Re: 497p front panel cal failure (CF and Ref Lvl)

John Miles
 

Caps are on the way, but I also just discovered the 5kHz scan per division is
actually scanning the same as 50kHz per division. Wonder if that is related to
the cal problem? Decoding issue on a board I suspect?
Could be. There's a chance that you have a low-resistance condition in one of the small epoxy-dipped ceramic caps on the span attenuator board (if I recall correctly, it's been a while). They don't necessarily fail shorted, but they can load down the TTL address and/or data lines to a point where they won't reliably talk to the peripheral ICs. I would have a look at the logic levels on the relevant boards to make sure they're in range.

-- john, KE5FX

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