8845A, DMM4040 & 8846A, DMM4050 ERROR Codes / Quick fix / troubleshooting FAQ

[Kiriakos GR]

Introduction :
6 1/2 precision multimeter (8845A, DMM4040 & 8846A, DMM4050) they are popular in to industrial environment (R&D labs, and service labs) but mostly in China, because it large number of established factories.
Now when such a multimeter demonstrates issues, then Fluke or TEK support team they will try to deliver a solution.
This translates that there is no information shared in public.


Few weeks ago I was performing in-depth inquiry about what can go wrong at used 8846A, DMM4050?  I was had to dive in to Chinese forums, translate over 100 pages of conversations in Chinese,  so to gather these tips which I am sharing here with ITTSB Blog visitors.
Feel free sharing your knowledge with our readers if you do have a useful tip to contribute. 

List of possible problems:


Problem  No 1 
The multimeter it is turned OFF due soft-power-off  switch and occasionally this gets powered-on all by it self ?

Answer: If Mains power failure did not occur in your building then power-on switch at the back of the instrument this is damaged and it must be replaced.
Power switch internal contacts are bad and sparking.




Problem  No 2 
All measurements at any range or function this seems having tremendous amount of noise ?

Answer: Mains power-on switch at the back of the instrument this is damaged and it must be replaced.
Power switch internal contacts are bad and sparking.  Also try another mains power cable and or request from an electrician to inspect  Mains wall plug and cables.




Problem  No 3 
When I am having issues with my measurements, by pressing a few times (Front or Back terminal inputs) buttons, the problem finds a temporarily solution, is there a permanent fix ?

Answer:  
Internal mechanism of the selector switch  for Front or Back terminal inputs this is equivalent to range switch of handheld multimeter. 
In order to troubleshoot, you must explore several possibilities.

a) Damage occurred because the user was using  selector switch  for Front or Back terminal inputs as this to was On-Off load switch at high current measurements.

b) The user dismantled the multimeter PCB and S2 (8845A-2013,SWITCH-BODY ) causing damage at contact pins.

c)  The user dismantled the multimeter PCB and S2 and caused damage at Switch-Body plastic housing.

e) The user exceeded service life of  S2 switch system, and PCB this is now permanently damaged.
 
The Fluke calibration manual this includes a few pages regarding available spare parts for 8846A, DMM4050, there you will find all relative part codes and its part description.

Gently used 8845A, DMM4040 & 8846A, DMM4050 will not demonstrate problems at S2 switch system,  but if you got a used one and this was previously in to a school lab ? Then by 90% this multimeter it was abused and cannibalized by thousands of careless users.

In the end of the day, its one multimeter it will last in time according the quantity of love which this received by it first owner.
The owner of second hand goods,  he will only identify the problems if any, and live with them or pay additional fee for repair and parts replacement.




 
Problem  No 4
DMM4040, DMM4050 ,  Dot matrix display brightness seems low even at highest brightness setting ?

Answer:  
It looks that TEK at year 2013 this selected Dot matrix display LENS filter this having wrong specifications and poor performance,  this explains of why Fluke 8846A stock pictures demonstrate vivid green digits and TEK branded ones they looking as dark blue.
In reality both multimeter they have identical bright dot matrix display this be vivid green.
By removing this face-plate LENS from a TEK DMM you will enjoy 70% brightness increase and digits are extremely bright even at lower brightness setting.
This is a problem which I am currently dealing with too, I did contact TEK so to find out if there is a Newer Revision (redesigned product) ?
If there is no any then I will contact Fluke so to purchase an 8846A LENS, because this has reasonable performance (due product design).



.

[Kiriakos GR]

I also came across this:  ( RS-232 Framing / Parity / Overrun Error  +511 ) when I did my first connection by using NI LabVIEW SignalExpress Tektronix Edition.

Instead of cable I am using industrial grade Bluetooth RS232  serial adapters ( LM048 )
My google search pointed out TEK forum, the fix this is changing the flow control to "Software" or "Hardware"

[Kiriakos GR]

Today I did a new discovery and this is relative to DMM4050 Driver support file for Labview.

This software driver (unfinished software) containing bugs since 12/2010 which was lastly updated.
Baud rate setting of 19200 this never worked for any one.

My testing of other baud rate settings this is now solid evidence that both DMM4040 & 4050 both are Baud Rate dependable regarding remote logging speed.
By using an RS232 cable I did perform this tests explained bellow.

I did set a number 60 iterations’ as mark and I did timing measurements at several Baud rates.

Integration time 0,02 / fixed range 10V DC /  4 ½ manual resolution / autozero off .

At 1200  --- 1m 17s
At 2400 --- 46s
At 4800 --- 28s
At 9600 --- 19s 
At 19200 --- FAIL

In conclusion,  Tektronix TekDMM4040.msi  (Support Driver) for Labview this still is containing several unfixed bugs including a very few Baud Rate choices (option) and 19200 which this is not working (never did).

I did notify TEK and you may also follow this conversation at TEK support forum
 

[overvolt]

I think as good idea establishing a link between this topic with the other relative one.
https://www.ittsb.eu/forum/index.php?topic=1482.0