OT Scope question. - Videokarma.org TV - Video

***Eric H*** · #1 06-25-2007, 07:42 PM

Found a Tek 2215 scope last weekend, comes on but there's just a dot on the screen, shouldn't it be sweeping across the screen horizontally?

Also you can adjust the vertical top to bottom but the horiz will only go from center to left side of the screen.

kbmuri · #2 06-25-2007, 09:14 PM

Sounds broken.

http://cgi.ebay.com/ws/eBayISAPI.dll...m=220123506627 shows a good closeup.

Not sure what Horizontal Mode "Alt" does. Unless it's a vector mode of some sort with external input. That might not sweep. Otherwise it should be.

EchoWars · #3 06-25-2007, 09:17 PM

If the time base is turned completely counter-clockwise, the scope may have a X-Y function and sweeps are dependant on the signal.

In every other time base position, you should have a horizontal sweep, with the rate increasing as you turn the dial clockwise.

***Eric H*** · #4 06-25-2007, 11:02 PM

I can't get a horizontal trace with the settings in any position so I guess it's toast.

Wonder if i can use the 7kv supply in an electrostatic TV?

Quote:

Originally Posted by EchoWars

If the time base is turned completely counter-clockwise, the scope may have a X-Y function and sweeps are dependant on the signal.

In every other time base position, you should have a horizontal sweep, with the rate increasing as you turn the dial clockwise.

Einar72 · #5 06-26-2007, 04:28 AM

Quote:

Originally Posted by kbmuri

Sounds broken.

http://cgi.ebay.com/ws/eBayISAPI.dll...m=220123506627 shows a good closeup.

Not sure what Horizontal Mode "Alt" does. Unless it's a vector mode of some sort with external input. That might not sweep. Otherwise it should be.

Alt mode normally traces one complete line per one channel before tracing the other. Chop literally does just that, jumping between both channels during a single trace. Looks really choppy, too. I have one of these that I got at a workplace equipment auction long ago. It was returned from the cal lab un-calibrated. I lost the tag from XTEK saying what was wrong with it. There is a way to lose sweep on the darn thing, but I'll be darned if I remember.

Eric, does the trigger LED go off if you apply a signal? Shove the probe in the cal-hole and see if it lights up. I honestly don't know where mine is

, or I'd look.

Einar72 · #6 06-26-2007, 04:47 AM

I just thought of one more thing. The two sweep-timebase knobs should be locked together and turn in unison (the clear one at the base of the grey one can be disengaged and adjusted separately for delayed-sweep work). This, as mentioned earlier, can make it look broken. Also, set the Horizontal mode to A, Var Holdoff to norm, A trigger to Auto, center it's Level knob as well and leave there for now. If it's gonna work at all, it should work now. The Cal-hole should give you enough signal if you turn the gain up a bit. I'm curious if you have any vertical deflection. Otherwise, you may have a bad P/S section or sweep stage...Factory replacements are now made of Unobtanium, but they occasionally pop-up on a Tektronix-employee's eBay store.

***Eric H*** · #7 06-26-2007, 10:34 PM

I played around with this thing today, took the cover off to look for any obvious problems.

I did find a small metal heat sink that had slid off a transistor, I though perhaps the transistor had burned up because of this but it checked OK with the Fluke. Another possibility is something was damaged when this metal heat sink shorted something out!

I could tell which section was the horiz by the wires going to the deflection plates on the CRT, I checked the components in the immediate area but didn't find anything shorted or smoked.

I might just make a (very small) Fish tank out of it.

Findm-Keepm · #8 06-30-2007, 11:14 AM

Have you tried out the Tek Scopes forum over on Yahoo groups? Great folks there and some real pros at troubleshooting your stuff via the forum. Here's one relevant post in regards to the 2215:

"The most common fault with the Horz on these is a deflection lead pulled off
the CRT (they are under the tube).
The leads were very short and the connectors with the gold pins often fell
off.
Tek had a mod to replace them with silver types that were purpose designed
and never fell off.
It's easy to check any Horz amp - just put the scope in XY and measure the
deflection voltage on the leads.
They should go from low to high as you move the spot on screen left or
right, the other lead should do the opposite.
From memory I think you are looking at 7-57V swing but check the manual.
With both leads removed you should see a spot about middle of screen."

Cheers