Got this HP 54501, raster based CRT scope Indications are that the NVRAM chip, which is more of an assembly because it has an internal battery has died. That is most likely due to the battery. The battery has a connection to pins on it. ;the presumption at this time is the battery is in too poor state of charge to operate the chip. This has all the setup information in it so it is not likely to work with it in a dead state. There has been some speculation about just taking the proper voltage to those IC pins. I think if we got access to that all it would take is a battery and two wires. Here is a thread on it from Tekscope@groups.io; https://groups.io/g/TekScopes/topic/2432a_ram_battery_module_or/7655544?p=Created,,,20,2,20,0::,,,0,0,0,7655544 They describe a similar situation with the Tek 2432 and 2440. In this, the chip is described as; Dallas DS 1235YW-120 One guy mentions the exact number in the Tek, so obviously the data will not be right, plus the calibration information will be who knows. I say keep the calibration. For example an old bigscreen, well not that old old. Had some bad things going on in the convergence, they said "Just change it, throw that one in and align it". Bullshit, I took the parts out of the boneyard replacement and fixed the original and when I put it in the convergence was perfect, as if it had never been touched. So I think that would be best for this. Just give it the damn voltage it wants. It works, evleybody appy ! What are the odds ? I will do anything within reason, up to maybe a Joule thief with a warning beeper.
Scope, RTC
Started by ●March 9, 2020
Reply by ●March 9, 20202020-03-09
On 3/9/20 10:18 PM, jurb6006@gmail.com wrote:> Got this HP 54501, raster based CRT scope Indications are that the NVRAM chip, which is more of an assembly because it has an internal battery has died. That is most likely due to the battery. > > The battery has a connection to pins on it. ;the presumption at this time is the battery is in too poor state of charge to operate the chip. This has all the setup information in it so it is not likely to work with it in a dead state. > > There has been some speculation about just taking the proper voltage to those IC pins. I think if we got access to that all it would take is a battery and two wires. > > Here is a thread on it from Tekscope@groups.io; > > https://groups.io/g/TekScopes/topic/2432a_ram_battery_module_or/7655544?p=Created,,,20,2,20,0::,,,0,0,0,7655544 > > They describe a similar situation with the Tek 2432 and 2440. > > In this, the chip is described as; > > Dallas > DS 1235YW-120 > > One guy mentions the exact number in the Tek, so obviously the data will not be right, plus the calibration information will be who knows. > > I say keep the calibration. For example an old bigscreen, well not that old old. Had some bad things going on in the convergence, they said "Just change it, throw that one in and align it". Bullshit, I took the parts out of the boneyard replacement and fixed the original and when I put it in the convergence was perfect, as if it had never been touched. > > So I think that would be best for this. Just give it the damn voltage it wants. It works, evleybody appy ! > > What are the odds ? I will do anything within reason, up to maybe a Joule thief with a warning beeper. >I've worked on a some pieces of uP-controlled gear from the 80s that store program work-data in battery-backed SRAM that's expected to still be there from the last time when the kit powers up, even if the user hasn't changed any settings from stock themselves. So if the SRAM battery fails it's often borked on power-up; garbled display, controls don't work right. Then a factory-reset procedure refreshes the SRAM and all works fine until it shuts down, start up, borked again. Wash rinse repeat until the battery is replaced
Reply by ●March 9, 20202020-03-09
On 3/9/20 10:18 PM, jurb6006@gmail.com wrote:> Got this HP 54501, raster based CRT scope Indications are that the NVRAM chip, which is more of an assembly because it has an internal battery has died. That is most likely due to the battery. > > The battery has a connection to pins on it. ;the presumption at this time is the battery is in too poor state of charge to operate the chip. This has all the setup information in it so it is not likely to work with it in a dead state. > > There has been some speculation about just taking the proper voltage to those IC pins. I think if we got access to that all it would take is a battery and two wires. > > Here is a thread on it from Tekscope@groups.io; > > https://groups.io/g/TekScopes/topic/2432a_ram_battery_module_or/7655544?p=Created,,,20,2,20,0::,,,0,0,0,7655544 > > They describe a similar situation with the Tek 2432 and 2440. > > In this, the chip is described as; > > Dallas > DS 1235YW-120 > > One guy mentions the exact number in the Tek, so obviously the data will not be right, plus the calibration information will be who knows. > > I say keep the calibration. For example an old bigscreen, well not that old old. Had some bad things going on in the convergence, they said "Just change it, throw that one in and align it". Bullshit, I took the parts out of the boneyard replacement and fixed the original and when I put it in the convergence was perfect, as if it had never been touched. > > So I think that would be best for this. Just give it the damn voltage it wants. It works, evleybody appy ! > > What are the odds ? I will do anything within reason, up to maybe a Joule thief with a warning beeper. >Is the "NVRAM chip" just SRAM with a backup battery in a unit package? Is getting an appropriate-sized SRAM chip and external battery and mounting to a bodge-board that slots into the original socket a possibility? Sounds like an easier proposition of the original package is say potted
Reply by ●March 10, 20202020-03-10
On 10/3/20 1:18 pm, jurb6006@gmail.com wrote:> Got this HP 54501, raster based CRT scope Indications are that the NVRAM chip, which is more of an assembly because it has an internal battery has died. That is most likely due to the battery. > > The battery has a connection to pins on it. ;the presumption at this time is the battery is in too poor state of charge to operate the chip. This has all the setup information in it so it is not likely to work with it in a dead state. > > There has been some speculation about just taking the proper voltage to those IC pins. I think if we got access to that all it would take is a battery and two wires. > > Here is a thread on it from Tekscope@groups.io; > > https://groups.io/g/TekScopes/topic/2432a_ram_battery_module_or/7655544?p=Created,,,20,2,20,0::,,,0,0,0,7655544 > > They describe a similar situation with the Tek 2432 and 2440. > > In this, the chip is described as; > > Dallas > DS 1235YW-120 > > One guy mentions the exact number in the Tek, so obviously the data will not be right, plus the calibration information will be who knows. > > I say keep the calibration. For example an old bigscreen, well not that old old. Had some bad things going on in the convergence, they said "Just change it, throw that one in and align it". Bullshit, I took the parts out of the boneyard replacement and fixed the original and when I put it in the convergence was perfect, as if it had never been touched. > > So I think that would be best for this. Just give it the damn voltage it wants. It works, evleybody appy ! > > What are the odds ? I will do anything within reason, up to maybe a Joule thief with a warning beeper. >Does this help at all: <https://www.instructables.com/id/HP-54501A-NVRAM-Replacement/> CH
Reply by ●March 10, 20202020-03-10
On 2020/03/09 7:18 p.m., jurb6006@gmail.com wrote:> Got this HP 54501, raster based CRT scope Indications are that the NVRAM chip, which is more of an assembly because it has an internal battery has died. That is most likely due to the battery. > > The battery has a connection to pins on it. ;the presumption at this time is the battery is in too poor state of charge to operate the chip. This has all the setup information in it so it is not likely to work with it in a dead state. > > There has been some speculation about just taking the proper voltage to those IC pins. I think if we got access to that all it would take is a battery and two wires. > > Here is a thread on it from Tekscope@groups.io; > > https://groups.io/g/TekScopes/topic/2432a_ram_battery_module_or/7655544?p=Created,,,20,2,20,0::,,,0,0,0,7655544 > > They describe a similar situation with the Tek 2432 and 2440. > > In this, the chip is described as; > > Dallas > DS 1235YW-120 > > One guy mentions the exact number in the Tek, so obviously the data will not be right, plus the calibration information will be who knows. > > I say keep the calibration. For example an old bigscreen, well not that old old. Had some bad things going on in the convergence, they said "Just change it, throw that one in and align it". Bullshit, I took the parts out of the boneyard replacement and fixed the original and when I put it in the convergence was perfect, as if it had never been touched. > > So I think that would be best for this. Just give it the damn voltage it wants. It works, evleybody appy ! > > What are the odds ? I will do anything within reason, up to maybe a Joule thief with a warning beeper. >You can always carefully cut the top off the Dallas RAM and access the lithium button battery and replace it - we used to do that in video games that used this brand of battery NVRAM, but why not simply grab a 62256 NVRAM such as used in pinball games and be done with the batteries? Assuming speed isn't a major factor that is... Caution - link to my sales shop for this Cypress based NVRAM: https://www.flippers.com/catalog/product_info.php/62256-nvram-module-p-8729 /Caution John :-#)#
Reply by ●March 10, 20202020-03-10
On Mon, 09 Mar 2020 19:18:02 -0700, jurb6006 wrote:> Got this HP 54501, raster based CRT scope Indications are that the NVRAM > chip, which is more of an assembly because it has an internal battery > has died. That is most likely due to the battery. > > The battery has a connection to pins on it. ;the presumption at this > time is the battery is in too poor state of charge to operate the chip. > This has all the setup information in it so it is not likely to work > with it in a dead state. > > There has been some speculation about just taking the proper voltage to > those IC pins. I think if we got access to that all it would take is a > battery and two wires. >If the battery still has some voltage on it, like above 1 - 1.5 V, the RAM contents may still be maintained, but not readable by the CPU. So, getting the required 3 V or so on it may bring back the system. If the data is totally gone, then you will have to go through whatever calibration procedures are required. Jon
Reply by ●March 10, 20202020-03-10
On Tuesday, March 10, 2020 at 3:07:02 PM UTC-4, Jon Elson wrote:> On Mon, 09 Mar 2020 19:18:02 -0700, jurb6006 wrote: > > > Got this HP 54501, raster based CRT scope Indications are that the NVRAM > > chip, which is more of an assembly because it has an internal battery > > has died. That is most likely due to the battery. > > > > The battery has a connection to pins on it. ;the presumption at this > > time is the battery is in too poor state of charge to operate the chip. > > This has all the setup information in it so it is not likely to work > > with it in a dead state. > > > > There has been some speculation about just taking the proper voltage to > > those IC pins. I think if we got access to that all it would take is a > > battery and two wires. > > > If the battery still has some voltage on it, like above 1 - 1.5 V, the > RAM contents may still be maintained, but not readable by the CPU. So, > getting the required 3 V or so on it may bring back the system. If the > data is totally gone, then you will have to go through whatever > calibration procedures are required. > > JonMy (increasingly volatile) memory says that this module is SRAM with a lithium cell to keep it alive. When the scope is powered, it would power the SRAM, bypassing the battery. So, if what you've got now is garbled, it's likely that the SRAM lost power completely and you are SOL as far as the data in there goes. Of course, I could be wrong - it's been quite some time since I used one of those.
