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Home Forums Color Classic Needs Serious Help — #24 Color Classic Needs Serious Help — #24
Post #24 by rickrob
Source ForumColor Classic Needs Serious Help — #24
CategoryTroubleshooting
Post DateTue, 18 Nov 2014 - 02:40
Original URLhttps://68kmla.org/bb/threads/color-classic-needs-serious-help.465/
Post
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.

mp.ls