Kudos on your job of presenting the edited work and summarizing the circuits' workings. There is a lot going on and a lot to check. This and the curve tracer were ambitious projects successfully completed. Congratulations! I'd like to see a followup when you get the calibration done and use machine to calibrate other lab equipment.
I think I'm in a decent ballpark now. But I really need to get myself at least one 6.5 digit bench meter calibrated for reference. Otherwise anything is a bit guesswork.
I put it into the "ideas" pile... but right now, I don't have much of stuff to go on, I'm afraid. I don't think I use all that special things really, but that might be biased.
I bought a new meter after 30 years. When the new and old meters showed the same measurement results, I was satisfied. Whether it is 4.9, 5.0 or 5.1 volts doesn't matter in practice. Thats +/-2%
Indeed, normally I totally agree; some calibration steps are a bit more critical though, like that "Vref" in this unit... I really like to have at least one device that I can either calibrate annualy or rent for such tasks and that can measure to that level. For normal stuff: 2 significant digits plus noise should do for just about anything I'm working on.
That little series will shorten the restoration of my 5101B by hours, I guess. Thank you for that! My unit works on the voltages and currents, but I do not trust the resistors section. Also, my 5220A Transconductance Amplifier is only pulling "overload" all times. I also need to re-cap the full unit and I expect to introduce some collateral damage that may happen by soldering around other "almost broken" parts. For the CPU board I think that Fluke discovered that the expensive part is the tape drive, but it is more expensive to logistically handle two different CPU boards. So, I think that from a certain point onwards all units were equipped with the 5101 CPU board, only the tape drive mechanics were an option. The only firmware that pops up on a google search is the 1.0.7. for both, the 5100B and the 5101B. I will send in my Solartron 7081 for calibration soon, then start to restore the 5101B and hopefully can calibrate the calibrator with the transfer standard.
These models seem to have been around for quite a long time and there have been lots of revisions. I agree that they might have put in the same controller for both eventually; but the difference on the controller was only the RAM chips and the firmware ROMs, which all are socketed... so, should not have been much of a difference even if they went with it. Companies are strange at times :D - I did dump the ROMs though. If they are socketed, that's usually the first thing I do, just to make sure I have the original on hand.
@@atkelar As I read the service part of the manual, the software is the same in all of the units. It says the revisions only differ in "one RAM chip and a few modifications". Probably there are some bridges to be set if option boards or cassette drive is added or removed later on. I'll figure it out from the schematics when I get there. KO4BB and Electrotanya have all the required information.
@@atkelar I checked the schematics further down the service part of the manual and there are a few bridges on the A20 Controller PCA that are different between 5100B, 5101B and other derivatives of the unit. Check figure 7-18 for these. Is there any forum for these units?
Indeed, I noticed some hints about the controller being used in different other devices; I even managed to score one of them for an upcoming project. The "same firmware, so let's just stick with one controller" theory has merit indeed. I based my assumption on the various different other PCBs in my unit and thought along the lines of "somebody kept repairing it and replacing things from a donor device" As for a forum: I am not aware of any specific ones, but I bet that the eevblog forums have a few people with experience in them. There's a "test equipment" section on there after all. I tend to avoid forums for questions though, since 9 of 10 answers tend to be in the form of "why do you even bother with that? the [insert more modern device here] unit is much better!" in my experience 😁
That's a lovely restoration. I'm still not entirely sure about changing so many electrolytics but I suppose they are cheap and by the time you've removed them and tested them...
Thanks! - I keep the old caps around, just in case I need an odd one and they are still somewhat good; but for the amount of effort I put into these projects, I really don't want to end up with an "I should have done that" situation. And the aluminium electrolytics are really the only thing in there that has a natural tendency to age beyond proper function. All the other things need some "driving event" to take damage, so I'm more comfortable to keeping those.
You should see if you could borrow a 34401A 6,5 digit multimeter or buy one second hand. They are usually good enough, even after years. Put it in 10GOhm input resistance mode and 6,5 digit mode and keep it with the calibrator to check whether outputs are what you expect them to be, the 10GOhm input R will prevent it from messing with the calibrator's output. Having a 34401A independently calibrated should also be cheaper than the calibrator itself.
A 34401A is far more accurate than the Fluke will ever be. Every Tech has one. I have 3! 😁 Use one to calibrate the Fluke. I'm looking forward to next 12 videos on the 5100B, as they are SUPER reliable! 😉
I'm currently waiting on a second "almost broken" Keithley 2000 unit, so I can make one for cheaper than a working one; I think that should be compatible from the feature and spec side of things. Not much going on in these modern things, so not much of a video project I'm afraid... might make a good filler video in between larger projects though...
Your exemplary patience and skills are rewarded with a fantastic piece of test gear for you and a great to watch video for the rest of us! Thank you.
peace be upon you sir
Kudos on your job of presenting the edited work and summarizing the circuits' workings. There is a lot going on and a lot to check. This and the curve tracer were ambitious projects successfully completed. Congratulations!
I'd like to see a followup when you get the calibration done and use machine to calibrate other lab equipment.
It gotta be the biggest catch 22 ever when you get a high end calibrator but you need a high end calibrator to calibrate the calibrator with
I think I'm in a decent ballpark now. But I really need to get myself at least one 6.5 digit bench meter calibrated for reference. Otherwise anything is a bit guesswork.
Beautiful job!
Nice repair, great to see another piece of vintage test gear restored.
Beautiful video mate
Impressive work. Congratulation.
Excellent work!
Great video as always. Would be great if you can make a video about all the restoration techniques, tricks and materials you use
I put it into the "ideas" pile... but right now, I don't have much of stuff to go on, I'm afraid. I don't think I use all that special things really, but that might be biased.
Boots was trying to have a conversation with the cat on the screen this time XD
You mean in VR?
@@atkelar No, he was standing on me and trilling at the screen
I bought a new meter after 30 years.
When the new and old meters showed the same measurement results, I was satisfied.
Whether it is 4.9, 5.0 or 5.1 volts doesn't matter in practice. Thats +/-2%
Indeed, normally I totally agree; some calibration steps are a bit more critical though, like that "Vref" in this unit... I really like to have at least one device that I can either calibrate annualy or rent for such tasks and that can measure to that level. For normal stuff: 2 significant digits plus noise should do for just about anything I'm working on.
That little series will shorten the restoration of my 5101B by hours, I guess. Thank you for that!
My unit works on the voltages and currents, but I do not trust the resistors section. Also, my 5220A Transconductance Amplifier is only pulling "overload" all times. I also need to re-cap the full unit and I expect to introduce some collateral damage that may happen by soldering around other "almost broken" parts. For the CPU board I think that Fluke discovered that the expensive part is the tape drive, but it is more expensive to logistically handle two different CPU boards. So, I think that from a certain point onwards all units were equipped with the 5101 CPU board, only the tape drive mechanics were an option. The only firmware that pops up on a google search is the 1.0.7. for both, the 5100B and the 5101B. I will send in my Solartron 7081 for calibration soon, then start to restore the 5101B and hopefully can calibrate the calibrator with the transfer standard.
These models seem to have been around for quite a long time and there have been lots of revisions. I agree that they might have put in the same controller for both eventually; but the difference on the controller was only the RAM chips and the firmware ROMs, which all are socketed... so, should not have been much of a difference even if they went with it. Companies are strange at times :D - I did dump the ROMs though. If they are socketed, that's usually the first thing I do, just to make sure I have the original on hand.
@@atkelar As I read the service part of the manual, the software is the same in all of the units. It says the revisions only differ in "one RAM chip and a few modifications". Probably there are some bridges to be set if option boards or cassette drive is added or removed later on. I'll figure it out from the schematics when I get there. KO4BB and Electrotanya have all the required information.
@@atkelar I checked the schematics further down the service part of the manual and there are a few bridges on the A20 Controller PCA that are different between 5100B, 5101B and other derivatives of the unit. Check figure 7-18 for these. Is there any forum for these units?
Indeed, I noticed some hints about the controller being used in different other devices; I even managed to score one of them for an upcoming project. The "same firmware, so let's just stick with one controller" theory has merit indeed. I based my assumption on the various different other PCBs in my unit and thought along the lines of "somebody kept repairing it and replacing things from a donor device"
As for a forum: I am not aware of any specific ones, but I bet that the eevblog forums have a few people with experience in them. There's a "test equipment" section on there after all. I tend to avoid forums for questions though, since 9 of 10 answers tend to be in the form of "why do you even bother with that? the [insert more modern device here] unit is much better!" in my experience 😁
That's a lovely restoration. I'm still not entirely sure about changing so many electrolytics but I suppose they are cheap and by the time you've removed them and tested them...
Thanks! - I keep the old caps around, just in case I need an odd one and they are still somewhat good; but for the amount of effort I put into these projects, I really don't want to end up with an "I should have done that" situation. And the aluminium electrolytics are really the only thing in there that has a natural tendency to age beyond proper function. All the other things need some "driving event" to take damage, so I'm more comfortable to keeping those.
Great! Thx! Hoping you will find an acceptable way to calibrate the beast
You should see if you could borrow a 34401A 6,5 digit multimeter or buy one second hand. They are usually good enough, even after years.
Put it in 10GOhm input resistance mode and 6,5 digit mode and keep it with the calibrator to check whether outputs are what you expect them to be, the 10GOhm input R will prevent it from messing with the calibrator's output. Having a 34401A independently calibrated should also be cheaper than the calibrator itself.
I reckon he's going to steal some ppms from @reps 😅
I've been wondering how you would calibrate it!
A 34401A is far more accurate than the Fluke will ever be. Every Tech has one. I have 3! 😁 Use one to calibrate the Fluke.
I'm looking forward to next 12 videos on the 5100B, as they are SUPER reliable! 😉
I'm currently waiting on a second "almost broken" Keithley 2000 unit, so I can make one for cheaper than a working one; I think that should be compatible from the feature and spec side of things. Not much going on in these modern things, so not much of a video project I'm afraid... might make a good filler video in between larger projects though...
@@atkelar Nice meters! Hope we'll be treated to a video! 👍
Send to Marco Reps for callibration , tell him that Vini sent you ;)
😶🌫
Hello!
Or perhaps send it to Curious Marc for cal?
The postage would be a tad bit too extreme I think 😆 That thing weighs about 35kg give or take a bit...
@@atkelar Hmmm, yes, from Austria? There will be someone around you with the right equipment.
@@atkelar Are you aware of this person? ruclips.net/video/zQDqnRsmPz0/видео.html
Only from the occasional video... not in person.
😊
🥳