Author Topic: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement  (Read 808 times)

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Offline dgo_42

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LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« on: December 26, 2019, 06:02:20 pm »
Hello all,

I've found what is wrong with my input module! I guess I've correct found the type (SOT143 code C8B). It is quad diode bridge, HSMS-2828 (Broadcom/Avago/HP).
With this part same signal on two channels looks like this:
896918-0

After I short this bridge:
896910-1

I get normal signal for both channels:
896914-2

HSMS-2828 is obsolete and do not exist anymore by digikey or mouser...
Question, can somebody suggest some replacement for HSMS-2828?

Best regards,
Dimitrij
 
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Offline shakalnokturn

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #1 on: December 26, 2019, 08:49:43 pm »
Couldn't find a drop-in equivalent, how about a couple of the right flavour of BAS69?
 

Offline madao

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Offline dgo_42

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #3 on: December 28, 2019, 06:19:54 pm »
BAS69 might be alternative, but there is no bridge and it is also obsolete...

I've already ordered by this ebay seller,.. but it get deliver the parts first in November 2020  :palm:  :rant:

Sad, that such good parts are not more produced...
 

Offline nctnico

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #4 on: December 28, 2019, 06:50:57 pm »
Delivery in November 2020? I'd cancel that order! It is a major PITA that Broadcom has obsoleted all the nice HP/Agilent/Avago semiconductor parts. Lots of people are pulling their hairs over that. But there has to be an alternative supplier by now. I wouldn't replace this diode with a jelly-bean part but very carefully match the specifications. Perhaps Nexperia (formerly Philips / NXP) has a replacement. They make lots of RF parts as well.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline xemax

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #5 on: March 06, 2020, 09:22:47 am »
I bought a WavePro 7100A from India. On 4 frontend the HSMS-2828 was broken. After replacing it all channels are fine.

I ordered the HSMS-2828 here:
https://www.ebay.com/itm/Avago-RF-Schottky-Bridge-Quad-Diode-HSMS-2828-SOT-143-10pcs/402027292164

 

Offline shakalnokturn

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #6 on: March 06, 2020, 07:24:37 pm »
Considering location and other items sold there are fair chances it is a genuine part.
Did you try measuring the diode capacitance before fitting the parts?
 

Offline xemax

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #7 on: March 07, 2020, 08:02:46 pm »
How do i measure it? With a LCR meter i got 1,5nF at 1kHz.
Not genuine?
 

Offline perdrix

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #8 on: March 08, 2020, 03:31:28 am »
Skyworks Solutions SMS3923 range may offer a part that will do the job

David
 

Online Mechatrommer

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #9 on: March 08, 2020, 04:19:03 pm »
is it possible with this HMS-2828 damaged we get this kind of distorted signal? (CH4 green)



from https://www.eevblog.com/forum/repair/gaining-access-to-the-acquisition-board-on-a-lecroy-wavepro-7200/msg2376651/#msg2376651

the AFE is below, from the picture (April 2019), i can see it almost exactly in the location like in OP (nearest to ADC (black heatsink), but the marking is like C81 ???


It's extremely difficult to start life.. one features of nature.. physical laws are mathematical theory of great beauty... You may wonder Why? our knowledge shows that nature is so constructed. We simply have to accept it. One could describe the situation by saying that... (Paul Dirac)
 

Offline shakalnokturn

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #10 on: March 08, 2020, 11:39:33 pm »
How do i measure it? With a LCR meter i got 1,5nF at 1kHz.
Not genuine?

Yes LCR with special attention to zeroing / subtracting leads capacitance.
You did mean 1.5pF didn't you?
That sounds reasonable without paying special attention to the measurement setup.


@ Mechatrommer: That could look like a bad AC/DC coupling relay.
« Last Edit: March 08, 2020, 11:42:26 pm by shakalnokturn »
 
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Offline nctnico

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #11 on: March 08, 2020, 11:55:45 pm »
@ Mechatrommer: That could look like a bad AC/DC coupling relay.
No. The channel is set to AC coupling. Look at the screen!
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online Mechatrommer

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #12 on: March 09, 2020, 12:24:11 am »
@ Mechatrommer: That could look like a bad AC/DC coupling relay.
is it one of the 2 white relays in the picture?
It's extremely difficult to start life.. one features of nature.. physical laws are mathematical theory of great beauty... You may wonder Why? our knowledge shows that nature is so constructed. We simply have to accept it. One could describe the situation by saying that... (Paul Dirac)
 

Offline shakalnokturn

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #13 on: March 09, 2020, 08:18:44 am »
@ Mechatrommer: That could look like a bad AC/DC coupling relay.
No. The channel is set to AC coupling. Look at the screen!

True, I spotted that after... It is quite unlikely an open relay would be showing closed intermittently, at first I thought a reed type may do that but RL1 is on the HF path...

Anyway considering the displayed defect I'd still be looking for a poor contact around a capacitor. How about BWL switching?

 

Offline nctnico

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #14 on: March 09, 2020, 09:25:17 am »
Can you show the same signal with the input set to DC1M first?
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online Mechatrommer

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Re: LeCroy WavePro 7200 input module failure, HSMS-2828 replacement
« Reply #15 on: March 09, 2020, 09:57:14 am »
I cant right now. Its hidden somewhere and my bench is full.. i'll get back to this later. I thought if its confirmed hsms2828 is broken, i might want to make an order now, so when i get to repair it again, i already have the part ready..
It's extremely difficult to start life.. one features of nature.. physical laws are mathematical theory of great beauty... You may wonder Why? our knowledge shows that nature is so constructed. We simply have to accept it. One could describe the situation by saying that... (Paul Dirac)
 


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