HP 3458A 8.5-Digit Multimeter: Precision Measurement Solution for PLC Industrial Automation

15 जनवरी 2026

Historical parts record: Photos and notes below belong to this record. Confirm the offered unit’s full model, condition and available test evidence before ordering.

What is the HP 3458A VFD display module?

This is the vacuum-fluorescent display module for the HP/Agilent 3458A — the 8.5-digit digital multimeter that has been the metrology-lab reference since 1989. This listing's title calls it the multimeter; the photographed part corrects that: it is the display module itself — the 16-character 5×7 dot-matrix VFD bar with the full status-lamp row (SMPL, REM, SRQ, TALK, LSTN, AZERO, OFF, MRNG, MATH, ERR, SHIFT, MORE INFO, REMOTE, SRQ, 4W, WARN, CAL, 330, ALK, LSPN) — the part that makes a dead 3458A read again. Board markings: HN4-151MAG3 on the glass edge, part number 2090-0217, unit 21-421-1083, SSOT frame code. Factory-new, one-year warranty as recorded at intake on 16 January 2026. All seven photos and the inspection video show this exact module.

2 min readContent reviewed 8 October 2026

Part details

3458A VFD display module, as read from the markings
Field	Value
Application	HP / Agilent 3458A 8.5-digit DMM — front-panel display module
Display	Vacuum fluorescent, 16 × 5×7 dot-matrix characters plus the status-lamp row
Status row	SMPL, REM, SRQ, TALK, LSTN, AZERO, OFF, MRNG, MATH, ERR, SHIFT, MORE INFO, REMOTE, SRQ, 4W, WARN, CAL, 330, ALK, LSPN
Markings	HN4-151MAG3 (glass edge); part number 2090-0217; unit 21-421-1083; SSOT frame code
Connection	Dual pin-header rows along the top and bottom edges
Condition	Factory-new, 1-year warranty, intake 16 January 2026

Scroll sideways to see the full table.

Values are read from the glass markings and the photographed construction in the photo set.

Why this module is the 3458A's usual failure

The 3458A is built around components that effectively do not age — its references and integrator are the reason it still holds 8.5 digits — but the VFD front panel is the one wear item: phosphor efficiency drops, the filament thins, and after decades of continuous duty the display dims, drops segments or goes dark while the meter underneath still measures perfectly. Replacing this module restores the front panel without touching the calibration: the pin-header rows land on the same sockets, the character set and status lamps are identical to the original, and the meter's stored calibration data is untouched by a display swap.

The module in this record is factory-new — an honest statement on a part most sellers can only offer as a pull: the glass is clean, the pin rows are straight, and the phosphor segments are the uniform pale green of an unlit new tube. For a metrology lab keeping its 3458A fleet alive, this is the part that turns a bench asset back into a working standard.

Photos

All images below are original KOEED warehouse photos. Click any photo to view it full size.

Front face — The front face: the 16-character dot-matrix bar over the full status-lamp row — SMPL REM SRQ TALK LSTN AZERO OFF MRNG MATH ERR SHIFT MORE INFO.

Glass flat — The module flat: the dark glass tube, the pin-header rows top and bottom, and the HN4-151MAG3 edge marking with part 2090-0217 and unit 21-421-1083.

Character row close — The status row close-up: SMPL REM SRQ TALK LSTN AZERO OFF MRNG MATH ERR SHIFT MORE INFO printed between the character cells — every lamp the front panel reads.

On edge: the depth of the VFD tube and the pin rows — the profile the front-panel board sockets.

Rear traces — The rear face: the filament and grid traces behind the glass, the 2090-0217 part number and the HNA-16MM63 frame marking.

Pin rows close — The pin rows close-up: the dual header banks with their solder tails, the SSOT frame code and the 21-421-1083 unit marking (archived png frame).

Final view — The final view: the complete display module on its foam — the part that brings a 3458A's front panel back to life.

Inspection video, recorded at the Koeed warehouse before dispatch.

For the front-panel assembly this display lives in, see the Agilent 3458A front panel record — the bezel, keyboard and display half of the same instrument, documented from the same warehouse.