DC offset on Cambridge Audio A1

[gmw76]

Hi, hope somebody can check my thinking on an amplifier repair. Cambridge Audio A1 mk3 fitted with 2x tda1514a chipamps. Both line fuses blown so powered up with a Dim Bulb tester. Bright glow indicated an issue!
Removed both tda1514s and one had several low ohm pins. I put the single chip back which was thought to be ok. No overcurrent issues so the first chip was responsible for blowing fuses.
I did a quick DC offset check on the one channel and found over 2.2v at the speaker terminals. Would this suggest a serious fault with the second chip also or am I missing something where that reading would be acceptable? All resistors check out and capacitors (not tested) look ok.
Many thanks
Mark

 

[Binkman]

Welcome to A.k.!
I don't know the amp however I'll post a schematic link but I don't know if it applies to the A1?
https://www.hifiengine.com/manual_library/cambridge-audio/a1.shtml

 

[gmw76]

Thank you for that. I have the schematic and have been working my way through it. Looks like one chip fully dead, the other appeared ok bit is puting out over 2.6vdc offset onto the speaker terminals. I suspect this chip also faulty. This level of offset is way above acceptble. Just checking if anyone knew anymore about the chip which would say this could happen.
Thamk you for replying.
Mark

 

[ian wilde]

HI - thanks for the heads up on this however although the specs are there for the a1 mk1 These schematics dont apply to the A1 mk1 they only apply to a1 mk 2/3. The original mk 1 or 1.5 scematics do not seem to exist.

all the best, Ian