No left channel audio, A3 LED not lit, wrong voltages and some smoke

Rix__Mix · 1618

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Offline Rix__Mix

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Hi all

I'm getting no audio on the left channel and the A3 LED is not lighting. Main voltage is 240v.

Voltage testing is off, whilst I was conducting the voltage testing I saw some smoke coming from around the top left capacitor (14u).

1. 42v (OK)
2. 64v (Not OK)
3. 0v
4. 19v (Not ok)
6. 0v
.... Testing stopped and power pulled due to smoke.

I'd appreciate any help please.

Please see below for photos:

(https://i.imgur.com/uSumMzm.jpg)

(https://i.imgur.com/JKX79vz.jpg)

(https://i.imgur.com/ZBQGsII.jpg)

(https://i.imgur.com/VJlwp7l.jpg)




Offline Paul Birkeland

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One of your blue 100uF capacitors is not where it's supposed to be.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Rix__Mix

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Thanks for the really quick response!

I've moved it over to where it should be, voltage checks are now all good and it works wonderfully!

Thank you again Caucasian Blackplate.



Offline fullheadofnothing

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Your input jacks are mounted incorrectly.

It looks like one of the UF4007s at 19 isn't in the joint, it's just tacked in place with a solder blob.

Joshua Harris

I Write the Manuals That Make The Whole World Sing
Kit Packer Emeritus


Offline Paul Birkeland

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Your input jacks are mounted incorrectly.

Good catch.  That mistake forces the chassis to carry signal current.  No bueno!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Rix__Mix

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Your input jacks are mounted incorrectly.

It looks like one of the UF4007s at 19 isn't in the joint, it's just tacked in place with a solder blob.

Hi fullheadofnothing

Can you explain a little more as to how the input jacks aren't mounted correctly?

Thanks



Offline architect5150

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Colored insulator rings go between solder tab with and chassis with the shoulders sliding into chassis hole to insulate signal ground from chassis ground.



Offline fullheadofnothing

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Pages 12-13. There are 4 close-up pictures showing how its done.

Joshua Harris

I Write the Manuals That Make The Whole World Sing
Kit Packer Emeritus