Cheap multimeter?

JSitthi · 9786

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Offline Laudanum

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Reply #15 on: November 09, 2011, 11:08:04 AM
Green, round and long wirewounds?  Or metal oxides?  Just curious.

Desmond G.


Offline Doc B.

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Reply #16 on: November 09, 2011, 11:40:22 AM
They are not metal oxide. They are Vishay Draloric 5 Watt wirewound resistors with ceramic centers and a cement coating.

Dan "Doc B." Schmalle
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Offline Cary

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Reply #17 on: November 10, 2011, 05:35:25 AM
Parts Express is having a sale, there's a multimeter for $2, #399-002.



Offline dbishopbliss

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Reply #18 on: November 10, 2011, 06:03:44 AM
I've used flukes since 1984.  I have replaced the batteries twice, blew a fuse once.  I have never even questioned the reading I have gotten.  Poster Paully has this one (I think):

http://www.ebay.com/itm/Fluke-15B-Auto-range-Digital-Capacitance-Inductance-multimeter-meter-Test-17B-/220868418663?pt=LH_DefaultDomain_0&hash=item336cc89c67

$55 +shipping is a good price.

Why are all the 15B flukes on ebay from China?  Any idea if they are real flukes or copies.  Just seems strange that they are only offered from chinese sellers. 

David B Bliss
Bottlehead: Foreplay I, Foreplay III, Paramour I w/Iron Upgrade, S.E.X. w/Iron Upgrade
Speakers: FE127E Metronomes, Jim Griffin Jordan/Aurum Cantus Monitors, ART Arrays
Other: Lightspeed Attenuator, "My Ref" Rev C Amps, Lampucera DAC


Offline JSitthi

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Reply #19 on: November 10, 2011, 06:39:21 AM
Parts Express is having a sale, there's a multimeter for $2, #399-002.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=399-002

Is it any better than the one I have now?

Also, how essential is it to bend the leads of the resistors at the specified length? After 6 hours of working on this, I got tired and skimmed the instructions when I got to the resistors - what a mistake! My resistors are curved into the terminals they need to be in rather than right-angled, and not necessarily at the right length either. Will this affect anything?

« Last Edit: November 10, 2011, 06:49:26 AM by JSitthi »



Offline JC

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Reply #20 on: November 10, 2011, 08:04:51 AM
For $2, I would think of getting one for a back-up, if I didn't already have enough back-ups.

If I understand your question about the resistors, you should be fine.  Just make sure you understand the instructions and follow them.  If you run across one you don't understand, just post a question here.       

Jim C.


Offline JSitthi

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Reply #21 on: November 10, 2011, 07:43:47 PM
Got through the resistance readings just fine with the $5 HF multimeter, except some readings in the 2.4K and 2.9K came out 100ohms higher. I also couldn't figure out where I would measure for the 90K-100K range on the RCA plugs, so I skipped that. After I hooked everything up to power, the fuse blew :|

It's gonna be a long night!



Offline Laudanum

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Reply #22 on: November 11, 2011, 02:42:34 AM
Got through the resistance readings just fine with the $5 HF multimeter, except some readings in the 2.4K and 2.9K came out 100ohms higher. I also couldn't figure out where I would measure for the 90K-100K range on the RCA plugs, so I skipped that. After I hooked everything up to power, the fuse blew :|

It's gonna be a long night!

Your 100 ohm higher readings on the two resistors are fine, well within the 10-15% variation.   I dont have the manual handy but I believe it states to turn the volume all the way down.  Doing that and with meters ground/black probe connected to a ground, touch the red probe to the center pin of each of the RCA jacks, first one then the other.  Assuming you used the kits included wire, the center pin would be the solder cup of the RCA jack where you soldered the red wire (for the right/red jack) and white wire (for the left/black) rca jack.  First check one, then the other.  This basically checks the wiring from the jacks to the volume control pot as well as indirectly checking the pot.  With the "volume" turned all the way down, the pot measures about in the 90-100K range and this should be what you measure at the jacks give or take a little either way.  There will probably be some variation between the measurements of the left and right jacks.  That's ok, the pot isnt perfectly matched between sections.

Do you have any spare tubes of both types used in Crack?  It's probably not a bad tube causing your blown fuse but it isnt uncommon.  If you got through the resistance checks ok and you do have spare tubes, try those first and see if the fuse holds up.   Radio Shack probably has spare fuses if you dont have any.  I believe it's a .5 amp fuse, take it with you and you can match it up.

« Last Edit: November 11, 2011, 02:48:58 AM by Laudanum »

Desmond G.


Offline Grainger49

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Reply #23 on: November 11, 2011, 05:00:02 AM
Blown fuses are most often caused by diodes being reversed or the power supply caps being reversed.  

Look in your manual at page 27. Observe the band on the diodes.  Check the two from T18 to T20 and T18 to T21.  Check the two from T19 to T20 and T19 to T22.

For the capacitors look at T20, it should be the white stripe of the cap, look at T14 that should be the white stripe and finally look at T13 that should be the white stripe.

These are the most often causes of blown fuses.  If you got a capacitor reversed it is probably blown now. 
« Last Edit: November 11, 2011, 05:30:16 AM by Grainger49 »



Offline Laudanum

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Reply #24 on: November 11, 2011, 08:31:27 AM
Grainger is the man as usual, so heed his words of wisdom fellow grasshopper :-)

Desmond G.


Offline JSitthi

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Reply #25 on: November 11, 2011, 10:37:05 AM
Blown fuses are most often caused by diodes being reversed or the power supply caps being reversed.  

Look in your manual at page 27. Observe the band on the diodes.  Check the two from T18 to T20 and T18 to T21.  Check the two from T19 to T20 and T19 to T22.

For the capacitors look at T20, it should be the white stripe of the cap, look at T14 that should be the white stripe and finally look at T13 that should be the white stripe.

These are the most often causes of blown fuses.  If you got a capacitor reversed it is probably blown now.  

Problem found! I seemed to have shifted a capacitor, the striped side that should be in T20 is in T19 instead...does that mean I've fried it? I will try resoldering it and report back. Thanks!

EDIT: It works! :D Thanks so much!
« Last Edit: November 11, 2011, 10:44:45 AM by JSitthi »



Offline Grainger49

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Reply #26 on: November 11, 2011, 11:05:50 AM
If the leads were swapped it is weakened and will fail.  If it was just on a wrong terminal, not swapped, you should be ok.



Offline JSitthi

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Reply #27 on: November 11, 2011, 11:35:47 AM
Everything is sounding great, I just hooked everything up and no problems at all! It's amazing how bad I am at DIY projects and how easy this was to put together!

Should I be feeding it through the headphone jack of my sound card or the line out? I have an Auzentech Forte card, so the headphone out is amplified. I'm assuming the line out would be the better choice?
« Last Edit: November 11, 2011, 10:49:27 PM by JSitthi »



Offline Laudanum

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Reply #28 on: November 12, 2011, 12:25:29 PM
Yep, line out is the better choice.

Desmond G.