Macintosh IICX No Video After Recap

[AlexTheCat123]

I just recapped my Macintosh IICX because it was having the common issue where the computer won't turn on and the power supply just clicks over and over again. Also, the sound wasn't working. After recapping the computer, the machine turns on just fine, but there is no chime and nothing is displayed on the screen. Do you think that I messed something up while recapping it or is there some other explanation to this problem? By the way, it worked fine before I did the recap on the rare occasion that it would actually power on without clicking repeatedly.

 

[beachycove]

The IICX needs a nubus card for video. Ist your card kaput?

 

[AlexTheCat123]

My video card is good. It worked fine when I tested the system before the recap.

 

[beachycove]

Well others may have a proper answer, but I will tell you about my IIci. I recapped it, and the nubus slots no longer work. They seem to get power (lights come on on select cards, etc.), but no workie.

Of course, you can still see what's going on in a IIci with no nubus slots functioning, but with a IIcx you are sort of cornered.... You could check that there is no gunk bridging the pins around the nubus controller. Maybe something got in there while the board was being cleaned?

 

[AlexTheCat123]

I will try to look into that this weekend. Do you have any idea why the NuBus slots would have stopped working if there is not anything bridging the pins?

 

[beachycove]

Nope, sorry. Nubus controller fried? 

 

[AwkwardPotato]

Not sure about this, but wouldn't you at least get a chime of some sort regardless of if the NuBus controller is good? Are all the voltages from the power supply good?

 

[AlexTheCat123]

Even when the computer sort of worked before the recap, I did not get a chime. One of the reasons that I recapped it was to try to fix the sound, but I am not sure if it is even working at all now. What are the voltages supposed to be on the power supply connector?

 

[Compgeke]

Did you recap the power supply? They do need recapped just as badly as the logic boards do.

 

[AlexTheCat123]

I have not recapped the PSU, but the fan spins, the power light comes on, and the floppy drive makes a short sound when the computer turns on. Doesn't that mean that the power supply is probably fine when you also consider the fact that I could occasionally get it to turn on before I did the recap?

 

[AlexTheCat123]

I just plugged headphones into the speaker jack and discovered that the computer plays the chimes of death immediately after I press the power button. Does this help to narrow down the problem?

 

[Macbuk]

Reseat memories and rom chips if socketed. 

Check fuses on the motherboard (labeled "F")

Check caps polarity and overall resistance between +5 and ground.

Sometimes you can find shorted (or low resistance) aluminum caps (even new) because of unefficient quality control.

 

[AwkwardPotato]

Check for continuity between C2 and R3, and between R3 and the internal speaker jack. Run patch wires between them if there isn't continuity to fix the sound issue. As for the chimes of death, a good starting point would be to make sure your RAM is good, if possible.

 

[AlexTheCat123]

I just checked between C2 and R3 and I realized that there was no connection. I touched up the solder on C2 and now the internal sound works fine. Unfortunately, I don't think that I have any way to test the RAM. Could I just try each stick of memory one stick at a time until I find one that works? Also, what is the purpose of the plastic bar on the RAM sticks that can be seen in the photo at the link below? I would have sent it as an attachment, but it wouldn't let me.

https://drive.google.com/open?id=1l4zALUBNmnA2ramvdqvQlL_Vvd4UX-Mi

 

[beachycove]

30-pin SIMMs need to be installed in identical sets of four, and I'm pretty sure that in the IIcx, that has to be in the correct slots as well. You might want to check that you have them installed correctly before moving to thinking about testing the RAM per se.

 

[AlexTheCat123]

All 8 slots are currently filled and I checked to make sure that each set of four is made up of the same type of stick. Does the Macintosh SE have SIMM slots that I could test the sticks in? I have one of those but I have not opened it up in a while.

 

[beachycove]

Easier to try with sets of four first, but yes, they should work in an SE. 1MB SIMMs should, at any rate.

 

[AlexTheCat123]

Perfect! I will try to test the SIMMs in my SE tomorrow afternoon and see if any are bad.

 

[AwkwardPotato]

That plastic bar isn't stock. It's hard to tell, but it seems that the tabs for some of the SIMM slots have been snapped off, so I'd guess the bar is there to hold the SIMMs in place (and maybe the RAM not being seated correctly because of this is part of the problem).