Home » Public Forums » GMCnet » [GMCnet] Re: The Importance of a Voltmeter
| [GMCnet] Re: The Importance of a Voltmeter [message #368226] |
Thu, 30 December 2021 12:58  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Thank you Ken for your input.
It only takes that one time issue to realize that having one one can be a
good thing to have,
On Thu, Dec 30, 2021 at 10:45 AM Ken Henderson
wrote:
> I just stumbled across this note from 2006; it's still applicable, so I'm
> posting it for everyone's consideration:
>
> Voltmeter to the Rescue
>
> Do you have a voltmeter monitoring your chassis battery voltage? You
> should. Here’s an example of why: We returned from Florida last night
> after a three week, two rally, two GMC alternator excursion. As we left
> Melbourne, FL enroute to Bowling Green, FL, Elaine and I both smelled
> something funny, so I stopped and tried unsuccessfully to find the
> source. When I restarted the engine, I noticed that my dash voltmeter was
> reading 16 VDC and sometimes jumping even higher. Knowing that much
> voltage would damage the batteries, we turned on the headlights, A/C
> blower, and every interior light we could find. That dropped the voltmeter
> reading to about 15 VDC, a marginally high voltage, but not terribly
> destructive, so we continued the trip. After about 15 minutes, the
> voltmeter reading dropped quickly to 12.5 VDC, which indicated that we were
> operating on the chassis battery alone, with no alternator contribution.
> With only 130 miles to travel, I decided to continue. Over the next 100
> miles, the voltmeter dropped steadily; at 10 VDC, the engine faltered so I
> switched on the house batteries using my non-momentary battery boost
> switch. The voltage quickly climbed back to 12.5 VDC, the engine ran fine,
> and we reached Bowling Green with no further difficulty.
>
> The next day, after failing to repair the dead alternator, I bought a
> rebuilt one and installed it. The voltmeter once again read 14.7 VDC, the
> exact voltage indicated on Advance Auto’s tester. I kept the old
> alternator so I can repair it for a spare and we continued our travels
> around Florida. About 100 miles before we got home, the voltmeter again
> jumped to over 16 VDC and the inverter I use to run my laptop computer
> kicked off because of the overvoltage condition. Even turning on all the
> lights would not bring the voltage back down and it would occasionally jump
> even higher, so I decided on a temporary repair. Reasoning that the
> just-replaced alternator was probably OK, the most likely reason for the
> voltage going high was that the voltage sense lead was not providing the
> battery voltage to the alternator, causing it to “think” it needed to
> produce more voltage. A jumper wire from the #2 lead on the alternator to
> the chassis battery corrected the problem and allowed us to continue to
> Americus without further difficulty.
>
> The voltmeter alerted me to the original alternator problem so I could take
> preventive action (by placing additional load on the alternator) before it
> damaged my batteries. Then when the second alternator began to act up, it
> enabled me to determine the probable cause of the problem and provide a
> temporary fix without damaging the batteries or the rebuilt alternator.
> Neither of those problems would have been indicated by the GEN light until
> the alternators actually failed. A voltmeter is money well spent.
>
>
> Ken H.
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--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
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Applied/GMC
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| [GMCnet] Re: The Importance of a Voltmeter [message #368238 is a reply to message #368226] |
Thu, 30 December 2021 14:52  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Back before the internet, there was Radio Shack. Anyone remember them? They
had EVERYTHING electrical and electronic that your feeble minds could
imagine. I bought a VTM vest pocket sized. I still have it. In the very tip
top center of my big shop roll-a-way. For quick voltage or continuity
checks, an analog tester is indispensable. Better than a digital one for
this. I also have a Fluke 77. Also a variety of idiot light testers.
Jim Hupy
Salem, Oregon
On Thu, Dec 30, 2021, 12:43 PM John Phillips
wrote:
> For those who just want to charge a phone or two and get a battery voltage
> indication, I think this is a good first step.
>
> https://www.amazon.com/Palumma-Charger-Adapter-Display-Battery/dp/B0773BYS6P/ref=asc_df_B0773BYS6P/?tag=hyprod-20&linkCode=df0&hvadid=30982116 3350&hvpos=&hvnetw=g&hvrand=4181744818749251922&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=90 32425&hvtargid=pla-571877554217&psc=1&tag=&ref=&adgrpid=57207177050&hvpone=&hvptwo=&hvadid=309821163350&hvpos=& ;hvnetw=g&hvrand=4181744818749251922&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032425&hvtargid=pla-571877554217
>
> On Thu, Dec 30, 2021 at 12:24 PM Jon Roche wrote:
>
>> I talk to a gmc owner of some sort every month that has no clue how to
>> test voltage on anything. Some have had same dead battery problems
> they
>> cant solve and still have not bought a volt meter to do troubleshooting
>> with.
>>
>>
>> --
>> Jon Roche
>> 75 palm beach
>> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
>> St. Cloud, MN
>> http://lqqkatjon.blogspot.com/
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
>
>
> --
>
> *John Phillips*
> _______________________________________________
> GMCnet mailing list
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>
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| [GMCnet] Re: The Importance of a Voltmeter [message #368241 is a reply to message #368238] |
Thu, 30 December 2021 15:22 |
CJV
Messages: 49
Registered: December 2021
Karma: 1
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Member |
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YES!! I remember Radio Shack! A great way to while away a couple of hours on an afternoon. And yes, I still have my VTM as well....
CJ Vermeulen, Scribbler
----- Original Message -----
From: "James Hupy"
To: "gmclist"
Sent: Thursday, December 30, 2021 2:52:31 PM
Subject: [GMCnet] Re: The Importance of a Voltmeter
Back before the internet, there was Radio Shack. Anyone remember them? They
had EVERYTHING electrical and electronic that your feeble minds could
imagine. I bought a VTM vest pocket sized. I still have it. In the very tip
top center of my big shop roll-a-way. For quick voltage or continuity
checks, an analog tester is indispensable. Better than a digital one for
this. I also have a Fluke 77. Also a variety of idiot light testers.
Jim Hupy
Salem, Oregon
On Thu, Dec 30, 2021, 12:43 PM John Phillips
wrote:
> For those who just want to charge a phone or two and get a battery voltage
> indication, I think this is a good first step.
>
> https://www.amazon.com/Palumma-Charger-Adapter-Display-Battery/dp/B0773BYS6P/ref=asc_df_B0773BYS6P/?tag=hyprod-20&linkCode=df0&hvadid=30982116 3350&hvpos=&hvnetw=g&hvrand=4181744818749251922&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=90 32425&hvtargid=pla-571877554217&psc=1&tag=&ref=&adgrpid=57207177050&hvpone=&hvptwo=&hvadid=309821163350&hvpos=& ;hvnetw=g&hvrand=4181744818749251922&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032425&hvtargid=pla-571877554217
>
> On Thu, Dec 30, 2021 at 12:24 PM Jon Roche wrote:
>
>> I talk to a gmc owner of some sort every month that has no clue how to
>> test voltage on anything. Some have had same dead battery problems
> they
>> cant solve and still have not bought a volt meter to do troubleshooting
>> with.
>>
>>
>> --
>> Jon Roche
>> 75 palm beach
>> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
>> St. Cloud, MN
>> http://lqqkatjon.blogspot.com/
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
>
>
> --
>
> *John Phillips*
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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| [GMCnet] Re: The Importance of a Voltmeter [message #368244 is a reply to message #368226] |
Thu, 30 December 2021 16:22 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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I ALWAYS, ALWAYS travel with my fluke 77, a couple of jumper wires with and
without 12 volt lights in them, a 100 psi tire gage, an infrared
temperature gage, 3/8" drive socket and ratchet set from 3/8" to 3/4" sized
sockets. Stubby and other length Phillips and standard screwdrivers,
extensions, pry bars, etc. God only knows what else is in that carry on
box. If you have it, you probably won't need it, but Murphy will get you if
you leave it at home.
Jim Hupy
Salem, Oregon
On Thu, Dec 30, 2021, 2:09 PM Douglas Smith wrote:
> Last summer I bought one even cheaper than the one like John P. posted and
> didn’t trust it as the voltage slowly settled to 10V while we were plugged
> in and on the Progressive charger. By the time I woke up and tested the
> brand new chassis battery with my good meter it was below 10V. Turns out my
> combiner had decided to go on vacation and disconnecting it forced it to
> reset so everything returned to normal. Of course, now I have to live with
> whatever damage the deep discharge caused. I ordered a couple of
> adapter/meters like John referenced and this time I’ll compare their
> readings with my good meter and trust them.
>
> There are many that go down the road with no more than a credit card, but
> I hope they also have a good meter stashed somewhere. It’s a source of
> nuanced diagnostic information that just can’t be gathered any other way.
>
>> On Dec 30, 2021, at 2:43 PM, John Phillips
> wrote:
>>
>> For those who just want to charge a phone or two and get a battery
> voltage
>> indication, I think this is a good first step.
>>
> https://www.amazon.com/Palumma-Charger-Adapter-Display-Battery/dp/B0773BYS6P/ref=asc_df_B0773BYS6P/?tag=hyprod-20&linkCode=df0&hvadid=30982116 3350&hvpos=&hvnetw=g&hvrand=4181744818749251922&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=90 32425&hvtargid=pla-571877554217&psc=1&tag=&ref=&adgrpid=57207177050&hvpone=&hvptwo=&hvadid=309821163350&hvpos=& ;hvnetw=g&hvrand=4181744818749251922&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032425&hvtargid=pla-571877554217
>>
>> On Thu, Dec 30, 2021 at 12:24 PM Jon Roche wrote:
>>
>>> I talk to a gmc owner of some sort every month that has no clue how to
>>> test voltage on anything. Some have had same dead battery problems
> they
>>> cant solve and still have not bought a volt meter to do troubleshooting
>>> with.
>>>
>>>
>>> --
>>> Jon Roche
>>> 75 palm beach
>>> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
>>> St. Cloud, MN
>>> http://lqqkatjon.blogspot.com/
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>>
>>
>>
>> --
>>
>> *John Phillips*
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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| [GMCnet] Re: The Importance of a Voltmeter [message #368246 is a reply to message #368241] |
Thu, 30 December 2021 16:38 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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Mmm I miss Radioshack.
Remember Heathkit? I have a Heathkit VOM, it's huge!
Keith Vasilakes
Mounds View MN
76 exRoyale
MicroLevel
________________________________
From: CJV
Sent: Thursday, December 30, 2021 3:22 PM
To: gmclist
Subject: [GMCnet] Re: The Importance of a Voltmeter
YES!! I remember Radio Shack! A great way to while away a couple of hours on an afternoon. And yes, I still have my VTM as well....
CJ Vermeulen, Scribbler
----- Original Message -----
From: "James Hupy"
To: "gmclist"
Sent: Thursday, December 30, 2021 2:52:31 PM
Subject: [GMCnet] Re: The Importance of a Voltmeter
Back before the internet, there was Radio Shack. Anyone remember them? They
had EVERYTHING electrical and electronic that your feeble minds could
imagine. I bought a VTM vest pocket sized. I still have it. In the very tip
top center of my big shop roll-a-way. For quick voltage or continuity
checks, an analog tester is indispensable. Better than a digital one for
this. I also have a Fluke 77. Also a variety of idiot light testers.
Jim Hupy
Salem, Oregon
On Thu, Dec 30, 2021, 12:43 PM John Phillips
wrote:
> For those who just want to charge a phone or two and get a battery voltage
> indication, I think this is a good first step.
>
> https://www.amazon.com/Palumma-Charger-Adapter-Display-Battery/dp/B0773BYS6P/ref=asc_df_B0773BYS6P/?tag=hyprod-20&linkCode=df0&hvadid=30982116 3350&hvpos=&hvnetw=g&hvrand=4181744818749251922&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=90 32425&hvtargid=pla-571877554217&psc=1&tag=&ref=&adgrpid=57207177050&hvpone=&hvptwo=&hvadid=309821163350&hvpos=& ;hvnetw=g&hvrand=4181744818749251922&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032425&hvtargid=pla-571877554217
>
> On Thu, Dec 30, 2021 at 12:24 PM Jon Roche wrote:
>
>> I talk to a gmc owner of some sort every month that has no clue how to
>> test voltage on anything. Some have had same dead battery problems
> they
>> cant solve and still have not bought a volt meter to do troubleshooting
>> with.
>>
>>
>> --
>> Jon Roche
>> 75 palm beach
>> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
>> St. Cloud, MN
>> http://lqqkatjon.blogspot.com/
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
>
>
> --
>
> *John Phillips*
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
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Unsubscribe or Change List Options:
_______________________________________________
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_______________________________________________
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Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] Re: The Importance of a Voltmeter [message #368247 is a reply to message #368226] |
Thu, 30 December 2021 17:32 |
blur911
Messages: 166
Registered: December 2020
Location: Kingston, Ontario
Karma: 4
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Senior Member |
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Radio Shack became The Source here in Canada, it's changed some, but same idea. I just read that RadioShack is coming back as a cryptocurrency company. https://abc13.com/radioshack-texas-electronics-cryptocurrency-company-business/11403659/
I still use a pair of Realistic Minimus 7 speakers in the boat.
For meters, I have 3 different Fluke multimeters, somewhere a tiny RadioShack one, plus an old portable Tektronix oscilloscope that can be powered by 12VDC, it's good for mobile troubleshooting.
Burl Vibert
Kingston, Ontario
1976 GMC 26 foot, Sheridan reno, don't know original model but we call her Roxie
[Updated on: Fri, 31 December 2021 08:21] Report message to a moderator |
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| Re: [GMCnet] Re: The Importance of a Voltmeter [message #368257 is a reply to message #368226] |
Fri, 31 December 2021 16:08 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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I want an ammeter, there's more information to be had. Twice (One of them last week) I've had problems that the voltmeter didn't dianose but an ammeter would have instantly. One a GMC, the pother my Ford pickup.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] Re: The Importance of a Voltmeter [message #368264 is a reply to message #368257] |
Fri, 31 December 2021 17:02 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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jhbridges wrote on Fri, 31 December 2021 17:08I want an ammeter, there's more information to be had. Twice (One of them last week) I've had problems that the voltmeter didn't dianose but an ammeter would have instantly. One a GMC, the pother my Ford pickup.
--johnny
Johnny,
I think you are about half or two-thirds correct.
When doing electric updates to performance cruisers (read retired race boats), we often discuss this. Unfortunately and true battery monitor would often blow the budget, but (as I tell them) at least a volt meter will tell you how much trouble you are in right NOW, and an ammeter in the system can tell you how much longer until you are in real trouble.
Much like our coaches, whenever possible I reconfigure the system to have an isolate engine battery. And yes, one client was very glad that he knew he could fire the engine up and have power to the VHF (Marine radio) so he could get help there fast.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Re: The Importance of a Voltmeter [message #368269 is a reply to message #368246] |
Fri, 31 December 2021 18:59 |
dsmithy
Messages: 210
Registered: July 2012
Location: Lincoln Nebraska
Karma: 0
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Senior Member |
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Keith,
I travel with a Heathkit tach/dwell meter in the GMC to this day.
I don't use it very often but it's the same vintage as my coach and makes me smile when I see it.
Shop music is from a vintage iPod through a heathkit power amp my dad made.
Garage music is a Heathkit AM/FM radio from the same era.
Douglas & Virginia Smith,
dsmithy18 at gmail,
Lincoln Nebraska,
’73 “Sequoia” since ‘95: "Wanabizo";
Quadrabag/6 wheel disks/3:70 final/Paterson QuadraJet/Thorley’s/Alloy wheels/Sundry other
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| Re: [GMCnet] Re: The Importance of a Voltmeter [message #368270 is a reply to message #368246] |
Fri, 31 December 2021 19:11 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Luckily we have always had good local electronics stores. So Radio Shack was seldom the place to go for something except after 5:30 PM or on Sundays. I went into one every 5 or 6 months. We still have one good electronics store here that I have used for 60 years. The thing that brought them down was their gradual shift away from true electronics to cell phones and toys plus their clerks lack of basic electronic knowledge. The last time I remember going there was for a piece of RG8X coax that they use to have in rolls. They did not have it any more and did not even know what I was asking for.
Bye Bye Cell Phone Shack.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| [GMCnet] Re: The Importance of a Voltmeter [message #368271 is a reply to message #368269] |
Fri, 31 December 2021 19:15 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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I learned vacuum tube radio theory when I was 14, I bought a power supply/
Short Wave receiver/ Transmitter kit from a Midwest firm called Walter Ash.
They sold surplus military electron tubes, etc. It came in a box full of
pieces starting with bare circuit boards and empty chassis and tube
sockets. It was a superhet circuit, 7 1/2 watts TX output. CW only. Late at
night, when the ionosphere settled down and there was a good skip, I could
easily contact ham radio nuts in Australia, Japan, Russia. I spent many
sleepless nights in my radio shack. Never followed it much after
transistors were invented. Hated change then almost as much as I do now.
(GRIN)
Jim Hupy
Salem, Oregon
On Fri, Dec 31, 2021, 5:00 PM Douglas Smith wrote:
> Keith,
> I travel with a Heathkit tach/dwell meter in the GMC to this day.
> I don't use it very often but it's the same vintage as my coach and makes
> me smile when I see it.
> Shop music is from a vintage iPod through a heathkit power amp my dad made.
> Garage music is a Heathkit AM/FM radio from the same era.
> --
> Douglas & Virginia Smith,
> dsmithy18 at gmail,
> Lincoln Nebraska,
> ’73 “Sequoia” since ‘95: "Wanabizo";
> Quadrabag/6 wheel disks/3:70 final/Paterson QuadraJet/Thorley’s/Alloy
> wheels/Sundry other
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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