9 Oct 2006

Keeping the Emulator III alive - Part 5: crashing & locking up

Recently my EIII started acting up again. This time the whole machine would crash. There were 3 kinds of crashes:
1. The EIII would lock up, the display would read "SCSI Hardware failure"
2. The EIII would just lock up. The screen showed junk characters and a random number of led's on the front panel would be active
3. The Hard Disk would shut down, but the EIII kept working. Sometimes the hard disk started spinning again. But most of the time the EIII would lock up.

At first I thought that the hard disk was failing but replacing the hard disk didn't solve the problem.

All the above problems were caused by one thing: The voltages on the power supply output were erraticly changing. Meaning that most of the time it was giving 11.00 Volt on a 12 Volt line (Orange wire), but sometimes the voltage would drop below 11 Volt causing the EIII to crash and the hard disk to shut down.

Solution: cleaning the trimpot on the power supply PCB and adjusting the voltage to the correct level (+12 V).

There's only 1 trimpot on the power supply so you can't go wrong.

I suggest you disconnect everything from the power supply, except the fans and/or the hard disk, when you adjust the voltage. Otherwise you migth fry something when the voltage peaks.

I used one of the fan connectors to read out the voltages.



Blogger Jerry Langford said...

Awesome. I'm going to give this a try. I have many of the same problems you are experiencing. Locking up, erratic characters on the display, all the LEDs on the front panel lit at the same time, trouble booting, etc....

I haven't tried a new drive yet, but if this solves the issue that would be fantastic.

5:19 pm  
Blogger Jerry Langford said...

I know the basics of a multi-meter (testing outlets and switches in the house and such), but I'm fearful of shorting something out here. Can you describe where you placed your multi-meter leads when testing? It sounds like you used the orange wire going to the fan, but I want to make sure I get both + & - leads in the proper place for testing.


5:29 pm  
Blogger dvdborn said...

Hi Jerry,

I placed my multi-meter on the power connector that is connected to the fan standing besides the card cage.
The connector has an orange (+12V) and a green wire (ground).
Just connect the 2 contacts with your multi-meter and make sure that you're measuring DC voltage.

At first it's best to read the voltage values for a few minutes without touching the trim pot. That way you'll see if the voltage is fluctuating or not.


7:47 pm  

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