...

 

[nglevin]

Astec PSU? Just a thought, because I've run into some really funny issues with those as they age.

Seems that Delta Electronics and Sony branded PSUs were built out of better bits.

 

[toples50]

Yes Astec PSU unfortunately...I have the same PSU to my Mac IIci.Can I try to exchange the PSU's and try the IIcx again?

 

[AwkwardPotato]

Agree with nglevin on the Astec's having issues.

Inspect UK2 and UL2 for any corroded/damaged traces (right next to the battery). The shutdown circuit for the IIcx sits right next to a bunch of caps so it's likely that there's a damaged trace if the PSU turns out to be good.

The PSUs are exchangeable.

 

[toples50]

Otherwise the machine runs fine!

 

[nglevin]

The compact IIs (IIcx, IIci), and the Quadra 700 all had the same PSU, and I am nearly certain that the Quadra 650, IIvx and the PM 7100 had an upgraded version of the same PSU that fits in the same form factor.

I've run a Quadra 650 logic board with the IIcx PSU one time when I was dealing with Astec fun, though I did notice it had trouble booting with too many NuBus cards. Replacing the PSU with one sourced from a dead PM 7100 ended up fixing the problem.

 

[toples50]

So I will try to swap the PSU from my IIci or Q700.

 

[toples50]

Agree with nglevin on the Astec's having issues.

Inspect UK2 and UL2 for any corroded/damaged traces (right next to the battery). The shutdown circuit for the IIcx sits right next to a bunch of caps so it's likely that there's a damaged trace if the PSU turns out to be good.

The PSUs are exchangeable.

Picture from the motherboard around the battery.

 

[AwkwardPotato]

UK2, UL2, and UM2 all still look pretty corroded. Clean them up with IPA and a toothbrush. If you have a multimeter, check for the voltages on these pins while holding down the case power switch and post what they are:

- Pin 3 of UL2

- Pin 4 of UL2

- Pin 5 of UK2

- Pin 6 of UK2

- Pin 9 of UK2

 

[Bolle]

That board has not been properly cleaned.

As said check all traces according to the schematic and if they are fine one of the logic gates is dead, which is a pretty common issue.

 

[AwkwardPotato]

In case it wasn't clear, I forgot to mention that the voltage tests I suggested should be done with the system turned on.

 

[AlpineRaven]

The board recapped by a friend who is professional.As for power switch I tried everything.Still nothing...

I'm sorry - I find it hard to believe if it was done by professional, but this re-cap job is rather messy - if it was a professional would've cleaned the board 100% and straighten the caps out.

Cheers

AP