IO-21 scope problem

[Peter A Markavage]

I would check the voltages on the CRT especially the deflection plates,
voltages on V4 and V5, and a run through of all the voltages in the power
supply section. Barring a tube problem, most likely a resistor opened up
or a capacitor has developed excessive leakage or has shorted. Voltages
are marked on the schematic.
Pete, WA2CWA

On Fri, 18 Jul 2003 21:18:04 -0700 George Yazzolino <Kc7hkp at TELEPORT.COM>
writes:
> Hi Guys
> I have a heathkit IO -21 scope. when i first turn it on the Spot
> last only
> for a couple of seconds and drops of to the lower right hand side. I
> can not
> do any adjustment on the front panel controls to bring it into
> view.!
>
> not sure where to start to look for the problem.....any ideas
> ?.....Tube or
> resistor or cap out of spec maybe ?
>
> thanks
>
>
> P. George Yazzolino
> 14801 NE 20 Circle
> Vancouver, WA.  98684
> KC7HKP...Grid CN-85

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