Author Topic: agilent 54845A project ( parts needed see last page )  (Read 4546 times)

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Offline charlyd

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agilent 54845A project ( parts needed see last page )
« on: April 29, 2019, 11:34:02 am »
Today my 54845A arrived. and after doing a quick inspection it was time to power on de dude.

first i saw a failing bios time.  01-01-1999 so i checked the cr2025 and it had to be replaced.  after replacing came the big question what are the actual optimal bios settings for the scope? some are in the manual. If the second IDE doesn t detect any drive, it is time to default the bios settings!!

i booted the unit and i got the error. "Fine Interpolator handshake failed: Service is required".

i did the self-test and many failed but also a lot passed. so from my opinion when the A13 has got the handshake ok we are back on track..
[editted] : later i found out that this input flat cable has nothing to do with the actual problem.

did somebody have this error yet?

and i still have issues after replacing the CR2025 in with the bios date...it is resetted to 1999 everytime. i have to look in the manual maybe the formal owner
played arround with the swithces and jumpers like he did with the wiring...

1 wire on the A13 was stuck behind the power supply and not connected. after gettting it  in place it was too easy to hope the unit would work.. because it doesnt.

but looking at some youtube i discoverd i am missing an important flatcable W13 is totally gone. |O.  see picture
 
Who can help me out??  with selling some parts? please PM me
i am missing 5 screw in the AQ board / the flat cable / 2 screws from other board
« Last Edit: December 31, 2019, 05:29:46 pm by charlyd »
 

Offline charlyd

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Re: agilent 54845A project
« Reply #1 on: April 29, 2019, 01:40:45 pm »
and of course i still have the bios date time reset after power off -> on    CR2025 being replaced
« Last Edit: April 29, 2019, 01:42:46 pm by charlyd »
 

Offline alpher

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Re: agilent 54845A project
« Reply #2 on: April 29, 2019, 04:01:15 pm »
I can try to unplug the cable on mine, to see if I can reproduce the error.
Will try tonight, in  the meantime can you see what's the software version yours running?
 

Offline charlyd

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Re: agilent 54845A project
« Reply #3 on: April 29, 2019, 07:25:17 pm »
Thanks alpher, my software is 4.50 the latest version my unit was refurbished by keysight in 2014 … it is equipt with the VA-503A

how can i get the lower input panel ( with the 4 ch inputs and 1 aux )  out. do i need to take the front off or is there a trick? i need to come get to the flat cable connector hidden behind the input panel.
« Last Edit: April 29, 2019, 07:31:03 pm by charlyd »
 

Offline alpher

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Re: agilent 54845A project
« Reply #4 on: April 29, 2019, 09:51:43 pm »
The panel is being held to the frame with 2 spring loaded clips, you have to push it from behind with something slim like thin long srewdriver for example.
Here's a picture of panel removed, the clips fit in the two vertical slots, the horizontal openning is where you should be pushing from behind.
It takes 5 seconds, really easy.



 

Offline alpher

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Re: agilent 54845A project
« Reply #5 on: April 29, 2019, 11:36:26 pm »
Just checked the operation with the ribbon cable disconnected, as I thought no difference whatsoever, no error.
 

Offline charlyd

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Re: agilent 54845A project
« Reply #6 on: April 30, 2019, 08:26:22 pm »
ahhh...so that mean i have problem with my board or pci card is that what it means?  maybe you can try to pull so connectors and bot up to see when i am getting this error..

btw my unit is VIN033. but i think that doesn t make sense with the error....

but still i need the 30 pin flatcable.. PM wanted..  ;)

 

Offline charlyd

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Re: agilent 54845A project
« Reply #7 on: April 30, 2019, 08:29:48 pm »
Hi alpher i also saw some power measure points  in the right down corner [+8.5] & [-5.0] & [+5.0] ..are different in my unit from the picture from a guy project found on the web.

how are yours alpher?  and my channel 3,4 AD hybrids get quickly hot and channel 1,2 normal warm... ( last calibration ch 1,2 were passed)
« Last Edit: April 30, 2019, 08:34:24 pm by charlyd »
 

Offline charlyd

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Re: agilent 54845A project
« Reply #8 on: April 30, 2019, 09:35:46 pm »
btw these are my errors.
 

Offline alpher

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Re: agilent 54845A project
« Reply #9 on: May 01, 2019, 12:32:28 am »
Here are a couple of pic of the acquisition board in my scope, hybrids stay just warm not hot at all.





 
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Offline charlyd

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Re: agilent 54845A project
« Reply #10 on: May 01, 2019, 06:29:33 pm »
hi Alpher can you please check if you have the same values on those check points? 
This is a screen shot from matthews project (the web) with HIS voltages but are these the real values because my checkpoints are different and some voltages are not in place.   ( pitty no schematic ) so i need other references..


what is the total stretched length from the flat cable.  so i can find it on ebay.. if nobody PM me.
« Last Edit: May 01, 2019, 06:35:16 pm by charlyd »
 

Offline charlyd

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Re: agilent 54845A project
« Reply #11 on: May 01, 2019, 08:39:56 pm »
tonight i did some checks and in blue are my values  see the difference with the above picture.

and i have still te message defaults loaded - my cmos is defaulted everytime, even with the CR replaced..

nearly everytime i get a NO screen when powering ………. the second time the picture shows up.  ( many this is oin combination with the so called "default cmos error".
 

Offline alpher

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Re: agilent 54845A project
« Reply #12 on: May 02, 2019, 02:26:28 pm »
Unfortunately I cannot power it up right now, I'm in the process of changing the motherboard.
The i810 mobo that I bought of ebay finaly arrived and the scope is in pieces.
Will have some time this weekend to put it together.
Your problems seem to be motherboard related, can you try a different mobo?
If I was desperate I may have tried a mini ATX mobo there, I think that the scope software will run on pretty much anything from the period ( socket 7 to 370 ).
 

Offline charlyd

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Re: agilent 54845A project
« Reply #13 on: May 02, 2019, 08:29:04 pm »
hi alpher, following you close ;-)  new motherboard… upgrade the W98 board ?   i started again. last night i took of out the motherboard and i fixed the problem from the bios. so the motherboard is. ok. the problem was in cr2025 spring.  i took the battery out and the bottom spring was bend so the the battery was not doing its work .. so. Problem 1 fixed.

the second more difficult one the AQ board. i miss the 8.5 volt. as i told before  i took the board out and checkt 6.3 volt next to the attentuator, in my case it is -12volt so.

the side board also has a eprom and more on the board  4 of the iron coolpads measure the same value and the top 4 coolpad also the same value.  3v and 12v.

@alpher what is the length of the flat cable. and the pitch of the pins.   is is 30 pins if i counted well.
 

Offline alpher

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Re: agilent 54845A project
« Reply #14 on: May 03, 2019, 02:19:53 am »
I don't know why that ribbon cable is so important to you, it only matters when you want to use special Agilent/HP probes that cost an arm a leg and then some. :-//
Nonetheless here it is, a simple 30 conductor flat ribbon cable , 1mm pitch, measured length ~32cm and there's plenty of room for longer cable.



 

Offline charlyd

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Re: agilent 54845A project
« Reply #15 on: May 03, 2019, 04:39:22 pm »
hi alpher thanks i understand it is not in the circuit but my feeling says that this one is difficult to get ( long time) in the end it is good to have one.. so that why i try to get it..as soon as possible.

thanks very much… is your unit online again?  if yes what about your voltages on in red in the picture..  and with the W11 disconnected?

yes i meaned W11  (small flate cable) is important W13 is only going to the end of the input circuitairy..W11 is in between the boards.
« Last Edit: May 03, 2019, 05:52:07 pm by charlyd »
 

Offline charlyd

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Re: agilent 54845A project
« Reply #16 on: May 04, 2019, 05:41:53 pm »
I am also curious if there is anybody who booted up the unit with all ADC hybrid out?  or with just only with channel 1 Hybrid in..

this way i can test the hybrid one by one. and know what error i can expect when hybrid are out or broken.  i mean to say is my error maybe related to 1 broken hybrid which distort my whole unit.

i hope someone can tell me more about the repsons with and without...
« Last Edit: May 04, 2019, 05:46:24 pm by charlyd »
 

Offline alpher

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Re: agilent 54845A project
« Reply #17 on: May 05, 2019, 01:54:08 am »
I don't know if you know of a big thread going on here on the same subject.
https://www.eevblog.com/forum/testgear/agilent-54835a-scope-(4-channel-1ghz-4gss)-repair-uphack/

Check it out if you didn't already.
 

Offline charlyd

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Re: agilent 54845A project
« Reply #18 on: May 05, 2019, 02:21:44 pm »
@Alpher yes i saw it and it is really worth readding it, great topic..!!

This afternoon i did a deeper dive.. to check the voltage "mathew project" is talking about but from what i saw in my unit they are different with his, i mean to say when looking in my pictures you see the measurment i did and like the 6.3 out [U39]and the -5 is not on the coolpad but on het output..  so do matthew pictures really match in real????

again i took the hybrid out so i could take a closer look at CH 3 and from what i saw under the microscoop CH 3 is really BAD(lost). so the next step is the get a new one of ebay..

but of course first i want to find out it the unit is 100% before i buy one.  to check this i have to know a few things:

can i bypass my " fine interpolator handshake error" by taking out hybrid(s) and try to get just 1 or 2 channels going. or maybe other tricks?

It is really difficult to work on the board, so i took both attentuators out and i check if my voltages are present when both attentuators are out or does the unit go in a protect mode.  :=\

At this point i am curious at what the real voltages are in the unit when both attenuators are out.  (easy measering).

and what would happen if hybrids are completly out, so if someone is intent to clean his hybrid for better trigger results please try powering on without  1,2,3 or all hybrids/attentuators out.. and see what error is cumming up.

« Last Edit: May 05, 2019, 02:34:54 pm by charlyd »
 

Offline TRN

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Re: agilent 54845A project
« Reply #19 on: May 09, 2019, 10:12:06 am »
You can measure voltages with the attentuators removed.

See attached PDF
 

Offline charlyd

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Re: agilent 54845A project
« Reply #20 on: May 09, 2019, 08:53:03 pm »
Hi thanks for you reply  they are all ok on both attentuators. when i boot i hear them clicking (i think) like they should…

my problem lies more arround the hybrid. what power supplies do i miss over there.. on the bottom side between each metal bracket is a yellow Tantalum cap  i measure -5Volt over the tants.

for the rest i can find any voltages arround those brackets on the bottom side.

what voltages would be going ( and should be found ) to the hybrid brackets?
 

Offline charlyd

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Re: agilent 54845A project
« Reply #21 on: May 09, 2019, 08:59:57 pm »
Here is an other thing which caught my eye and finger  >:D
what i found are 2 black big SMD resistors in the corner where the fan connectors are located on the bottom side of the board.  Both these resistors coded " 201" are HOT HOT. is this normal ??

 

Offline TRN

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Re: agilent 54845A project
« Reply #22 on: May 10, 2019, 11:27:25 am »
Regarding the selftest errors; enable the "service extension option" and then run the individual selftests for the items which failed. (i.e. for:)

Test Time Tag
Test Interpolator Tag
Test Timebase

Maybe this will narrow down the problem.


 
 

Offline charlyd

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Re: agilent 54845A project
« Reply #23 on: May 10, 2019, 08:44:44 pm »
ok here is my logging the scope file pasted and series attached.

my feeling says i am missing some voltages/power line(s) but where??

**Test Run** : Scope Self Tests Test  --- 10 MAY 2019 22:17:45
Self Test invoked cal executed.
 Test FAILED on channel 1
Acquisition Error: Acq not completed in alloted time
 Test FAILED on channel 2
Acquisition Error: Acq not completed in alloted time
 Test FAILED on channel 3
Acquisition Error: Acq not completed in alloted time
 Test FAILED on channel 4
Acquisition Error: Acq not completed in alloted time
 Test FAILED on channel 1
Acquisition Error: Acq not completed in alloted time
 Test FAILED on channel 2
Acquisition Error: Acq not completed in alloted time
 Test FAILED on channel 3
Acquisition Error: Acq not completed in alloted time
 Test FAILED on channel 4
Acquisition Error: Acq not completed in alloted time
 Test FAILED on channel 1
Acquisition Error:
 Test FAILED on channel 3
Acquisition Error:
 Test FAILED on channel 1
Acquisition Error:
 Test FAILED on channel 3
Acquisition Error:
Test A to D Converter FAILED.
Self Test invoked cal executed.
FISO test failed on channel 1
FISO data bit error not correctable.
FISO test failed on channel 2
FISO data bit error not correctable.
FISO test failed on channel 3
FISO data bit error not correctable.
FISO test failed on channel 4
FISO data bit error not correctable.
Test FISO FAILED.
Self Test invoked cal executed.
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Hi Imped. Mode Offset Dac FAILED on channel 1
Acquisition Error:
Check A to D converter selftest.
Hi Imped. Mode Offset Dac FAILED on channel 2
Acquisition Error:
Check A to D converter selftest.
Hi Imped. Mode Offset Dac FAILED on channel 3
Acquisition Error:
Check A to D converter selftest.
Hi Imped. Mode Offset Dac FAILED on channel 4
Acquisition Error:
Check A to D converter selftest.
Self Test invoked cal executed.
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Lo Imped. Mode Offset Dac FAILED on channel 1
Acquisition Error:
Check A to D converter selftest.
Lo Imped. Mode Offset Dac FAILED on channel 2
Acquisition Error:
Check A to D converter selftest.
Lo Imped. Mode Offset Dac FAILED on channel 3
Acquisition Error:
Check A to D converter selftest.
Lo Imped. Mode Offset Dac FAILED on channel 4
Acquisition Error:
Check A to D converter selftest.
Test Offset Dac FAILED.
Self Test invoked cal executed.
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
Acquisition Error: Acq not completed in alloted time
 Test FAILED on channel 1
Acquisition Error:
Check A to D converter selftest.
 Test FAILED on channel 2
Acquisition Error:
Check A to D converter selftest.
 Test FAILED on channel 3
Acquisition Error:
Check A to D converter selftest.
 Test FAILED on channel 4
Acquisition Error:
Check A to D converter selftest.
Test Gain FAILED.
Test Probe Board PASSED.
30.4deg.C
Test Temperature Sense PASSED.
Test Trigger Level PASSED.
Test Logic Trigger PASSED.
Test Pattern Trigger PASSED.
Test State Trigger PASSED.
Interpolator test failed.
Interpolator test timed out.
Interpolator test failed.
Interpolator test timed out.
Time Tag test failed.
Time Tag Counter does not reset to zero.
Time Tag test failed.
Time Tag Counter fails lower limit. Counter = 6
Expected value = > 19,500,000 < 20,500,000 .
Test Time Tag FAILED.
Interpolator test failed.
Interpolator test timed out.
Interpolator test failed.
Average (long interval cnt - short interval cnt) =  0
Expected value =  > 910 and < 1113
Test Interpolator FAILED.
Arun not clear when post trigger cnt zero and FF Clk mode.
50MHZ Clk mode.
25MHZ Clk mode.
10MHZ Clk mode.
FF Clk mode.
Test Timebase FAILED.
Max. Chan 1 Relay actuations: = ÚÚÚ50001
Max. Chan 2 Relay actuations: = ÚÚÚ45706
Max. Chan 3 Relay actuations: = ÚÚÚ45311
Max. Chan 4 Relay actuations: = ÚÚÚ44354
Test Attenuator Contacts PASSED.
Test Scroll Mode Counter PASSED.
Test Non-Volatile SRAM PASSED.
Test Video Ram PASSED.
Test Video SRam PASSED.
Test Tri-state Register PASSED.
Test Timer PASSED.
Test Video Control Register PASSED.
Test Acquisition Status/Control Register PASSED.
Test Scope Self Tests FAILED.
« Last Edit: May 12, 2019, 07:47:43 am by charlyd »
 

Offline TRN

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Re: agilent 54845A project
« Reply #24 on: May 11, 2019, 10:49:40 am »
That is weird,
None of the ADC tests passed, and it is very unlikely that all 4 ADC's are bad, so it looks indeed that one of the voltage rails supplying power to the ADC's failed.

Today I don't have time, but tomorrow I will remove a hybrid from my scope and measure the DC voltages from the contact pins.
 


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