I've been working on K4900s recently. I had one sitting on the shelf that I picked up years ago that had a tag on it that said "good."
I plugged it in to test it, and the fuse on my test rig blew immediately. Fuse on the chassis was fine, though. Did a cap kit, then started to look at transistors...and found that someone had installed a 2SC1106 voltage regulator in place of the HOT!
After correcting that, I plugged it back in and only get a nasty ticking sound, so I've got more troubleshooting to do on this one.
So the reminder about working on unknown monitors is two-fold:
I plugged it in to test it, and the fuse on my test rig blew immediately. Fuse on the chassis was fine, though. Did a cap kit, then started to look at transistors...and found that someone had installed a 2SC1106 voltage regulator in place of the HOT!
After correcting that, I plugged it back in and only get a nasty ticking sound, so I've got more troubleshooting to do on this one.
So the reminder about working on unknown monitors is two-fold:
- Don't believe a repair tag, unless you know who did the work
- Always check the board and core components closely before testing!!
