Products > Test Equipment

AN8008 US $19, 9999count, 1uV, 0.01uA, 0.01Ohm, 1pF resolution meter

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floobydust:
Lifted the 24C02 EEPROM's SDA, SCL pins and attached wires. Used an Arduino and 3V level translator.
Bytes match a Russian AN8008 dump, aside from the CAL factors.

The DMM IC is full featured but the multimeter's hardware (rotary switch, die-bonding PCB) prevents their use. LCD has all annunciators though. I don't have the exact datasheet for the DMM IC, just its predecessors.

RS-232 output - I can't see the IC TXD pin bonded.
hFE test - needs transistor socket and 3 resistors but could be done from the front banana jacks.
Mid-range amps - not possible as rotary switch does not bypass 99R (uA) shunt. I still hear Dave yelling about this gyp. Could add a switch, lol.
Temperature - I enabled in EEPROM on the mV function, works °C/°F and factory CJC CAL is already set at 25°C fixed.
NCV - could be used with antenna 10MEG resistor added.
Clamp-on CT - could add if you enter CAL factors.

Presently only two buttons: SEL/HOLD and RANGE/BL.
To add MAX/MIN & RELATIVE buttons- I haven't checked if that MCU pin available; they are muxed.

So you can enable the temp function (although shown here it's advertised in Russia; my meter did not have the function). 
Also you can change timer settings for BL and power off etc. or change calibration.
Factory alarms set to 1,000VDC and 750VAC. OL at 1,100VDC and 800VAC.

It was a fun adventure.

Gandalf_Sr:
Flooby, seems like you're much deeper into the guts of the AN8008 than most of us - well done!  I'd like to make a couple of mods when mine gets here so I'm interested in your thoughts:

1. Change Amps to mA - I know you've stated that it can be done by changing shunt resistors but can the EEPROM also be hacked to give the correct display?  I don't want to measure Amps, just mA and uA.
2. Take out the elCheapo electrolytic Cap on the 3 volt rail and put in 1206 caps as suggested by you a couple of pages back (search he thread for "1206")
Any other low-hanging fruit?

plazma:



--- Quote from: floobydust on July 22, 2017, 08:14:49 pm ---RS-232 output - I can't see the IC TXD pin bonded.

--- End quote ---

How did you check this?
For one AN8002 unit I removed die potting epoxy to reveal pin 20 pcb pad. I added a pull-up resistor and measured the signal. Nothing was visible. I sacrificed this unit and removed the potting epoxy to reveal the bonding wires and the die. The pin was unbonded.

bitseeker:

--- Quote from: Gandalf_Sr on July 23, 2017, 12:00:17 pm ---1. Change Amps to mA - I know you've stated that it can be done by changing shunt resistors but can the EEPROM also be hacked to give the correct display?  I don't want to measure Amps, just mA and uA.

--- End quote ---

+1 Seems the best mod for electronics use.


--- Quote ---Any other low-hanging fruit?

--- End quote ---

Temp? I wasn't sure if that really worked. Some posts said yes, I think one said it didn't.

ocw:

--- Quote ---1. Change Amps to mA - I know you've stated that it can be done by changing shunt resistors but can the EEPROM also be hacked to give the correct display?  I don't want to measure Amps, just mA and uA.
--- End quote ---

I changed the 0.01 ohm shunt resistor for the AmA jack to 0.095 ohms and now with the leads in the COM and AmA jacks, but the AN8008 rotary switch in the uA position, I measure mA current up to 99.99 mA with 0.01 mA resolution and 0.1 mA resolution up to 999.9 mA with the decimal in the correct location.  999.9 mA is the maximum current which can be read now.  The mA readings are now typically 0.35% high.  I haven't tried to change the meter's software yet.  Others might need a slightly different value shunt resistor.

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