Fluke 5790A Repair Issue

Started by Hawaii596, 10-01-2012 -- 10:16:03

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Hawaii596

10-01-2012 -- 10:16:03
Any Fluke 5790A repair experts out there.  Channels 1 & 2 both died.  Wideband still works.  No matter what value I put into Ch 1 or 2, it won't read the voltage level.  The frequency reads what ever is input (so it is making it as far as where ever Frequency is read).  But it reads LLLLLL (underrange).  I tried about a full range voltage value for each voltage range on both channels 1 and 2.  And I tried a variety of frequencies from as low as 10 Hz, 100 Hz, 1 KHz, 100 KHz and even 1 MHz.  So it doesn't appear to be frequency dependent.  I ran diagnostics and get a bunch of WARNINGs including WARNING 410 A10 TRANSFER OVERLOAD CHECK, and a series of WARNING 408 A10 TRANSFER xxV RANGE (where xx is every range).  I got a WARNING 411 SENSOR INPUT/OUTPUT MATCH, a WARNING 419 A10 TRANSFER LOOP SETTING, and when I tried to do a zero cal, it wouldn't pass.  I even tried doing a DC calibration and it stopped with errors at C1 and C2 sensors.  So I am thinking maybea thermal converter is blown or something like that.

With all of the errors being at A10 Transfer assembly, I am tempted to buy an A10 board, but don't want to spend that unless I get good definitive symptoms.

Thanks anyone for any expert advice you may have.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

measure

#1
10-02-2012 -- 12:30:34
I can't swear to it, but it is highly likely that the thermal converter is blown. Inputs 1 and 2 share everything but the input terminals and interconnecting wire and relay; Wideband has its own dedicated thermal element. The fact that you're getting overload errors and won't pass zero cal suggests that as well. Have you checked the input (LF) selection relay? Are you able to perform the "Xfer Offset Adjustment"? If not the latter, the likelihood of being blown is almost a certainty. However, don't pay the $$$ based solely on my input - I don't want anyone to be ticked off at me.

Hawaii596

#2
10-09-2012 -- 18:42:49
For reasons I can't comment on, I went ahead and bought the A10 board, which I think includes the TVC's (if that's technically what's used there).  I'm hoping it will arrive maybe as early as tomorrow.  I'll pass along what happens.  I won't pass any blame if it isn't right.  I had already troubleshot and based on my own hypothesis, believe it was the TVC's.  It was good having a second opinion that just gave me a little further confidence of the verdict.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

Bryan

#3
10-10-2012 -- 11:52:03
I maintain 2 of them and both have similar issue in the history files pointing to A10.  We sent them to Fluke for repair but they are or at least were weak on providing a service reports so I didn't get specifics on either.  Good luck with it.

Hawaii596

#4
11-02-2012 -- 10:05:51
Update on Fluke 5790A A10 issue.  I just received the A10 board, installed it, and it did fix the problem.  I'm going to button it up and let it cook for a couple of weeks before sending it out for new cal.  Since it is not "street legal" any way, I'm thinking of "calibrating it myself (not legal - just for a qual check) on my Fluke 792A.  I have an in process standards lab project that I hope to make street legal in the next 12 to 18 months.  I have a Fluke 792A that is not yet re-cal'd, but had data for 10 - 15 years or so up to 2008 or so.  I may do a little lfit curve for predicted values, use them to "calibrate" the 5790A (since there is a new set of TVC's in it, previous cal is completely invalidated).  Any way, do a test cal on the 5790A, then send it in to Fluke Primary lab for proper cal and see how close it is.

Anyone know other places better for sending a 5790A for primary lab cal?  I plan to use two year specs due to the cost and small difference between 1 year and 2 year tolerance limits.

Can't wait till I can get my 792A on line and cal it myself. 

But... best news is the 5790A is fixed.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

Bill the Cat

#5
11-05-2012 -- 19:48:37
I worked at the Fluke Service Center in Everett, WA.  They provide Service Detail reports upon request.  Notify them you want one when you get your RMA.  If they forget to provide it just call them and they will still send it out.  Also, their standards lab is in Everett, WA.  I can't imagine you're going to get a better calibration on the 5790A or the 792A anywhere else.  It is their equipment and you will get all critical Product Changes installed at no additional expense.  Granted, they are not cheap, but if you're looking for a cheap calibration on a 5790A or a 792A you're probably in the wrong business. 

Hawaii596

#6
01-02-2013 -- 15:53:12
My 5790A that I repaired is out there now.  It was indeed the A10 board, and hopefully they are aligning sowftware coefficients to make it nice and accurate.  It is a really good instrument.  I think we'd had it maybe 10+ years when it died (might have been technician error - we'll probably never find out).
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

markove

#7
01-24-2013 -- 08:33:13 Last Edit: 01-24-2013 -- 08:40:58 by markove
Quote from: Hawaii596 link=topic=2547.msg19083#msg19083 date=
Hi mr hawall 560 plzz i have same problem  warning 413 so i will change A10 or  what and what is TVC technique thanks

Hawaii596

#8
02-08-2013 -- 08:10:37
I don't want to make recommendations about that repair as I am not an expert on this one.  I am by training, an electronic technician (US Navy) prior to branching into PMEL.  I would say that if you are just getting zero readings on inputs 1 and 2, the main sensing elements (TVC's = Thermal Voltage Converters) may well be blown out.  But this is an expensive board, so without looking at your system, I want to be careful not to tell you for certain what the problem.  That board cost $2500.  Company paid for it.  Then we had to send it out for re-certification, which was still about another $8000. 
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

jwilley127

#9
08-02-2013 -- 11:47:27
Still need repair support on this unit?  I know a private company offering great support.  Drop me a note to find out more....
JW Solutions
Resistance, Temperature & Pressure Standards
Test Equipment & Accessories
Calibration & Repair Referrals
407.340.7323
jwilley127@gmail.com

Hawaii596

#10
08-05-2013 -- 07:58:25
We did manage to fix the 5790A.  It sits right in front of me as we speak. 
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

USMCPMEL

#11
08-05-2013 -- 09:35:06
Quote from: Hawaii596 on 08-05-2013 -- 07:58:25
We did manage to fix the 5790A.  It sits right in front of me as we speak.
I did not know we were speaking...what are we talking about

Hawaii596

#12
08-05-2013 -- 09:54:15
I have my 5790A trained to talk.  With option 03, by the way.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

USMCPMEL

#13
08-05-2013 -- 18:08:49
I wonder sometime if there is a prerequisite to be a calibration technician?? Is there a section of the ASVAB that addresses level of smartalleckness and based on that level they decide if you would make a good calibration tech???

Hawaii596

#14
08-06-2013 -- 07:38:34
99% AFQT.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883
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