I was in the tail-end of the TV service industry, and cleaning mechanical tuners was a daily job. That does tell my age, somewhat. Several years ago, I purchased a Tektronix 7000 series scope with the plugins and scopemobile. The only thing wrong with it was dirty switches.
Great video, thank you! It's amazing how well these old devices were built. Reviving them is really worth the effort, it's akin to restoring old music instruments. Thank you for doing this.
+kvitekp What's great about these older instruments is that they have had possibly thousands of power on hours (as evidenced by the burned out bulbs) and decades behind them. Therefore, once calibrated, they tend to drift very little and require little further calibration down the road. The bad part is all of the (electrolytic) caps going bad, because they are not meant to last for forty years.
That is beautiful! Once again, proof that Fluke = Quality. Also, your 34401A is agreeing very well with your friend's 34461A! You can be confident with its measurements. I discovered your YT channel some days ago, and I must admit I like the way you carefully and calmly explain stuff. Love it, I'm hooked!
Excellent video and addition to your lab. I have a datron 4700 calibrator that has a problem with the ac section. Hope to find a service manual which up to now has been impossible to find. Your channel is one of my favorite and thanks for sharing with us.
Nice video. I just finished with restoration of 343A 7.5 digit voltage Calibrator (big brother of 341) and i can add few comments. Even it looks like caps are ok they aged much more than is acceptable So i would change them. But ..big but.. 1. Those nice simple looking Sprague capacitors are pain in butt Capacitors. They are part of Family Little Lytic capacitors. I think you can still buy them if you are from USA( i bought few from Farnell). They were manufactured there. I think Vishay is own it now...Anyway. Those 5uF caps..(you changed to 6.8..btw i did as well as no more 5uF ones) are pretty important..so changing them to normal caps is not good. They needs to be very low leakage types...I personally used Hermetically sealed tantalum caps with even better parameters. So i would suggest to do it for rest low capacity ones as well. Those bigger Sprague ones the best would be to changed them for same model but new ones...rest normal ones not a big deal 2. I would also suggest to change IC1 ..old one used Motorola 1709 opamp i used now obsolete alternative LT 1007 (obsolete because i used same package) ..This will increase accuracy and lower the noise and increase stability. 3. Then i would suggest to change Dual JFET for LSK 389B. This will increase stability and lower noise.. 4. I also changed those binding posts at front for new ones..as old ones were pretty used up.. 5. Btw.. Increase size of those capacitors on lefts sides..(those blue ones. This will increase stability of +15 Reference power Supply and -15V )...
I just got myself 343A in a seemingly good condition and with Fluke stickers intact. It exhibits similar symptoms as this 341A I repaired years ago. Perhaps it is time for another repair video.
@@feedback-loop Would be nice to see it. Don't forget to upgrade IC1 and replace those 5uF for good tantalum ones ..and rest should be easy to fix..I would love to have two 343A .but i have only one..it cost too much ..but one extra would be perfect :)
@@feedback-loop Not bad ..I expect it is newer model than mine. But i would still go for LT1007 ACH /LT1007 ACH or even better LT1012AMH - unfortunately both are now obsolete (because of that TO99 package)so only chance is e-bay the second FET i didn't find relevant datasheet ( so i would suggest my choice i used LSK 389 or even better choice U440 or U441 or even better U421/U423 - These 4 are metrology grade dual fets used in multimeters such as Keithley 2001 so best of the best .. Good luck and Please make some Video about it..I would love to see it :)
Nice repair as usual, thanks for sharing! I'm envious of you being able to go to your "local electronics store" and find so many replacement parts, waiting for Mouser, DigiKey, etc. to deliver them is always a drag!
+Dino Papas Yes, but you save money and get a better selection of parts for larger orders. Also, having a good assortment of resistors/capacitors on hand if you're into repairing equipment is a must. Finally, the 34401A is a great instrument, the 34461A, although newer, I wouldn't put much faith in, in terms of long term drift. Fortunately, the one he used was calibrated a year ago, so it can't be too bad (btw, two meter agreement on value means little - they could have both drifted in the same direction).
+SteelBlueVision Hmmm, not sure why my comment didn't appear publicly, didn't have any links included. Oh well. Yes, I also have a very good stock of parts on hand so that on Sunday afternoon I can generally build or fix something, but you can't have everything!
+Dino Papas Well, guess my comments did in fact make it thru after signing out and in back again. Keep up the great repair videos, I always learn something new!
The shorted cap was part of what looks like an astable multivibrator in a section labelled "CHOPPER AMPLIFIER". I wonder if the offset was simply because that multivibrator didn't work and thus the amplifier was not actually chopper stabilized at this point. In that case it's still a pretty low offset... for a late 60s discrete op amp.
Thanks for taking the time to make such a clear video. I have been a subscriber for some time. Is that a broken lead from the large black power resistor @15:10 ?
I was in the tail-end of the TV service industry, and cleaning mechanical tuners was a daily job. That does tell my age, somewhat. Several years ago, I purchased a Tektronix 7000 series scope with the plugins and scopemobile. The only thing wrong with it was dirty switches.
Great video, thank you! It's amazing how well these old devices were built. Reviving them is really worth the effort, it's akin to restoring old music instruments. Thank you for doing this.
+kvitekp What's great about these older instruments is that they have had possibly thousands of power on hours (as evidenced by the burned out bulbs) and decades behind them. Therefore, once calibrated, they tend to drift very little and require little further calibration down the road.
The bad part is all of the (electrolytic) caps going bad, because they are not meant to last for forty years.
I was just about to look at my 343A because its showing an offset, glad I ran into your video.
The front panel cleaning job is the best, looks really good now!
Those plastic support blocks look like a good application for a 3D printer.
That is beautiful! Once again, proof that Fluke = Quality.
Also, your 34401A is agreeing very well with your friend's 34461A! You can be confident with its measurements.
I discovered your YT channel some days ago, and I must admit I like the way you carefully and calmly explain stuff. Love it, I'm hooked!
Great video! I like your way you repair stuff, very calm, clever, experienced. And the nice russian (?) accent
Seems yes, I also think it’s russian accent)
What a great piece of kit !
Another great job from the best Electronics Engineer on RUclips.
Nice job. Fluke makes fine equipment. Thanks for sharing.
Very Good, Please do more of these repairs.
Great instrument and repair!
Excellent video and addition to your lab. I have a datron 4700 calibrator that has a problem with the ac section. Hope to find a service manual which up to now has been impossible to find. Your channel is one of my favorite and thanks for sharing with us.
I'm glad I found your Channel!
Nice video. I just finished with restoration of 343A 7.5 digit voltage Calibrator (big brother of 341) and i can add few comments. Even it looks like caps are ok they aged much more than is acceptable So i would change them. But ..big but..
1. Those nice simple looking Sprague capacitors are pain in butt Capacitors. They are part of Family Little Lytic capacitors. I think you can still buy them if you are from USA( i bought few from Farnell). They were manufactured there. I think Vishay is own it now...Anyway. Those 5uF caps..(you changed to 6.8..btw i did as well as no more 5uF ones) are pretty important..so changing them to normal caps is not good. They needs to be very low leakage types...I personally used Hermetically sealed tantalum caps with even better parameters. So i would suggest to do it for rest low capacity ones as well. Those bigger Sprague ones the best would be to changed them for same model but new ones...rest normal ones not a big deal
2. I would also suggest to change IC1 ..old one used Motorola 1709 opamp i used now obsolete alternative LT 1007 (obsolete because i used same package) ..This will increase accuracy and lower the noise and increase stability.
3. Then i would suggest to change Dual JFET for LSK 389B. This will increase stability and lower noise..
4. I also changed those binding posts at front for new ones..as old ones were pretty used up..
5. Btw.. Increase size of those capacitors on lefts sides..(those blue ones. This will increase stability of +15 Reference power Supply and -15V )...
I just got myself 343A in a seemingly good condition and with Fluke stickers intact. It exhibits similar symptoms as this 341A I repaired years ago. Perhaps it is time for another repair video.
@@feedback-loop Would be nice to see it. Don't forget to upgrade IC1 and replace those 5uF for good tantalum ones ..and rest should be easy to fix..I would love to have two 343A .but i have only one..it cost too much ..but one extra would be perfect :)
IC1 in my unit is LM709CH, and Q35 (dual JFET) is FD1786
@@feedback-loop Not bad ..I expect it is newer model than mine. But i would still go for LT1007 ACH /LT1007 ACH or even better LT1012AMH - unfortunately both are now obsolete (because of that TO99 package)so only chance is e-bay the second FET i didn't find relevant datasheet ( so i would suggest my choice i used LSK 389 or even better choice U440 or U441 or even better U421/U423 - These 4 are metrology grade dual fets used in multimeters such as Keithley 2001 so best of the best .. Good luck and Please make some Video about it..I would love to see it :)
Amazing work~
Nice repair as usual, thanks for sharing! I'm envious of you being able to go to your "local electronics store" and find so many replacement parts, waiting for Mouser, DigiKey, etc. to deliver them is always a drag!
+Dino Papas Yes, but you save money and get a better selection of parts for larger orders. Also, having a good assortment of resistors/capacitors on hand if you're into repairing equipment is a must. Finally, the 34401A is a great instrument, the 34461A, although newer, I wouldn't put much faith in, in terms of long term drift. Fortunately, the one he used was calibrated a year ago, so it can't be too bad (btw, two meter agreement on value means little - they could have both drifted in the same direction).
+SteelBlueVision Hmmm, not sure why my comment didn't appear publicly, didn't have any links included. Oh well. Yes, I also have a very good stock of parts on hand so that on Sunday afternoon I can generally build or fix something, but you can't have everything!
+Dino Papas Well, guess my comments did in fact make it thru after signing out and in back again. Keep up the great repair videos, I always learn something new!
The shorted cap was part of what looks like an astable multivibrator in a section labelled "CHOPPER AMPLIFIER". I wonder if the offset was simply because that multivibrator didn't work and thus the amplifier was not actually chopper stabilized at this point. In that case it's still a pretty low offset... for a late 60s discrete op amp.
Amazing, thank you
Very nice unit
great video
Thanks for taking the time to make such a clear video. I have been a subscriber for some time. Is that a broken lead from the large black power resistor @15:10 ?
+Rob B
No, it just looks so from that angle. Here is a photo from another angle:
drive.google.com/file/d/0B3NWgPtazb_tWGpwWnFCVHdPV00
But what about precision voltage reference? I don’t see it inside, but seems it must be somewhere
@16:07
FeedbackLoop Да, похоже я смотрел недостаточно внимательно)) Спасибо!
4:50 Must be one of those "Random" voltage calibrators.
Very good restoration work. You would enjoy Mr. Carlson's Lab, also on RUclips.
👍👍👍👍👍