Author Topic: $7 DT9205A?  (Read 2023 times)

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Offline kalel

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$7 DT9205A?
« on: June 24, 2017, 08:32:55 pm »
While searching for the cheapest multimeter that offers some additional functionality over the $3 models, I ran into this for around $7 on eBay:



With the same name, I found different models however, so I'm referring specifically to one in the image.

It seems to offer capacitance, temperature and frequency measurement, which are all additional functionality comparing to the $3 meters (there is a $4 version that does measure temperature, but not capacitance).
It may or may not have a fuse, as the description says: "Fuse proteciton: F 200mA/250V", but that might also mean "insert the fuse".
It says "auto power off" on the case, which if true is a nice feature since sometimes I do forget to turn the cheapo meter off, and it does drain the battery in that case after a while.
The screen angle might be adjustable, or it might just look that way while being fixed.

Does anyone have any information on this meter and perhaps some images of the inside?
« Last Edit: June 24, 2017, 08:36:15 pm by kalel »
 

Offline JLNY

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Re: $7 DT9205A?
« Reply #1 on: June 25, 2017, 12:25:10 am »
Interesting meter. Probably one of the cheapest I have seen with capacitance measurement. Most of the listings I have seen for these come with a yellow rubber case around it, though. Does this one not come with the case? I guess the ones that do cost extra, but seems like it would be worth the extra buck or two to get it with a case. The probes that come with it look like the super trashy kind that come with other similarly cheap meters.

The fact that it looks to have a "hard" on/off switch that physically disconnects the battery is a feature that I always really like. If it has an automatic shut off that's even better.

I don't see any range for temperature measurement or frequency on that meter, but it seems that there is also a DT9208A variant which has the 200mVAC range replaced with a temperature measurement mode and also has frequency measurement. Not sure if that variant mentions anything about an automatic shutoff, though. I tend to prefer meters with temperature measurement when available. That 200M resistance range is also unusually high for a handheld.

There is an article with several internal images here (it looks to have a glass fuse installed, LCD does not look adjustable). That said, it seems like these cheap meters often have multiple different board revisions floating around, so it's hard to be certain if the one you get will have a fuse or not.:

http://www.petervis.com/meters/Excel_DT9205A/Excel_DT9205A_Inside.html
« Last Edit: June 25, 2017, 12:32:22 am by JLNY »
 
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Offline kalel

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Re: $7 DT9205A?
« Reply #2 on: June 25, 2017, 01:04:11 am »
Interesting meter. Probably one of the cheapest I have seen with capacitance measurement. Most of the listings I have seen for these come with a yellow rubber case around it, though. Does this one not come with the case? I guess the ones that do cost extra, but seems like it would be worth the extra buck or two to get it with a case. The probes that come with it look like the super trashy kind that come with other similarly cheap meters.

The fact that it looks to have a "hard" on/off switch that physically disconnects the battery is a feature that I always really like. If it has an automatic shut off that's even better.

I don't see any range for temperature measurement or frequency on that meter, but it seems that there is also a DT9208A variant which has the 200mVAC range replaced with a temperature measurement mode and also has frequency measurement. Not sure if that variant mentions anything about an automatic shutoff, though. I tend to prefer meters with temperature measurement when available. That 200M resistance range is also unusually high for a handheld.

There is an article with several internal images here (it looks to have a glass fuse installed, LCD does not look adjustable). That said, it seems like these cheap meters often have multiple different board revisions floating around, so it's hard to be certain if the one you get will have a fuse or not.:

http://www.petervis.com/meters/Excel_DT9205A/Excel_DT9205A_Inside.html

This one doesn't seem to come with a case, but you're right about temp measurement. I should stop reading titles and descriptions and start looking more carefully, e.g. the description for that item was:
Quote
Resistance (Ohm): 200, 2k, 20k, 200k, 2M, 20M, 200M, 2000M?

Capacitance (F): 2nF, 20nF, 200nF, 2uF, 200uF 

Frequency: 2K, 20K, 200KHz

Temperature: -20?~1000?

The cheapest version with the yellow case is about $7.9, so not more than $1 difference. With so many cheap multi-meters appearing, it's difficult to differentiate them and see which one might offer more for the price. DT-9208A is also similarly priced at about $9, so for $2 the addition is the yellow cover, temperature and frequency measurement.

As for the probes, just adding some hot glue can really help make them last longer (as they don't have proper support). It's a cheap solution that really helps. It won't do much about the resistance, however, it's difficult to expect some high end leads and those should last with the glue gun method (hopefully).
« Last Edit: June 25, 2017, 01:10:52 am by kalel »
 

Offline JLNY

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Re: $7 DT9205A?
« Reply #3 on: June 25, 2017, 01:35:42 am »
As for the probes, just adding some hot glue can really help make them last longer (as they don't have proper support). It's a cheap solution that really helps. It won't do much about the resistance, however, it's difficult to expect some high end leads and those should last with the glue gun method (hopefully).
Instead of using hot glue, one might also use a couple layers of adhesive-lined heatshrink tubing instead. Done correctly, it can make for an excellent strain relief, and I know it is often used in industry to ruggedize things like higher-end and phase-stable RF coax assemblies.

The idea is to have multiple layers in such a way that the strain relief still flexes along its length, thereby actually increasing the bend radius rather than just shifting the strain point farther back like most rigid strain reliefs.

Edit: Added image. not the highest resolution, but you get the idea.
« Last Edit: June 25, 2017, 01:42:27 am by JLNY »
 

Offline kalel

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Re: $7 DT9205A?
« Reply #4 on: June 25, 2017, 01:48:06 am »
Quote from: JLNY
Instead of using hot glue, one might also use a couple layers of adhesive-lined heatshrink tubing instead. Done correctly, it can make for an excellent strain relief, and I know it is often used in industry to ruggedize things like higher-end and phase-stable RF coax assemblies.

The idea is to have multiple layers in such a way that the strain relief still flexes along its length, thereby actually increasing the bend radius rather than just shifting the strain point farther back like most rigid strain reliefs.

Edit: Added image. not the highest resolution, but you get the idea.

Yes, that sounds best as long as you can get the heatshrink over the probe (that is, if the size that goes over the probe is small enough so that it can shrink down nicely). Otherwise some soldering and hacking would be necessary. Glue gun is definitely not as good as that, but it's also not rigid, so it can somewhat do the same task up to a point.
 

Offline retiredcaps

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Re: $7 DT9205A?
« Reply #5 on: June 25, 2017, 02:30:59 am »
Hmm, I have no confidence in the meter when the picture shows -1666 when the rotary switch is set to ACV with probes open.

Yes, I realize it is probably photoshopped by some clueless person, but it still doesn't inspire confidence.
 
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Offline joseph nicholas

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Re: $7 DT9205A?
« Reply #6 on: June 25, 2017, 02:48:41 am »
I have the M version and have been using it for a few years.  When I got it the probes fell apart after a few days, and of course they don't come apart so...not fixable.  The bale broke off 6 months later of light and careful use, not after a drop.  The AC volts range stopped working and seems unfixable.  That said the meter is quite large and the display is easy to read.  The on/off push button is a nice feature as you don't have to mess with the range switch to turn it off.  Like all these cheap meters that use the chip mentioned it is remarkably accurate in all ranges including measuring capacitance.  Continuity test is instantanious.  It measures forward voltage in the milliamps in the diode check mode.  On the milliohm range, the display floats and I don't think it really works.  It's suppose to measure up to 20 amps but when I tested it, it seemed to top out about 10 or 11 amps, but that could be my lack of using a dummy load to check this.

I like this meter and after using it for some time I ordered another one from ebay with the Hz and temp settings.  It also comes with an excellent English language manuel.

I think if you buy it and aren't disappointed when the probes break it will earn you respect.
 
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Offline JLNY

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Re: $7 DT9205A?
« Reply #7 on: June 25, 2017, 02:59:26 am »
Yes, that sounds best as long as you can get the heatshrink over the probe (that is, if the size that goes over the probe is small enough so that it can shrink down nicely). Otherwise some soldering and hacking would be necessary. Glue gun is definitely not as good as that, but it's also not rigid, so it can somewhat do the same task up to a point.

They aren't too hard to pull apart. Clamp the front of the probe pin in a vice and twist the body of the probes to crack the overmold, and the pin pulls right out. From there, the heatshrink can be threaded on and the probe pin can be re-soldered (yes, it is just a single solder joint holding it, which is probably why they break so easily).

Just for laughs, I tried making these just now:
« Last Edit: June 25, 2017, 03:01:34 am by JLNY »
 
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Offline kalel

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Re: $7 DT9205A?
« Reply #8 on: June 25, 2017, 03:12:03 am »
I have the M version and have been using it for a few years.  When I got it the probes fell apart after a few days, and of course they don't come apart so...not fixable.  The bale broke off 6 months later of light and careful use, not after a drop.  The AC volts range stopped working and seems unfixable.  That said the meter is quite large and the display is easy to read.  The on/off push button is a nice feature as you don't have to mess with the range switch to turn it off.  Like all these cheap meters that use the chip mentioned it is remarkably accurate in all ranges including measuring capacitance.  Continuity test is instantanious.  It measures forward voltage in the milliamps in the diode check mode.  On the milliohm range, the display floats and I don't think it really works.  It's suppose to measure up to 20 amps but when I tested it, it seemed to top out about 10 or 11 amps, but that could be my lack of using a dummy load to check this.

I like this meter and after using it for some time I ordered another one from ebay with the Hz and temp settings.  It also comes with an excellent English language manuel.

I think if you buy it and aren't disappointed when the probes break it will earn you respect.

Yes, the probes of that style will break unfortunately (I had the same experience on cheap DT meters that come with them).

They aren't too hard to pull apart. Clamp the front of the probe pin in a vice and twist the body of the probes to crack the overmold, and the pin pulls right out. From there, the heatshrink can be threaded on and the probe pin can be re-soldered (yes, it is just a single solder joint holding it, which is probably why they break so easily).

Just for laughs, I tried making these just now:

Looks great. I wish I knew that when I was trying to repair one. :)
Those should last long now.
« Last Edit: June 25, 2017, 03:16:09 am by kalel »
 

Offline blueskull

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Re: $7 DT9205A?
« Reply #9 on: June 25, 2017, 03:14:04 am »
Hmm, I have no confidence in the meter when the picture shows -1666 when the rotary switch is set to ACV with probes open.

Yes, I realize it is probably photoshopped by some clueless person, but it still doesn't inspire confidence.

It's not - sign. It's DT (data hold?) in inverted display.
1666 is just a lucky number in China, Cantonese guys like that number.
Same goes 8888 and 6666 and similar combinations of 6 and 8.
In Cantonese, 6 means free of trouble, and 8 means to get rich.
 
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