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.
>

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.
>

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.
>>? ? ? ? >
>>
>>
>>
>>
>>
>>
>
>
>
>
>
>

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.?

On Wed, Feb 26, 2025 at 5:38?AM Jim Ford via <james.ford=[email protected]> wrote:

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.
>>? ? ? ? >
>>
>>
>>
>>
>>
>>
>
>
>
>
>
>

I lifted today the CRT card, just enough to have some access to the battery, but I'm still unsure how it's supposed to come off. I tried prying the top spring "leaf," but it seems attached (possibly soldered) to the battery - or is that a top lid over the battery? And then there's a piece of foam underneath, possibly double-sided sticking. I'd rather not remove the whole mainboard just to replace this, but I don't think I can try many more prying and pulling before?I risk something more serious due to the lack of access.?

Hoping someone having done this before?recognizes the type of battery and its socket from the enclosed pictures?and has some good pointers. I am not seeing any other battery on this board - I was expecting?a bigger, cylindrical?type, but I think this must be it for the 54512B.?

Thanks a bunch in advance.

Radu.?

On Wed, Feb 26, 2025 at 7:08?AM Radu Bogdan Dicher via <vondicher=[email protected]> wrote:

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.?

On Wed, Feb 26, 2025 at 5:38?AM Jim Ford via <james.ford=[email protected]> wrote:

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.
>>? ? ? ? >
>>
>>
>>
>>
>>
>>
>
>
>
>
>
>

On 2025-02-27 2:32 PM, Radu Bogdan Dicher via wrote:
> I lifted today the CRT card, just enough to have some access to the
> battery, but I'm still unsure how it's supposed to come off. I tried
> prying the top spring "leaf," but it seems attached (possibly
> soldered) to the battery - or is that a top lid over the battery? And
> then there's a piece of foam underneath, possibly double-sided
> sticking. I'd rather not remove the whole mainboard just to replace
> this, but I don't think I can try many more prying and pulling
> before?I risk something more serious due to the lack of access.

Stop prying! I've used that type battery many times. The tab on top is
spot-welded to the cell, with two fingers soldered thru the PCB.
underneath is another, smaller tab, with a single finger soldered thru
the PCB. You will need to gain access to the bottom side of the PCB to
desolder that.

Steve Hendrix

Awesome. Thank you guys! I only did just about enough prying to figure this mustn't be the right way to remove, then asked here. It sounds like it's not a ten minute deal and needs weekend time to do.?

If I understand this right, the correct procedure is to desolder both tabs?... Given the top tab is spot welded, it may not be reusable? So, replacing?this with the appropriate coin battery socket and a new battery is the way to go?

Thanks again!

Radu.?

On Thu, Feb 27, 2025 at 12:09?PM Steve Hendrix via <SteveHx=[email protected]> wrote:

On 2025-02-27 2:32 PM, Radu Bogdan Dicher via wrote:
> I lifted today the CRT card, just enough to have some access to the
> battery, but I'm still unsure how it's supposed to come off. I tried
> prying the top spring "leaf," but it seems attached (possibly
> soldered) to the battery - or is that a top lid over the battery? And
> then there's a piece of foam underneath, possibly double-sided
> sticking. I'd rather not remove the whole mainboard just to replace
> this, but I don't think I can try many more prying and pulling
> before?I risk something more serious due to the lack of access.

Stop prying! I've used that type battery many times. The tab on top is
spot-welded to the cell, with two fingers soldered thru the PCB.
underneath is another, smaller tab, with a single finger soldered thru
the PCB. You will need to gain access to the bottom side of the PCB to
desolder that.

Steve Hendrix

On 2025-02-27 3:47 PM, Radu Bogdan Dicher via wrote:
> If I understand this right, the correct procedure is to desolder both
> tabs?... Given the top tab is spot welded, it may not be reusable? So,
> replacing?this with the appropriate coin battery socket and a new
> battery is the way to go?

When you get to the bottom side of the PCB, I'm pretty sure you'll find
three "leads" sticking thru. Two go to the top side of the cell, and one
to the underside. You'll need to carefully desolder all three to remove
the cell, then clean up the holes. Not sure if you will find a socket
that neatly fits the same footprint; you may have to just solder in the
new battery. Those tabs are a permanent part of the battery. If you find
a socket that will fit, you can just buy a standard coin cell without
the tabs of course.

Steve Hendrix

Thank you, Steve.?

One other unfortunate effect?of the spot-welding of the top tab is that the battery code is not visible. I can probably destroy the battery once out, and read the CRxyzt?battery code, but would anyone have good info offhand on it? I couldn't track this info in any of the manuals.?

Or alternatively a link to the correct replacement would be even better, of course. Some years ago, I'd be confident I could source it from Keysight, but these days availability of parts seems to not quite be there anymore.?

Thanks a bunch!

Radu.?

On Thu, Feb 27, 2025 at 12:53?PM Steve Hendrix via <SteveHx=[email protected]> wrote:

On 2025-02-27 3:47 PM, Radu Bogdan Dicher via wrote:
> If I understand this right, the correct procedure is to desolder both
> tabs?... Given the top tab is spot welded, it may not be reusable? So,
> replacing?this with the appropriate coin battery socket and a new
> battery is the way to go?

When you get to the bottom side of the PCB, I'm pretty sure you'll find
three "leads" sticking thru. Two go to the top side of the cell, and one
to the underside. You'll need to carefully desolder all three to remove
the cell, then clean up the holes. Not sure if you will find a socket
that neatly fits the same footprint; you may have to just solder in the
new battery. Those tabs are a permanent part of the battery. If you find
a socket that will fit, you can just buy a standard coin cell without
the tabs of course.

Steve Hendrix

Has anyone mentioned to watch out for grounded soldering iron tips when doing this (if the cell is not discharged or memory contents need to be kept alive using an external PSU)

?

Peter