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

Cut the rear panel out to provide access to internal components.

Crossover Design

Resistor: 3.3ohm Colber  5% 7w

Capacitor: "Procond 2.2k 250v MKT". Suitable replacement Mouser part 80-C4GAFUC4220AA0J / Kenet C4GAFUC4220AA0J / Film Capacitors 400volts 2.2uF 5%

Inductor: Unknown

Conclusion

This is a speaker of it's time. It was never designed to be serviced:

• The cabinets/drivers/pcbs are all glued.
• Internal wires are 'birdsnest' wired
• Insulation tape is used to join internal twisted cables.
• Fibreglass is used to internal dampen the cabinets.

The reason one of the speakers had failed was a dry joint on the main driver and a faulty internal cable and a degraded capacitor.

The only way to access the crossover is to cut the back panel out of the speaker and then re-glue when done - so not a very satisfying or elegant repair.

It was also very time consuming repair - so not really economically viable. 

My recommendation: Spend your money on a new pair and enjoy the memories....