Trying to repair an APC SU1000 (pre-NET model)

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Trying to repair an APC SU1000 (pre-NET model)

David Ranch
Hello Everyone,

My SU1000 died some time ago but I thought I'd try to repair it one more time.  It runs off AC fine but won't charge it's batteries anymore.  It can run just fine off batteries when needed until they get depleted (self-discharge or when the AC power is out).  Does anyone have any ideas what might be wrong here?  I tore through the entire unit can couldn't find anything burnt, etc.  I also went through it with the closest schematic I could find with a fellow electronics expert and though it's analog DC charging circuit is pretty slick, it kept looking like one of the IC's was bad.  Never could prove it though.

--David

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Trying to repair an APC SU1000 (pre-NET model)

Dave Carpenter
Check ESR value of all electrytic caps? These are always #1 suspect when servicing modern electronics.

Dave

David Ranch <[hidden email]> wrote:
Hello Everyone,

My SU1000 died some time ago but I thought I'd try to repair it one more time.  It runs off AC fine but won't charge it's batteries anymore.  It can run just fine off batteries when needed until they get depleted (self-discharge or when the AC power is out).  Does anyone have any ideas what might be wrong here?  I tore through the entire unit can couldn't find anything burnt, etc.  I also went through it with the closest schematic I could find with a fellow electronics expert and though it's analog DC charging circuit is pretty slick, it kept looking like one of the IC's was bad.  Never could prove it though.

--David

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Re: Trying to repair an APC SU1000 (pre-NET model)

David Ranch

Hello Dave,

Can this be done while still soldered to the PCB or do I need to remove each one?  That would be very tedious as there has to be at least a dozen or more.  I also somewhat question how a bad cap could result in zero voltage (battery charge/float) to the battery terminals when the UPS has good AC power.  I'm open to ideas though as I have zero to loose here.

--David


On 08/07/2016 08:45 AM, Dave C wrote:
Check ESR value of all electrytic caps? These are always #1 suspect when servicing modern electronics.


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Re: Trying to repair an APC SU1000 (pre-NET model)

Ted Mittelstaedt-5
Just replace all of the smaller electrolytic caps.  No need to replace
the large caps that are part of the inverter supply.

The charging circuit in these is temperature compensated.  It would be
quite possible that an invalid temperature input to the charging IC
would result in that IC shutting down the circuit completely.

Your earlier statement regarding the Beige UPSes is correct.  The Beige
ones do indeed overcharge the batteries.

Ted


On 8/7/2016 12:25 PM, David Ranch wrote:

>
> Hello Dave,
>
> Can this be done while still soldered to the PCB or do I need to remove
> each one?  That would be very tedious as there has to be at least a
> dozen or more.  I also somewhat question how a bad cap could result in
> zero voltage (battery charge/float) to the battery terminals when the
> UPS has good AC power.  I'm open to ideas though as I have zero to loose
> here.
>
> --David
>
>
> On 08/07/2016 08:45 AM, Dave C wrote:
>> Check ESR value of all electrytic caps? These are always #1 suspect
>> when servicing modern electronics.
>
>
>
> ------------------------------------------------------------------------------
>
>
>
> _______________________________________________
> Apcupsd-users mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/apcupsd-users
>


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Re: Trying to repair an APC SU1000 (pre-NET model)

Dave Carpenter
For long-term reliability yes, replace all el. caps except the largest. But to troubleshoot the failure and get it running again, test each el. cap in-circuit using ESR meter. Replace any that are wildly (50 percent or more) out of tolerance.

Dave

Ted Mittelstaedt <[hidden email]> wrote:
Just replace all of the smaller electrolytic caps.  No need to replace  the large caps that are part of the inverter supply.

The charging circuit in these is temperature compensated.  It would be quite possible that an invalid temperature input to the charging IC would result in that IC shutting down the circuit completely.

Your earlier statement regarding the Beige UPSes is correct.  The Beige ones do indeed overcharge the batteries.

Ted


On 8/7/2016 12:25 PM, David Ranch wrote:
>
> Hello Dave,
>
> Can this be done while still soldered to the PCB or do I need to remove
> each one?  That would be very tedious as there has to be at least a
> dozen or more.  I also somewhat question how a bad cap could result in
> zero voltage (battery charge/float) to the battery terminals when the
> UPS has good AC power.  I'm open to ideas though as I have zero to loose
> here.
>
> --David
>
>
> On 08/07/2016 08:45 AM, Dave C wrote:
>> Check ESR value of all electrytic caps? These are always #1 suspect
>> when servicing modern electronics.
>
>
>
>
> > > >
> Apcupsd-users mailing list > [hidden email] > https://lists.sourceforge.net/lists/listinfo/apcupsd-users >

Apcupsd-users mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/apcupsd-users

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