Seiko PS-105 Electronic Starter

The Seiko PS-105 is a discontinued portable electronic starter made by Seiko Time Systems Inc. of Tokyo, the earliest documented member of the company’s エレクトロニックスタータ line that leads to the current PS-110J. Pulling the trigger of its pistol fired a xenon strobe, sounded a simulated pistol shot through a separate battery-powered speaker box, and closed a contact that could start a connected timer.¹ Like every unit in this line it is general sports equipment rather than swimming-specific. Seiko lists it under multi-timing rather than swimming and publishes no governing-body certification for it, where its poolside PS-1200 generator of the same period was listed as conforming to FINA rules and certified by the Japan Swimming Federation.²³ This article is a starting point; the start-systems overview covers the shared background that applies to every starter.

Models and naming¶

Seiko manufactured the PS-105 until 1997 and replaced it with the PS-107.² The company does not publish a parts-support end date for it; its general policy is that repair and parts supply for a discontinued product run, as a rule, for seven years from the end of production, with the caveat that they may not be possible for the whole of that period.⁴

The system shipped as three part-numbered components, the starter pistol PS-70, the headset microphone PS-60 and the speaker box PS-50, together with a cable with box that the manual does not give a model number or a length, four AA cells and four C cells.¹ The manual is Japanese only and carries the document number R-I3002.

Design and hardware¶

The pistol is moulded ABS in grey, 205 W × 156 D × 38 H mm, and weighs about 250 g without batteries or cable. It runs on two lines of two AA cells. The strobe is a xenon lamp.¹

The speaker box is ABS resin with an aluminium plate, in ivory, 266 W × 92 D × 176 H mm and about 1.5 kg without cells, powered by four C cells at 6 V.¹

The headset microphone is a condenser type of 160 W × 170 D × 68 H mm weighing about 45 g including its cable, the same unit Seiko carried forward unchanged into the PS-107 and PS-109.¹

Operation¶

The PS-105 offers one start sound. Its power switch has three labelled positions, OFF, S and S&F, and at S&F pulling the trigger produces the pistol sound, the strobe flash and the contact signal together.¹ The manual glosses both OFF and S as 電源 切, power off, which appears to be a misprint, since it gives the S position no other function. Later units in the line added a second, electronic tone.

A separate whistle switch on the speaker box sounds a whistle at a fixed level that the volume control does not affect.¹

Audio¶

The speaker box is rated at 6 W with a maximum of 10 W, and its practical sound pressure level is 93 dB at 10 m. Its audio input is rated at -20 dB into 100 kΩ. The pistol delivers its microphone input at -50 dB and its pistol and microphone output at -10 dB.¹

Seiko states that the speaker box can be used on its own, in multiples, or connected to other equipment, but the manual sets no limit on the number of boxes and gives no maximum cable length. Those limits appear only in the later PS-110 manual and must not be read back onto this unit.¹

The manual gives the speaker-box cell life against manganese cells as 91 dB at 10 m after about 3,000 pistol flashes, and the pistol’s strobe life as about 350 flashes, counted as the cumulative number of flashes at 30-second intervals for as long as the charge-complete lamp still relights within 30 seconds.¹

Connections¶

The start signal is a make contact of 0.2 Ω or less rated at DC 30 V and 0.5 A, output between pins 1 and 3 of a Hoshiden TCS0250-01-0301 connector, with TCP0556-01-0201 as the mating cable-side part. The contact is closed for as long as the trigger is held.¹

The PS-107 and PS-109 replaced this mechanical contact with a semiconductor relay output synchronised to the electronic sound, while keeping the same Hoshiden connector part numbers. The later PS-110 changed the connector as well, to a Marushin MJ-192.⁵

Specifications¶

Starter pistol (PS-70):

Power	DC 3 V (2 × AA cells) × 2 lines
Strobe	Xenon lamp
Strobe life	Approx. 350 flashes (manganese cells)
Audio battery life	Approx. 300 hours (continuous use at normal temperature)
Start signal	Make contact, 0.2 Ω or less, DC 30 V / 0.5 A
Microphone input	-50 dB
Pistol and microphone output	-10 dB
Current draw	Max. approx. 11 mA (audio); max. approx. 3 A (strobe)
Enclosure	ABS resin, grey
Dimensions	205 W × 156 D × 38 H mm
Weight	Approx. 250 g (excluding cells and cable)
Operating temperature	-5 to +50 °C
Storage temperature	-15 to +60 °C

Speaker box (PS-50):

Power	6 V (4 × C cells)
Current draw	Approx. 3 A on pistol sound; approx. 150 mA silent
Battery life	91 dB at 10 m after approx. 3,000 pistol flashes (manganese cells)
Audio input	-20 dB (100 kΩ)
Rated output	6 W (10 W maximum)
Sound pressure	93 dB at 10 m
Enclosure	ABS resin and aluminium plate, ivory
Dimensions	266 W × 92 D × 176 H mm
Weight	Approx. 1.5 kg (excluding cells)
Operating temperature	-5 to 40 °C
Storage temperature	-15 to 50 °C

Headset microphone (PS-60):

Type	Condenser microphone
Output impedance	1.6 kΩ ±30%
Sensitivity	-68 dB ±3 dB
Dimensions	160 W × 170 D × 68 H mm
Weight	Approx. 45 g (including cable)

The manual makes no statement about weather protection, and names no other Seiko equipment.

See also¶

• Seiko PS-107 Electronic Starter: the successor
• Seiko Electronic Starting System: the current unit in the same line
• PS-1200 Electronic Start Sound Generator: the swimming-certified generator of the same period
• Start systems: the start-system overview and governing-body requirements
• Seiko: the manufacturer
• Equipment: the wider equipment reference

References¶

Footnotes¶

1. Seiko Time Systems, エレクトロニックスタータ PS-105 取扱説明書 (document R-I3002, Japanese). ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹

2. Seiko Time Creation, discontinued multi-timing products (製造時期 ～1997年). ↩ ↩²

3. Internet Archive, Seiko swimming products index, 18 April 2009 snapshot (the PS-1200’s FINA and Japan Swimming Federation certification lines). ↩

4. Seiko Time Creation, discontinued products (repair and parts supply run, as a rule, for seven years from the end of production). ↩

5. Seiko Time Creation, Electronic Starting System PS-110 Operating Manual (the MJ-192 connector on the later model). ↩