Datron 4000A Questions - Page 1
Forum section: electronics / general

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 09, 2017, 01:52:52 am
content: I know there is so much information available on this forum I need some help with a new purchase.This morning I had the chance to pick up a Datron 4000A not working and showing a Fail 3 error code.A few moments after turning unit on a very bad smell originated from unit so I immediately turned off power and started looking for the culprit.After pulling each board examining and re-seating didn't see anything unusual.With cover off I turned unit back on Fail 7 error code and smoke began rising off the power supply board.2 tantalum capacitors are a chocolate brown with oozing.Not the pretty yellow of their neighbors.While preparing to order parts I need to find some schematics for this unit.And maybe operation manual.Any assistance would be appreciated.One other thought... I am reading the Options as 20 and 80.Does this mean the unit only does AC or does it have Ohms and DC Calibration also.Not sure I understand how options relate to features.

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 09, 2017, 01:54:09 am
content: Front Panel

author: Mickle T.
author_rank: Frequent Contributor
timestamp: May 09, 2017, 05:27:02 am
content: Datron 4000A is DC only calibrator. Option 20 = DCI and Ohms functions. Option 80 = 115V 60 Hz Line operation.

author: manganin
author_rank: Regular Contributor
timestamp: May 09, 2017, 09:04:33 am
content: Quote from: Johnny10 on May 09, 2017, 01:52:52 amClassic problem. Looks and smells worse than it actually is. Changing the tantalums usually returns the analog supplies which are down.

author: ap
author_rank: Frequent Contributor
timestamp: May 09, 2017, 09:39:02 am
content: General issue with Tantalums is that they often were used beyond spec. They were supposed to do PSU rail filtering, and saw a high ripple current, especially when electrolytic caps decreased their capacitance due to aging effects. Many companies did not observe this.I would recommend not to replace by Tantalums but by organic cap such as Oscon. Better AC behaviour and not that sensitive against ripple.

author: chris_11
author_rank: Contributor
timestamp: May 09, 2017, 01:43:30 pm
content: Tantalum capacitors, if left alone (read without voltage applied) for a long time can exhibit dendrite growth through their isolation barrier. You can cure that with a current limited switch on. However with a hard switch on without current limit they go up in smoke.They can even exhibit a nice fire.Replacing them all with OSCON or similar is a good choose.You have some corrosion on the nuts and screws. Might be a good idea to check the complete instrument and clean the PCBs since it has run or being stored in a very humid environment.

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 09, 2017, 02:54:13 pm
content: I am in Florida and I believe storing items with no de-humidification or AC causes this corrosion.Yes, I see the corrosion but the boards and traces look quite good.Closer examination will be necessary.Changed the tantulums, but on start-up still get Fail 7 error.Cannot change switches front panel switches.This error must lock out keyboard.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: May 09, 2017, 03:08:11 pm
content: FAIL 7 - 400 V PS failure.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 09, 2017, 10:09:03 pm
content: I will look later tonight if I have the 4000A manual.Where in Florida do you live?

author: manganin
author_rank: Regular Contributor
timestamp: May 09, 2017, 10:33:10 pm
content: Still a good idea to check the low voltage power rails (ramp up and stability). Especially those feeding the fault detect comparators can generate random fault indications.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 10, 2017, 03:43:58 am
content: I have the manual set for the 4000/4000A. A quick comparison between it and the digital copy of the 4708 SM shows the failure codes have different descriptions. Manganin may be correct with the direction for t/s this error.Attached is a copy of the error description. The quality is not great but it is readable. I can get copies of particular sections once I clear off my scanner.I have a 4700 and 4808. The 4700 had several tantalums fail with other failures on the inguard supply board. The 4808 also had a couple bad parts on the inguard supply. You could bench test the board by connecting to a power supply.Let me know what you need and I will scan some copies for you.

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 10, 2017, 04:27:18 am
content: I have been looking for a problem with the 400V supply for the past few hours.But I have to say I have also been reading the 4708 manual thinking the boards were the same.After pulling out the inguard supply and comparing the actual board with the schematic not quite the same and other boards are even more different than 4708.That +-50v is interesting since I have not found 50V anywhere in my testing.Well it is only the first day !Many more to come.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 10, 2017, 05:44:03 am
content: I scanned in all the pages referenced by the manual. It is a large file at 40M. I can be upload it to xDevs for now until it can be converted to a more manageable size.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: May 10, 2017, 06:05:00 am
content: It's better to upload it to the Didier's KO4BB site too.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 10, 2017, 11:22:39 am
content: The file is uploaded to xDevs herehttps://xdevs.com/doc/Datron/4000A/Datron_4000_Fail_7.pdfI have also uploaded it to KO4BB.The outguard supply was also included for reference.

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 10, 2017, 04:12:46 pm
content: Great!!Really Appreciate the effort and the quality.And it proved that no 50V is present.I do have 86V from transformer and through to test points.But no 50 V, will have to study description this evening.Again, Appreciate the effort.

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 12, 2017, 05:05:48 pm
content: OK,Quick update.I repaired the Inguard Board.Problem was no + 15 V which created no 50V replaced the 7815 and surrounding burnt Capacitors.I now have +- 15, +- 50, 2.5 ReferenceNow no more Fail message.However I still can't operate front panel controls.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 12, 2017, 05:41:50 pm
content: Good news that it is now working in a smoke free zone. The 7815 was also dead on my 4808.The 4700 manual states that the keyboard won't work if the letter B is on the MODE and OUTPUT displays. This means that the processor is busy.I also had a problem with sticking keys. They were catching on the overlay for the front panel. I had to trim the overlay freeing them up.

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 12, 2017, 09:04:30 pm
content: My Mode screen is completely blank.I set the internal reset switch received a Fail 5 error and then pressed the Front Panel Reset.Key worked quickly and released Fail Mode.So I don't think it is all bad or sticky switches.Have you read where any other errors set lock the keyboard?

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 13, 2017, 03:45:27 am
content: Ok.Does your MODE display show anything on power up?The RESET key is separate from all the other keys. It basically resets the watchdog circuit. The only information I have found for an inactive keyboard is if the calibrator is in REMOTE mode through the GPIB.I wonder if the CPU is going into reset? You could always try communicating with it remotely to see if it responds. You may have to scope out the front panel and look for signs of life and also check the CPU reset line. That can be seen on TP7 of the digital PCB. It is tied in with the power supply fail detector.The schematic for the 4708 is pretty close. The quality isn't the greatest but I can scan that section for you if needed in the morning.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: May 13, 2017, 05:27:55 am
content: Is it possible that internal "Clear" key was pressed too? If so, 4000A losts all of NVRAM content, including the calibration constants and factory precal constants. FAIL 5, blocked MODE display - these are typical signs of precalibration lost.

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 13, 2017, 01:20:54 pm
content: I am going back in to check all voltages today.My feeling was Digital board was working since the 0 and -15V error flags are sent to CPU.I may be missing supplies to digital components.Mickle T.Where is the internal Clear Key?

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 13, 2017, 05:09:46 pm
content: OKChecked lots of voltages this morning, all seemed within spec.So I took Manatee Mafias advice and connected unit to GPIB.Sent some messages to the unit and for now I tested DC voltages 1 through 100 volts.I have control of DC output I guess I will read up on program commands to see if I can get keyboard access again.Using the programming commands found in the Datron 4708 manual.I only have 6 1/2 digit DMM HP 3457 that I repaired a number of months ago.Thanks Manatee Mafia and manganin and Mickle T.Time to go learn about my unit, do some clean-up and put it back together.

author: Vgkid
author_rank: Super Contributor
timestamp: May 13, 2017, 05:23:51 pm
content: That is good news. That front panel lockout reminds me of what happened to my solartron dmm. Powered it on one day all buttons were un responsive. Power cycle did nothing (remote led was continuously on). Ended up having to pull the remote card.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 13, 2017, 06:09:22 pm
content: I might have some spare parts here if you can't find it. My 4000A has been sitting around and I have no urge to fix it up. Both displays are broken on it and I used it for t/s the 4700.

author: Johnny10
author_rank: Frequent Contributor
timestamp: May 13, 2017, 09:33:00 pm
content: The remote signifier goes on and off in the Mode window.Thanks for the offer Manatee Mafia.If I can't find problem maybe I should just replace keyboard drive board?And maybe a couple of new output posts to replace my broken one.If I keep this unit the Operating and Service manual would come in handy.The service manuals don't seem to exist for sale.Bottom Pic of -1.000000vdc after HP 3457A Warm for 8 hours

author: bbford352
author_rank: Newbie
timestamp: May 25, 2017, 08:26:28 pm
content: Hi ManateeI a repair tech for a calibration house in Florida I have a couple of 4000As on for repair but all I have a re the manuals for the 4708 (Paper) and 4700 (digital) any chance I could get a copy of the manual I have one that came back from a custome that is working great except for the 1A range is completely dead I have a pretty decent group of manuals if you want to swap or something. Have a good one

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 26, 2017, 09:23:11 pm
content: bbford352,I have promised the manuals to another forum member but I intend on scanning them first. I will be uploading them for everyone to use for their repairs. I will try and get some done this weekend but if you need a certain section with schematics and/or description, let me know. I can always do that section first and add it to the finished job later.

author: Ronsine
author_rank: Newbie
timestamp: December 27, 2018, 03:34:51 pm
content: Hi all,I have just bought a 4000A with a fail 6 message on the lh display.Did copies of the manuals get uploaded anywhere?Thanks in advanceRon

author: Johnny10
author_rank: Frequent Contributor
timestamp: December 27, 2018, 05:29:38 pm
content: Fail 6 is Calibration

author: Ronsine
author_rank: Newbie
timestamp: December 28, 2018, 12:00:17 am
content: Thanks for that,does anyone have manuals for the 4000A available?Also have a Datron 4200A which I have had for some years but have never been able to find out the specs compared to the 4200.Anyone have any info on the 4200A specs?Ron

author: Ronsine
author_rank: Newbie
timestamp: January 05, 2019, 12:55:00 pm
content: Anyone out there willing to sell copies of the Datron 4000A manuals?

author: serg-el
author_rank: Regular Contributor
timestamp: January 06, 2019, 08:15:13 am
content: http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=06_Misc_Test_Equipment/Datron/Datron_D4000A

author: Ronsine
author_rank: Newbie
timestamp: January 06, 2019, 11:27:37 am
content: Hi Serg-el,Yes found those but need a full set...Also have a fail 2 on the 4000A to diagnose.Thanks

author: Johnny10
author_rank: Frequent Contributor
timestamp: January 06, 2019, 12:54:46 pm
content: A couple of members here have 4000A units and the first action to take is change all the tantalum caps on the power supply boards and the DC board.Examine the board closely for any burnt resistors.I have found since I changed all tantalums even Fail 2 disappears.xdevs has the Power Supply board on those schematics.

author: Ronsine
author_rank: Newbie
timestamp: January 06, 2019, 03:20:47 pm
content: Thanks Johnny 10,I have checked all the caps with a capacitance/esr meter and found no problems but will replace them anyway.I know it is a problem on the Darton units and had a couple go up on smoke on my 1061 multimeter and the 4200A calibrator.I have manuals for the 4200 and have been trying to find out the presumably better specs for the 4200A over the 4200 so far without success.Have got the info from Xdevs to peruse.Thanks again.