Alarm system transformer + power supply (would both go bad at once?)

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On 11/23/2013 3:11 PM, Danny D'Amico wrote:

Looking at your picture, right above where the transformer leads connect to the terminal strip, there is an electrolytic capacitor right above a small bridge rectifier. I can't quite tell but the capacitor could be swollen and shorted. The 3 terminal voltage regulator is above that capacitor attached to the aluminum plate heat sink. Those are the main components of the AC to DC power supply and if one of them is shorted, that could kill the power transformer. ^_^
TDD
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On Sat, 23 Nov 2013 17:10:37 -0600, The Daring Dufas wrote:

I'm surprised you knew *where* the transformer leads entered the board, because I didn't say, so, but I see what you're talking about.
Also, I'm surprised you knew that was a bridge rectifier, because, well, because I didn't - but - looking at it from the side, I can see four uninsulated legs, which indicate it has four leads, one of which is marked "+".
Here is the same picture, but, with a few things marked that I know of (including the electrolytic capacitor I think you're talking about):
http://farm6.staticflickr.com/5486/11018768016_8962578375_o.png
I looked and touched and that cap seems OK visually; but, of course, it's probably 20 years old...
For the first time, I'm wondering if it's not just a new transformer, but, that I probably need to replace the entire board...
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You could try www.tech-man.com for a used replacement board, bearing in mind that any used replacement board is likely to be close to the same age as yours.
I would tend to upgrade to a current system.
Doug
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On Sat, 23 Nov 2013 17:11:27 -0800, doug wrote:

Any recommendations, given my goal would be to use all the existing equipment except the board itself and the power supply?
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Yes. Voltage spike, lightning strike, leg dropped across from power company, or some moron accidentally touching the neutral in the breaker box to the other leg of the incoming power. They can cause both to fail. All are sudden over voltage conditions.
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It is a real simple circuit. There is an NPN transistor (Q1) that drives the relay. The black diode is across the relay coil to protect the transistor. The other diode is a zener in series with the 2.4 k resistor to the base of the transistor. When the battery voltage is above 9.x volts, the zener will conduct and turn on the transistor that will in turn operate the relay. The relay will make the connection from the red wire to the battery (W1) to the J2 terminal marked power. It will supply voltage to the alarm panel until the battery voltage drops below the zener diode conduction point.
Charge your battery for a while and see if it will light a simple tail light bulb. Measure the battery with the bulb connected and lit.
tm
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tm wrote:

Hi, You should. That Omron relay contats can be open or closed. Is it NO or NC relay? Is the coil good? Have you metered them out? What is the findings? Did you looked up the specs. of that very common relay?
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On Mon, 25 Nov 2013 20:16:21 -0700, Tony Hwang wrote:

Now that the alarm system is (almost) fixed, I can spend the effort to look more closely at this D135A battery protection circuit. resource.boschsecurity.com/documents/Data_sheet_enUS_2548187915.pdf resource.boschsecurity.com/documents/Installation_Guide_enUS_2548185099.pdf
Even though nobody will tell you a price, I found this Bosch price list on the web: http://www.industry.usa.siemens.com/topics/us/en/btus/CommonwealthMA/Documents/bosch-intrusion-ifas-msrp-price-list-3-1-13.xlsx
The D135A retails for $22.56 according to that spreadsheet.
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On Mon, 25 Nov 2013 20:16:21 -0700, Tony Hwang wrote:

Since the D135A is to protect the battery, I assumed it's not actually *required* for operation.
So, I concentrated first, and foremost on replacing the AC power supply.
Luckily, that worked!
http://farm8.staticflickr.com/7440/11078202843_a0e09daa9a_o.gif
Sort of ...
http://farm4.staticflickr.com/3765/11078125064_68d907e787_o.gif
My next step is to replace the battery.
If I were a repair technician, I'd have all these parts in stock, but I don't, so, it takes me a while to get them from the manufacturer.
PS: The application calls for a 12V, 5AH to 7 AH gel cell. Assuming I get something in that range, are they all pretty much alike, or are there caveats to buying these gel cells?
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tm wrote:

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On Mon, 25 Nov 2013 20:50:39 -0500, tm wrote:

Hi tm,
That was a FANTASTIC explanation! You're one of the reasons why the USENET is so great! Thank you very much for that detailed explanation.
I picked up an electrolytic cap, and I will replace it, and test the battery-protection circuit out.

It failed this loaded test. So, now I know I have a bad battery and a bad transformer.
Luckily, the *new* 16.5VAC transformer arrived.
It sure tested funny:
http://farm6.staticflickr.com/5532/11078019855_b27612e531_o.gif
a) Secondary output = 20VAC b) One side to ground = 3.5 Volts c) The other side to ground = 1 Volt
Anyway, the moment I plugged that transformer in, the battery charging circuit came to life at 13.6 Volts:
http://farm8.staticflickr.com/7440/11078202723_a6deb1394f_o.gif
And, the alarm system control panel powered up & beeped (almost) normally:
http://farm8.staticflickr.com/7440/11078202843_a0e09daa9a_o.gif
With the battery in, or out, it gave the following error: *ALL ON, SYSTEM TROUBLE*
http://farm4.staticflickr.com/3765/11078125064_68d907e787_o.gif
And, when I tried to read the error, it merely said: *CALL FOR SERVICE*
http://farm4.staticflickr.com/3829/11078125174_95cb163704_o.gif
I'm not sure how to get the actual service problem, but, I am pretty sure it's the battery now that the new transformer is in place.
So, I'll google for a good source of batteries online. (Any suggestions or are they all essentially the same?)
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No, it changes at 280. And 85 hasn't been "new" for almost 20 years.
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On Tue, 03 Dec 2013 16:44:56 +0000, Scott Lurndal wrote:

I was sure you were wrong, so, I googled, and, well, I was wrong. You are correct.
http://farm6.staticflickr.com/5519/11210465305_7b202a0df7_o.gif
Actually, Google shows 880 also below the 280 crossing, but, it is close enough for me to agree with you! :)
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You should have roughly 16.5 V AC (maybe a little more) between the two screws marked "AC" with the wires disconnected. If you don't have that, your transformer died. These transfomers often have an internal, non- replaceable fuse; if it goes out, you replace the transformer. A local electronics shop (not Radio Shack) probably stocks them; if not you can get them online. This is a standard size; $20 plus shipping is a good price online.

Get any 12 V light bulb, except a headlight, from a car (preferably your car), disconnect the battery from the alarm system, and connect the light bulb across the battery terminals. The dome light is often easy to get to and a convenient shape. This will draw somewhere between 0.25 and 2 A from a working battery. The battery voltage under load will go down a little, but if it goes way under roughly 11.6 V, the battery is probably toast.
If the battery voltage doesn't go that far down, leave the light bulb on the battery for a few minutes, then disconnect it. Measure the battery voltage, then reconnect the battery to the alarm (with a working AC transformer connected to the alarm) and measure again. If the alarm is successfully charging the battery, the voltage will have gone up by a noticeable amount - like at least half a volt.
Alternatively, if the battery is more than about 5 years old, just replace it; it's probably bad. There may be a date code on the battery, or you may know when the alarm was installed or last serviced. Computer UPS batteries do a similar job and I can only get about 7 years tops out of them, even with the brands I like.
You have a sealed lead-acid or "gel cell" battery, and they come in several standard sizes and capacities. The label inside the door calls for a 7 Ah battery, but there is a 5 Ah battery installed in your panel; if you can confirm that the label matches the hardware, it's probably better to install a 7 Ah battery. The manufacturers are always tweaking the specs (if not the actual battery), so your size battery may be advertised as a 7 Ah, 7.2 Ah, or even 7.5 Ah. Any of these will work as long as it will fit in the panel. Also, note that the "7 Ah" size can come with 3/16" wide or 1/4" wide tab terminals; matching what you have now is best. Some 7 Ah batteries with 1/4" terminals are sold with reducers for 3/16" terminals, which also works.
I have had good luck with both Panasonic and Powersonic sealed lead-acid batteries, and bad luck with everything else I've tried, including BB Battery, UB, CSB, and Power Patrol. I'd be inclined to trust a Yuasa, based on experience with their flooded batteries, but I have no experience with their sealed lead-acid batteries. The local hardware stores carry some (look for the emergency light / EXIT sign parts), a local battery store may have them, the local electronics store will, or you can order online from Digi-Key or Mouser. I checked Amazon and a few sellers there are showing *pictures* of a Powersonic battery but probably *shipping* some junk battery. Caveat emptor.
For a 7 Ah battery online, $23 to $32 plus shipping is a good price. Locally, add $5 or so to that for shipping, plus however much the store marks it up.
When you get a new battery, write the current date in marker on the new battery and maybe on the inside of the alarm panel door.

The capacitor (that blue cylinder) on the power supply sure is an interesting shape. It shouldn't have that dent near the right end.
One test you can do: unplug W1 and W2 from the battery, unplug the wires from J1 (PWR) and J2 (GND), and unplug any other wires from that power supply. Measure the resistance between J1 and J2, and between W1 and W2. If it's less than a few hundred ohms on either reading, the power supply may be bad.

Maybe. Have you ever measured the AC line voltage in your house when the generator starts up? Does it go a lot above 120 V on either leg? 132 V (120 V + 10%) is about as high as it *should* go for a sustained period of time. If it's more than this, you have a problem. Also, try measuring each 120 V leg as you or a helper turns a heavy 120 V load, like a microwave oven, or a hair dryer or space heater on full, on and off. You should usually see a slight voltage dip under load. If the voltage goes *up* when the load is on, you might have a loose neutral, which is bad. Call an electrician or the power company.
I think you have a combination of a marginal battery and a marginal power supply (inside the alarm box). As long as AC power was on, it all sort of worked. When you interrupted and restored the AC power, the power supply or battery tried to draw too much current from the transformer, which blew the fuse in the transformer, and may have also finished off the power supply. Then, the alarm ran for as long as it could on the battery, until it shut off for low battery voltage.

If you have to hire someone to fix it, don't hire whoever did that wiring originally. It looks a mess.
Standard disclaimers apply: I don't get money or other consideration from any companies mentioned.
Matt Roberds
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Danny D'Amico wrote:

I'm totally guessing here, but I think the transformer may have blown when you tripped the generator, and the alarm ran on batteries until they were exhausted. Then, the alarm shut down to prevent destroying the battery. Although the 13.5 V seems really high for a 12 V gel cell not being charged. So, there may be another fault, such as a shorted rectifier in the alarm panel. That would blow the transformer. But, then the panel should have run off the battery for at least a while, and in the process partially discharged the battery. So, it is a bit puzzling.
Jon
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Jon Elson wrote:

If some thing shorted or popped or burned, you can smell it and see it as well.
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On Fri, 22 Nov 2013 15:54:59 -0700, Tony Hwang wrote:

I should mention that I was pretty sure I smelled burnt "plastic", but, since the garage door was open, I wasn't sure if it was coming from outside, as it was windy, or if it was from the garage.
But, the smell *was* within minutes of the alarm wailing three loud beeps before dying an untimely death.
The funny thing though, was that the Generac accident was the day before, so, if it burned up at the time I smelled the burnt plastic smell, that was a day after I had messed with the main breaker panel.
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On Fri, 22 Nov 2013 06:09:02 -0800, snipped-for-privacy@optonline.net wrote:

I didn't see any; but they might be there...
Still, the transformer is definitely dead.
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"Danny D'Amico"

** There must be a fuse inside that unit - wired in series with the 16.5V secondary.

** It's probably worn out .

** Open circuit testing a gell cell tells you nothing.

** The voltages on the transformer went high enough to cause a big increase in current and fuse failure, maybe something inside the alarm box failed too.

** Get a new tranny and a new battery and try them - the battery first.
... Phil
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On Sat, 23 Nov 2013 11:00:25 +1100, Phil Allison wrote:

That makes a lot of sense, since the battery, in and of itself, should power the system adequately.
I have a new transformer on order, although I belated realized there is a "limited lifetime warranty" on the ELK-TRG-1640, as described here: http://www.elkproducts.com/product-catalog/elk-trg2440-ac-transformer-24-vac-40-va-auto-resetting-grounding-prong-and-terminal
Anyone ever take them up on their "limited" lifetime warranty? http://www.elkproducts.com/_literature_63744/P1216,TRG1640,TRG2440_Data_Sheet
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