Are these things I should consider bad

[Username1]

as long as those larger ones are under control, don't worry too much about the smaller ones right now.... Stick to the ones you are getting that look too high. tp5.

[TinCanAlley]

Originally Posted by Username1

as long as those larger ones are under control, don't worry too much about the smaller ones right now.... Stick to the ones you are getting that look too high. tp5.

Okay, went after the TP5 again. My DMM has it at 134VAC, but my scope has a PP of 170V. Am I missing something? I guess I'll find some other TPs and see if their voltage matches the waveforms in Sams. If they, then something is wrong with TP5. If they don't, then it's my scope and/or probe or Sams is not accurate.

[TinCanAlley]

With the scope on 50V/Div and putting the probe near the FB, I get this waveform. If you notice, the bottom of the form is ringing the number of jail bars I see on the screen. Is this normal to see this when probing w/out actually making electrical connection to the FB? I get the same form when placing the probe on the collector of the HOT (plastic tip on probe). It's even worse if I go anywhere near the focus wire.

[TinCanAlley]

Originally Posted by Username1

as long as those larger ones are under control, don't worry too much about the smaller ones right now.... Stick to the ones you are getting that look too high. tp5.

Okay, just checked the horizontal pulse which should be 50VPP. I set my scope to 50V/Div and got the noted waveform in Sams as well as a PP of one division. So that one is correct, so the scope seems to be working properly. I've found another TP I'm going to try. It goes to the convergence board and is 170VPP. That should tell me if my scope and/or probe is handling higher voltages correctly.

[TinCanAlley]

Okay, so how do I go about checking my scope for proper AC voltage calibration? I just tested another point that is supposed to be 170VPP. With the scope on 50V/Div I get almost 4.5 divisions. That's almost 225VPP. I checked with my DMM and it reads as 130VAC. I check the one next to it that was supposed to be 20VPP and it showed as 25VPP. The DMM had it as 16.9VAC. I'm pretty sure my DMM isn't showing the exact voltage (everyone keeps writing about RMS and such).

I need to know if there's something wrong with my scope. If so I need to return it to be fixed.

Thanks!

[andy]

...

[TinCanAlley]

Originally Posted by andy

The first thing to do is to check the calibrator output on the front of the scope. You should see a perfect square wave with the amplitude specified. If the top and bottom is curved, then adjust the probe (this applies to X10 mode only).

Comparing things to the Sams folder is a bad way to check your scope for accuracy. Sams often have mistakes, many of the circuits in the TV (which isn't working properly) have wide tolerances, and your 465 probably has 10 times the bandwidth as the one Sams used (meaning high frequency signals, and fast pulses will appear larger on your scope).

Yes, the calibrator is 1V and with the probe in 1x and .5V/Div I get a perfect square wave. I then put the probe in 10x and 50m/Div and get another perfect square wave.

See my other post where the 125VAC shows up as 325V on the scope.