Siren blows fuses. HELP !!!!!

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n9upc
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Joined: Mon Oct 21, 2002 3:43 pm

Siren blows fuses. HELP !!!!!

Post by n9upc »

Greetings, working on an issue with an Astro siren box blowing fuses on a regular basis.

The siren is mounted with the spectra draw unit on one shelf on a double shelf trunk draw unit.

The power is ran from the a 100 amp circuit breaker which is connected directly to the battery.

From this 100 amp circuit breaker is a heavy duty power wire (unsure of gauge) which is ran to an ATC (big flat balde. The size right above the current fuses used in new vehicles) distribution fuse block.

Off of this fuse block is one slot with a 20 amp fuse with the power wiring going to the spectra drawer unit. Another slot has a 20 amp fuse which is ran to a relay panel with 9 relays to control light functions.

The third fuse slot has a 30 amp fuse with a power wire running to the siren box.

Now the siren will blow the 30 amp fuse just about in 5 minutes regardless if the siren or PA was being used???

Has anybody else ran into this problem??? Is it the siren box or something else???

Nothing else is blowing fuses at all just the siren box. I am going to try a different siren box to see if this solves the problem or not???
" ah the fatman made a funny!" - Stewie from the family guy.

I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
thebigphish
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Joined: Sat Nov 29, 2003 10:10 pm
What radios do you own?: AM/FM

Re: Siren blows fuses. HELP !!!!!

Post by thebigphish »


The third fuse slot has a 30 amp fuse with a power wire running to the siren box.
start small, have you tried the same siren box in another slot, with another wire, and another fuse? might be locallized to the fuse holder and line

Now the siren will blow the 30 amp fuse just about in 5 minutes regardless if the siren or PA was being used???
readily admit i don't know the draw for an AS siren unit, but i would break out ol' Jack-the-Multimeter and go to town and figure out current draw whil the unit is on, off (if any), standby, and active (all states) and figure out if it readily increases or if there is any other reason for the 30amps to pop off

Nothing else is blowing fuses at all just the siren box. I am going to try a different siren box to see if this solves the problem or not???
always a good idea....if you can.
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"With a knight and bishop combination; I will destroy his flank.
" --Antonious Block
SlimBob
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Post by SlimBob »

When I've played with the HLN1185B, I've noticed that only under the speaker short condition will it draw more than 12A (if configured for 100W). And since my test rig is a 25A power supply (with shutdown current limiting), I have to assume it would blow a 30A fuse if one were there... SPKR SHORT isn't immediately detected, IIRC.
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jim
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Post by jim »

The speaker's coil resistance is probably decreasing from whatever reason. It's also possible to have an intermittently shorting speaker wire.

These sirens don't like Gall's or Dynamax speakers either. Too low of a resistance. I have had a few problems with the Whelen 314 series, too.

Use a good ol' fashioned Federal 100 series speaker on these whenever possible.
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n9upc
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Post by n9upc »

I swapped out siren boxes and found that with the different one the radio is now showing speaker short.

I then checked all wiring and found the wires were not shorted (just to be on the safe side,) and then replaced the speaker.

Connected new speaker and found that this was the case. To check the old box I put it back in and it still blew fuses.

So I sent the siren box back to Motorola and the siren back to Dynamax.

This siren box came with an XTL5000 we ordered and the XTL was bad out of the box so I should have guessed the siren box would have been bad also.

Thanks to everyone who helped and gave advice. I have never had this happen as I am not really an installer but I am willing to help out when the main person is out or unavailable.

Once again thanks to all.
" ah the fatman made a funny!" - Stewie from the family guy.

I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
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thomsoningreen
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What radios do you own?: I use all of Motorola's Lines.

Re: Siren blows fuses. HELP !!!!!

Post by thomsoningreen »

I have the same issue here at the City of Charlotte. I have the Astro / Spectra Siren boxes with XTL5000 radios. The siren does the same thing. However we are fixing the boxes our seleves and ordering parts from Motorola and so far no fix for three of them. I have found that there is a short not and open some where in the box but upon inspection by visual and with multimeter I have not turned up any answers so far. I will let you know if I find some thing. However maybe some other fellow techs out there find something let me know.

I have found the fix for the siren box turning into a stealth siren(just kidding). If the siren goes quite but you can barley hear it at the speaker, then most likely it will be the capacitor in the box right there where the two main power wires coming off of the outlet. That cap tends to go bad it's easy to replace and isn't too expensive from motorola. Just look at the info on the cap and talk to motorola parts dept and they can help.
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thomsoningreen
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Joined: Tue Feb 10, 2009 12:36 pm
What radios do you own?: I use all of Motorola's Lines.

Re: Siren blows fuses. HELP !!!!!

Post by thomsoningreen »

I have found that when these boxes have been repaired before some times the tech before me may not have checked the polarity of the diode next to the capcitor I was talking about. The part in question is mark with part number 018752T42. The diode is designed to be there so if some one jumps the car it will throw the surge back at the fuse and blow it. well if the diode is backwards it will always blow the fuse.
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