My third TDS3000B, acquired as dead machine, blank screen, no response to any key. I guess this is very possible caused by the oscillator. So I bought them. when I measure the out put of the crystal out put, no signal. My normal TDS3012B has 75.757M output. so definitely, this oscillator is dead. then I found it was soldered in wrong direction. check the other oscillator (48M), wrongly installed as well. and both frequency are wrong.
I bought 2 oscillators and they arrived today. replaced the wrong oscillators. power on the scope, wooo, it boot up normally!
Then I do some measurements. it functins well.
But, it always has a but, I can't find a 75.7575 oscillator, now using a75M, it works well. only the frequency measurement reading is a little wrong, for the 1K square wave, it shows 1.010K. This is obviously because of the 75M oscillator.
Now I need to find the strange frequency 75.757 oscillator.
BTW, this scope also missed the handle anchor assembly, and the trigger level potentiometer broken. Will try to repair them.
Anyway, already a happy success. it's time to have a beer.