The Linn Komri was introduced in 2001 and discontinued in 2010. 

The speakers are no longer serviced or supported by Linn.

Information on this page is provided to document the components in the Komri for those attempting service/repair.

Please get in contact if you require service on your Komri loudspeakers.

Disclaimer: This page describes procedures involving mains voltage and potentially hazardous electronic components. These repairs should only be performed by qualified personnel with appropriate knowledge, tools, and safety precautions. Incorrect handling can result in serious injury, electric shock, fire, or equipment damage. Proceed entirely at your own risk.

Drive Units

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Passive Crossover

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Power Supplies

2 x PCAS254 (Non-Dynamik) - Could be replaced by Dynamik PSU PCAS754 (with power input modified connections)

These are the same power supplies found in Chakra Amps (Akurate 2200, Majik DSM etc) of this period with modified mains input on one of the boards.

Fuses

There is a fuse in the IEC mains input on the rear of the speaker (with a spare). 

There is also a fuse on the input power supply PCAS254 behind the internal IEC.

Linn PCAS254 Power Supply outputs

Amplifier Boards

The Komri has two actively driven bass speakers. The main amplifier boards are held on a large heatsink on the rear of the speaker.

The three boards are:

LED display board:

Upper bass amplifier:  PCAS281

Lower bass amplifier: PCAS281

Amplifier Board Components (PCAS281)

Here is a summary of the main componets on a Komri amplifier board.

Drivers TDA7293 - "TDA7293 high-power DMOS audio amplifier IC made by STMicroelectronics — the heart of a 100 W class-AB audio amplifier channel"

6 x TDA7293 - Mouser Part Number: 511-TDA7294HS

1 x LM337 - negative adjustable voltage regulator (–1.25 V to –37 V)

Electrolytic Capacitors

Probably one of the first things to test and change given the age. 

2 x 220uF 100v Radial 16mm diameter x 26mm height
1 x 120uF 50v Radial 8mm diameter x 15mm height
1 x 100uF 63v Radial 10mm diameter x 14mm height
16 x SMD caps 22uF 50v (2250s2k8) Mouser Part Number: 667-eee-1ha220wp
1 x SMD cap 2.2uF 50v

Polypropylene Film Capacitors

Blue cube like

22 x 150nF  5%

SMD Capacitors

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SMD IC Packages

Another go at ICs

Relays

White rectangular boxes

2 x OMRON 2961Y1 G6S-2 12 VDC - signal-level DPDT relay

FAULT FINDING

First Clues

On the customer Komri a visual inspections shows the regulator U800 / LM2594 burnt out - the next steps are to test all the components around this for a short on the 12v/5v rail. Place your bets on the capacitors. 

Quick ESR check shows:

C800 -120uF 50v electrolytic - ok

C804 - 100uF 63v electrolytic - leaky

C820 - 22uF 50v smd - leaky

C819 - 22uF 50v smd - leaky

C113 2.2uF smd esr > 40ohm

C114 22uF 50v leaky

C131 22uF 50v - ESR 13.9ohm

C816 22uF 50v smd - measures cap 27uF/ESR 0.11

Next steps 

• Remove components near burnt out LM2594.
• Test values out of circuit
• Test for shorts
• Replace LM2594 + resistors + smd caps
• Replace all caps.

Removed Suspect Capacitors around the LM2594 - main culprit is C804 - 100uF 63v electrolytic which tests as ESR > 40ohm, the SMD caps are all only just in spec.

Continue with plan to remove all caps and LM2594

Test SMD resistors and diodes next