Re: Is my Tek 468 beyond repair?
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Mouser has 788 in stock at 41 cents each.RaySent from my T-Mobile 4G LTE device------ Original message------From: Roger Evans via groups.ioDate: Mon, Sep 21, 2020 12:48To: TekScopes@groups.io;Cc: Subject:Re: [TekScopes] Is my Tek 468 beyond repair?John,
540uF and 390uF sound like 'preferred values' as in resistor values. As far as I know there is no reason for any great precision on the values of reservoir and smoothing capacitors, too small and they don't do the job, too large and they are expensive, take up more space and stress the rectifier diodes on switch on. Quite commonly large value electrolytics will be toleranced at -20% +50%. (or at least they were in my younger days).
The 74LS112 spec sheet quotes maximum clock frequencies of 25MHz or 30MHz depending on the loading of the outputs. It is going to be decidedly marginal at 50MHz.