[Boatanchors] measuring ripple?

[Rodger]

Eugene,

Check your scope manual but most vintage Tek scopes and probes are rated 
for 600 volts or higher.  If you use a X10 probe (probably the most 
common probe) then the input of the scope will only see 10% of the 
voltage applied to the probe, just make sure you don't exceed the probe 
voltage rating.  This should not be a problem with the 215 volt supply.  
I got the Tektronix X1000 high voltage probe with one of the scopes I 
bought years ago but I rarely have need for measuring the high voltages 
it was designed to read.

A quick and dirty check for ripple is to simply set your DVM for AC and 
see what it measures on the 215 volt DC bus.  This won't provide the 
ripple frequency or waveform that your scope does but it is a quick 
check to see if there is a large ripple percent on a supply.

73, Rodger WQ9E

eugene at hertzmail.com wrote:
> Hello all,
>
> I have been working on a heathkit sb-610. Seems my tone output has 60hz
> hum on it. So I want to use my scope to look at the ripple on the +215V
> plate supply for this circuit.  My scope is a tek 475.  Can I simply put
> the coupling on AC and connect to the 215v line? I am afraid that 215 is
> too much for the scope. I understand that putting the scope in AC mode
> puts a cap in series to block any DC, but surely there must be a limit
> to how much DC it can block, no?
>
> Are there other ways to do this? Can I use my DVM in AC mode or
> something? 
> Thanks
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