68kMLA Classic Interface

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Colour Classic strange noises/transformer replacement
Posted by: robin-fo on 2021-12-15 14:36:56
Hi everybody,

My Colour Classic has some stange issues. When I plug it in and the AC switch is on, some crackling noises come from the inside. The noises are not very loud, but clearly noticeable. Otherwise, it runs fine since I recapped the LB. Furthermore, after letting it run for some time, I heard a sound like that of escaping steam (or rather like the ‘explosion‘ of a capacitor during desoldering).
But when I removed the analog board, there was no obvious damage on the caps… The only suspicious thing is one of the transformers, which possibly has melted sealant. I conclude that this sealant gets hot and escaping air from bubbles inside make the second noise I described above.

Does anybody know what the problem might be and how I cold solve it?

Is there a modern (or NOS) replacement transformer available?

Robin
Posted by: Plasticoat on 2021-12-15 14:50:58
Pretty sure that’s just Glue.

not sure about a new/old replacement but I’m waiting on a response like you
Posted by: Johnnya101 on 2021-12-15 15:10:56
Have you resoldered any bad joints on the AB yet? Are you seeing any video flashing or jitters when it is crackling?
Posted by: robin-fo on 2021-12-15 15:28:12
Have you resoldered any bad joints on the AB yet? Are you seeing any video flashing or jitters when it is crackling?
I didn‘t notice any bad joints (I’m refreshing some now during recapping of the AB)

The video is absolutely fine…
Posted by: robin-fo on 2021-12-15 15:31:13
Pretty sure that’s just Glue.

not sure about a new/old replacement but I’m waiting on a response like you
But it still looks somehow suspicious, doesn’t it? There is another, similar tansformer on the AB without any traces of brown stuff coming out…
Posted by: techknight on 2021-12-16 06:30:13
But it still looks somehow suspicious, doesn’t it? There is another, similar tansformer on the AB without any traces of brown stuff coming out…

it looks normal to me, and even if it was sus, lets hope its not because there is no fix. that transformer is specific to that analog board.
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