Thanks techknight. I think you're right. Uniserver and I were also half-right!
Well last night, I was concerned so I looked up the motorola 68030 cpu datasheet.
I was looking up the max temperature ratings, to get an idea of what i should expect with a normally working cpu... I happened to be glancing at the cpu when I noticed something odd. It was a d'uh moment. Apparently pin 50 was bent toward pin 49 to the point it was basically touching. Well I was already in the datasheet so I looked up those two pins. And what do you know - pin 49 is Vcc, and 50 is n/c. I carefully seperated the pins, and started it up.
The results are a definite improvement. Instead of getting very hot very quickly, it now still gets hot as it did before - but instead of taking about 30 seconds or so - it now takes it around 5-10 minutes to get up to the same temperature. I'm really lucky pin 50 was a no connection pin, and not something vital.
Also i measured caps c2 and c13 again - instead using the power supply metal case as ground - instead of the negative side of the capacitor - and I got the correct voltages that uniserver originally posted. So I think it's ok... Those caps negative side doesn't go to ground, at least directly.
looking at the datasheet for a cqfp package (as is on the lciii), the max temperatures are as follows:
airflow in linear ft/min
0 200 500
maximum - no heatsink (estimated) 46 28 24
typical (- no heatsink estimated) 43 25 21
Degrees Celcius.
So that means no airflow would be at max 114.8 deg farenheit with a typical temperature of 109.4 degrees farenheit. I'm reading at least 108 deg farenheit. So that might be normal. Yes there is airflow, but it's not directly over the cpu - I don't think the cpu sees much of the airflow from the fan.
I've got 3 other lciii boards to fix... I guess it's time I fixed another one so I have something to compare them to. Once I have another board fixed, I'll be able to determine once and for all if it's ok (it probably is - but I like to verify). At least pin 49 and 50 aren't connected anymore! I might add a heatsink in the fututre to help it keep a little cooler. Hopefully it will last longer that way.
Uniserver - when you measured caps c2 and c13 - where did you put the negative lead? Specifically - did you use the negative side of the cap or did you use another ground?
I remember a few years ago the '020 in my LC was not very warm. I think the '030's gets warmer and this might be normal. I'll report back in a month or two when I get another board working... Let everyone know my results.
Well last night, I was concerned so I looked up the motorola 68030 cpu datasheet.
I was looking up the max temperature ratings, to get an idea of what i should expect with a normally working cpu... I happened to be glancing at the cpu when I noticed something odd. It was a d'uh moment. Apparently pin 50 was bent toward pin 49 to the point it was basically touching. Well I was already in the datasheet so I looked up those two pins. And what do you know - pin 49 is Vcc, and 50 is n/c. I carefully seperated the pins, and started it up.
The results are a definite improvement. Instead of getting very hot very quickly, it now still gets hot as it did before - but instead of taking about 30 seconds or so - it now takes it around 5-10 minutes to get up to the same temperature. I'm really lucky pin 50 was a no connection pin, and not something vital.
Also i measured caps c2 and c13 again - instead using the power supply metal case as ground - instead of the negative side of the capacitor - and I got the correct voltages that uniserver originally posted. So I think it's ok... Those caps negative side doesn't go to ground, at least directly.
looking at the datasheet for a cqfp package (as is on the lciii), the max temperatures are as follows:
airflow in linear ft/min
0 200 500
maximum - no heatsink (estimated) 46 28 24
typical (- no heatsink estimated) 43 25 21
Degrees Celcius.
So that means no airflow would be at max 114.8 deg farenheit with a typical temperature of 109.4 degrees farenheit. I'm reading at least 108 deg farenheit. So that might be normal. Yes there is airflow, but it's not directly over the cpu - I don't think the cpu sees much of the airflow from the fan.
I've got 3 other lciii boards to fix... I guess it's time I fixed another one so I have something to compare them to. Once I have another board fixed, I'll be able to determine once and for all if it's ok (it probably is - but I like to verify). At least pin 49 and 50 aren't connected anymore! I might add a heatsink in the fututre to help it keep a little cooler. Hopefully it will last longer that way.
Uniserver - when you measured caps c2 and c13 - where did you put the negative lead? Specifically - did you use the negative side of the cap or did you use another ground?
I remember a few years ago the '020 in my LC was not very warm. I think the '030's gets warmer and this might be normal. I'll report back in a month or two when I get another board working... Let everyone know my results.