Thanks, Jim. I still have to perform that test where I play The Cure from my garage with the door open, which?I'm sure you'd hear from your bench!! ;))))
I tried?to pry off the battery this morning without further disassembly, but it doesn't want to come off that easily. There seems to be a blob of solder - has anyone seen that before? - on top of the holder, and some sort of?foam?tape below it. Maybe I need to apply force a little bit differently.?
Unless there's some secret?regarding how to remove the battery, I'll have to at least remove at least the CRT module to gain?better access to it. I really think access to a battery - even one guaranteed?a decade - should be easier than this. So this should be possible later in the week when I have more time.? Radu.?
Speaking of CR2032 coin cells, don’t spend $$ at a local store; order from Digital-Key for about $0.50 in quantity.? I usually buy 50 pieces at a time.? But then I have a keychain LED flashlight (torch for the Brits) that my kids bought me some years ago (best gift ever!) that takes 2 cells and a 3-LED baseball cap that I wear when walking my dogs at night that takes 4.? So I go through a lot of them.? Mouser might have them as well.? I’ve not ordered from D-K for a while because they buried the big product table, and it seems like something else they did got me PO’d at them.? HTH.
Jim Ford
Laguna Hills, California, USA
> On Feb 25, 2025, at 7:46?PM, Peter Gottlieb via <hpnpilot=[email protected]> wrote:
>
> ?CR followed by numbers indicates the physical size, CR2032 etc.? I would say if you're already in there, replace them as even if they are good they won't last much longer.? I always replace memory hold up cells in anything that crosses my bench.? Low hanging fruit.
>
> The power supply might be low because of an overload caused by a shorted capacitor.? Perhaps try unplugging the supply connections. I can't remember if that model's supply will run correctly without load.? But if you do go inside it, check the capacitors for capacitance, leaks and ESR.
>
> Peter
>
>
>> On 2/25/2025 9:35 PM, Radu Bogdan Dicher via wrote:
>> I've gotten a bit of a chance tonight to check a couple of things with one of the units:
>>
>> *Unit #2 *(S/N: 3214A00704: consecutive units!)
>>
>>? * Voltages on rails:
>>? ? ? o +11.924V
>>? ? ? o +12.050V
>>? ? ? o -3.27V(fluctuating somewhat; no significant ripple on it)
>>? ? ? o -5.2289V
>>? ? ? o 3.5285V
>>? ? ? o 5.2067V
>>? * There's a coin battery on the main board, which I didn't remove yet (I'd
>>? ? rather measure its voltage before I do, in case it's still good and holds
>>? ? the memory). It's a Panasonic and I can only read "CR..." from it. Would
>>? ? there potentially be more harm done by removing it, than simply losing the
>>? ? cal constants, in case it's still good for some reason? I'm thinking of
>>? ? biting the bullet and removing it, replacing it, and then seeing where
>>? ? that takes me.
>>
>> So this second unit has more issues than just a dead battery (in case the latter checks out). I'll have to remove the power supply module and see what could be wrong with the -12V rail. I'm provisionally blaming the unruly -12V rail for the additional error this second unit has, which the first doesn't. So my money's on that the first one has a good -12V rail.
>> Radu.
>>
>> On Tue, Feb 25, 2025 at 7:14?AM Radu Bogdan Dicher via <> <vondicher=[email protected]> wrote:
>>
>>? ? Awesome, thank you, Peter.
>>
>>? ? I wonder if anyone has a fresh recollection of what battery or maybe
>>? ? battery-backed RAM would be suspect and possibly needed so I'd start
>>? ? working on an order to have the parts ready by the time I carve out some
>>? ? time to open these. From what I know about these generation scopes,
>>? ? replacing the battery is probably a good idea anyway. The cal constants
>>? ? seem to be gone, so nothing to lose there.
>>
>>? ? I wasn't able to find this information (particularly info on the battery)
>>? ? in the manuals, which I find odd.
>>? ? Radu.
>>
>>
>>? ? On Tue, Feb 25, 2025 at 5:26?AM Peter Gottlieb via
>>? ? <> <hpnpilot=[email protected]> wrote:
>>
>>? ? ? ? Seems like you are on the right track.? Many HP scopes of that era
>>? ? ? ? lose their
>>? ? ? ? minds if the memory battery goes dead.
>>
>>? ? ? ? Peter
>>
>>
>>? ? ? ? On 2/24/2025 11:09 PM, Radu Bogdan Dicher via
>>? ? ? ? <> wrote:
>>? ? ? ? > Hi all,
>>? ? ? ? > Over the weekend I've got a couple of 54512Bs at my desk to seek to
>>? ? ? ? bring back
>>? ? ? ? > to full functionality. My main scope is a 54522A, and I assume they
>>? ? ? ? have some
>>? ? ? ? > commonalities, but I've yet to open mine (it came to me fully
>>? ? ? ? refurbished and
>>? ? ? ? > never needed to open the case). I'm not very familiar with this
>>? ? ? ? other series,
>>? ? ? ? > and hope on some good input and recommendations.
>>? ? ? ? > The documentation is not as good as others I've seen from HP.
>>? ? ? ? Specifically for
>>? ? ? ? > this unit (54512B), Keysight only seems to have a very skinny (by HP
>>? ? ? ? > standards) Service Manual which can't honestly be called
>>? ? ? ? "module-level Service
>>? ? ? ? > Manual," as it doesn't really into much detail on the different
>>? ? ? ? modules. Then
>>? ? ? ? > there's a "Front Panel Reference," which is an odd other way of
>>? ? ? ? naming what I
>>? ? ? ? > think is the Operating Manual. A couple other manuals have to do with
>>? ? ? ? > programming. That's it.
>>? ? ? ? > Sometimes in a series you have to look for the main unit, but in
>>? ? ? ? this case I'm
>>? ? ? ? > not sure that's the 54501A, as the catalog spec sheet seems to
>>? ? ? ? suggest, or the
>>? ? ? ? > 54505B, as per the SM. Maybe someone very familiar with the series
>>? ? ? ? would know.
>>? ? ? ? > Artek doesn't have manuals for the 54512B at all, but they do for
>>? ? ? ? the 54501A,
>>? ? ? ? > and if applicable, I'd get the series of six manuals they sell as a
>>? ? ? ? bundle. If
>>? ? ? ? > no go, I'll be a bit in a bind with fixing this given what I have at
>>? ? ? ? hand. I
>>? ? ? ? > am aware HP was not longer offering component SMs by this point,
>>? ? ? ? though I
>>? ? ? ? > don't know for a fact on this specific series and scope (but I do
>>? ? ? ? regarding
>>? ? ? ? > the better?/later? 54522A).
>>? ? ? ? > Is this really capable of FFT to 500MHz, even if the scope is rated
>>? ? ? ? to 300MHz?
>>? ? ? ? > I can't make sense of that.
>>? ? ? ? > Now, on to the specific issues with the units.
>>? ? ? ? > *Unit #1 *(S/N: 3214A00705)
>>? ? ? ? >
>>? ? ? ? >? ?* Upon starting it, it reports something like "TRYING TO START
>>? ? ? ? REALTIME
>>? ? ? ? >? ? ?CLOCK," which is unsuccessful after a time countdown from I
>>? ? ? ? think 60:
>>? ? ? ? >? ? ?"REALTIME CLOCK FAILED TO START - DISABLED."
>>? ? ? ? >? ?* Once I get it to display the default screen and output a trace,
>>? ? ? ? it stated
>>? ? ? ? >? ? ?"Default cal loaded. Re-cal instrument."
>>? ? ? ? >? ?* Self Test passes all.
>>? ? ? ? >? ?* I'm also seeing a solid and apparently accurate 5V from the DC
>>? ? ? ? Cal output
>>? ? ? ? >? ? ?in the back. I haven't tried the AC Cal output.
>>? ? ? ? >? ?* Note this one had the Cal switch in the back in the UNPROTECTED
>>? ? ? ? position
>>? ? ? ? >? ? ?when I got it.
>>? ? ? ? >? ?* I'm able to display the square wave test signal from the front
>>? ? ? ? panel.
>>? ? ? ? >
>>? ? ? ? > *Unit #2 *(S/N: 3214A00704: consecutive units!)
>>? ? ? ? >
>>? ? ? ? >? ?* Upon staring it, it stated "CALIBRATION FACTOR CHECKSUM ERROR.
>>? ? ? ? MOVE REAR
>>? ? ? ? >? ? ?PANEL CAL SWITCH TO UNPROTECTED. POWER INSTRUMENT OFF AND THEN
>>? ? ? ? ON AGAIN.
>>? ? ? ? >? ? ?RE-CAL INSTRUMENT."
>>? ? ? ? >? ?* It also says "Trying to start realtime clock (09290)." Maybe
>>? ? ? ? that's an
>>? ? ? ? >? ? ?error code?
>>? ? ? ? >? ?* Upon switching the rear Cal switch to UNPROTECTED, it boots
>>? ? ? ? successfully,
>>? ? ? ? >? ? ?goes to a default measurement screen, but gives me a warning "Failed
>>? ? ? ? >? ? ?interpolar cal." The trace seems to jump around on Y a bit.
>>? ? ? ? >? ?* Self Test passes all /but/ Timebase. It also displays the same
>>? ? ? ? error as
>>? ? ? ? >? ? ?default screen ("Failed interpolar cal").
>>? ? ? ? >? ?* 5V out at DC Cal is good.
>>? ? ? ? >? ?* This one had the Cal switch in UNPROTECTED position, so maybe
>>? ? ? ? that's why
>>? ? ? ? >? ? ?it booted successfully.
>>? ? ? ? >? ?* I'm able to display the square wave test signal from the front
>>? ? ? ? panel,
>>? ? ? ? >? ? ?though it seems to be offset vertically a bit.
>>? ? ? ? >
>>? ? ? ? > To me, this seems to tell me the battery holding the cal constants
>>? ? ? ? is done -
>>? ? ? ? > going by what I know about my 54522A. It's also possible some Dallas
>>? ? ? ? RAMs are
>>? ? ? ? > out of battery - though I don't know if this uses those for
>>? ? ? ? non-volatile
>>? ? ? ? > memory. I have not yet opened the units, so I've no idea where the
>>? ? ? ? rails are,
>>? ? ? ? > if any caps have leaked, etc. But maybe the information above gives
>>? ? ? ? some clues
>>? ? ? ? > on what's going on, enough to start thinking on it. It also seems
>>? ? ? ? the issues
>>? ? ? ? > are shared very similarly, so maybe that's making the repair more
>>? ? ? ? streamlined.
>>? ? ? ? > Looking forward to your input.
>>? ? ? ? > Thank you,
>>? ? ? ? > Radu.
>>? ? ? ? >
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