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BLI F7b Pargon question, and how to test a speaker?

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  • Member since
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  • From: Maryville IL
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BLI F7b Pargon question, and how to test a speaker?
Posted by cudaken on Friday, January 04, 2019 4:54 PM

 Lost the sound in both my BLI B&O F7's, while the sound was dying it sure souned like bad speakers.

 Decided to tackel the B unit first, easyer to get the shell off. I forgot the B units had two speakes? But I happened to have 2 speakers so I replaced both. B Unit has sound again! Big Smile

 Now the real question. Way the Pargon B unit was wired, if one speaker died would both stop working?

 How do I test the speaker? I have a meter just don't remeber what settings to use? By the way it is one of the cheap red ones from harbour freight. I am hopping one of the speakers is still good so I can get the sound going in the F7a.

 Thanks for the coming answers!

 Cuda Ken

I hate Rust

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  • From: Reading, PA
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Posted by rrinker on Friday, January 04, 2019 5:48 PM

 They are probably wired in series. One goes open, no sound.

You can try testing using the ohms setting in the meter. Nominal reading should be 4 or 8 ohms, infinite means the coil is burned out and open. You can also try a 1.5 volt battery and touch it to the terminals. One way, the coil will move forward if it's good, flip the battery around and the coil will move in if it's good. That doesn't really prove much other than that the coil can still generate a magnetic field.

                               --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by cudaken on Saturday, January 05, 2019 4:42 PM

 Thanks Randy for your time!

 Ken

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Posted by gmpullman on Saturday, January 05, 2019 6:27 PM

When I'm doing sound decoder installs I test the speakers by playing music from an old MP3 player I have that the headphone jack got messed up. I opened up the player and wired a pair of 30 ga. wires to where the plug used to be. I combined the L + R outputs to make it mono.

You can do the same thing with a 3.5mm mini plug, say from a cheap pair of earbuds and plug it into any low-level audio source (computer, Ipad, MP3, etc) cut the earbuds off and make a teat lead out of it.

I can play full range music and get a feel for how the speaker is going to sound before going through the installation process. I usually wire speaker pairs in series, depending on the audio output of the decoder, but sometimes in parallel, too. This way I can mix or match 4, 8, 16 Ω speakers for the best match.

You can pick up cheap MP3 players just about anywhere. You could even load train sounds on it if you really want to get an idea how the output would be from your locomotive.

After the speakers are wired into the locomotive I do a final test before connecting them to the decoder.

Good Luck, Ed

  • Member since
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  • From: Maryville IL
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Posted by cudaken on Sunday, January 06, 2019 5:36 PM

 Ed, what is a Ear Bud and a MP3 player? WhistlingLaugh Remember I still have a flip phone, run XP Pro, have a tape deck, CD player and head phones Ken Patterson would love! Big Smile Need to read up a little about the meter to see if the speaker is open, meaning dead.

 See you in the dinner Ed.

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    February, 2002
  • From: Reading, PA
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Posted by rrinker on Sunday, January 06, 2019 8:53 PM

Got a clock radio with an earphone jack? Or a small radio? You can wire the speakers to a 1/8" plug and plug it in to said radio and see if you hear anything.

                                    --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    June, 2006
  • From: Maryville IL
  • 9,030 posts
Posted by cudaken on Monday, January 07, 2019 9:30 PM

 Thanks Randy.

 Ken

I hate Rust

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