Does this unit have serperate H-Scan and EHT or combined.
If it is seperate take out the EHT switching transistor and try it, then the HOT and try it, which ever removal stops the noise then suspect that circuit.
If it is combined take out the HOT and try it.
I suspect FBT but try above and see.
Rich
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Some monitors have 2 seperate circuits for EHT and H Scan although unusual on a 17".
HOT = Horizontal Output Transistor
Some people call the switching transistor that controls the EHT in the seperate EHT circuit a HOT this is not correct.
So in seperate type you will have 2 switching transistors one would be high current rated for Scan (HOT) and the other lower rated for the EHT, they would also likely have 2 fets one for controlling the supply to the scan and the other to the EHT, in this circuit you can modulate the supply to the H Scan circuit for width & Geometry as it does not affect the EHT
The combined EHT and scan has one FET and one high current Transistor, plus some method of controlling width & geometry without affecting EHT. In this type of circuit it is correct to call the high current transistor a HOT as it does switch the H Scan.
Rich
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The internal Cap in the FBT opens up alot, and can cause weird noises on power up like Rich describes. One Tech I spoke to actually got theirs to power up ok by placing a HV probe on the anode. I guess the external Capacitance the probe had was just enough to do the trick.
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