bk 2125 oscilliscope

jonmessenger · Joined: 14 Apr 2012 Posts: 4

Hey all, I am new to the forum, and new the wonderful world of electronics. I just purchased a bk 2125 oscilliscope, off ebay. while the unit seems to be functioning i am having some trouble. I have the owners manual, and the application guide, and have been going through the first use and probe calibration procedure. the unit dispalys both traces, the component checker works, it draws a circle for a capacitor, an angled line for a resistor, a bent line for a diode etc. so it would seem that the defection plates are functioning but when I hook to the cal output, or try to see a signal from my arduino board i can't see the vertical parts of the waveform, the horizontal part is easliy visible, but nothing on the vertical. while fiddling with the probe just touching it to my finger i can see a complete waveform, albeit jumpy and wierd, and i can use it to measure straight voltage etc. the pos controls work, as well as the chop mode and everything else. I am just wondering if there is some simple thing that i have overlooked? the square wave is the proper voltage (.2) and the wave is 1 graticule wide at .5ms. The probes are 100mghz 1X10

tell me what kind of info you need to know from me to help me figure this out.
Thanks

vtech · Joined: 08 May 2006 Posts: 1264 Location: USA

Does the intensity/brightness/focus has any effect on the missing part of the trace?

jonmessenger · Joined: 14 Apr 2012 Posts: 4

no, the problem persists at all intensity levels, some more playing around and i have been able to see some wave forms but not square ones. wierd huh?

vtech · Joined: 08 May 2006 Posts: 1264 Location: USA

Go to electrotanya and get the schematic and check for any visuals inside.
Also check around the blanking circuit.

jonmessenger · Joined: 14 Apr 2012 Posts: 4

tried the link, and for whatever reason, it won't download the pdf file, as for the second half of your reply, I have no idea what you mean.

Could you explain it further?

Thanks

vtech · Joined: 08 May 2006 Posts: 1264 Location: USA

Electrotanya has a limit of 2 dload per day and it does work. Need to click on the "get manual" at the bottom of the page that may not show up right away.
Thought you were familiar with circuitry.
Suggest doing a little research if intrested? Blanking circuit is part of a video/ deflection circuit used with CRT application.

jonmessenger · Joined: 14 Apr 2012 Posts: 4

Yeah, in the first post i kinda mentioned that I was new to this world. But thanks anyway. I have noticed in dim lighting, and high intensity that i can sort of see the verticals, but it's ok because the scope served the purpose that i bought it for, i was able to see my pwm wave and determine what the problem was. And as for the rest of the wave forms it works fine. I am not going to go tearing into the machine, I know when I have exceeded my limit.

Thanks for the help though.