Getting a scope again
As some of you know, due to an unfortunate incident (family problems) i had to sell my scope in November.
I looked around and $300 could buy me a Tek 2235 - however it would've taken about 3 months for me to save that much, and that would be 3 months without buying random parts, and we all know that isn't possible.
So, i found a 2x 10MHz National (Panasonic) scope for $106. That should be plenty enough for SMPS work. I used to have a 100MHz Russian-made single channel scope, but i had no use for the bandwidth as it was too low for FM radio and motherboard clocks anyway, and too high for SMPS and audio. I could have used an extra channel instead of the bandwidth, and that's exactly what i'm doing now.
Before telling me to check ebay... 1) I lost my credit card. 2) With shipping costs, i'd end up around the same price. Scopes tend to be on the big and heavy side so shipping costs are killer. Also this scope is advertised as being serviced and calibrated, and he has more than 1 for sale, so i believe the calibration part.
Picture is attached. The volts/div knob looks like it maxes out at 5v/div so with an x10 probe that would be 50v/div, and with 8 divisions on the vertical this translates to 400 vpp max, but i'll be making my own probes anyway, so no problem making a x20 or or x50 probe if need be. By far more interesting are the numbers on the right side - which although obscured by the angle, logic says they're 50, 20 and 10mV. With a x10 probe that's a minimum of 100mV/div - the scope i used to have had a 5mV/div setting and that was just barely enough for viewing SMPS output ripple with a x10 probe, so this is going to be some trouble. Although, whipping up an amplifier to increase vertical sensitivity shouldn't be too hard.
Anyway, i've closed the auction already and got the seller's details. He lives close to me so that was an extra decision point there. I'll probably go pick it up tomorrow evening. Oh wait, make that today since it's 2:30AM already. Back to SMPS land it is. 
I looked around and $300 could buy me a Tek 2235 - however it would've taken about 3 months for me to save that much, and that would be 3 months without buying random parts, and we all know that isn't possible.
So, i found a 2x 10MHz National (Panasonic) scope for $106. That should be plenty enough for SMPS work. I used to have a 100MHz Russian-made single channel scope, but i had no use for the bandwidth as it was too low for FM radio and motherboard clocks anyway, and too high for SMPS and audio. I could have used an extra channel instead of the bandwidth, and that's exactly what i'm doing now.
Before telling me to check ebay... 1) I lost my credit card. 2) With shipping costs, i'd end up around the same price. Scopes tend to be on the big and heavy side so shipping costs are killer. Also this scope is advertised as being serviced and calibrated, and he has more than 1 for sale, so i believe the calibration part.
Picture is attached. The volts/div knob looks like it maxes out at 5v/div so with an x10 probe that would be 50v/div, and with 8 divisions on the vertical this translates to 400 vpp max, but i'll be making my own probes anyway, so no problem making a x20 or or x50 probe if need be. By far more interesting are the numbers on the right side - which although obscured by the angle, logic says they're 50, 20 and 10mV. With a x10 probe that's a minimum of 100mV/div - the scope i used to have had a 5mV/div setting and that was just barely enough for viewing SMPS output ripple with a x10 probe, so this is going to be some trouble. Although, whipping up an amplifier to increase vertical sensitivity shouldn't be too hard.
Anyway, i've closed the auction already and got the seller's details. He lives close to me so that was an extra decision point there. I'll probably go pick it up tomorrow evening. Oh wait, make that today since it's 2:30AM already.
Back to SMPS land it is.
Attached Files
There's a coil around the tube that i have no idea what it does, as IIRC oscilloscopes used electrostatic deflection. Maybe degaussing or magnetic field compensation? It has a resistance of about 570 ohms and has 0.783v DC on it when the scope is on. No AC signal could be detected on it.
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