Resistance sourcing is probably not miscalibrated at all. Please note that there was a similar absolute offset of around 0R45 at all measurement points. I bet it is caused by the resistance of the connection between Fluke and Keithley
Great video! For the membrane keyboard I tend to use a 6B drawing pencil (super soft) and "paint" the rubber pad with graphite again. Tends to work quite well to revive dead rubber keyboards. Far from ideal but will keep you going in a pinch. (other harder pencils might also work but you probably need to first draw a very dense spot on paper and the rub that paper onto the rubber some). I guess you can but replacement conductive pads with adhesive on maazon but unfortunately they are impossible to source here in Argentina. Awesome work!!
Hola Diego, perdona la molestia, tendrás de casualidad el pinout para la interfaz HART del equipo, no he podido localizar el cable de interfaz HART? saludos desde Chihuahua, México.
I miss the days of theory, design and characterisation tutorials. Yes repairs and theoretical descriptions are fist class and enjoy them immensely however, mixing it up a tad might be a nice change. As usual another Wonderfully educational video. Kudos
very good video, I need some help to find out the HART cable interface for the Fluke 744, because I can't find it to buy it new, do have the Pinut to built a OEM hart cable interface? regards
I have received a 743B and replaced the NiCd cells with two LiPo and a small power management PCB. I put a jump wire from the DC jack negative to the negative battery contact and now the device can charge the battery by itself. However the low battery sign is constantly showing. May I ask at what voltage level did the sign go away?
The "errors" may not be actual offsets. The Keithley has a spec plus a temperature coefficient error. Your test leads most probably add small uV errors. The Keithley might have a small drift error as well. The resistance error / offset could be due to the fact you did not zero the test leads. Calibration does NOT mean something reads exactly a specific value and does not include adjustment . Calibration is the testing an unknown value against a known value that can be traced back to a National Standard. The kg standard which is in France is changing value over time and is NOT exactly 1.0000000000000 kg Good repair and very well presented, well done.
Exactly how does it implement the resistance emulation? Hard to tell exact sizes from the video but if those NiMH cells are the same dimensions as modern 18650, it looks like you can stuff 6x 18650 into the case and get really good runtime out of it. (Maybe just 4x if there's not enough space left for the BMS.) Then add a 2S charger board inside the unit so you can plug it in to charge just like most modern electronics.
I understand the secrecy required behind not disclosing the source of the rom/fw updater. Could you at least tell me if there is something there to update my Fluke 199 (first gen) Scopemeter from the original FW (1.23 I think) to the later versions? EEVBlog had a thread on someone else trying the same update, but lacking any solution.
Would be nice to see actual repair process, skipping thru it might be somewhat confusing for people who never worked on these, or bootloader process in general. Also 3458A is sad, sitting neglected ;) I can help you with hobby calibration against my 5720A and standards :)
I used a USB-RS232 converter directly connected to the RS232 port of the Fluke 744. I then ran the Firmware Update file and followed the instructions. I kept on trying with different power on conditions until the software established a connection and then it worked! Yes, I promise to show the 3458A soon! :) It would be cool to calibrate this thing against your reference.
From what I saw, it measures the current delivered by the external device and overwrites it with the equivalent voltage that the resistance would generate. Anyway I would also be interested if it is explained in more detail.
i have a Fluke 741B with similar condition. The device cannot boot normally. i tried to test and in this case i can power it on and off. when i press the start button it has a small beep then it will keep on beeping. I see there is an unsoldered RS232 port on the PCB, can I solder a jack and connect them to the PC?
I think the 74x series uses Fluke's own communication protocal and they charge quite a bit for the software. Not sure if you could directly communicate with the device through that.
Hi Liu. Nice to meet you. Have a nice day. I found a jumper next to the MAX694 and it's identical to the Fluke 701, GND and Reset. I just tried soldering the DB9 jack and connected them to the PC, opened the Fluke744 Firmware Update software, when I was about to upload I tried to short the jumper on but the software said it failed. "Error:Lost connection & Protocol Error: Compliance." The device continues to beep. I want to know Max694's Reset pin state configuration, any idea?
Also remember that don't cheat on the battery, but try to get the battery as right as possible, maybe a tad higher than stock. The reason is that the meter uses the battery as its own internal voltage reference (it has nothing else to reference against). Also try looking in the schematic what the 2 unused terminals are for (1 terminal was common GND, one terminal was thermistor, and one terminal is battery+) . It MIGHT be that it exist some sort of compensated battery which have a good refvoltage. Either it COULD be balancing terminals for Li-ion battery, or it could be reference terminals which uses some sort of precision circuit to create a refvoltage with a known difference or similiar. I have noticed many multimeters - including fluke's, that give weird measurements once their 9v is starting to go flat. Once you get weird measurements with the probes connected to nothing, especially in ohm mode, you know that the battery should be replaced.
i worked on a fluke 123 recently and on that device you press two arrow buttons while powering it on to get into the mask rom which i assume is for flashing the FW
Looks like the rating is 7.2 V and 3500 mAh. Two of these www.adafruit.com/product/353 wired in series to the battery terminals would make 7.4 V 6600 mAh. Nearly double the battery storage capacity for longer run time! Huzzah! Should be pretty straight forward to create a charger for those embedded packs.
There is a patent, US4176331A, registered to two scientists from Hughes Aircraft Company for a device using an op amp and a resistive voltage divider to simulate low noise temperature resistors. I wonder if this may be using a similar technique?
try to put in a new flash storage chip. the one in the Fluke is more than 20 years old, and it's just a matter of time till it corrupts the firmware again.
Thumbs up Shahriar!
Thank you my friend.
so when is the colab probably gonna happen?
Hopefully after COVID!
@@Thesignalpath It would be an honor to meet you, and shake your hand Shahriar.
RIP to the guy that said it was nice to see a failed attempt at repair once in a while.
he still needed a hint from someone else so it's not a complete loss xd
Resistance sourcing is probably not miscalibrated at all. Please note that there was a similar absolute offset of around 0R45 at all measurement points. I bet it is caused by the resistance of the connection between Fluke and Keithley
exactly what i was thinking. He should try with a 4-wire measurment.
I had already zeroed the DMM. But I noticed that the contacts on the Fluke where very dirty and after cleaning them, the result improved a lot.
Great video! For the membrane keyboard I tend to use a 6B drawing pencil (super soft) and "paint" the rubber pad with graphite again. Tends to work quite well to revive dead rubber keyboards. Far from ideal but will keep you going in a pinch. (other harder pencils might also work but you probably need to first draw a very dense spot on paper and the rub that paper onto the rubber some). I guess you can but replacement conductive pads with adhesive on maazon but unfortunately they are impossible to source here in Argentina.
Awesome work!!
Hola Diego, perdona la molestia, tendrás de casualidad el pinout para la interfaz HART del equipo, no he podido localizar el cable de interfaz HART?
saludos desde Chihuahua, México.
@@luisbayloncarrera7066 no. No tengo nada. De hecho ni siquiera tengo este equipo. Perdona!
Nice save. A USB charge port poking out of the battery would be a fine addition!
I miss the days of theory, design and characterisation tutorials. Yes repairs and theoretical descriptions are fist class and enjoy them immensely however, mixing it up a tad might be a nice change.
As usual another Wonderfully educational video. Kudos
very good video, I need some help to find out the HART cable interface for the Fluke 744, because I can't find it to buy it new, do have the Pinut to built a OEM hart cable interface?
regards
I have received a 743B and replaced the NiCd cells with two LiPo and a small power management PCB. I put a jump wire from the DC jack negative to the negative battery contact and now the device can charge the battery by itself. However the low battery sign is constantly showing. May I ask at what voltage level did the sign go away?
Wow what a capable device. Keep upgrading it! Your Fluke videos are pretty entertaining.
"Good addition to the lab" ;-) ...... any potential measuring device is present at least 10 times already ;-)
Hello,how to solve the issue showing " no firmware in device detected" after loading the firmware
The "errors" may not be actual offsets. The Keithley has a spec plus a temperature coefficient error. Your test leads most probably add small uV errors. The Keithley might have a small drift error as well. The resistance error / offset could be due to the fact you did not zero the test leads.
Calibration does NOT mean something reads exactly a specific value and does not include adjustment . Calibration is the testing an unknown value against a known value that can be traced back to a National Standard.
The kg standard which is in France is changing value over time and is NOT exactly 1.0000000000000 kg
Good repair and very well presented, well done.
Do you have video tutorial for scandura pascal 100?
Exactly how does it implement the resistance emulation?
Hard to tell exact sizes from the video but if those NiMH cells are the same dimensions as modern 18650, it looks like you can stuff 6x 18650 into the case and get really good runtime out of it. (Maybe just 4x if there's not enough space left for the BMS.) Then add a 2S charger board inside the unit so you can plug it in to charge just like most modern electronics.
Resistance measurements: with MOSFETs ( look up electronic Load). Yeah the batteries look close enough.
Very interesting videos, every time!
I understand the secrecy required behind not disclosing the source of the rom/fw updater. Could you at least tell me if there is something there to update my Fluke 199 (first gen) Scopemeter from the original FW (1.23 I think) to the later versions? EEVBlog had a thread on someone else trying the same update, but lacking any solution.
It's not a secret, you can find the link in the comments of the previous video.
Nice
Would be nice to see actual repair process, skipping thru it might be somewhat confusing for people who never worked on these, or bootloader process in general. Also 3458A is sad, sitting neglected ;)
I can help you with hobby calibration against my 5720A and standards :)
yes, i couldn't quite understand how exactly it was fixed after all. how was it wired up to computer?
I used a USB-RS232 converter directly connected to the RS232 port of the Fluke 744. I then ran the Firmware Update file and followed the instructions. I kept on trying with different power on conditions until the software established a connection and then it worked!
Yes, I promise to show the 3458A soon! :) It would be cool to calibrate this thing against your reference.
Please see my response below.
Great!
How device source resistance? What is schematic solution? It is interesting to me.
From what I saw, it measures the current delivered by the external device and overwrites it with the equivalent voltage that the resistance would generate.
Anyway I would also be interested if it is explained in more detail.
i have a Fluke 741B with similar condition. The device cannot boot normally. i tried to test and in this case i can power it on and off. when i press the start button it has a small beep then it will keep on beeping. I see there is an unsoldered RS232 port on the PCB, can I solder a jack and connect them to the PC?
I think the 74x series uses Fluke's own communication protocal and they charge quite a bit for the software. Not sure if you could directly communicate with the device through that.
Hi Liu. Nice to meet you. Have a nice day.
I found a jumper next to the MAX694 and it's identical to the Fluke 701, GND and Reset. I just tried soldering the DB9 jack and connected them to the PC, opened the Fluke744 Firmware Update software, when I was about to upload I tried to short the jumper on but the software said it failed. "Error:Lost connection & Protocol Error: Compliance." The device continues to beep. I want to know Max694's Reset pin state configuration, any idea?
Awesome job Sir.
Also remember that don't cheat on the battery, but try to get the battery as right as possible, maybe a tad higher than stock. The reason is that the meter uses the battery as its own internal voltage reference (it has nothing else to reference against). Also try looking in the schematic what the 2 unused terminals are for (1 terminal was common GND, one terminal was thermistor, and one terminal is battery+) . It MIGHT be that it exist some sort of compensated battery which have a good refvoltage. Either it COULD be balancing terminals for Li-ion battery, or it could be reference terminals which uses some sort of precision circuit to create a refvoltage with a known difference or similiar.
I have noticed many multimeters - including fluke's, that give weird measurements once their 9v is starting to go flat. Once you get weird measurements with the probes connected to nothing, especially in ohm mode, you know that the battery should be replaced.
How have you recovered the firmware or program? Have you received any special tool for reprogramming it?
No, just RS232 directly to PC.
I'm curious....do you keep all the units you repair, or do you sell some of them off? That's a lot of units to have around if you keep them all!
It really depends. Sometimes I sell them, but not often.
Very good!
i worked on a fluke 123 recently and on that device you press two arrow buttons while powering it on to get into the mask rom which i assume is for flashing the FW
Looks like the rating is 7.2 V and 3500 mAh. Two of these www.adafruit.com/product/353 wired in series to the battery terminals would make 7.4 V 6600 mAh. Nearly double the battery storage capacity for longer run time! Huzzah!
Should be pretty straight forward to create a charger for those embedded packs.
This one is a little too large I think to fit into the space. But I like the approach.
There is a patent, US4176331A, registered to two scientists from Hughes Aircraft Company for a device using an op amp and a resistive voltage divider to simulate low noise temperature resistors. I wonder if this may be using a similar technique?
Inane comment to boost the algorithm - lol -.
Now we're happy - lol -.
3500mA 7.2V : 6 MiMH to 2 LiPo, boy have batteries got better - lol -.
I love how your job lets you play arround with 100k plus equipement and lets you film it to satisfy the internets desire for wierd ass tech
This is my personal lab.
@@Thesignalpath Which probably rivals Bell Labs
Good job :o
try to put in a new flash storage chip. the one in the Fluke is more than 20 years old, and it's just a matter of time till it corrupts the firmware again.
I wonder if a custom battery build video would be interesting to anyone other than me. Its probably too simple these days.
aha victory at last
Nice!
Another one saved. :D
Kelvin connection for low ohmic
There is a video you can watch to make a Fluke 19x into Li-On same applies here
This one is even easier. Because the instrument itself doesn't even have a charging circuitry built in.
The Signal Path splendid, do it via an inductive charging coil
Can you please open your channel on lbry.tv? I think a lot of people would thank you.
ایمان داشتم امکان نداره شکست بخوری
I am like 666 🤣