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Modern Powered PA Speaker Repair

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Modern Powered PA Speaker Repair

Post  GallopingGhostler on Wed May 31, 2017 6:44 pm

Last year July, I on-line purchased a Gemini ES-15TOGO powered PA speaker from Musician's Friend. It's price was $300 US retail, plus with a 15% discount coupon, I thought it a sweet deal. It has a 15" dia. woofer with heavy duty tweeter, 200 Watts RMS at 800 Watts peak power. It came with two wireless microphones, Bluetooth capability, built in AM/FM radio, MP3 player with SD card and USB slots for media, plus jacks for external audio sources such as microphones, computers, preamps, and etc. It also has an internal 12 Volt, 7 Amp-Hour sealed lead acid battey for use where there is no power and a telescoping luggage style carry behind handle with 4 small wheels on the bottom.




Last week while preparing to play my sax at a nursing home, my powered speaker for some odd reason would not operate under battery power. tongue (I plugged it into A.C. there, so no loss.)

At home, I pulled out the factory warranty. It is good for one year, but requires me to ship the unit at my expense to their service center. Then they return the repaired unit at their expense. Speaker weighs 40 lbs., box and packing adds another 10 - 15 lbs. UPS Ground is $71 to their service center.  Shocked

Several days ago, I removed the 12 screws holding the 200 Watt Class AB plate amplifier assembly. It took me more than 15 minutes to wrestle the 8x32 metric equivalent screws that held the steel battery compartment holder bar. The plastic socket screws mounted in had considerable friction. Torque to remove was so high that I rounded the head on one of the soft steel screws, that I used a pair of pliers to to remove it.

They had soldered the leads to the battery, silent so I broke out my 1970's Graymark 40 Watt soldering iron and unsoldered. Then I added female spade crimp connectors to the wires for the new battery. They also had the wrong color codes, black was for power, red was for ground. Huh... Using a label maker, I made two labels with "Positive" and "Negative" to label each wire.

These next 2 photos, the new 12 V 8 AH battery same size is on top, defective on bottom.




I replaced the battery clamp screws with wood screws, which held sufficiently in the plastic and should do me good. You'll see the chewed up head of one screw being replaced.



After installing battery and temporarily holding the plate amplifier in place, I turned it on. Now radio plays under battery power. Next, I plugged the A.C. cord in, charge light now comes on. I buttoned it up, problem is fixed. Smoking

I had a spare battery for my RC power panel that was little used, essentially new, so this is now in the PA speaker. A replacement battery is under $20 from Amazon.com shipping included. This is much cheaper than a warranty repair at $71. Cool
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Re: Modern Powered PA Speaker Repair

Post  dckrsn on Wed May 31, 2017 7:04 pm

Glad you got that fish in the boat, George.
Not only did you fix the problem, you also
made the unit readily serviceable.
That's a pretty neat rig too, by the way.
Bob
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Re: Modern Powered PA Speaker Repair

Post  roddie on Wed May 31, 2017 9:09 pm

Congrats on the repair George. Maybe you should leave the unit plugged in all the time? It may trickle-charge with the power switch off or on stand-by? Maybe not.. but if it did, this battery might last longer.

Those are nice units. The Bluetooth is really convenient. One of the bands I play in occasionally, uses a digital mixing-console with a router. Any band-member having a smart-phone with the app, can control their own separate monitor-mix. The sound-engineer can control all functions using a tablet.. from anywhere in the room. It's the ultimate set-up to have.
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Re: Modern Powered PA Speaker Repair

Post  GallopingGhostler on Wed May 31, 2017 9:36 pm

Thanks Bob and Roddie. Yes, it is a really nice unit, very useful. 15" speaker really belts out the bass. Backing tracks played from my netbook as an MP3 player sounds like a live combo band. Radio sounds vibrant also, even though mono. Now I understand why the really old radios had large cabinets with huge speakers. I vaguely remember them playing as a kid and man, even though tube amplified sound was gorgeous.

Regarding plugged in, this is also my practice amp and I use the radio regularly, so it was rarely unplugged. Date on the battery appears to be 2015, so it should have lasted. The amp goes to trickle charge when full and plugged in, even with switch off. In this case I gather it was a marginal battery to begin with. It didn't even hold a charge, zero current when I connected an external charger to it. At 5 lbs., it would make for a good battery hurl. Laughing
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Re: Modern Powered PA Speaker Repair

Post  roddie on Thu Jun 01, 2017 7:31 pm

GallopingGhostler wrote:Thanks Bob and Roddie. Yes, it is a really nice unit, very useful. 15" speaker really belts out the bass. Backing tracks played from my netbook as an MP3 player sounds like a live combo band. Radio sounds vibrant also, even though mono. Now I understand why the really old radios had large cabinets with huge speakers. I vaguely remember them playing as a kid and man, even though tube amplified sound was gorgeous.

Regarding plugged in, this is also my practice amp and I use the radio regularly, so it was rarely unplugged. Date on the battery appears to be 2015, so it should have lasted. The amp goes to trickle charge when full and plugged in, even with switch off. In this case I gather it was a marginal battery to begin with. It didn't even hold a charge, zero current when I connected an external charger to it. At 5 lbs., it would make for a good battery hurl. Laughing

Yes.. your recent "My Masquerade" cover sounded nice George! I listen to my web-audio through my workshop system.. which uses a Denon AV Surround Receiver AVR-1506 with five two-way enclosures and a small Polk sub. It makes listening very realistic.

I hope your replacement battery does the job for you. It's very strange that the connection-wire's color-coding was reversed. Good that you labelled those wires. You may have the option in the future, to adapt a lithium battery-pack for extended run-time.
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Re: Modern Powered PA Speaker Repair

Post  Admin on Thu Jun 01, 2017 7:58 pm

Glad you got it going again!

We gone through 3 sets of SLA batteries in my grandparent's stair-lifts since they got them installed in 2013. The first set was replaced about a year after they were installed by the company who installed them. Then they started to slow down again about a year after that so I ordered a set of batteries off Amazon (I think they were by ChromeBattery as well). Those lasted until my grandma passed last year. The stair-lifts don't really get used much now, I run them every so often and the batteries are acting like they are on their way out again.


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Re: Modern Powered PA Speaker Repair

Post  Oldenginerod on Fri Jun 02, 2017 5:11 am

roddie wrote:
Those are nice units. The Bluetooth is really convenient. One of the bands I play in occasionally, uses a digital mixing-console with a router. Any band-member having a smart-phone with the app, can control their own separate monitor-mix. The sound-engineer can control all functions using a tablet.. from anywhere in the room. It's the ultimate set-up to have.

Our sound guy has a digital mixer as well, a Behringer unit. I have a small cheap android tablet mounted to an adjustable tablet stand I bought from Aldi, standing beside me on stage. I now generally wear in-ear monitors to save exposure to on-stage sound levels. Being able to adjust my own personal foldback mix is absolutely fantastic. I was ready to give away live electric gigs due to my ear problems, but now I'm able to make it right through the gig without any discomfort, or needing to get the attention of the sound guy to make necessary adjustments. I just tweek as I go. Plus I can go to bed and sleep without the sound of freight trains in my head.
Some of this new tech stuff is truly amazing.
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Re: Modern Powered PA Speaker Repair

Post  GallopingGhostler on Sat Jun 17, 2017 9:25 pm

Now that my powered speaker is whole again with a charging battery, I did a little research and found a You-Tube video on rejuvenating old SLA batteries. Seems what often happens is the battery acid over time loses water through evaporation. I scribed the cover over the top of the battery with a utility knife, then using a combination of it and a pocket knife, pried off the top cover.

There are 6 rubber cover cups over the cells. I popped those off. Sure enough, several of the battery cells are dry with remaining hardly no water over the plates. Using a syringe filled with distilled water, I carefully refilled each cell. The opening is so small that simply pouring water from a beaker doesn't work. the top puddles and no more goes in. The battery is thirsty. I filled one of those 2 ounce Nyquill medicine cups 4 or 5 times to replenish the battery. The battery is noticeably heavier now.



After, I reinstalled the rubber cups and hooked up the charger. Now it seems to be charging. When I returned an hour later, 2 of the rubber cups popped off from the gases given off by the charge process. I removed the charger, removed all caps, then reconnected the charger.



We'll see after 24 hours whether the old battery now has a charge, and whether it can be salvaged.
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Re: Modern Powered PA Speaker Repair

Post  Oldenginerod on Sat Jun 17, 2017 10:22 pm

I'd suggest that the build up of gas pressure while charging indicates the battery is overheating during charge, indicating that the plates may have a sulphation build-up and are shorting.  If the electrolite was very low then the excessive heat during charging may have caused the lead plates to distort and short against each other.  The only way to get any more life out of a battery in this state is to clean off the sulphation.  You can buy certain "battery rejuvinators" which do this, or as I have done, you can carefully empty the acid into a clean plastic container- stress carefully
Refill with clean water and add a teaspon full of Epson Salts into each cell.  Agitate by swishing the battery around and let sit for half an hour or so.  Then, give it a final swish and discard the solution.  Rinse again with clean water & empty again.  Then, carefully refill each cell with the acid that you previously drained out, recharge & see how you go.
*This can be pretty hazardous Blow up Mad!  so I'm not recommending this ahead of the need to accept that batteries simply reach the end of their lives.  Then again, I have had this work effectively myself.
Ultimately, the safest option is to dispose of it, or at least use a commercially available product to rejuvinate the battery.  These don't require you to drain the battery- you simply add it to each cell.  I believe these would be less effective than my method as the sulphation cleans off the plates but remains as a sludge in the bottom of the battery.  Done as I've described, you remove the sludge by rinsing the battery out.

Remember, eyes, skin, clothes and anything else around can be damaged by battery acid.  Get rid of it, unless you're too adventurous to resist giving it a try. No!
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Re: Modern Powered PA Speaker Repair

Post  GallopingGhostler on Sun Jun 18, 2017 5:37 am

Thanks, Rod,

Following are my observations. I don't have the plastic cover that holds these air tight rubber seals in place. During a battery's charge, there will be a certain amount of bubbles developed, which will even build up a slight pressure. This is why standard lead acid car batteries are vented. These rubber caps when placed over the cells are basically air tight and light weight so it doesn't take much for them to pop. I don't have the plastic seal cover in place to hold them down.

Your idea of Epsom salts sounds good and I have heard similar advice somewhere in the past, too.

After charging for 12 hours, voltage is less than 11 V. I put my Hobbico power panel on it. The glow plug bad light comes on, a sign that voltage is below that of its 11 V minimum for the LED expanded scale voltmeter to show. Most likely I have a dead cell. A small bottle of battery treatment is almost the cost of a battery. The very small cells on this battery makes it more challenging to work on. A warning on one battery treatment to reduce sulfation warns that it cannot rejuvenate a dead cell.

I'll let it charge another 12 hours, but most likely this battery is toast.
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Re: Modern Powered PA Speaker Repair

Post  Oldenginerod on Sun Jun 18, 2017 6:54 am

I recall when I was a teenager I had a "Paddock bomb", an old car that I used to drive around the farm.  I remember my dad drilling a hole in the top of the battery and screwing a bolt in because one end cell was dead, effectively making a 10 volt battery.  It was just enough to start it on a good day.
I recall dad doing this Epson Salts treatment which revived the dead cell and allowed us to use all 6 cells again at 12 volts.
I have seen numerous youtube clips about using epson salts but the majority of U.S. clips I see don't show them draining the battery, just adding the epson salts directly to the electrolite, waiting and then charging.  This may work to some extent, but doesn't remove the crud from the battery, just from the plates.  My method may be worth a try just for the experiment.  WITH CARE.
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Re: Modern Powered PA Speaker Repair

Post  GallopingGhostler on Sun Jun 18, 2017 9:24 am

Rod, your Dad was neat, teaching you all sorts of practical tips and more from living on the farm. During WW2 here in US, most people, something like 3/4 came from farms. Moral values helped sustain US through the war, basically we could produce more equipment than the enemy could destroy. I imagine Australia with its mostly rural population was similar.

The openings to the cells in the battery are very small, something like 3/16" diameter. I attempted to pour water, but the droplets were large enough that they plugged the hole after a couple. That required going to a syringe to inject water into the cells. Attempting to turn it upside down and drain the water will in my estimation be just as difficult.

Now that I am 63, I don't have the ambitions to try new things for the sake of trying that I had when I was 50 or younger. A no name battery same rating is $16 shipping included. For the price of two Cox .049 glow heads I can have a new battery.

A voltage check 16 hours later shows 8.5 V. I'm going to see if this improves, but there is a possibility that I have a dysfunctional cell or two. Never thought of it, but a standard wet cell motorcycle battery of similar capacity, which can be easily topped off with distilled water might be a good alternative. With a maintainer on it, it is easier to maintain. Caveat is spillage, but with care could be doable. Those are more expensive, though, just a few thoughts.
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Re: Modern Powered PA Speaker Repair

Post  fredvon4 on Sun Jun 18, 2017 10:05 am

George I know you already got your replacement Batts but just to add to the knowledge base

I lost a LOT of stuff the early years living here from lightning...modems, computers, TVs, Dishwasher, washing machine

So I started buying Tripp Lite and other brand Uninterruptible power supplies and surge suppressor strips

Most of the UPS came with sealed 12vdc 7Ah batts... over the years I have a habit of just changing out the batts every 3 years. I buy 9Ah versions for about $16 each ( I buy 7 at a time) and occasionally I get lucky and the source offers free shipping

BTW a box of 7 batts kills my UPS driver and I am smart enough to take a dolly to the mail box...grin

I kept 10 used ones: 1 for my power panel box, and the others got spades removed and are my stash of heavy compact weights for holding or pressing during model building

http://www.atbatt.com/amstron-12v-9ah-vrla-battery-f1-terminal.asp

Google shopping one year, I found Yeusa (sp?) versions for $13.95 each

Locally, this sized batt is easy to find at Big box or Tractor supply--- BUT they want $39 to $54 just for one 7Ah version
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Re: Modern Powered PA Speaker Repair

Post  GallopingGhostler on Mon Jun 19, 2017 1:19 pm

Fred, you certainly have an eye for bargains. Smoking

When I worked for the US Public Health Service on the Navajo Reservation, I purchased UPS for all of us, can't remember the exact number but was over a dozen (we were a small department. USPHS was the gov HMO for 155,000 people.) We'd have a power glitch once or twice a week. Since our facilities management department was funded differently, we didn't receive IT equipment support, so we purchased all our computers. (That's why we had the better and faster ones. Laughing ) I did a number of buys for us at area and the facilities managers at the 8 service units reservation wide. We were the only area department (besides the servers) that had desktops up when hit with those glitches.
(Electrical power grid in rural Arizona is a pipe dream. Tired w/ Coffee Read I also learned that if I wanted something, to buy it for my supervisor. Then he'd say, "While you're at it, get one for you and the deputy too."  Eyebrows )

Friends who lived in rural homesteads had similar problems with power, PC's cutting out needing rebooting and disk checks. I suggested to them the source and they bought for themselves. Back in the '90s a favored was a mail order outfit in the Phoenix area because of their good prices.

Battery voltage did not come up but degraded to 6V. I'm not wasting any more time with this, so off to being disposed of it belongs.
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Re: Modern Powered PA Speaker Repair

Post  fredvon4 on Mon Jun 19, 2017 2:11 pm

George I know form other posts how you were a band guy...me a artilleryman and then aviation armament

some how we both were early computer literate and the militarily exploited these skills as they adapted to new tech

Would be fun to sit n chat about all the stuff from late 80s to present

Like officers with extra duty responsibility like " Commissary Officer"...as a E-6 SSG I was a IT tech and small computer instructor (extra duty----no extra pay) for the new Dos PCs and Xenix mini computers the aviation school house was getting

All that, while still doing my instructor or project managment +COR duties

I find it ironic NOW that seemingly simple problems with these newer OSs elude me
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