Two way bookshelf speaker designed by Dick Sequerra.

Distinctive metal grills.

Serviced October 2025

SN 14579 - working - 4ohm measured across input terminals

SN 14505 (possibly 14565) - failed - open circuit mesasured across terminals

Construction

Mainly glued cabinet. Only access through driver. Wadding material cut sheet fibrglass. Polyester wool?

Crossover

Coil: No markings. Continuity tested OK.

Film Capacitor: Capacitance 2.2 µF (K = ±10% tolerance)

• PROCOND - Brand/manufacturer series
• 2.2K - Capacitance 2.2 µF (K = ±10% tolerance)
• 250V~ 250 V AC rated (often ~400 V DC equivalent)
• MK T - Metallized polypropylene film capacitor

Resistor: Colber

3.3ohm, 5%, 7W

Driver Units

Tweeter: Voice coil TBC. Manufacture TBC

Bass/Mid: Voice coil OK. Manufacture TBC

Peak level detection circuit for Red/Green LED

Breadboard - stripboard

Left to right:

Resistor 1: TBC

Resistor 2: TBC

Diode 1: TBC

Diode 2: TBC