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TWGS capacitor question [message #395265] Tue, 02 June 2020 19:59 Go to next message
Anonymous
Karma:
Originally posted by: chris.todd

In a little too-rough handling of my TWGS in the course of a move, I noticed a couple of ceramic disc capacitors near the edge of the card (C7, C15) have been damaged - one bent to nearly breaking off and one broken off completely. C20 also looks a little beaten up.

My understanding is that C17 and C15 are 39pf 1Kv capacitors, and C20 is a 100pf 1Kv. No big deal to replace, but my question is why in the world did AE use 1KV capacitors in these locations, and is there any benefit in replacing them with the same? In looking, it seems ALL of the disc capacitors on my board are 1 kilovolt.

50-100v 10% tolerance I have a bucket of, 1 kilovolt not so much. In a quick look in the schematic, these appear to all be tied to ground mainly as decoupling / bypass capacitors.. ESR shouldn’t matter so much here as in the 4 electrolytic 10uf filter capacitors (which I have replaced) - so why the 1000 volt caps elsewhere on a 12v/5v card? ESD maybe?

Hopefully some wizened electronics gurus have an answer - as is like to go ahead and just fix the board, but not sure if I need to order in some heavy duty capacitors.
Re: TWGS capacitor question [message #395272 is a reply to message #395265] Wed, 03 June 2020 01:03 Go to previous messageGo to next message
Michael Kinnaird is currently offline  Michael Kinnaird
Messages: 7
Registered: February 2014
Karma: 0
Junior Member
On Tuesday, June 2, 2020 at 6:59:10 PM UTC-5, chri...@gmail.com wrote:
> In a little too-rough handling of my TWGS in the course of a move, I noticed a couple of ceramic disc capacitors near the edge of the card (C7, C15) have been damaged - one bent to nearly breaking off and one broken off completely. C20 also looks a little beaten up.
>
> My understanding is that C17 and C15 are 39pf 1Kv capacitors, and C20 is a 100pf 1Kv. No big deal to replace, but my question is why in the world did AE use 1KV capacitors in these locations, and is there any benefit in replacing them with the same? In looking, it seems ALL of the disc capacitors on my board are 1 kilovolt.
>
> 50-100v 10% tolerance I have a bucket of, 1 kilovolt not so much. In a quick look in the schematic, these appear to all be tied to ground mainly as decoupling / bypass capacitors.. ESR shouldn’t matter so much here as in the 4 electrolytic 10uf filter capacitors (which I have replaced) - so why the 1000 volt caps elsewhere on a 12v/5v card? ESD maybe?
>
> Hopefully some wizened electronics gurus have an answer - as is like to go ahead and just fix the board, but not sure if I need to order in some heavy duty capacitors.
Re: TWGS capacitor question [message #395273 is a reply to message #395265] Wed, 03 June 2020 01:07 Go to previous messageGo to next message
Michael Kinnaird is currently offline  Michael Kinnaird
Messages: 7
Registered: February 2014
Karma: 0
Junior Member
Use whatever you have, there is NO difference for this application, just happened to be what they chose for production. The change in value, tolerance, etc. is negligible.
Re: TWGS capacitor question [message #395285 is a reply to message #395273] Wed, 03 June 2020 04:07 Go to previous message
Anonymous
Karma:
Originally posted by: chris.todd

Thanks. I replaced with what I had on hand per your suggestion, and the board seems to be working fine. Appreciate the info.
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