TL;DR
- Casio LED-20 released in January 1993 within the LED series.
- LED indicator with optional silent LED-only alerts.
- Twin Stopwatch and Multi-Stopwatch modes for speed, finish time, and stroke.
- Rarity: black is most common, yellow is the rarest.
- Module 1016 (QW-1016), CR2016 battery, acrylic glass, 17 mm lugs.
Casio LED-20 – Technical Data & Model Information
Casio LED-20 is a digital sports watch from the early 1990s LED series, released around January 1993. It is the direct successor to the Casio LED-10 and continues the LED family concept introduced by that model. The LED-20 uses module 1016 (also noted as QW-1016) and focuses on precise timing for training and sports use. Its standout feature is an LED indicator that flashes for alarms, countdown alerts, and time signals, with support for a silent LED-only alert mode. The watch combines standard timekeeping and alarm functions with Twin Stopwatch and Multi-Stopwatch modes, enabling speed measurement, estimated finish calculations, and stroke rate tracking.
Quick Technical Data
| Parameter | Value |
|---|---|
| Model name | Casio LED-20 |
| Module number | 1016 (QW-1016) |
| Production years | January 1993 |
| Manual | Casio Module 1016 Manual (PDF) |
| Battery type | CR2016 |
| Glass type | Acrylic |
| Strap lug width | 17 mm |
| Strap case width | 21.5 mm |
| Color versions | Yellow Color Version; Black Color Version |
| Special / unique features | LED indicator with optional silent LED-only alerts; 12/24-hour time with PM indicator; Twin Stopwatch Mode; Multi-Stopwatch (speed, estimated finish time, stroke); Stopwatch 1/100 s up to 59’59.99″; Data Recall for lap/split; Countdown Alarm 1 minute to 9:59’59”; Daily Alarm and Hourly Time Signal; Auto calendar correction except Feb 29 in non-leap years; Optional LED flash at specific seconds in Timekeeping. |
Color Versions
The Casio LED-20 was produced in two distinct colorways, black and yellow.
Black Color Version
Matte black case and bezel with integrated black buttons. Dark dial with green, yellow, and white highlights. Black strap with yellow/white text. Clean monochrome feel with subtle accents.
Rarity: most common color version.
Yellow Color Version
Bright yellow case with matching bezel, black side buttons, and a black dial with yellow/white accents. Black strap with yellow text. Strong high-contrast look.
Rarity: rarest color version.
Overall model rarity: the LED-20 itself is considered rare.
Features of the Casio LED-20
Casio LED-20 focuses on precise timing with smart visual cues.
- 12-hour and 24-hour formats.
- PM indicator in 12-hour mode.
- Automatic calendar correction, except February 29 in non-leap years.
- LED indicator for alarms, countdown alerts, and the hourly signal.
- Optional LED flash at specific second intervals in Timekeeping Mode.
- Silent alarm option with LED-only indication.
- Automatic return to Timekeeping after inactivity during a flashing setting state.
Casio LED-20 Manual
The official Casio LED-20 manual for module 1016 is available on the CasioRestore.com drive:
What are the functions and modes of the Casio LED-20?
Casio LED-20 packs multiple timing modes for daily use and training.
- Timekeeping Mode: hours, minutes, seconds, month, date, and day of week.
- Stopwatch Mode: lap and split timing with 1/100-second resolution and 59’59.99″ maximum.
- Twin Stopwatch Mode: two simultaneous measurements using the upper and lower displays.
- Multi-Stopwatch: speed measurement, estimated finish time, and stroke calculation.
- Multi-Stopwatch presets: requires lap distance and/or total distance depending on measurement type.
- Data Recall Mode: review stored lap and split data in order.
- Data retention: stored data remains until overwritten by new measurements.
- Countdown Alarm: set from 1 minute to 9:59’59”.
- Countdown notifications: beeps and LED flashes at specific remaining time thresholds and during final seconds.
- Countdown completion: alarm sounds when the timer reaches zero.
- Alarm Mode: Daily Alarm.
- Hourly Time Signal: beeps and LED flash at the top of the hour.
Display layout of the Casio LED-20
Casio LED-20 uses a clear dual-display concept with helpful graphics.
Check my LED-20 restoration here, or on the instagram below:
- Fields shown: hours, minutes, seconds, month, date, and day of week.
- PM indicator visible in 12-hour mode.
- Graphic display assists with visual time representation.
- Seconds digit flashes when selected for adjustment.
- LED indicator flashes during alarms, countdown alerts, and signals.
- Twin Stopwatch uses the upper and lower displays for simultaneous timing.
Strap and fit of the Casio LED-20
Casio LED-20 uses a compact strap layout that feels purpose-built for sports timing.
- Strap lug width: 17 mm.
- Strap case width: 21.5 mm.
- Replacement band option: 71604978 (originally for CA-56-1 and LDF-40-1A, module 3208) is reported to fit well.
- Collector practice: strap swapping with the LED-10 has been noted due to scarce originals.
How do the memory features work on the Casio LED-20?
Casio LED-20 stores lap and split time data generated in its Stopwatch modes for later review. The watch automatically records lap and split measurements in memory and manages storage by overwriting the oldest entries when capacity is exceeded. Recorded results can be reviewed in Data Recall Mode in chronological order, and stored data remains available until it is replaced by new measurements.
Known issues and limitations of the Casio LED-20
Casio LED-20 has a few caveats to keep in mind.
- Frequent LED operation increases battery consumption.
- The LED indicator must be manually turned off when not needed.
- Calendar handling excludes February 29 in non-leap years.
- Stored timing data is overwritten when memory capacity is reached.
What collector notes apply to the Casio LED-20?
Casio LED-20 sits in a niche corner of 1990s Casio collecting.
- Overall model rarity: reported as rare by user note.
- Color rarity: Black is most common, Yellow is the rarest.
- Observed condition note: “shadow marks” on the front were reported on one unit.
- Status note: planned disassembly was mentioned to verify operation on that unit.
- Original straps are extremely rare and prone to perishing.
What are the related models of the Casio LED-20?
Casio LED-20 belongs to Casio’s LED series and sits between two closely related models in the same line. The Casio LED-10 is its direct predecessor and introduced the LED-series concept, while the Casio LED-30 followed as a successor and expanded the idea further by adding a twin-LED configuration. In addition to these core models, the series also includes the Casio LED-100 and Casio LED-200. The LED-200 uses the same internal module as the LED-20 but differs in construction, featuring a metal case paired with a leather strap rather than a resin sports case.
Key facts of the Casio LED-20
Casio LED-20 packs timing power into a compact format.
- Model identity and module: LED-20, Module 1016.
- LED behaviors: flashes for alarms, countdown alerts, and signals. Optional timed flashes in Timekeeping Mode. Silent alarm allows LED-only alert.
- Twin and Multi-Stopwatch: dual simultaneous timing, plus speed, estimated finish time, and stroke calculation with required distance presets.
- Countdown alarm: settable from 1 minute to 9:59:59 with staged notifications and a completion alarm at zero.
- Rarity snapshot: overall rare; color ranking places Black as most common and Yellow as rarest.
FAQ – Casio LED-20
Is the LED indicator on the Casio LED-20 user-configurable for silent alerts?
Yes. On the Casio LED-20 you can enable a silent alarm that uses the LED only, without sound. You can also set the LED to flash at specific seconds in Timekeeping Mode.
How does Twin Stopwatch Mode operate on the Casio LED-20?
Twin Stopwatch Mode runs two measurements at once using the upper and lower displays. Resolution is 1/100 second and each timer measures up to 59 minutes 59.99 seconds.
Which color version of the Casio LED-20 is rarer for collectors?
The Yellow color version is rarer. The Black version is the most common, though the overall model is scarce.
What timing functions does the Casio LED-20 include beyond a standard stopwatch?
Beyond a standard stopwatch, it offers Twin Stopwatch, Multi-Stopwatch for speed, estimated finish time, and stroke calculation, plus a Countdown Alarm with audible beeps and LED flashes at set thresholds. You can store lap and split data and review it in Data Recall Mode.
What strap replacements fit the Casio LED-20 if the original has perished?
Original straps are rare and perish easily, but replacement band 71604978 has been reported to fit well. The lug width is 17 mm, and some collectors swap straps with related models due to scarcity.
Sources & Research Notes
For this Casio LED-20 write-up, we used hands-on inspection, vintage Casio catalogs, Japanese blogs and archives (google.co.jp), old brochures, printed manuals, and community knowledge from collectors on Reddit, Facebook groups, and in private discussions.
Daniel is the person behind Vintage Casio Restore, a project dedicated to restoring and documenting vintage Casio digital watches from the 80s and 90s. Based in Poland, he combines technical precision with a passion for retro design, bringing forgotten models back to life and sharing their stories online.Outside the workshop, Daniel works in a digital agency, managing SEO and content strategy for technology clients, blending his professional experience with his love for classic tech and design.
Leave a Reply