Re: Help! I bricked a perfectly functioning 2467B!
On Fri, Apr 5, 2024 at 06:08 PM, Sigur?ur ?sgeirsson wrote:
Hey Don,
While rewriting the scope’s previous calibration is better than nothing,
calibrating the scope is best. If it’s between spending time on restoring
calibration that’s decades past due, or spending time on fresh calibration,
I know which I’d rather do.
If you’re local to me (Montreal, Quebec), you could pop in for an afternoon
and we should be able to do a passable job of it. If not, maybe there’s
someone local to you that’s geared up.
If you have a decent synthesized signal generator or ARB, that’ll do most
or all of the job for timing. The voltage signals you need aren’t terribly
demanding either, most any 12 bit or better signal generator would do a
good job. You also need a second scope, though for most here, that’s not an
issue (except for choosing between N-1 “spares” :).
Siggi
Hi Siggi, I agree that a fresh calibration would be best. However, I don't have the equipment to do a half-decent job. The manual lists about 23 different pieces of equipment for the calibration process. Of these, I only have a couple of signal generators (an HP 8640B and an HP 3325B). The synthesized signal generator that I have (the HP 3325B) only goes up to 21 MHz (not sure if that is enough). Also, I have reviewed the calibration steps in the service manual and I find it quite daunting. So, at this point, all I am looking to do is to get the scope back to where it was before I started tinkering with it. Thank you for your offer to do an informal cal. I wish I could take you up on it, but I am not local to you (I am in North Dakota). Don
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Re: Help! I bricked a perfectly functioning 2467B!
Hi Don,
A 27C512 will be fine. What's in there now? Or did they cover it up with the sticker? You can peel it back a bit; it won't be erased by exposure to room light.
Technically, you don't need an eraser for a one-time shot at doing this, but I would have to get the program right on the first shot. Restoring the cal data hasn't been done this way before to my knowledge, and I was hoping to have more of a collaborative try at it. Once we get it right, others can repeat.
I don't want to discount the informal re-cal as Siggi suggests, but I think there's value in developing a calibration data restoration technique that does not require the GPIB interface.
-mark
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Re: Help! I bricked a perfectly functioning 2467B!
Don, regardless of any data you succeed to write to the RAM, etc,you must do a new and complete CAL , which then resets the error message when complete.
Beware the CAL procedure requires a lot of test generators and equipment and has about 150 steps.
Takes half a day if you have the right equipment and expertise
Jon
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Re: Help! I bricked a perfectly functioning 2467B!
Mark,
I found an online source that is selling used but " machine cleaned and legs straightened, and programmer verified blanked and erased, completely ready to program" 27512 EPROMs. If using this, would I still need an EPROM eraser if I am not going to reuse that EPROM? Also, are all 27C512 EPROMs interchangeable with 27512s?
Don
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Re: Help! I bricked a perfectly functioning 2467B!
Hi Don, EPROMs are erased with UV light. Typical erase time is 20-30 minutes of exposure. It's an old technology before flash became mainstream for storing firmware. That's what's in these scopes. The erase window is usually covered up with a sticker. It's also possible to try a Winbond W27C512. It's pin compatible with the old 27512, and it's electrically erasable. There's at least one report on TekScopes of someone having success with it: /g/TekScopes/message/127337You could try that before investing in a EPROM eraser. They said they got theirs on ebay. I personally haven't had good luck with genuine (and working) chips on ebay lately, but maybe worth a try. There's also the GLS27SF512 and SST27SF512, but both also out of production. Perhaps someone else has a suggestion for a 27512 stand-in that's electrically erasable? -mark
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Re: Help! I bricked a perfectly functioning 2467B!
Hey Don,
While rewriting the scope’s previous calibration is better than nothing,
calibrating the scope is best. If it’s between spending time on restoring
calibration that’s decades past due, or spending time on fresh calibration,
I know which I’d rather do.
If you’re local to me (Montreal, Quebec), you could pop in for an afternoon
and we should be able to do a passable job of it. If not, maybe there’s
someone local to you that’s geared up.
If you have a decent synthesized signal generator or ARB, that’ll do most
or all of the job for timing. The voltage signals you need aren’t terribly
demanding either, most any 12 bit or better signal generator would do a
good job. You also need a second scope, though for most here, that’s not an
issue (except for choosing between N-1 “spares” :).
Siggi
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Re: OT: need info for ILD855 optocoupler
I guess it could be anything, but the marking is ILD855. What I do know is that the "D" in ILD usually means a dual whatever it is - two opto functions, usually the same kind. It's not a big deal. I have lots of optos of various sorts, but I especially like to find specs for the ones that I have a fair number of, for possible later use. It's really weird that this one fairly modern part is so obscure. I've found data on almost every other part I've looked at recently, even going back to ones from the 1970s. I even just tried 1 (one rather than letter "I") LD855 - no good. It's not all that complicated, so I can figure out the function with some simple experiments, but it's way nicer to just have the datasheet.
Ed
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Re: Help! I bricked a perfectly functioning 2467B!
Mark,
That sounds intriguing. I might go that route if Chuck can't help me write the cal data to the RAM via the screen. In the meantime, I will be looking at acquiring a 27512 EPROM and the EPROM programmer and eraser. I am curious: why is an EPROM eraser needed?
Don
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Re: OT: need info for ILD855 optocoupler
Ed:
Any chance that this is ILD55 rather than ILD855?? Mouser has the Vishay
ILD55 available (DIP8 optoisolator, in-stock,? but nearing June 2024
end-of-life).
Mike D? N4MWP
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On 4/5/24 18:21, Ed Breya via groups.io wrote: I have a bunch (11) of these 8 pin DIP optos, clearly marked ILD855, date code 9426H, also marked with the modern UL symbol. I believe they are Siemens brand marked, with the elongated "S" overstruck with an "H" in the middle. They were pulls from some kind of junked boards sometime back.
I have searched far and wide many variations of this ID, including Siemens brand and anything else I could think of, with no luck - it seems to have disappeared from the earth. Does anyone recognize this part type, or maybe a clue to some variation or subset or equivalent that makes sense?
Ed
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Re: Help! I bricked a perfectly functioning 2467B!
Hi Don,
The EPROM is where the firmware is stored. In your 2467B it would be U2160 and U2260 which are 27512 EPROMs.
The RAM chip is separate, and is used to store run-time data. And because it is backed up with a battery on these scopes, it is also used to store the calibration data and other non-volatile information.
What I'm proposing is to replace U2160 temporarily with a specially programmed EPROM that would re-write the cal data. I would supply an image that would do that, given the EXER 02 data that you extracted. You would still need an EPROM programmer and an EPROM eraser.
Maybe not happening; was just an idea...
-mark
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On Fri, Apr 5, 2024 at 05:48 PM, Don wrote:
Hi Mark,
Thank you for your response. What you have suggested is interesting and may
well work, but it is way over my head. I have no computer programming
experience (other than a bit of dabbling with Arduino stuff). Not sure if what
you are referring to as the EPROM is the same as the RAM chip (which in my
scope is an NEC D4464C-15L chip).
It would be terrific if I can find a way to write the cal data via the screen.
I recall reading in one of the posts from Chuck Harris on this Forum where he
appeared to imply that it was possible to do so, but no details were
forthcoming. I am hoping that Chuck will respond and clarify the issue.
Don
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OT: need info for ILD855 optocoupler
I have a bunch (11) of these 8 pin DIP optos, clearly marked ILD855, date code 9426H, also marked with the modern UL symbol. I believe they are Siemens brand marked, with the elongated "S" overstruck with an "H" in the middle. They were pulls from some kind of junked boards sometime back.
I have searched far and wide many variations of this ID, including Siemens brand and anything else I could think of, with no luck - it seems to have disappeared from the earth. Does anyone recognize this part type, or maybe a clue to some variation or subset or equivalent that makes sense?
Ed
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Re: Help! I bricked a perfectly functioning 2467B!
RAM is read/write random access memory.? Power goes off, contents vanish.? EPROM is erasable programmable read only memory.? Power goes off, data stays.
RAM is the arduino's ram memory, EPROM is two varieties in an arduino, and is either the EEPROM, or the FLASH memory program storage.
Chuck Harris is to be found on the Tekscopes2 forum.
Harvey
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On 4/5/2024 5:48 PM, Don via groups.io wrote: Hi Mark,
Thank you for your response. What you have suggested is interesting and may well work, but it is way over my head. I have no computer programming experience (other than a bit of dabbling with Arduino stuff). Not sure if what you are referring to as the EPROM is the same as the RAM chip (which in my scope is an NEC D4464C-15L chip).
It would be terrific if I can find a way to write the cal data via the screen. I recall reading in one of the posts from Chuck Harris on this Forum where he appeared to imply that it was possible to do so, but no details were forthcoming. I am hoping that Chuck will respond and clarify the issue.
Don
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Re: Slightly off topic, but I'm getting desperate. Looking for the Adjustment Program for the HP/Agilent 4263B
Hi Jared,
Silly question, but is your unit actually out of specification?
If you follow the Performance Check procedure in the User manual, what fails?
Regards,
- Guy
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Re: Help! I bricked a perfectly functioning 2467B!
Hi Jon,
I have searched the Forums and did not find any guides or directions to write cal data via the screen of the scope. Could you tell me where you saw the method to rewrite data in a low SN A5 with discrete RAM and a separate battery?
Don
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Re: Help! I bricked a perfectly functioning 2467B!
Hi Mark,
Thank you for your response. What you have suggested is interesting and may well work, but it is way over my head. I have no computer programming experience (other than a bit of dabbling with Arduino stuff). Not sure if what you are referring to as the EPROM is the same as the RAM chip (which in my scope is an NEC D4464C-15L chip).
It would be terrific if I can find a way to write the cal data via the screen. I recall reading in one of the posts from Chuck Harris on this Forum where he appeared to imply that it was possible to do so, but no details were forthcoming. I am hoping that Chuck will respond and clarify the issue.
Don
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Re: Help! I bricked a perfectly functioning 2467B!
The Cal data is stored on an NEC D4464C-15L chip. The battery is separate from this chip (unlike in the DALLAS NVRAM chip)
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Re: trigger problem with 7B70
On Fri, Apr 5, 2024 at 11:14 AM, Mark Vincent wrote: The high speed transistors could be replaced with KSP10BU. The pinout is BEC. I need a PNP transistor, though. Pretty sure KSP10BU is NPN, as I have some and checked everything in my limited stash as a potential replacement. Finding a PNP over 500 MHz looks unlikely, especially in the 2 GHz range of the 151-0271. thanks, Adam
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Re: trigger problem with 7B70
Adam,
The high speed transistors could be replaced with KSP10BU. The pinout is BEC. The voltage ratings are a bit higher. It is a TO-92 case. I have, as well as others here, have used these as replacements. If you find 0367s that are leaky, the replacement is what I used to replace the original leaky one. The 0367 transistor is used in many plug-ins and some scopes. Only the 7D15 has a different p/n yet is the same transistor. From my experience, the KSP type fixed problems the leaky 0367s had in the pieces I have.
Mark
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Re: Help! I bricked a perfectly functioning 2467B!
Bonsoir cher monsieur
You did NOT "BRICK" the scope. Loss,of NV ram cal is easy to fix.
see the many threads here and especially tekscopes2 for NVRAM and CAL data, also eevblog "2465B 0" teardown
if you have the low SN A5 discret with RAM.and separate battery see the method to rewrite the data to default, or a saved copy.
the reference to prom programming is for the later SN with SMD A5 and Dallas NVRAM with internal battery.
Finally Menacham at Condor Audio in Isreal and Qservice in Greece will respond to email questions a,de are very helpful, selling Tektronix spares, recap kits, ICS, etc.
bon courage
Jon
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Re: Help! I bricked a perfectly functioning 2467B!
Hi Don,
I have the same question: "Do you have an EPROM programmer?", but for a different purpose.
One way is to write a small 6802 assembly program with the calibration data embedded in it, and have it copy that back to the NVRAM. You could burn this small program to an EPROM, plug it into the scope in place of your regular EPROM, and turn on the scope to perform the copy. Then, put your original EPROM back.
I was working on such a program, but never quite got it completed. If you are game for trying, I can work with you to finish it. You would need to get an extra EPROM or two for your scope, and you also need to have an EPROM eraser.
I am still hoping to find a way to write cal data via the screen, similar to reading it via EXER 02, but I have not found any clues that a hidden utility like that exists.
-mark
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Jean-Paul
Mike Dinolfo