Thread
Color Classic Needs Serious Help
can you go ahead and just say a little more about what you did?
he mentioned what he did? replaced the mosfet, thermistor, and driver IC?
Yes, That's all I had to do, replace those three parts.
When the fuse originally popped, I replaced it and it popped again.
So I started looking for damaged components-- and saw the damaged Thermistor.
I thought those were supposed to protect against high current? Maybe it did and that's why it went up.
Then I checked components for shorts-- Transistors/FETS first, then diodes then caps, then resistors.
I pulled a few caps out of circuit and tested them with a cap tester in my meter when they looked suspect, but all were OK.
I checked just about every component on the board (in circuit), and couldn't find anything else that looked obviously bad. (Shorted)
I replaced that NTC 10 ohm Thermistor with a 3A , from what I read they're suppsed to protect from blowing the fuse from
inrush current, The main fuse is 3.15A, so that's why I went with a 3A.
When I tried the first power up after replacing those, I half expected it to pop the fuse again. I figured it couldn't be that simple.
But when I hit the power switch, I heard the CRT fire up. (That quick hum sound--Degauss?) Hit the switch on the keyboard and got a chime.
No problems yet-- Maybe I got lucky, and it was just the switching FET that failed.
I'll eventually recap the analog board, probably sooner than later.
When the fuse originally popped, I replaced it and it popped again.
So I started looking for damaged components-- and saw the damaged Thermistor.
I thought those were supposed to protect against high current? Maybe it did and that's why it went up.
Then I checked components for shorts-- Transistors/FETS first, then diodes then caps, then resistors.
I pulled a few caps out of circuit and tested them with a cap tester in my meter when they looked suspect, but all were OK.
I checked just about every component on the board (in circuit), and couldn't find anything else that looked obviously bad. (Shorted)
I replaced that NTC 10 ohm Thermistor with a 3A , from what I read they're suppsed to protect from blowing the fuse from
inrush current, The main fuse is 3.15A, so that's why I went with a 3A.
When I tried the first power up after replacing those, I half expected it to pop the fuse again. I figured it couldn't be that simple.
But when I hit the power switch, I heard the CRT fire up. (That quick hum sound--Degauss?) Hit the switch on the keyboard and got a chime.
No problems yet-- Maybe I got lucky, and it was just the switching FET that failed.
I'll eventually recap the analog board, probably sooner than later.
They do fail, but when they do they usually take the SMPS IC out with it.
Ah ha! for a moment I thought he had figured out what was causing the Color Classic Boards to be dead.
There is like 3 other threads about CC's goin. But good job on fix'n up the A/B!
back to the mystery of the dead Color Classic MOBO's
There is like 3 other threads about CC's goin. But good job on fix'n up the A/B!
back to the mystery of the dead Color Classic MOBO's