Author Topic: HP 3458A ; A/D board spare part availibilty and cost  (Read 1390 times)

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Offline voltampere

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HP 3458A ; A/D board spare part availibilty and cost
« on: February 16, 2020, 10:38:51 pm »
Dear voltnuts,

i aquired a HP3458A fromm ebay in decent optical condition.
According to the date codes on the ic's it should be from 1989.
The A9 reference seems to be stable but i suspect the A3 PCB ( A/D board ) to be drifting seriously.
The drift is very random and unpredictable.
Sometimes it will not drift for about 12 hours. Sometimes it is running away 3 to 5 ppm in 12 hours.
It will always come back within 0,2 ppm after an ACAL DC.

I got in contact with Keysight Germany to get an idea how much a replacement A3 board would be.
First problem was finding the right part number. The part that is inside my unit seems to be the first edition.
The part number is 03458-66503. In the keysight part database you will get 03458-66513 as the replacement part number for it because the 66503 is obsolete now. But findapart@keysight.com emailed me that this part is"NFTS" meaning not for trade sale and that i should contact tech support at keysight germany for a repair of the HP3458.
I asked KS germany to quote for the 03458-66513 and the first reply was that they only have a few of these boards and they will not sell the spare parts but i can send the unit and they will replace the board. Material + labour = 2.000 € ( + VAT ).
I talked to some KS support guys on the phone and asked which part they would use to repair a new HP3458A ( RoHS version ).
They were unsure if that part would be compatible and said to contact me when they found out.
I read a post here where somebody confirmed that the new version of the A3 board ( part 03458-66523 ) would definitely work in older units ( fully backward compatible). So asked them if they would sell the 66523 spare to me.
Got an email two days later where they told me that they usually dont sell the new version either but would make an exemption and quoted 2.000€ ( + VAT ) for the board only!!!

That is just a bit too much i think.
Now my questions.

Does anybody have any experience about getting an A3 spare board ( tested, no second hand ).
Should i try to get it from another support center , UK for example?
Are the old version ( 66513 ) boards really that rare already?

I dont think i want to spend that much many for the spare board.
How are the chances to get my drifty boar cured?
I had the ( crazy ? ) idea to put the board in the oven at 60 degrees celsius for some hours to get the humidity out that might be the cause of the drift.
Would it cause more harm than help?

Hoping to get some ideas from the HP3458 repair experts...
( TIN ?!!! hello...  :D )

Thanks to all for any input on this

Best regards

joerg
 

Offline TheSteve

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #1 on: February 16, 2020, 11:11:58 pm »
Your only choice is to buy a refurb board from Keysight as far as I know. They tend to have unknown drift/noise, some are certainly better then others.
If you can't find anything else and do really need one I have a refurb that has been tested for noise and drift I can sell.
VE7FM
 
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Offline Edwin G. Pettis

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #2 on: February 16, 2020, 11:58:28 pm »
Voltampere, your drift problem sounds suspiciously like a bad solder joint or cracked PCB trace, you might take a very close up look at your board and see if you can spot anything before popping for a replacement board.
 

Offline TiN

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #3 on: February 17, 2020, 05:12:26 am »
Graphs. This thread is pointless without graphs. I'd also wouldn't have any conclusion about ADC stability untill you ran the unit for a month, non-stop, to rule out storage/settling issues.

There are also more than two A3 versions, but even cheaper refub one would set you back $900+ USD if you are in US. Since you are in Germany, add extra and transform currency to EUR. So 1500 EUR+ is what I would expect as reasonable. :)
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Offline voltampere

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #4 on: February 17, 2020, 08:16:40 am »
I did a quick inspection of the board. But will have a closer look again.

TiN ar you saying that i could still get a -66503 verision refurbished/tested from keysight?
Where ? At what price?

I did let the unit run for about 10 days and if i remember it right the situation got worse.
I want to do a longer run with logging. But before i do that i want to be sure that power supply incl. all relevant components are in good health. Dont want that ugly smoke coming out when i am not around...

I think that my board is the oldest version. Pictures attached.

Regards

Joerg
 

Online MiDi

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #5 on: February 17, 2020, 10:00:35 am »
Not long time ago the refurbished A3 were orderable from service Homepage at keysight.
I do not have the link on hand, but I think it was posted in the 3458 black thread.
 

Offline Dr. Frank

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #6 on: February 17, 2020, 11:22:54 am »
The refurbished A3 boards probably were also not offered any more, as far as we have found out.
The new designed RoHS compliant A3 board is in series production already since Spring last year, and therefore this is the only version left for spare parts.
And yes, all new boards are fully backward compatible.

Frank
 

Offline TheSteve

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #7 on: February 18, 2020, 10:50:53 pm »
Keysight stopped selling the refurb A3 boards a while back. They then sold them again after a few phone calls but it seems that it was short lived and there is no longer anyway to buy a bare A3 board. They offer only a service option.
VE7FM
 

Offline ScoobyDoo

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #8 on: February 22, 2020, 08:44:14 am »
Hello - I have been following the price evolution of the A3 board over last couple of years:

03458-69503                     755€                     (One board – through hole components)
03458-66513                     1258€                   (multiple stacked boards)
03458-66523                     2046€                   (SMD version - latest "release")

Yes - the public sale of these A3 boards is set on hold for an undisclosed reason.
Also the 03458-66529 VREF board with 2ppm HFL spec was withdrawn despite market demand.

Also new A9 DC Reference boards are listed:

03458-66539   PC Assembly-DC Ref Tested 8ppm              469€ (orderable)
03458-66549   PC Assembly-DC Ref Tested 4ppm              469€ (orderable)

We spotted same price info for both 4ppm and 8ppm board on KS site.
These superseed the 03458-66509 and 03458-66519 DC Ref boards

Herzliche Grüße/Meilleures salutations/Best regards
ScoobyDoo
« Last Edit: February 23, 2020, 07:57:15 am by ScoobyDoo »
 
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Offline notfaded1

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #9 on: February 24, 2020, 04:48:37 am »
I just looked it up on USA Keysight found same basically.  Not in stock and the price is the same? :-//  which would you choose lol
« Last Edit: February 24, 2020, 04:58:04 am by notfaded1 »
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Offline rastro

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #10 on: February 24, 2020, 02:48:24 pm »
Sounds like KS is may be using the supply of new boards for their 3458A Black rollout and keeping the stock of older boards/refurbish to support units that are sent back for repair.
 

Online Kleinstein

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #11 on: February 24, 2020, 05:26:23 pm »
I just looked it up on USA Keysight found same basically.  Not in stock and the price is the same? :-//  which would you choose lol

There may be a small down side to the 4 ppm reference. I have not checked the specs, but chances are the high stability reference runs at a slightly (e.g. some 10-20 K) lower temperature and this would also mean that the maximum environmental temperature is lower. Not a problem for use in an air conditioned lab, but it could be in a hot environment in a populated rack with additional heat sources. So chances are the 4 ppm/a version would be better for most, but not for all.
If the main difference is a slightly different resistor value, there is no need for a different price.

I can somewhat understand they don't want to sell the new A3 board. As a service only option they can do a few more checks to make sure the new board really works OK in older units. Even if designed as a 100% replacement a few more checks may be needed until they have enough experience.  Even with ACAL one may still want a new calibration after such a repair - so the meter would have to be send out anyway.  For large customers who can do the calibration in house Keysight may make an exception  :), though they may still out a meter for repair.
 

Offline e61_phil

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #12 on: February 24, 2020, 08:07:53 pm »
I have a 4ppm reference in my 3458A and it has the same 15k resistor.
 

Offline TiN

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #13 on: February 25, 2020, 01:53:53 am »
All A9 variants use same 1k/15k oven setpoint resistors, there is no BOM difference, only selection process.
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Offline notfaded1

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Re: HP 3458A ; A/D board spare part availibilty and cost
« Reply #14 on: February 25, 2020, 03:35:52 am »
I would for sure order the 4 ppm model if the prices are correct.  My lab is almost constant 74°F in the winter and 76°F in summer.  I live in desert of the southwest USA in Arizona with always low humidity.  On another note to partner with my 3458 I bought this today.  I'm still building some my own references because it fun to build things and a hobby for me.  I found out the seller ran a lab and was selling all his gear because of a death in the family.  I asked the seller to include any history he has on the 732A as well and he's shipping it in a foam blown thick walled box.  Unfortunately it hasn't been powered the whole time... I couldn't get that lucky... not for what I paid.

BTW... you forsaw this TiN.  I've got some nice resistance decades but... how can I not want a certain certain 10K.

Bill
« Last Edit: February 25, 2020, 03:55:41 am by notfaded1 »
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