Terry,
Best of luck with finding your oscilloscope. Many bargins can be found on the Tektronix 465. The 465 sold in such large numbers back in the 1970 and early 1980's that if your scope ever failed it is very possible to get it repaired. Many calibration and repair houses have stock piled 465's as sources for repair parts. I only have one word of caution for you. Remember, oscilloscope measurements are referenced to ground unless you are using a differential probe or making an A-B measurement. The ground lead of the scope is literally connected to ground so you can not connect you probe across a component in a circuit. If you do this, the side of the component that you connect the probe ground lead to, will be shorted to ground. I know you are fairly new and this is a common and often costly mistake.
Best of luck with finding your oscilloscope. Many bargins can be found on the Tektronix 465. The 465 sold in such large numbers back in the 1970 and early 1980's that if your scope ever failed it is very possible to get it repaired. Many calibration and repair houses have stock piled 465's as sources for repair parts. I only have one word of caution for you. Remember, oscilloscope measurements are referenced to ground unless you are using a differential probe or making an A-B measurement. The ground lead of the scope is literally connected to ground so you can not connect you probe across a component in a circuit. If you do this, the side of the component that you connect the probe ground lead to, will be shorted to ground. I know you are fairly new and this is a common and often costly mistake.
kilowattski, it's a good time for a workout.
K-amps, Tek put a really excellent guide to oscilloscopes on their website- I thought the link went there. I'll check it out and see if I can get you a more precise link.
Edit: the link takes you to the ABCs of oscilloscopes. I have that guide in one big pdf, which is probably somewhere else on the site. Nonetheless, the concepts of sweep, triggering, delay, and the like are all there. Start downloading and reading, it will be a great education. And there's no substitute for spending an afternoon with a signal generator and scope diddling the controls until you understand them.
K-amps, Tek put a really excellent guide to oscilloscopes on their website- I thought the link went there. I'll check it out and see if I can get you a more precise link.
Edit: the link takes you to the ABCs of oscilloscopes. I have that guide in one big pdf, which is probably somewhere else on the site. Nonetheless, the concepts of sweep, triggering, delay, and the like are all there. Start downloading and reading, it will be a great education. And there's no substitute for spending an afternoon with a signal generator and scope diddling the controls until you understand them.
kilowattski said:
With the TDS series of scope probes the ground lead will fry itself -- literally evaporating -- if you accidentally cross ground. Replacement ground leads are $6 each!
With the 7000 series the 7A22N Differential Amplifier is a good plug-in -- they usually go for around $20 - $30 -- sensitivity is 10uV/cm and it is truely differential.
Andrew --
this is where you need a differential probe, or a differential amplifier -- Charles Hansen wrote a nice article in the last (mbe Jan or Feb) issue of AudioXpress using the AD629 diff amp -- which can really hold off a lot of voltage. You shouldn't need the magazine to figure it out, however.
This is exactly the type of application -- as in measuring a shunt in a high voltage supply.
this is where you need a differential probe, or a differential amplifier -- Charles Hansen wrote a nice article in the last (mbe Jan or Feb) issue of AudioXpress using the AD629 diff amp -- which can really hold off a lot of voltage. You shouldn't need the magazine to figure it out, however.
This is exactly the type of application -- as in measuring a shunt in a high voltage supply.
SY said:
Thanks, will try to read most of it.
The probes have 1x and 10x selectors, but one is stuck, and its not really possible to open it up... It also has a lever on the side of that sweep dial, doesnt want to move though, maybe its broken.
btw my scope is actually 100mhz as well. Maybe it is the same model as yours (cos6100)?
SY said:
Nice, any tips on using it, or cleaning it up? and do you happen to have the manual?
Mine makes this sparking noise after a bit of use and the CRT goes all wacky. I read a post saying it is a common problem with the power supply and just needs resoldering.
But it would be nice if I had schematics..
thanks
Well, I guess I made a stupid move. I bought This scope. I guess I was hoping since the seller admitted that they didn't know how to operate it that perhaps it was OK. Wrong, I can't get any image on the screen. The lights light for the buttons but no image. Is there a way to test to see if the CRT is bad?
Should I just cut my losses and resell it and wait for another deal?
To be honest, I figured the leads and stuff that came with it were probably worth what I paid for it except for the shipping.
Anyway, any suggestions on whether or not to attemp to fix this thing will be greatly appreciated.
Thanks, Terry
Should I just cut my losses and resell it and wait for another deal?
To be honest, I figured the leads and stuff that came with it were probably worth what I paid for it except for the shipping.
Anyway, any suggestions on whether or not to attemp to fix this thing will be greatly appreciated.
Thanks, Terry
I don't know if you have some knowledge about scopes. If yes, do not read. If not, try to do following:
1. Insert a probe into Chanell A
2. Set VOLTS/DIV selector to minimal voltage. It should be something like 5mV
3. Set TIME/DIV selector to 0.5mS.
4. Chanell A has pot for position. With this pot you shift the picture vertically.
5. There is another pot below the screen for Y axiss.
With this two potentiometers you can adjust your picture into a visible part of the screen.
Touch the probe tip with your finger and if the scope is working you should se something on the screen. If not that doesn't neceserilly means that the scope is not working. Try with channell B.
I don't see the big picture on eBay, but I am guessing that the trigger (right side) portion of the scope is simillar to mine (475A).
You can check wether your trigger is working properly or not. You have source switch at channel A trigger section. Switch it to EXT.line position. Set the volts/div selector to 50mV. Push the Trigger View button (the one between Channel 1 and 2 selector and you should see the sample of line voltage.
1. Insert a probe into Chanell A
2. Set VOLTS/DIV selector to minimal voltage. It should be something like 5mV
3. Set TIME/DIV selector to 0.5mS.
4. Chanell A has pot for position. With this pot you shift the picture vertically.
5. There is another pot below the screen for Y axiss.
With this two potentiometers you can adjust your picture into a visible part of the screen.
Touch the probe tip with your finger and if the scope is working you should se something on the screen. If not that doesn't neceserilly means that the scope is not working. Try with channell B.
I don't see the big picture on eBay, but I am guessing that the trigger (right side) portion of the scope is simillar to mine (475A).
You can check wether your trigger is working properly or not. You have source switch at channel A trigger section. Switch it to EXT.line position. Set the volts/div selector to 50mV. Push the Trigger View button (the one between Channel 1 and 2 selector and you should see the sample of line voltage.
Terry,
There is really no way to test the CRT on one of these scopes externally. Some of the older scopes had a beam finder button. Pressing it put a dot on the CRT so the horizontal and vertical controls could be adjusted easily. I don't recall if the 455 had that button. If it does just press it and look for the dot. You may have to adjust vertical and horizontal positioning a bit. If there is no beam finder button, make sure that the trigger MODE is set to AUTO and the SOURCE to Channel 1, LEVEL to about 50%, TIME/DIV to 1 millisecond and the VOLTS/DIV to 1 volt. There should be a trace on the screen at this time if the scope is working. Oh, don't forget the intensity button and the horizontal and vertical controls to position the beam.
There is really no way to test the CRT on one of these scopes externally. Some of the older scopes had a beam finder button. Pressing it put a dot on the CRT so the horizontal and vertical controls could be adjusted easily. I don't recall if the 455 had that button. If it does just press it and look for the dot. You may have to adjust vertical and horizontal positioning a bit. If there is no beam finder button, make sure that the trigger MODE is set to AUTO and the SOURCE to Channel 1, LEVEL to about 50%, TIME/DIV to 1 millisecond and the VOLTS/DIV to 1 volt. There should be a trace on the screen at this time if the scope is working. Oh, don't forget the intensity button and the horizontal and vertical controls to position the beam.
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