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Ms9 died after installing a cap kit

Posted: February 11th, 2019, 1:57 am
by copados33
Did a complete cap swap, turned it on and it showed vertical collapse, then it shutted off after a few seconds, now it doesn't turn on anymore, what could be tbe problem?

Re: Ms9 died after installing a cap kit

Posted: February 11th, 2019, 5:53 am
by chibishin
Cap installed backwards, wrong spec caps since you're using a kit, bad solder joint, solder bridge, etc.

There's quite a lot that could've went wrong, your best bet is going to be to go back over your work carefully and verify capacitor location, values, and polarity.

Re: Ms9 died after installing a cap kit

Posted: February 11th, 2019, 8:53 am
by grantspain
if the chassis was fully working before the cap kit you have either installed a cap incorrectly( either polarity or value) or have bridged traces with solder
if the chassis was not functioning correctly before the cap kit then the vertical ic la7837 is bad

Re: Ms9 died after installing a cap kit

Posted: February 11th, 2019, 11:12 am
by copados33
I think I have found the problem, it vould be the liquid silicone that I used to fix a ceramic cap under the LA7837, that could explain the vertical collapse before the shutdown.

Should I remove the gunk and test or do I need to replace LA7837 straight ahead?

Re: Ms9 died after installing a cap kit

Posted: February 11th, 2019, 11:41 am
by grantspain
i doubt the silicon caused it unless its conductive, i expect the la7837 was about to fail in any case

Re: Ms9 died after installing a cap kit

Posted: February 11th, 2019, 1:50 pm
by copados33
I didn't use solid silicone but a liquid one that I had lying around that needs some time to dry.

Re: Ms9 died after installing a cap kit

Posted: February 11th, 2019, 6:34 pm
by PunkicCyborg
I had a MS8 collapse after a cap kit a couple years ago. Replaced the vertical hold IC and it fixed the issue and was fine ever since

Re: Ms9 died after installing a cap kit

Posted: February 11th, 2019, 11:23 pm
by copados33
chibishin wrote: February 11th, 2019, 5:53 am Cap installed backwards, wrong spec caps since you're using a kit, bad solder joint, solder bridge, etc.

There's quite a lot that could've went wrong, your best bet is going to be to go back over your work carefully and verify capacitor location, values, and polarity.
I checked and double checked the solder joints, the caps I installed were the correct uf, but higher voltage, which AFAIK is ok to do, example: original cap was 2.2uf 35v, I installed a 2.2uf 50v, I just wanted to put 105°C rated ones.

As I posted earlier I think I have found the problem, now I'm waiting for the LA7837 to arrive, we'll how it goes...
PunkicCyborg wrote: February 11th, 2019, 6:34 pm I had a MS8 collapse after a cap kit a couple years ago. Replaced the vertical hold IC and it fixed the issue and was fine ever since
hope I can fix this one that way.

Re: Ms9 died after installing a cap kit

Posted: February 12th, 2019, 4:31 am
by chibishin
copados33 wrote: February 11th, 2019, 1:50 pm I didn't use solid silicone but a liquid one that I had lying around that needs some time to dry.
yeah a non-neutral cure silicone could be a problem