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Old 08-28-2019, 02:00 PM   #1
yz250f_spud
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Default Capacitor Identification

I have a Uni-T UT61E multimeter that quit working after checking high current DC connected to the low current probe (facepalm). I've check both fuses (good) and battery (good) but it will not turn on. The screen will not illuminate nor can I get the continuity buzzer to chime when I touch the probes together.

I checked resistance of all diodes, capacitors, and resistors. The following read OL and I consider suspect.

C19 - "10 16V RVT" - I think I can find this one
C39 - "106 16K 621 - I think I can find this one
C27 - no text
C41 - ceramic disc capacitor "16" or "6"
C42 - ceramic disc capacitor "8"
D2 - LED diode - no text

I was planning to start with swapping the two ceramic disc capacitors (C41, C42). How do I identify these with only one digit?

Any ideas how to ID the right part for the LED (D2) and C27?
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Old 08-28-2019, 03:20 PM   #2
R_J
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Default Re: Capacitor Identification

The caps will likely be fine, you can't check them with an ohm meter (unless they show shorted), Do you have the schematic?
The caps C41,C42 (8pf) will not stop the meter from turning on. The led is for data transfer and C27 (4n7) also will not stop the meter from turning on.
If you are testing the meter out of the case, the rotory swich needs to be in place to turn it on.

Last edited by R_J; 08-28-2019 at 04:17 PM..
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Old 08-28-2019, 06:32 PM   #3
yz250f_spud
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Default Re: Capacitor Identification

That's what I was doing with the caps. Just checking if they were shorted. I have not tried to test the meter out of the case but understand your comment about the rotary switch. I did find a schematic. Any suggestions what I could start testing?
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Old 08-28-2019, 07:06 PM   #4
stj
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Default Re: Capacitor Identification

why post a scaled image that cant be read?
start by checking the voltages at the chip - there is a regulator supplying it.
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Old 08-28-2019, 08:02 PM   #5
R_J
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Default Re: Capacitor Identification

What exactly were you checking when the meter quit? was it a high DC voltage? If you were connected to the current inputs you would have blown the fuse (unless someone replaced them with 1/4" bolts)
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Old 08-28-2019, 08:12 PM   #6
yz250f_spud
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Default Re: Capacitor Identification

R_J - I was checking if a dog shock collar was functioning. Has stock Asia-fuse fuses, 1A and 10A. Both pass continuity and ~0 Ohm.
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Old 08-28-2019, 08:40 PM   #7
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Default Re: Capacitor Identification

it's probably dead, you hit it with several KV atleast.
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Old 08-28-2019, 08:48 PM   #8
yz250f_spud
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Default Re: Capacitor Identification

VB- to VREF reads 1.24 V. If I need to get voltage at pin 1, I'll have to get creative with jumpering for the rotary switch.
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Old 08-28-2019, 09:20 PM   #9
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Default Re: Capacitor Identification

Where is VREF ? If it took a hit from a shock collar it likely damaged the ic, Why would you want to supply voltage to pin1? If the ic is not damaged yet, that would likely kill it. that's not how the circuit works.
VB_ is the negative of the 9v battery, The positive VB+ connects to VC+ (via the rotery switch) and connects to W1 regulator, The output of the regulator ▄ connects to pins 2,4,5 ▄. Check the voltage across C35 it should be 3 volts
The ic operates from 3 volts not 9 volts

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