Omega Owners Forum
Omega Help Area => Omega Electrical and Audio Help => Topic started by: Lampynoiseboy on 18 February 2011, 23:42:36
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Hi All
Due to the excellent advice here, I removed my 10 year old PS last week. Haven't tried cracking it open, but there's no obvious signs of damage...... yet!
Anyone want it for testing? I know a few here have been experimenting, but can't find the relevent post.
Free to anyone who wants to play... but to any newbies DON'T take this as a replacement..... you may get a visit from the boys in the big red truck :(
Cheers
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If you don't want it I'd be happy to do a post-mortem. :y
I can bring the requisite instruments (a hacksaw) to the cam belt meet next week if you like?
It might be salvageable with a new pair of batteries.
Kevin
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If you don't want it I'd be happy to do a post-mortem. :y
I can bring the requisite instruments (a hacksaw) to the cam belt meet next week if you like?
It might be salvageable with a new pair of batteries.
Kevin
Indeed it might be, as long as no damage has occurred from leakage, there is no reason why a new set of batteries wouldn`t give it a new lease of life.
:y
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It's currently languishing on the front footwell.... many thanks guys
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It's currently languishing on the front footwell.... many thanks guys
You may want to remove it to a new (non combustible) site to await disposal/seeing to, as if there is any internal acid leakage it can still overheat/spontaneously combust while languishing on your nice flammable carpet :D :y
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Fair point, but if you knew my memory like I do (or used to!) chances are I'll forget the damn thing on Saturday!
Now where did I put that fireproof document box...... :D
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I believe these might be the right batteries - from maplins.
http://www.maplin.co.uk/pcb-mounted-nimh-batteries-30958
Product code BN24B - 3V150H (£6.99 each).
Going to cut mine in half sometime soon and check, if they are the correct batteries (can someone confirm please) I'll get some and replace. These are NiMh rather than NiCad so should last longer.
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I believe these might be the right batteries - from maplins.
http://www.maplin.co.uk/pcb-mounted-nimh-batteries-30958
Product code BN24B - 3V150H (£6.99 each).
Going to cut mine in half sometime soon and check, if they are the correct batteries (can someone confirm please) I'll get some and replace. These are NiMh rather than NiCad so should last longer.
there's guide here.... :y
http://www.omegaowners.com/forum/YaBB.pl?num=1240077701
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I believe these might be the right batteries - from maplins.
http://www.maplin.co.uk/pcb-mounted-nimh-batteries-30958
Product code BN24B - 3V150H (£6.99 each).
Going to cut mine in half sometime soon and check, if they are the correct batteries (can someone confirm please) I'll get some and replace. These are NiMh rather than NiCad so should last longer.
They can be made to fit but are a little larger and don't have the same pin footprint (and are a bit pricy).
I can't remember where I found the exact ones from (need to buy some actually). Rapid electronics rings a bell, for some reason.
Kevin
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Thanks Andy B,
Yep the batteries in the second set of photo's in the guide look the same as the Maplin ones so that's looking promising, hope they are the same as in mine. Looks like I will be warming up my hacksaw and soldering iron soon then!
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If you don't want it I'd be happy to do a post-mortem. :y
I can bring the requisite instruments (a hacksaw) to the cam belt meet next week if you like?
It might be salvageable with a new pair of batteries.
Kevin
Yes please. I would very much like to know what is causing these to go short. I doubt its going on fire, a 10year old battery hardly holds enough energy to sound the sounder, never mind combust.
I guess maybe the battery is leaking something, which somehow causes something to go short which nukes the basically unfused supply going into it. I would love to know how, cause I can't see how it can happen. If they use a series regulator, they would have to short the base up to 12V to turn it full on, but corrosion will eat tracks, not short them.
I would love to find out what is really happening with these. OK, the appropriate fusing seems the best protection, but knowing what the fault is means you can cure it.
Ken
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Thanks Andy B,
Yep the batteries in the second set of photo's in the guide look the same as the Maplin ones so that's looking promising, hope they are the same as in mine. Looks like I will be warming up my hacksaw and soldering iron soon then!
I shouldn't really say this, but a decent soldering iron is quite good at cutting through plastic housings and welding them back together afterwards.
Ken
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If you don't want it I'd be happy to do a post-mortem. :y
I can bring the requisite instruments (a hacksaw) to the cam belt meet next week if you like?
It might be salvageable with a new pair of batteries.
Kevin
Yes please. I would very much like to know what is causing these to go short. I doubt its going on fire, a 10year old battery hardly holds enough energy to sound the sounder, never mind combust.
I guess maybe the battery is leaking something, which somehow causes something to go short which nukes the basically unfused supply going into it. I would love to know how, cause I can't see how it can happen. If they use a series regulator, they would have to short the base up to 12V to turn it full on, but corrosion will eat tracks, not short them.
I would love to find out what is really happening with these. OK, the appropriate fusing seems the best protection, but knowing what the fault is means you can cure it.
Ken
My 'new' Astra also has as powersounder, and although it doesn't appear to be causing problems, it threw up a fault of sorts when CptnZok used his diagnostic programme ::) So I'm guessing it's also on borrowed time. :-?
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... and welding them back together afterwards.
Ken
I've used my large soldering iron as a welder quite a few times with reasonable results. :y :y :y
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Thanks Andy B,
Yep the batteries in the second set of photo's in the guide look the same as the Maplin ones so that's looking promising, hope they are the same as in mine. Looks like I will be warming up my hacksaw and soldering iron soon then!
I shouldn't really say this, but a decent soldering iron is quite good at cutting through plastic housings and welding them back together afterwards.
Ken
.. if you can stomach the smell. ;D
Kevin
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Yes please. I would very much like to know what is causing these to go short. I doubt its going on fire, a 10year old battery hardly holds enough energy to sound the sounder, never mind combust.
I guess maybe the battery is leaking something, which somehow causes something to go short which nukes the basically unfused supply going into it. I would love to know how, cause I can't see how it can happen. If they use a series regulator, they would have to short the base up to 12V to turn it full on, but corrosion will eat tracks, not short them.
I would love to find out what is really happening with these. OK, the appropriate fusing seems the best protection, but knowing what the fault is means you can cure it.
Ken
I am also sceptical that a (by that time pretty much dead) Ni-Cd can muster enough heat to start a fire. Apparently it has happened in storage, but I think the majority of Omega fires have involved at least a contribution from the supply to the sounder having shorted (perhaps promoted by a battery failure). The damage around the fusebox area bears witness to this, if nothing else.
The other theories I have:
The batteries are being charged at 15mA on the (admittedly slightly damaged) PCBs I've tested. This exceeds the maximum continuous charge rate for the batteries.
Having said that, one of the live data parameters visible by tech2 suggests that the unit has two charge rates so perhaps after the batteries become fully charged it drops to a lower charge rate.
One PCB that I've post-mortemed had leakage around the MOSFET that switches the signal to the primary of the transformer that drives the piezo siren. It had started to conduct but was caught before it got any worse.
If enough leakage had developed to turn on the MOSFET fully we have the 12v supply across a transformer with a quite low primary DC resistance. Enough to heat it up and catch fire? Maybe. :-/
I have only looked at the later style of sounder without potted PCBs. It seems that the ones that have actually caught fire were on older cars which would suggest they were the earlier design.
Kevin