See this web page
- There is what is known as the 'Bob Parker' design this is a cheap accurate ESR meter upon which countless commercial implementations have been built upon. I use the BLUE meter myself it is more than accurate enough for service work.
But read the information and decide for yourself
Paul Kraemer wrote:
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ESR meter
Do you have a recommendation? Works well, cost effective.
Thanks
Paul
----- Original Message -----
*From:* Scott McGrath <mailto:mcgrath@...>
*To:* go_boating_fast@... <mailto:go_boating_fast@...>
*Cc:* Tek Scopes <mailto:TekScopes@...>
*Sent:* Wednesday, October 01, 2008 1:24 PM
*Subject:* Re: [TekScopes] 7603 filter caps
Using higher Voltage/Capacitance ratings usually is not a problem
especially since many of the old can type electrolytics were rated
-20/+40% of nominal rating.
Higher voltage is usually ok as long as the voltage differential
is not
extreme anything less than 3:1 is probably ok more than that and the
capacitor will not work effciently
Pay attention to temperature ratings and a ESR meter would be a good
investment
- Scott
Robert Simpson wrote:
> Hi folks,
> Thanks for all the tips in this forum. I am just stating to work
on a used 7603 with three plug-ins (7A18A, 7D15, 7B70) I acquired
cheap as a second scope with a 442 I got also got cheap (neither
working, both for $50, 442 now works)
> Thanks for the article on washing scopes as the 7603 really
needed it. With the plug-ins removed so they could be washed
separately, I used the siphon spray wand for my air hose with a
bucket of water with dish soap (avoiding the front panel). Rinsed
it off with the garden hose, blew it mostly dry with the air hose,
and then let it sit in the sun all afternoon. Then let it sit
inside overnight.
>
> It now turns on. And with no plug-ins installed gets a spot beam
in the center using the beam finder button. Most of the voltages
are within spec except for +5 which is 4.4V. All voltages except
130V have too much ripple; I am guessing filter cap problems.
>
> So, since exact replacement caps are hard to find and incredibly
expensive, I am thinking of using substitutes. For example, in
place of the 1800uf 75V caps I could get 2000uf 100V caps. Would
slightly larger specs work being they are used as filter caps?
>
>
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> ------------------------------------
>
> Yahoo! Groups Links
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