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I have an E4402 that displays Lo Unlock below about 900MHz, I've checked the obvious, PSU rails, and following the Youtube video checked the RF output of the prescalers etc all looks fine.
On the main RF board,? DS2 is lit permenantly when on frequencies below about 950MHz, above 1GHz, tboth DS1 and DS2 are off and the VCO lock message is noit shown, it appears to work perfectly above 1GHz at least it shows signals I feed in on 1300MHz and 2400MHz.
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Taking a picture with the thermal imager about 30 seconds after switch on, U54 is about 80 degrees C, which cannot be right, and is probably I am guessing where the fault lies, but on the Schematic I have (the one from Artek Media) there is no U54 listed.
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Can anyone who has a schematic where it is listed, please let me know what that IC is, and what it's role is please so I can see if it relevant to the fault I have.
It is located to the left of the YIG when viewed from the front, it's an 8 pin SO8 package. Going from the left? edge of the PCB in line with the YIG, there is U119, an SO16 IC, then to the right of that U94 an SO8, then to the right of that U54, it looks like it is marked H5002 5 L940FBN.
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Of course, if a schematic of that secton is available that has U54 on, that would be even better, as the one I purchased a few years ago from Artek, isn't the same PCB as mine as U54 is not listed or shown on the schematic.
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Tony
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Hello Tony,
Yes, the scans from Artek must me some initial release of the CLIP and
they are missing newer board revisions. Also the tracking generator part
is not matching with mine.
I think Shahriar (The Signal Path) has a much newer revision which is
not from Artek. You can try to contact him if he is willing to share it.
73,
Razvan
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On 30/01/2025 12:39, Tony G1HMO via groups.io wrote: I have an E4402 that displays Lo Unlock below about 900MHz, I've checked
the obvious, PSU rails, and following the Youtube video checked the RF
output of the prescalers etc all looks fine.
On the main RF board,? DS2 is lit permenantly when on frequencies below
about 950MHz, above 1GHz, tboth DS1 and DS2 are off and the VCO lock
message is noit shown, it appears to work perfectly above 1GHz at least
it shows signals I feed in on 1300MHz and 2400MHz.
Taking a picture with the thermal imager about 30 seconds after switch
on, U54 is about 80 degrees C, which cannot be right, and is probably I
am guessing where the fault lies, but on the Schematic I have (the one
from Artek Media) there is no U54 listed.
Can anyone who has a schematic where it is listed, please let me know
what that IC is, and what it's role is please so I can see if it
relevant to the fault I have.
It is located to the left of the YIG when viewed from the front, it's an
8 pin SO8 package. Going from the left? edge of the PCB in line with the
YIG, there is U119, an SO16 IC, then to the right of that U94 an SO8,
then to the right of that U54, it looks like it is marked H5002 5 L940FBN.
Of course, if a schematic of that secton is available that has U54 on,
that would be even better, as the one I purchased a few years ago from
Artek, isn't the same PCB as mine as U54 is not listed or shown on the
schematic.
Tony
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Wow. If Shahriar has this, I would also like to obtain a copy.
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Mark
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I remember asking about this when I was working on my E4407B and he was going to look into sharing them but it never happened. Maybe you will have better luck.?
Sam Sam Reaves
ARS W3OHM
Owner / Moderator of: LeCroy Owners Group on 开云体育
Sencore Owners Group on 开云体育 Sprint Layout Group on 开云体育?? Pulsonix EDA Group on 开云体育
LPKF Owners Group on 开云体育
Electronics and Mechanical Hardware Design Engineering Manager
Staff Scientist Andritz Rolls Global Research Center (RETIRED)
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I've reached out to Shahriar, but as yet heard nothing back, but the PCB that he is working on in the Youtube video clearly has U54 so looks like the same revison as the unit I have here.
I'll post back if I hear anything and he is willing to share the schematics
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Tony
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Hi Tony,
Thank you very much for contacting Shahriar. Let's hope that he is
willing to share his CLIP.
73,
Razvan
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On 31/01/2025 05:54, Tony G1HMO via groups.io wrote: I've reached out to Shahriar, but as yet heard nothing back, but the PCB
that he is working on in the Youtube video clearly has U54 so looks like
the same revison as the unit I have here.
I'll post back if I hear anything and he is willing to share the schematics
Tony
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No prob, though I don't really hold out any hope of a reply, i've since seen several posts on other forums all of which say people have emailed him with questions about his Youtube videos and asked for clarity etc, but it looks like he doesn't reply to posts or emails unfortunatly as nobody seems to have had any replies from him.
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Tony
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Hm interesting. My E4402 (that also doesn't match the Artek schems) has totally different part numbering; there is nothing like? "U54", all is numbered by group spaced by hundreds, so U8xx, U7xx around the pll charge pump, etc. If you have a good photo of your RF board that points to the location of U54 maybe we can narrow things down somewhat.
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Something I didn't get around to trying when I had unlock problems on mine, was to somehow force the YIG drive signal to different levels, and look at the prescaler output (map frequency + power) to see how it behaves. I am not equipped to measure directly the YIG output so it would have been of limited use maybe.
I agree that an IC running high temperatures like that is suspicious, but not necessarily wrong. If by chance it is a prescaler IC, for some reason these seem to be the bane of HPAK gear; they run hot and fail often.
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I just checked my docs, and at some point I stole this screenshot from somewhere ( I definitely don't have the original doc, nor do I know exactly who it came from), but the numbering seems to match your board revision. If you recognize anything from this, we can narrow down a guess a lot - I think everything upstream of U59 is nothing but amplifiers and filters; IIRC U60 is the first LO prescaler in that chain.
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That screenshot may have come from me. I don't have the CLIP handy right now but it's the same one Shahriar used in his videos. (PLL Unlock) I fixed 2 440x units that had the same fault as in the videos from Shahriar. I verified the problem by following his instructions. (you need a working SA to do this)
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I'd have to check my CLIP to see if the is a U54 or not. I came across another SA (4407) with this issue but it was a newer board and did NOT have the div-by-4 counter. :-(
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Mark
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"Mark Bielman via groups.io" <mbielman@...> writes: That screenshot may have come from me. I don't have the CLIP handy
right now but it's the same one Shahriar used in his
videos. (PLL Unlock) I fixed 2 440x units that had the same fault as
in the videos from Shahriar. I verified the problem
by following his instructions. (you need a working SA to do this)
I'd have to check my CLIP to see if the is a U54 or not. I came across
another SA (4407) with this issue but it was a
newer board and did NOT have the div-by-4 counter. :-( I didn't follow the thread closely so ignore me if I write something that was said already. I have an E4407B which also had LO Unlock errors. It had a newer RF board as you described. In my case it had a switchable /4 /8 divider that is also used in the ESG generators. I used the 1GC1-4210 Replacement module, which works fine. I learned that measuring whether output and input frequency are divided by 8 or 4 doesn't help - in my unit it did scale down on most frequencies, but failed at some. That of course confused the PLL while sweeping.
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Ah, yes. That rings a bell. That newer unit I looked at had that chip. (1GC1-4210) The unit was from work so I decided not to experiment. (I looked at the replacement module as well. It's a good one. I think it used 2 of the HMC365S8 div by 4 counters or similar.)
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My employer ended up sending the unit in for repair. I'm sure they just replaced the board.
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Mark
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Found the source of the screenshot:
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Has info on the replacement module(s).
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Found the source of the screenshot:
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Thanks, that is just my website : )
I tried collecting information there about the different revisions of RF boards and what LO dividers they use. Would welcome any further data points from E440x owners here.
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@Mark when you get access to that CLIP again, please share !
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Excellent, really appreciate the help , i'll take the case back off and take a high res picture of the area around U54, I couldn't see it on the posted screenshot though? it was clearly visible on the PCB in Shahriar's repair video.
Mark, if you do get chance to look at the version of CLIP you have, and U54 is there, please do post a screenshot of the area around it would you, or even better the entire CLIP.
The odd thing with my unit is it seems to work perfectly well above around 960MHz, though the exact frequency that it goes in / out of lock does seem to change slightly, below this 'critical frequency' it is just out of lock.
The fault has present since I got hold of the analyser, I replaced the divider shown in the Shahriar video but it made no difference whatsoever, so probably not related to that, when it is in lock, the output signal from the prescaler is perfect looking on another analyser, it is almost as if once the RF frequency is below 960MHz, that the YIG frequency is wrong.
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Tony
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This is the part I used to fix mine. Cheaper and easier to get. I think Digi-Key or Mouser.
Sam Reaves
ARS W3OHM
Owner / Moderator of: LeCroy Owners Group on 开云体育
Sencore Owners Group on 开云体育 Sprint Layout Group on 开云体育?? Pulsonix EDA Group on 开云体育
LPKF Owners Group on 开云体育
Electronics and Mechanical Hardware Design Engineering Manager
Staff Scientist Andritz Rolls Global Research Center (RETIRED)
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Thanks Sam, that was the part I replaced in mine after following the Shariah video, I got it from Mouser.
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Didn't help though in my unit it seems unfortunately.
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Tony
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Tony - I checked my CLIP and there is NO U54. The assembly is E4403-60057.
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Mark
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Sam Reaves
fenugrec