Keysight MSOS104A Repair Attempt - Page 1
Forum section: electronics / general

author: Extrasolar
author_rank: Contributor
timestamp: July 17, 2022, 09:30:56 pm
content: I found a MSOS104A 1GHz Oscilloscope from Keysight. It was marked as offline and not working so I thought I could try to repair it and eventually picked it up and set it on my bench.The problem seems to be related to the timebase clock and PLL2 as we can see on the image."Timebase error detected in PLL2", perhaps a missing clock, maybe some buffer decided to take a vacation, or the internal 10MHz Oven Controlled Oscillator is bad...By feeding an external 10MHz Reference and the specified magnitude and changing the trigger type on the horizontal scale, for a brief moment I was able to get a Square Wave on the screen as Ch1 was connected to the Cal terminal on the front panel. So, maybe there is a bad buffer or routing mechanism for the clock (I'm just assuming at this point) that is intermittent...There is absolutely nothing online on the public domain except for a "General Service Guide" which is really reduced to only "Board Swap" kind of repairs.The Acquisition Board looks really intimidating but hopefully the problem might be isolated only to the Timebase section.

author: Extrasolar
author_rank: Contributor
timestamp: July 17, 2022, 09:47:30 pm
content: So, There are 4 Clock related sections, a clock Ref (10MHz) output, Oven Controlled Oscillator , Main VCO and PLL gen and a negative 11.5V Oscillator made of discrete components.I've tested the OCO and by powering it up locally and I was able to see an output at 10MHz which confirms this section to be working (also I checked a few buffers and all working).For the moment will continue to the VCO section.

author: Extrasolar
author_rank: Contributor
timestamp: July 17, 2022, 09:54:59 pm
content: I tried to do the same with the VCO, 5V rail (was pulling 5mA), Applied a Voltage on the Tuner (PIN2) and the SMU went in Current compliance (it was pulling 100mA at 2.1V)To me this is a good indicator that the VCO is bad. I decided to remove it and try to power up in a different environment.

author: KE5FX
author_rank: Super Contributor
timestamp: July 17, 2022, 10:02:12 pm
content: I can't see what the PLL chip part number is, but it's possible that the VCO tuning line simply went straight back to it with the loop filter components in parallel. PFDs with charge pump outputs often don't use series R, and in that case, you might have forward-biased some protection diodes somewhere.

author: Extrasolar
author_rank: Contributor
timestamp: July 17, 2022, 10:09:20 pm
content: I desoldered the lid or the shield of the VCO, but managed to knock out a few components, no problem tho because I got everything back and soldered.My suspicion that the VCO was toasted got confirmed, the part was pulling nothing, and I was not able to get an output from it.Here is also the Diagram of the Crystek CVCO55 602934 1702-02 (seems a custom part number as I was not able to find this part online).I have ordered a few Crystek VCO with output ranging from 500MHz to 2GHz, with the same form factor, lets hope for the best at this point

author: Extrasolar
author_rank: Contributor
timestamp: July 17, 2022, 10:21:00 pm
content: The VCO is driven by a LTC6945 Ultralow Noise and Spurious 0.35GHz to 6GHz Integer-N Synthesizer, Neat !! (I have a few of those parts !!)I was able to RE the schematics of the synthesizer block.Unfortunately I must wait for the VCOs to continue this repair, but in the meantime I will continue to probe around the Timebase Section, just to rule out any other problem it might have ...Any help on finding the datasheet of the VCO will be greatly appreciated !!

author: gamalot
author_rank: Super Contributor
timestamp: July 17, 2022, 11:27:45 pm
content: The component with 'UA' top marking on it looks like a RF BJT 2SC5606, not a NMOS.https://vakits.com/sites/default/files/2SC5606.pdf

author: Extrasolar
author_rank: Contributor
timestamp: July 19, 2022, 01:21:18 am
content: True about the Transistor, thank you Gamalot !!I tried today to fix the VCO and kind of succeeded, well sort of !!The VCO outputs around 840MHz, when powered up correctly and by correctly I mean had to short the capacitor at the base with tweezers !!It works, but has a lot of phase noise, unstable and intermittent operation.

author: picburner
author_rank: Frequent Contributor
timestamp: July 19, 2022, 05:10:27 am
content: What you have indicated as C5 most likely is an inductor or resistor instead.The base/gate of 'UA' could not be polarized otherwise, that's why shorting it with the tweezers the circuit starts to work.

author: wraper
author_rank: Unknown
timestamp: July 19, 2022, 06:05:44 am
content: Quote from: picburner on July 19, 2022, 05:10:27 amIMHO he probably switched some components while resoldering them, thus ended up with capacitor on the base (if it's 2SC5606) as by its looks it's certainly a capacitor.

author: Extrasolar
author_rank: Contributor
timestamp: July 19, 2022, 10:17:47 am
content: Hi wraper,There were 3 parts that were knocked off when I removed the lid.I opened up a similar VCO and saw the Resistor (820 Ohms) forming a divider with a 1.5k resistor. The inductor is a larger package than the capacitor and there was only one pad that could actually accommodates it.I think there might have been a resistor as well in parallel(on top) of the capacitor at the base.Nonetheless, will try to rearrange the inductor to see what happens ...

author: gamalot
author_rank: Super Contributor
timestamp: July 19, 2022, 10:42:10 am
content: Some SMD multilayer inductors look similar to MLCCs.

author: Extrasolar
author_rank: Contributor
timestamp: July 19, 2022, 07:26:07 pm
content: The VCO is now working. I soldered the inductor to the BJTs base. Its operational from 4.635GHz with 0.5V to 4.703GHz with 4.7V at the tuner.

author: emoco
author_rank: Newbie
timestamp: August 26, 2022, 08:08:48 am
content: Hi,I just got the same warning on my scope. Did the VCO solve the problem?

author: HighVoltage
author_rank: Super Contributor
timestamp: August 26, 2022, 08:20:04 am
content: Nice repair!Any idea what the failure mode was for the VCO?

author: Extrasolar
author_rank: Contributor
timestamp: August 26, 2022, 01:45:24 pm
content: Hello,Sadly the VCO did not resolve the problem, but on the bright side, I now have it characterized completelyI've swapped the LTC6945 Synthesizer with a new one and still did not work.I am going to investigate further at the output of the Synthesizer, because somehow I have a feeling that some buffer might have failedIt has to be for sure a HF switch or buffer at some point, because by feeding an external 10MHz signal, I was able to briefly see the Cal Out quadrature appear on the screen.Regards

author: emoco
author_rank: Newbie
timestamp: August 30, 2022, 05:05:28 pm
content: Thank you for the update.

author: emoco
author_rank: Newbie
timestamp: September 06, 2022, 11:55:45 am
content: If it is of any help. After having my DSOS104A disassembled, connectors removed, and assembled again the error ""Timebase error detected in PLL2" did not appear. But the message comes back occasionally when the scope is started.

author: Extrasolar
author_rank: Contributor
timestamp: September 06, 2022, 06:05:46 pm
content: Intermittent problems, hmmm this is a bit problematic, it is a strong indicator that probably a power rail on the PLL2 is in fact intermittent !!I will check a few signals on the Timebase as I can see the PLL2_Lock LED indicator does not turn on. Again I suspect that some signal is not present.There is a Fully Differential amplifier that is polarized only by a negative 3.3 rail (very strange) that "Buffers/Amplifies" the Synthesizers output (4.64GHz to 6GHz). I have prepared a HF probe to check for the input - output and will post updates soon.

author: BeamDump
author_rank: Contributor
timestamp: November 08, 2022, 03:57:37 pm
content: Lots of interesting discoveries here. Thank you for putting in the effort.In the processes of repairing one my self. Same error.From power ON only the PLL1_lock LED is on but once the software starts PLL2 comes on too.Measured RF output from the VCO, during OS boot it sits at 4,950GHz, once the soft starts loading and PLL2 LED comes on, frequency jumps to 4,978.900 and oscillates between that and 4,979.800. Not sure how there can be a lock in this case.5.12V on VCC, 4.6V on TunerAny idea where it's possible to get a similar VCO? It's Keysight authorized part and Crystek won't sell without their permission. Have some contact in there, see how that goes.

author: Extrasolar
author_rank: Contributor
timestamp: November 08, 2022, 04:31:26 pm
content: Hi there !!I've made some progress on this and reverse engineered the entire signal chain from the OXO to the output of the Synthesizer.I will be probing around now as I strongly suspect that either the fully Differential Amplifier next to the Synthesizer or the OXO output buffer (ref input of the synthesizer)is bad.In the case of the first problem, I am putting up together a simple passive RF probe and will be using a Spectrum Analyzer to "see" the signal.The OXO buffer is easy enough to be probed with a normal scope. One thing that is absolutely needed is a cooling fan on the ADC, otherwise it will get toasted.Will post the results this week !!Regards

author: BeamDump
author_rank: Contributor
timestamp: November 14, 2022, 11:46:10 am
content: I would say don't run the acquisition board without the fans hitting it's full surface, apart from the ADC every other heat sink and memory get's roasty toasty fairly quickly.In my case it's definitely the VCO, output is sporadic. Measured in the acquisition board and out. Too bad i don't have a signal or spectrum analyzer that can go over 4 GHz but my 20GHz CSA8000 does the trick to "see" the signal. Interestingly that with such a mess the board still lights up the PLL2_Lock LED.Ordered a few Crystek VCO's in this range and some LTC6945's for experimentation. Otherwise conversation with Keysight's Finish department has reached a dead end. Part can't be sold and can't be authorized for selling by the Crystek. Instead send the scope in for "repair". Further clarification on "repair" - they don't do any component level repair and acquisition board gets swapped.

author: vtp
author_rank: Regular Contributor
timestamp: November 14, 2022, 01:57:30 pm
content: One of the Infiniium S Series scopes in office threw that error some months ago.It was repaired under factory warranty and apparently is a known problem to KS.Excerpts from service note:QuoteJust FYI.

author: BeamDump
author_rank: Contributor
timestamp: November 14, 2022, 09:18:27 pm
content: Probably. A colleague with an S-series had a PLL2 error today. Guess it is plagued with this issue. Wonder if it's Keysight or Crystek to blame. If they are well familiar with this, then why indeed sell a ~50EUR part when they can charge 6K for repairs.If I'm to believe what I've been told, this is suppose to be 5GHz VCO.Desoldered the transistor from my VCO:

author: Extrasolar
author_rank: Contributor
timestamp: November 15, 2022, 10:51:46 pm
content: Hi,I can fully characterize the VCO, frequency bandwidth and Voltage control range.The only problem is that my VCO might be faulty as wellLast time I checked it was spot on 4.6... GHz and remained stable with no noticeable phase noise, 0.5V to 4.7V Control. (removed from Acquisition Board).I have attached the Synthesizer RE Schematics below, the circuit if fairly easy to follow... My question is, where is the PLL2 synthesized/generated ??There is another Synthesizer on the board, slightly different part but overall same functionality (which I haven't checked yet...)

author: BeamDump
author_rank: Contributor
timestamp: November 17, 2022, 03:19:42 pm
content: HiWhat do you mean? It's generated in LTC6945, it's what it's suppose to do. Pin3 (status), which in this case has to be programmed through SPI as lock, even goes through resistor to the base of MMBT3904LT1 that goes to PLL2_Lock LED.4.6GHz is low for this VCO, it's suppose to be 5.

author: Extrasolar
author_rank: Contributor
timestamp: November 17, 2022, 09:47:00 pm
content: HiI was able to trace the status Pad of the synthesizer to PLL1, and was unable to find the path for PLL2 !!

author: BeamDump
author_rank: Contributor
timestamp: November 21, 2022, 05:21:47 am
content: HiI also can't find any trace from the 2nd output of the buffer. Then the lock status is communicated through SPI?Another question, when the PLL2 error pops up, are you able to perform any software function? Self test or anything at all.

author: Extrasolar
author_rank: Contributor
timestamp: November 21, 2022, 09:45:38 am
content: HiNo it does not do anything in the sense that after the autocal routine it sprays out the same error and does not do anything. You can try an external Reference 10MHz and change the horizontal trigger.I got it working for an instant by doing that. Another thing is that I could not detect the 10MHz reference at all on the board. Now all my focus is on the signal path from the oven controlled oscillator to the REF input of the Synthesizer.Kind regards

author: BeamDump
author_rank: Contributor
timestamp: November 21, 2022, 10:58:38 am
content: HiReplaced the transistor in my VCO, it is a 2SC5606. Now the output is clean, stable and sits at 5.0GHZ at 4.3V. Plugged it back in to the board, PLL2 is locked and the LED is considerably brighter than it was before but the software error remains.Since i don't see a test point for Y2 buffer out for PLL2 status and probing front and back was unsuccessful i can only assume it's sending the status via SPI. Then why bother routing pin 3 of the synthesizer to the buffer if the output wont be used...Ordered spare LTC6945's and evaluation/communication boards to better understand the synthesizer. Buffers are difficult to find. Ordered some from the one place i could find them in China, see how that goes.I'll try your method.

author: Extrasolar
author_rank: Contributor
timestamp: November 21, 2022, 11:03:59 am
content: Hi,Thats very interesting !! Thank you for the information. Does any trace appear on the screen ??If yes, then I believe you can factory restore the scope at this point, to clear the error message !!

author: BeamDump
author_rank: Contributor
timestamp: December 03, 2022, 12:00:04 am
content: HiHaven't tried yet. I've been waiting for parts to arrive and they finally have. Shipping times are horrible and companies stopped caring in the slightest.Got some spare LTC6945's and NC7WZ17 buffers. I'll post any updates later.

author: max-bit
author_rank: Frequent Contributor
timestamp: December 08, 2022, 11:56:12 am
content: Here, the control of the frequency synthesis system is probably damaged, and not the PLL (LT..) or VCO itself is damaged. Therefore, the system does not hold the frequency.Check how the LT IC is controlled and whether there are control signals at the LT IC inputs.That would explain why the oscilloscope ended up in the trash.If the damage was simple, Keysight would fix it, but due to the FPGA (and / or ASIC) system, unfortunately, they do not replace a single IC, but replace the entire board.And that probably costs as much as the entire oscilloscope.

author: BeamDump
author_rank: Contributor
timestamp: December 10, 2022, 09:00:50 am
content: Any FPGA/ASIC can be replaced. Maybe not in EU anymore, since most factories that would do such repair are either gone or won't provide the service. I replaced an A-ASIC in a Fluke 199c few years back. True, Fluke sold the IC for 120EUR but was possible.All the frequency synthesis happens in the LTC6945 for the time base, that's it. It does have SPI where of course it can be programmed and read out.They could easily sell the IC, knowing where the problem is but instead it's more profitable to them to charge 6K for initial inspection and possible board swap. Same reason why these scopes have no schematics or part lists.Just got everything i need, now to get some time with it. December is the worst time.

author: Extrasolar
author_rank: Contributor
timestamp: December 10, 2022, 09:20:36 pm
content: Hi All,A second MSOS804 just failed at work, with the same problem !!Will capture the SPI protocol as I have a few evaluation boards with the same synthesizer.I could not find any problem on the signal chain from the oven to the synthesizer. Anyone knows the part number of the fully differential amplifier which is right after the Synthesizer (U33003) ??I cannot find the Positive Supply for this Amplifier !!!!

author: TheSteve
author_rank: Unknown
timestamp: December 10, 2022, 09:39:20 pm
content: Maybe temporarily add one to see what happens.

author: KE5FX
author_rank: Super Contributor
timestamp: December 10, 2022, 09:40:21 pm
content: That might be an LMH5401 or something in the same family. It may use both positive and negative supplies (e.g. -1.8 and +3.3).

author: BeamDump
author_rank: Contributor
timestamp: December 11, 2022, 06:44:31 am
content: Slightly better photo.Sounds like a repeat of my story lately. Same thing with this one, no lock on PLL2?

author: gamalot
author_rank: Super Contributor
timestamp: December 11, 2022, 07:05:52 am
content: It looks like fanout buffer HMC720https://www.analog.com/media/en/technical-documentation/data-sheets/hmc720.pdf

author: BeamDump
author_rank: Contributor
timestamp: December 11, 2022, 07:42:23 am
content: Yeah, all the pins match and it works only on a negative supply.Extra, can you check the eye diagram coming out of yours?

author: Extrasolar
author_rank: Contributor
timestamp: December 11, 2022, 02:06:30 pm
content: Hey,Wow, mystery part no more, I have ordered a few HMC720s !!I've received an ultra high bandwidth scope last week and will absolutely probe everything possible on that motherboardSo, on a systematic approach:1. Check Oven and signal path up to the synth.2. Check VCO3. Check Synth and Buffer4. if signal (+/-) is present at Buffers output (both outputs) then:Check SPI comms.5. Check FPGA/ASICLast week the same story repeated, one other MSOS804 broken with the same problem, and also a few weeks ago another MSOS404 same problem.I wonder if Keysight uploads some artificial errors (functions) with updates on such scopes

author: BeamDump
author_rank: Contributor
timestamp: December 11, 2022, 03:07:00 pm
content: HiWas thinking the same, that a flag went high somewhere during an intermittent event or maybe with an update. Can't speak about Keysight but one known offset printing quality control system was caught doing so.So far swapped the n-synth and dual buffers, same thing. External ref also didn't show anything unfortunately.What's the date on yours and what soft revision are they running?

author: HighVoltage
author_rank: Super Contributor
timestamp: December 11, 2022, 04:16:11 pm
content: Quote from: Extrasolar link=topic=333397.msg4575013#msg4575013Too many problems with these S-Series scopes.I always wanted one, maybe that is not such a good idea anymore.Thanks for all the great info in this thread.

author: Extrasolar
author_rank: Contributor
timestamp: December 12, 2022, 03:33:40 pm
content: Hi,I dont recall the version and to get it I would have to reassemble the whole thing.HMC720 chips on the way (the percs of being ADI employee).

author: BeamDump
author_rank: Contributor
timestamp: December 12, 2022, 03:54:33 pm
content: Quote from: Extrasolar on December 12, 2022, 03:33:40 pmSome perk thereI ordered 2 my self. Price is really something on these. Then again, not your run of the mill part.With that, would like to advice to stay away from the Chinese. Good thing i ordered two sets of NC7WZ17P6, one from their bay, other from sets of evaluation boards. Wondered why theirs didn't work. Just a case with pins sticking out and nothing inside.After i bought the 1st 5 pcs for 3EUR, price jumped to 42EUR.

author: Extrasolar
author_rank: Contributor
timestamp: December 24, 2022, 03:48:03 pm
content: Hello,I've replaced the HMC720 and now the PLL2 is intermittently locking. which means that the level of the signal is low despite being on the right frequency.There is a dual buffer that is on the OCO output (50MHz) which seems to be bad, as the output drops a lot compared to the input.I've discovered that the output from the VCO is bad (see photos).I was probing with a high bandwidth oscilloscope about (6GHz), and I could verify the presence of the signal beyond the dual buffer at the output of the Synth.So I am suspecting 2 things now, VCO improper output and maybe some sort of buffer for the PLL2 beyond the HMC720.Will check it later this evening and then will also check the Synth SPI coms.

author: seebeck
author_rank: Contributor
timestamp: December 29, 2022, 10:51:57 am
content: The same old problems would surface, Keysight should pay attention to his product quality！

author: Extrasolar
author_rank: Contributor
timestamp: May 16, 2023, 05:23:16 pm
content: Hi guys,Hmm, I brought it back to life, well, for a short while !!Most definitively, its a power issue. We have been looking in the wrong place so far.Replace all the Power Rail Caps ( tantalum mostly ) around the timebase !! I have ordered a bunch and I'm impatiently waiting to perform the recapCheers !!!

author: Extrasolar
author_rank: Contributor
timestamp: May 16, 2023, 05:30:04 pm
content: Second Unit in Operation after 1 Hour still no PLL2 Error !!

author: HighVoltage
author_rank: Super Contributor
timestamp: May 16, 2023, 05:37:38 pm
content: Nice find.Power Rail Caps, especially tantalum types are known to fail in test equipment. These should be visible in the ripple of the rails.

author: BeamDump
author_rank: Contributor
timestamp: May 31, 2023, 10:00:27 am
content: Good find.Still going?

author: seebeck
author_rank: Contributor
timestamp: September 21, 2023, 04:37:36 am
content: Hi Extrasolar,The same PLL2 issue happened to my Keysight DSO-S 404A Digital Storage Oscilloscope.You mentioned a replace of all the Power Rail Caps（tantalum mostly） around the time-base area, was it just that?Thanks a lot.I will try to repair my DSO this weekend.With best regards.Seebeck.

author: veloyage
author_rank: Newbie
timestamp: October 04, 2023, 01:39:27 pm
content: Hi all,TLDR: I just made an account to tell you that Keysight seems to repair this issue for freeWe have a DSOS054A which has been sitting unusable with this error for a year or so. I looked around and found only this thread, with repair seeming very difficult, so it sat some more. With the note about a recap being successful I recently opened it up, checked it out, and put some tantal caps into my mouser cart. Before actually doing it though I wanted to hear from Keysight what an official repair would cost, and while going to create a service request I found some service notes which detail the repair procedure (board swap), the most recent one (https://keysightsales.file.force.com/sfc/dist/version/download/?oid=00D1a000000awb5&ids=0685a00000nYQsW&d=%2Fa%2F5a000002gh2L%2FmeC7tIclK9L9B1_CDON938jLsjuTkG8X0XQbeUeKEKg&asPdf=true) saying "NO CHARGE AVAILABLE UNTIL: December 31, 2023".So I wrote them and got told to send it to DHL for forwarding and subsequent repair "on warranty". The actual warranty ended years ago, but for this known production issue they seem to not care about that.I am not sure if the "no charge" will actually expire or they will extend it again, as they seem to have done before.Hope this helps someone,Thomas

author: HighVoltage
author_rank: Super Contributor
timestamp: October 04, 2023, 03:11:25 pm
content: Quote from: veloyage on October 04, 2023, 01:39:27 pmWhat a nice surprise, good to know.Keysight sometimes is very generous with scope problems, even if they are out of warranty.

author: BeamDump
author_rank: Contributor
timestamp: October 18, 2023, 10:37:52 am
content: Haven't tried to continue repairing mine yet. So much work, it's nearly impossible to find free time for anything else anymore.Last time i brought this problem up with Keysight they quoted me an initial 6000EUR cost for replacing acquisition board. I've sent them another request referencing the attached service note. Let's see what happens.

author: BeamDump
author_rank: Contributor
timestamp: November 17, 2023, 10:36:53 am
content: Well i can safely say that replacing all tantalum caps on board, doesn't solve the PLL2 problem. Still same effect, lock light on but soft start with fault and nothing past that.Thanks to Extrasolar butnotthe solution.

author: Extrasolar
author_rank: Contributor
timestamp: January 09, 2024, 01:57:33 pm
content: Hello All, It has been a while !!I restarted my repair on the MSOS104A. Recaping does not solve the issue. It is a serious problem that perhaps has a lot more to do with Firmware !!I was told that a recent Firmware update, effectively solved this issue on a known PLL2 Timebase failure unit.I am going to try to reinstall windows and the scope drivers from the most recent firmware update from Keysight.For some strange reasons, the SSD on the scope broke all of a sudden and there are only 2 options to save it now : 1: install from scratch and hope for the best, 2:send to Keysight and pay ...I will update the progress soon ...Kind Regards

author: Extrasolar
author_rank: Contributor
timestamp: January 09, 2024, 09:08:44 pm
content: Hi All,I successfully installed the instrument drivers on a freshly installed Win 10 system. The acquisition board is recognized properly and the software works fine. However the PLL2 problem persists...I have managed to prove that the scope actually works when we operate it remotely via USB:There are different waveforms I wanted to test and curiously enough the scope followed with the :DIGITIZE command.This makes me think the problem is actually some sort of firmware/software bug.Kind Regards

author: BeamDump
author_rank: Contributor
timestamp: February 20, 2024, 11:26:02 am
content: I got to talking with Keysight. PLL2 light will come on even if there is problem with VCO and the entire issue here is the VCO.What they told me: " The VCO and perhaps the synthesizer that drives it. But right now VCO is the concern as it swings widely in the MHz on the output. Even though board shows it's in a lock, it's obviously false.

author: hch
author_rank: Newbie
timestamp: October 01, 2024, 08:57:57 am
content: Hello,first I'd like to thank all contributors to this thread, which turned to be paramount to fix problem with our MSOS104a. Our problem had very similar symptoms to these mentioned here.We narrowed search for fault by cooling (using freezing spray) area of time base and found that if we cool down the VCO chip we were able to obtain PLL2 lock.Finally we replaced the part with stock CVCO55BH-4940-4940 (Thank you again for info that VCO is 5GHz which turned to be correct)After replacing the VCO the warning "Timebase error detected in PLL2" finally disappeared and scope seems to be working, at least for now

author: HighVoltage
author_rank: Super Contributor
timestamp: October 01, 2024, 09:40:58 am
content: That is a nice confirmation with CVCO55BH-4940-4940, thanks!

author: Calzie
author_rank: Newbie
timestamp: December 10, 2024, 12:23:23 pm
content: Hi there, I also can confirm this part CVCO55BH-4940-4940 (from Mouser $30 plus post) fixed the PLL2 error with my MSOS804A scope.Bit tricky getting the old part off, there are lots of small surface mount components really close by, I put several layers of Kapton tape over them and used hot air at 440C, took a while as the devices shield can is a big head sink. The device is only secured by the 10 joints, three are signals and easy, the rest are to a large PCA ground plane (and the devices ground and case) these take a while to melt, there is no central solder ground under the device.Its also tricky fitting the new device as the clamps for the circuits covering shield can limits solder iron access not helped that the large ground needs a big iron to solder.Ran the scope for 1 hour without issues, passed its self tests ok, magic result, thank you.CalzieEdinburgh, UK