I have a blue esr meter and its screwed up. Q1 overheats and the display partially turns on for a second then dims and shows only certain segments.
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Jacked up ESR Meter
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Re: Jacked up ESR Meter
I think they overheat in the order of Q1 then IC1 then Q1 again. I don't have another exact 5v regulator, I tried to substitute but IC1 and the new regulator started overheating. With the new regulator display was bright for a few seconds then segments started getting dim and nothing would light until the battery was reconnected.
I've changed the caps, the PNP and NPN transistors and still it does the same thing. I don't see any shorts but the bipolar cap or the tiny caps could be bad, no way to test. Its as if the circuit is oscillating. Maybe some resistors went. I got this kit mostly completed, I don't think it ever worked some resistors were flipped, 100k where 10k should be but I put them in the correct spots.
Will try running with the regulator disconnected and probably order another one tomorrow.
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Re: Jacked up ESR Meter
IC1 is the 5v regulator - 3 pin
IC2 is the microcontroller Z86E0412 - 18 pin
IC3 is the CMOS shift register/display driver 4094 / MC14094 - 16 pin
This was someone else's unfinished unit? Then I would go from A-Z with a component list sheet and schematic and make sure every last component is installed correctly. Mark them with a marker or something to make sure you've verified every last one. The resistors can be especially confusing as you're dealing with both 4 & 5 band coding. Confirm that the IC sockets were installed correctly with the pin 1 markings.
I doubt any caps or resistors are bad, but the electrolytic caps could be in backwards. Double check C1 & C3-100uF, C2-10uF.
Resistors from 100-1K ohms, if they failed, would be obvious as a burn, overheat mark on board, or blistered paint. Above the 1K ohm value here, there's not enough voltage to damage them.
Verify that the regulator is putting out 5v. If it's shorted from input to output, it would pass the 9v from the battery, and that could take out many items -> Primarily the microcontroller and LED driver IC's.
If you don't have the assembly manual PDF, let me know you email where I can send it as it's too large to attach here.
Good Hunting!
Toastveritas odium parit
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Re: Jacked up ESR Meter
Sounds like Q1 is bad then. Unit should not turn on immediately when batt is connected. Q1 is the "electronic switch" to power the unit.
Input to IC1 should be batt voltage. Output MUST be 5 volts.
>>The caps it came with were swollen but not in backwards.<<
WHAT !! Replace them all. Not possible unless reversed.
Toastveritas odium parit
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Re: Jacked up ESR Meter
There's something seriously wrong with that meter. When it's just sitting there idle with only "- " showing, it should only pull around 10mA which isn't enough to heat up any components at all.
What you're describing is a major overload on the +5V rail. I bet it's pulling 100mA or more from the poor little 9V battery. Are you really sure that none of the electrolytic caps on the board are installed backwards?
If you can't find some component mis-installed, you should be able to find the cause of the overload by feeling around with your fingertip because whatever it is will get very warm from dissipating a lot of power.It is a good shrubbery. I like the laurels particularly...
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