Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss
Crest Audio Pulse 2 1100 power amps, 1999
3 views
Skip to first unread message
N_Cook
Jul 9, 2010, 3:35:14 AM7/9/10
to
Owner has 5 of these and 3 have gone into protect mode, all the same
symptoms. All look the same but not sequential serial numbers. He's getting
someone technical to look at the speakers and leads and as they are used
from a diesel generator maybe a problem there. All failed in use , not
abuse, not failing at switch on , and no earlier odd noises before failing.
Anyway these 3 amps show clip LED on both ch, and then drop into protect.
I've the schematics for them but before going down false paths ,anyone been
here before. ? I've looked inside one and all healthy appearance. SMPS fires
up enough to deliver about +/- 100V rails, both ch, for half a second , fans
ok and relays click over but then drops into protect. No excessive mains
current draw at any time.
This one and the others , both channel o/p measure about 13 to 15K to ground
and not tied to + or - rails so will assume PAs are ok at this stage and
maybe falsely going into protect.
symptoms. All look the same but not sequential serial numbers. He's getting
someone technical to look at the speakers and leads and as they are used
from a diesel generator maybe a problem there. All failed in use , not
abuse, not failing at switch on , and no earlier odd noises before failing.
Anyway these 3 amps show clip LED on both ch, and then drop into protect.
I've the schematics for them but before going down false paths ,anyone been
here before. ? I've looked inside one and all healthy appearance. SMPS fires
up enough to deliver about +/- 100V rails, both ch, for half a second , fans
ok and relays click over but then drops into protect. No excessive mains
current draw at any time.
This one and the others , both channel o/p measure about 13 to 15K to ground
and not tied to + or - rails so will assume PAs are ok at this stage and
maybe falsely going into protect.
N_Cook
Jul 10, 2010, 10:56:10 AM7/10/10
to
I'm wondering if it could be related to prolonged brownout if used with
generator set all the time. Anyone know the definition of brownout? mains 5
percent down? 10,20% ? Google thinks I'm trying to get Gordon Brown out
generator set all the time. Anyone know the definition of brownout? mains 5
percent down? 10,20% ? Google thinks I'm trying to get Gordon Brown out
Meat Plow
Jul 10, 2010, 11:01:46 AM7/10/10
to
I'd consider a brownout here in the US of A to be in the range of 75 to
90 volts out of 120. Certainly noticeable by amplifier and other
electronics performance by any competent music tech or even a musician.
N_Cook
Jul 10, 2010, 11:19:36 AM7/10/10
to
Meat Plow <mhy...@yahoo.com> wrote in message
news:3t6nhs....@news.alt.net...
news:3t6nhs....@news.alt.net...
These people think they are Douglas Adams' Disaster Area with 10KW of power
, now having to make do with 4KW, perhaps less loading on the generator will
keep the remaining 2 alive for longer , if a brownout issue.
Meat Plow
Jul 10, 2010, 12:07:59 PM7/10/10
to
It's as easy as a voltmeter plugged into the amplifier mains and
occasionally monitored.
0 new messages