72-Position Backplane Header, 0.053" Pitch, Press-Fit — Impact 76155 Series
The Molex Impact 761553304 is a 72-position, 12-row header in the Impact 76155 series, designed for high-density differential-pair backplane routing. The 0.053" (1.35 mm) pitch packs 24 differential pairs into a compact footprint — the tightest column spacing in the Impact family, which means the board layout engineer has to watch trace-width and spacing limits on inner layers to keep impedance control. Press-fit termination eliminates the wave-solder step, so the header presses into plated through-holes on a backplane and stays there through rework cycles without solder-joint fatigue. Rated 30 V — this is a signal-path connector, not a power rail. The Guide Left keying (offset guide pin) forces mating with a Guide Left receptacle only, preventing a 180° mis-mate or wrong-row insertion on the production line.
Press-Fit Termination — Solderless Backplane Build
That makes this header a fit for high-reliability backplane assemblies where rework access matters: a damaged pin can be staked out and replaced without desoldering a whole column.
Guide Left Keying — Mating Alignment Detail
The 'Impact, Guide Left' designation means the header carries an offset guide pin on the left side (viewed from the mating face). This mates only with a Guide Left receptacle — the keying prevents a 180° flip and ensures the 24 differential pairs land on the correct column. On a production line where multiple Impact headers sit side-by-side, the guide-pin offset also prevents inserting a 6-column header into a 4-column receptacle, or vice versa.