The ECL and EECL chips are located on A22 (arming board), A19 + A20 (interpolator boards), A18, A17 (count chain assembly) A8 (reference buffer), A21 (multiplier assembly). The interpolator boards are more or less directly in line with the ducted airflow from the fan as are the reference buffer and frequency multiplier boards. A22 which has most of the ECL and EECL logic is mounted at right angles to the initial ducted fan airflow which impinges on its rear surface. >From this point some air flows through the gap between A22 and the side panel and flows across the font of A22, the input amplifier and schmitt trigger boards and the front panel board. The rear of A22 also deflects airflow back through thecard cage and the other boards. The crystal oscillator is screened from direct airflow by a sheet aluminium shield.
Thus the airflow is quite complex and one would need to monitor the temperatures of a large number of chips and other components to ensure the cooling is appropriate. Since the top and bottom covers also affect the airflow it would be difficult to use a thermal camera to meaningfully monitor chip temperatures. Even if the top and bottom covers were replaced with infrared transparent materials, a thermal vision camera won't have a clear view of all the EECL and ECL chips. Bruce Rick Karlquist wrote: > Hal Murray wrote: > >> How much ECL is used in a 5070? >> > > A bunch > > How tightly are they packed? > > You need a high cooling velocity even if just one chip. > > >> How much of >> the heat goes directly from the chip to the air rather than from chip to >> board to air? >> > > A substantial amount of cooling is from DIP to air, unlike tiny > SMT packages used now. > > >> How much room is there above the chips? Many years ago I saw some neat >> > > Probably not much extra room. > > Rick Karlquist N6RK > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.