Author Topic: Fluke 123 Scopemeter and battery replacement (Read 85985 times)

Cones · « **on:** March 02, 2013, 03:25:46 pm »

Hi,

I bought a cheap Fluke 123 scopemeter from ebay with lines on the screen and a flat battery. No problem I thought, I can live with the lines and I will just get a new 3rd party battery for £15 from Amazon here in the UK.

This is where all the fun and games starts!

The original Fluke battery is a BP120 and is a 2000mAh NiCd unit. It would not charge in the scopemeter and would only maintain the unit for 30 second or so before it powered down.

The new replacement battery is made by Cameron Sino and is a BP130 Equivalent 3000mAh NiMh unit.

But on comparing the wiring on the 6 pin connector for the two batteries the new 3000mAh one is wired wrong and will not work at all in the scopemeter. As it was low cost and not worth the hassle of changing it. I have investigated further and resolved all of the problems with it.

This is the correct pin wiring for the scopemeter battery connector.

Pin 1 Not Connected
Pin 2 +
Pin 3 -
Pin 4 I Identification (0 Ohms=NiCd) (825 Ohms=NiMh) Return on Pin 3
Pin 5 Not Connected
Pin 6 T Temperature Sensor (NTC Resistor) Return on Pin 3

So I swapped the connector pins round in the plug on the new battery and then the meter would power on with it. But it still would not charge fully or perform a battery refresh operation.

After a bit of Googling and a look at the Fluke service manual I found the above pinout information and I also discovered the correct resistance value for the NiMh battery.

I measured the value on my battery Identification resistor and I got a resistance of 0.8301 Meg Ohms not the 825 Ohms it is supposed to be. So the manufacturer not only wired the plug wrong they also compounded the problem by putting the wrong resistance value in as well!

So I have now cut open the heat shrink and corrected their mistakes as you can see in the pictures below.

Battery

Original and pending replacement resistor

Crap insulation on the opposite side of the original resistor

Removed resistance value

Replacement Resistance Value

Correct Plug wiring

Repaired and heatshrink added for a slightly better insulation

Red insulation tape as I have run out of larger heatshrink. This may get replaced in future if I can be bothered!

Original Battery pack

Refresh now detects the NiMh and changes from 12 (NiCd) to 19 Hours! Result.

SeanB · « **Reply #1 on:** March 02, 2013, 03:34:28 pm »

Are you sure they got the thermistor right as well? Often I just do a transplant from the old to the new and it almost always works.

Cones · « **Reply #2 on:** March 02, 2013, 04:07:13 pm »

Hi, yes I remember the values being similar on the thermistors. I will check again after it has finished the 19 refresh cycle it is currently running.

As a further footnote to the old battery I have cycled it on my hobby charger a few times. The first time at a 1 amp charge rate to try and get the cell chemistry started. After 3 cycles at 200mA charge and discharge is now reports just over half its original capacity and will run the scopemeter for 2.5 hours. I might try a few more cycles and see what happens!

NiCd and NiMh are relatively low capacity and old tech compared with the new Lipo or LiIon. But I suspect not of those would still take a charge after nine years!! Progress is not always what it seems.

Mark

amyk · « **Reply #3 on:** March 03, 2013, 02:08:00 pm »

The wrong resistor looks like orange and brown mixup. They do look very similar colours in the photos.

Wrong resistor is grey-red-green-orange brown, 825k +/- 1%
Right resistor should probably be grey-red-green-black brown, 825 +/- 1%

jivega · « **Reply #4 on:** May 28, 2013, 11:59:47 pm »

Hi.
I also recently bought a Fluke 123 with V1.08 firmware without battery. I made a purchase of a Cammeron Sino BP120 NiMh 3000mA, the connector goes both ways, I had to check the manual for how to connect.
The connector also bad wiring in the terminal (Identification). No has resistor identification (0 ohms) to negative. I made the modification and included a 820ohm resistor between Identification cable and negative terminal, but when I do the refresh battery, this indicates 12 hours for NiCd battery not 19 hours. I tried with various resistor values ??but does not work. I dont know if it's the firmware version supports this type of battery.
Cones: What is the firmware version on your Fluke?, thnks.

ScubaShan · « **Reply #5 on:** August 15, 2013, 07:19:47 am »

I think its safe to assume the guys at Cameron Sino are colour blind. Mine arrived with a completely different resistor measuring 3.9Meg Ohm

rsivan · « **Reply #6 on:** August 19, 2013, 11:05:06 am »

Hello guys
about fluke 123 and also 124 I done mod let the instrument to charge and use 2x 18650 Li-Ion battery
I have modded 2 units and running from 6 months still work great no autodischarge like NiMh and run time is very long, the hack consist in:
1 mod charge voltage to 8.4v to charge in safe 2 cells from 3.7v (4.2+4.2)
2 mod max current charge limit to 600-800mA charge more fast
3 add voltage divider between AD multiplexer and MCU to make battery indicator as real possibile
if you interested I will post some pictures and schematics with mods!!

archaelus · « **Reply #7 on:** August 20, 2013, 07:36:20 am »

rsivan: I'd be really interested in seeing the modifications you made as I need to get a replacement battery for my 123.

How much battery life do you get out of it now?

rsivan · « **Reply #8 on:** August 20, 2013, 12:30:40 pm »

My fluke 124 at 8v input drain 320mA with full backlight and 280mA with dimmed backlight so with 3400mA cells run time should be 8-10h also in stand by drain 1.5-2mA very low you can leave for moths without using and eliminate self-discharge of Ni-Cd Ni-Mh battery!

rsivan · « **Reply #9 on:** August 23, 2013, 02:39:13 pm »

here some more pics
look at battery curve at 5.9v /2 = 2.95v is good to match the empty battery icon

rsivan · « **Reply #10 on:** August 23, 2013, 02:47:39 pm »

for service manual
http://assets.fluke.com/manuals/123_124_smeng0000.pdf

ScubaShan · « **Reply #11 on:** October 07, 2013, 11:01:06 am »

What sort of cells are they?

mcleod · « **Reply #12 on:** October 07, 2013, 04:36:29 pm »

The horizontal lines on any of the Fluke scopemeters (123/192/192B/ETC) are caused by a failure of the adhesive on the ribbon cable.

I bought a 192 and 192B on ebay earlier this year that both had horizontal lines and was able to get them fixed. After doing a bit of googling on the problem I was able to figure out a way to fix it. If you are interested in repairing yours I can do a short write up, but you would have to give me a day or two to pull one of mine apart to take some pictures.

macboy · « **Reply #13 on:** October 07, 2013, 04:44:23 pm »

I would have simply put the 825 ? in parallel with the 830 k? one, instead of doing surgery to remove the old resistor. You could have added the parallel resistor anywhere on the cable or even at the connector.

ron · « **Reply #14 on:** November 15, 2013, 09:57:44 pm »

Quote from: mcleod on October 07, 2013, 04:36:29 pm

The horizontal lines on any of the Fluke scopemeters (123/192/192B/ETC) are caused by a failure of the adhesive on the ribbon cable.

I bought a 192 and 192B on ebay earlier this year that both had horizontal lines and was able to get them fixed. After doing a bit of googling on the problem I was able to figure out a way to fix it. If you are interested in repairing yours I can do a short write up, but you would have to give me a day or two to pull one of mine apart to take some pictures.

I would like very much to see your method. It's common for these displays to develop this problem.

cjones · « **Reply #15 on:** December 19, 2013, 07:04:20 pm »

Hello,
My work has a fluke 123 that hasn't been turned on in 5 yrs or so. Now it isn't powering on at all. I cut open the shrink on the battery and found two of the cells are completely dead. It will not power up with the battery removed and the power supply is reading 20V instead of 15.

Should this thing work with the battery removed? I'm trying to decide if I should buy a battery, a power supply or both (for now I wouldn't mind leaving it plugged in just for use around the lab). I'd like to troubleshoot it more but it won't be seen as a good use of time right now.

ron · « **Reply #16 on:** December 19, 2013, 07:14:15 pm »

Quote from: cjones on December 19, 2013, 07:04:20 pm

the power supply is reading 20V instead of 15.

I just checked 2 chargers and they read ~21V without load.

cjones · « **Reply #17 on:** December 19, 2013, 07:22:39 pm »

Thanks for checking that. Do you know if these will run from wall power with the battery removed?

rsivan · « **Reply #18 on:** December 19, 2013, 07:46:31 pm »

yes without battery have to work 100%
also if battery very discharged or like shorted when press on must only make a flash and one beep and after off

cjones · « **Reply #19 on:** December 20, 2013, 01:20:23 pm »

Good to know. Thanks rsivan and ron.

klim · « **Reply #20 on:** September 12, 2014, 09:43:37 pm »

Hi i'm interested in the 18650 Battery battery mod for Fluke 123. Is there not a problem to drive the Fluke 123 with 150% (7,4V instead of 4,2V) of it's specified voltage battery level?

This is the original battery pack pinout.

Pin 1 Not Connected
Pin 2 +
Pin 3 -
Pin 4 I Identification (0 Ohms=NiCd) (825 Ohms=NiMh) Return on Pin 3
Pin 5 Not Connected
Pin 6 T Temperature Sensor (NTC Resistor) Return on Pin 3

How do you have connected the identification resistor und NTC in your 18650 battery pack?

klim · « **Reply #21 on:** September 20, 2014, 12:14:37 pm »

One more question: have you used cells with protection board (built in cell / external pcb)?

rsivan · « **Reply #22 on:** September 22, 2014, 03:59:15 pm »

Quote from: klim on September 12, 2014, 09:43:37 pm

Hi i'm interested in the 18650 Battery battery mod for Fluke 123. Is there not a problem to drive the Fluke 123 with 150% (7,4V instead of 4,2V) of it's specified voltage battery level?

This is the original battery pack pinout.

Pin 1 Not Connected
Pin 2 +
Pin 3 -
Pin 4 I Identification (0 Ohms=NiCd) (825 Ohms=NiMh) Return on Pin 3
Pin 5 Not Connected
Pin 6 T Temperature Sensor (NTC Resistor) Return on Pin 3

How do you have connected the identification resistor und NTC in your 18650 battery pack?

yes I've used normal cells but protection board is on battery holder,I leaved resistor on wiring, keeping NiMh setting,about higher voltage: I done some test,starting from 4,5v to 10-12v and watching at current drain, from 4 to 9-10v current drain going down while increasing voltage,this good because internal LDO in fluke controller doing the right job,after 10-12v start to rise ,and this not good,but for us running on Li-Ion is perfect because will never go above 8.4v(4.2*2) ,also stand-by current drain is very low like 1-2mA same as original or lower.

klim · « **Reply #23 on:** September 25, 2014, 07:39:51 pm »

Hi rsivan and thank you very much for your reply.
Now it's time to renew my Fluke 123 with new state of the art li-ion powered energy ;-)

melhookv12 · « **Reply #24 on:** February 03, 2015, 04:51:13 pm »

Hi I have also purchased a Cameron Sino battery from e bay. I tried a refresh cycle and had no luck. After using Google I ended up here.

I also think my battery is wired incorrectly but I have no reference to relocate the wires. Can someone confirm the location of pin 1. I have tried to attach a picture and it is with the security tag facing upwards. In the op's it doesn't show a tag on the connector, does this mean its facing downwards or it doesn't have one.

Any help greatly appreciated.


EEVblog Main Site	EEVblog on Youtube	EEVblog on Twitter	EEVblog on Facebook	EEVblog on Odysee

Author Topic: Fluke 123 Scopemeter and battery replacement (Read 85985 times)

Share me