Re: Analog scope trace ref height

Apr 01, 2004 3 Replies


I'm borrowing an old 2 chan 20MHz analog scope - a Hitachi V-212


Those are actually nice little scopes. Nothing like Tek quality, but still reasonable for a cheap scope.


After I set the trace height to zero (or whatever reference point) -
>there's a big height change (sometimes by 2 or 3 grids) when I change
>the (vert) Volts/DIV to the next setting. This is with no input
>signal. This is abnormal(?), as it should remain fairly stable, right?
>
>Is also weird that the recessed DC balance pots appear bent - facing
>down - and are not readily accessable

You adjust the DC balance pots to get the trace not to move up or down when you change ranges, the fault you mentioned above. It is most likely that the PC board inside has just shifted somewhat, or that it never was quite right so that it's hard to get to these pots.


-

----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA



-----------------------------------------------


If you ground the input, rather than leaving it dangling, is it still the case?

Jim Adney wrote in news: snipped-for-privacy@4ax.com:

Most likely,someone slid the cabinet on wrong(carelessly) and snagged the pots.I've seen people cut coaxes,and break switch wafers this way,too.

Jim Yanik jyanik-at-kua.net

Thanks for all of the responses. You guys were right - I can see where one of the front base foot pads has been pushed up, into the bottom of the chassis shell by + 1/4", bending the bottom panel up, most likely shifting the PC board & pots

Lance

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required