How to date a circuit board in 30 seconds

Updated 2026-08-05 · Microscrapping

Two boards can look identical and differ tenfold in value. The difference is almost always when they were made. Three industry transitions do most of the work, and you can read all three without a magnifier.

The three transitions that set the price

Everything in board-level scrap value hinges on three dates. Learn these and you can price a board before you've identified a single component.

1. Palladium to nickel MLCCs, roughly 1998–2005. Palladium ran from about $120 an ounce in early 1997 to $359 by March 1999, and the capacitor industry fled to base-metal electrodes. Pre-1998 ceramic capacitors can carry 0.5–2% palladium. Modern ones carry about 0.1%. Same part, same appearance, twenty times the metal.
2. Leaded to lead-free solder, 1 July 2006. The EU RoHS deadline. This one is visible from across the room: leaded solder is bright and mirror-shiny with smooth feathered fillets, lead-free is matte, frosty and grainy with steeper, fatter fillets.
3. Gold to copper bond wire, roughly 2010–2014. By late 2013 copper was 65% of packaging wire revenue at one major assembler, and by 2014 one large chipmaker reported 71% of its total wire usage was copper. A pre-2010 plastic IC holds 0.5–0.7 g of gold per pound. A post-2014 one holds a fraction of that.

Reading the date code

Most integrated circuits carry a four-digit code in YYWW format — year then week. 0432 is 2004, week 32. Two sanity checks catch nearly every misread: the week must fall between 01 and 53, and the year has to be plausible for the package. A plastic dual in-line package cannot be from 1932.

Three digits means YWW with a single year digit. 832 is week 32 of either 1998 or 1988, and you have to get the decade from context — package style, brand name, the rest of the board.

Bare circuit boards default to the reverse, WWYY. If one pair is greater than 53 it has to be the year, so 3298 reads as week 32 of 1998. If both pairs are 53 or under you have a genuine ambiguity and need a second component to break the tie.

One habit worth forming: read three or four chips and take the latest code. A board is normally assembled four to forty weeks after the newest part on it, so the latest code is your floor. Older codes just mean old stock sitting in a warehouse.

Watch out for lot numbers masquerading as dates. Codes like P3476 on Intel parts are traceability strings, not calendar dates, and misreading one is the most common dating error there is.

Brand names are hard date brackets

Corporate acquisitions happen on specific dates, which makes the name printed on a chip more reliable than almost anything else on the board.

• Signetics — before about 1993
• SGS-Thomson — before May 1998
• Siemens on a semiconductor — before April 1999, when it became Infineon
• Motorola on a semiconductor — before July 2004, when it became Freescale
• Philips Semiconductors — before September 2006, when it became NXP
• National Semiconductor — before 2012, when TI absorbed it
• Freescale — 2004 to 2015
• Atmel — before 2016

A Motorola-branded chip cannot be from 2010. That single fact tells you the board predates the copper bond wire transition.

The lead-free mark

A crossed-out Pb symbol, or a circled e followed by a digit, usually sits at the lower right of the topside silkscreen. The designators come from the J-STD-609 standard:

• e0 — contains 3% or more lead. This is the marker you want: leaded solder, pre-2006 board.
• e1 — tin-silver-copper with silver above 1.5%
• e3 — pure tin
• e4 — precious finishes: silver, gold, nickel-palladium

No mark at all is the same signal as e0. The board predates the requirement, which puts it in the era of gold bond wire and palladium capacitors.

The connector fingerprint

You can date a computer board from six feet away by what you can plug into it.

• ISA with no PCI — 1984 to 1996
• VESA local bus — 1992 to 1995, and very diagnostic
• AGP, the brown offset-keyed slot — 1997 to 2006
• IDE 40-pin ribbon headers — dominant before 2005
• SATA, the small L-shaped connector — 2003 onward
• PS/2 mini-DIN keyboard and mouse — 1987 to about 2008
• USB-C — 2015 onward

The combination worth memorising is AGP plus IDE plus PS/2 with no SATA. That pins a board to roughly 1998–2004: leaded solder, gold bond wire, and a coin-flip on whether the ceramic capacitors carry palladium. It is the single best buy signal in consumer e-waste.

Physical tells when there are no markings

Curved, wandering copper traces are one of the most reliable pre-1985 indicators. They come from artwork laid out by hand with adhesive tape, before CAD forced everything onto orthogonal and 45-degree angles.

Brown paper-based substrate that smells acrid when cut is FR-2 phenolic, a pre-1990 consumer-goods material. Green-tinged woven glass is FR-4, which is everything since.

Layer count climbs steadily: one or two layers before 1985, two to four through the early nineties, four to eight by 2000, six to twelve after 2005. Count the laminate lines at a cut edge.

FCC identifiers give a hard cutoff. Grantee codes were three characters until 1 May 2013 and five characters after. A five-character grantee code means the grant is 2013 or later, no exceptions.

Copyright years are a floor and never a date. A board marked © 1997 was made that year or later, often one to five years later.

What each era is actually worth

Pre-1985 boards are the best material there is — gold-lidded ceramic packages, thick gold plating, heavy pins, palladium capacitors. From 1985 to 1995 you are in the peak palladium capacitor era with thick gold fingers. From 1995 to 2005 the gold bond wire is still there and the solder is still leaded, which is why that window is the practical sweet spot.

After 2005 things thin out fast. By 2014 the bond wire is copper, the capacitors are nickel, and the only gold left is the surface plating on the pads — at which point the value of the item is what it does, not what it is made of.

Questions

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