Re: What replacement for 22uF tantalum beads?


Brian Bloom
 

I'm confused..
>> I suppose you are aware that there is no "+13V" rail in the 485?
>>
>There is, if you know where to look, and that isn't the power inverter :)
>

Ah, gotcha. I haven't had any real trouble involving those circuit areas (yet) that led me to remember about it off the top of my head. Now I will certainly remember!

>
I wouldn't have heard a clicking in any circumstances short of someone >dropping
>a CRT :(
>

Wait.... are you saying you dropped a CRT?? I don't remember hearing about that!


I've had it a couple of weeks. I was picking up a CRT for a dead 465, and I
>couldn't resist the seller's offer - which is a little worrying :)
That sounds very similar to how I ended up with 4 485s.... and 2 7854s... I don't think I can stop!! haha

>It would take 60s to start, unless it had previously been "warmed up". That >was
>C1848 (almost certainly) in the inverter being a deceptive little b*gg*r. Hence
>I had already recapped all the ali electrolytics in that area, and this was an
>unpleasant surprise.
>

That's certainly interesting.. One of the 485's that I've been attempting to get running will start up normally at first.. run for 10 seconds, then the U1610 kicks the inverter off. The 20ms sampling period is getting stretched to over 50ms somehow, and it's not the 2.7uf 50v tantalum cap. It's got me a bit confused, but maybe I should go back and lift/measure that cap.



>> I don't know enough about Tek's SN info or manufacturing to date >them by that
>> - if it's possible. The way I date my scopes is by seeing what the >most
>> recurring, earliest date codes off of components are.
>
>One PCB is copyright 1970, but the 74 series logic appears to be 1982.
Look at the date code on L1835 on the inverter board. Chances are it's original to the scope (unless the board was swapped for some reason). That'll at least get you a "built after" date for your scope.

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