Considering purchasing a Logic Analyzer

[stj]

Re: Considering purchasing a Logic Analyzer

http://bitsavers.informatik.uni-stuttgart.de/

[Spork Schivago]

Re: Considering purchasing a Logic Analyzer

If you have a chip number on the IC we could look up the data sheet to see how it works. That would help in troubleshooting the problem. Also, if you can give me the model number of the O-scope I will also look. The service manual should tell you how to calibrate the scope and that will also give you an indication of what has gone bad. You might what to go to this site and see if anyone has your schematics. http://www.keysight.com/owc_discussi...7356&tstart=-2

I did ask for help on KeySight's site, they're the ones who told me the schematics have long since been destroyed, along with most of the other information (like source code to the HPUX OS, etc). However, I did find a service manual on the oscilloscope module, just no schematics. I also found a datasheet on the IC but it's kind of lacking. The oscilloscope module is HP 16534A. The IC is an AMCC Q20025-0080B. This is the closest thing I could find for a datasheet for that IC...



Service manual for the 16534A is here:


Here's another link for the same document:
https://cdn.badcaps-static.com/pdfs/...dcd515e29b.pdf

The logic analyzer that the oscilloscope module goes into is an HP 16702B
Thanks for the help!

[Spork Schivago]

Re: Considering purchasing a Logic Analyzer

old gate arrays usually had an external "boot" eeprom or they had to be "mask" programmed at the factory - they didnt have flash in them then.

Yeah, someone on EEVBlog said something about "mask" programmed. Not really sure what that meant.

There's a daughter board that has something to do with trigger too, real close to this IC I believe. I wonder if that daughter board has the firmware on it. It'd be nice, that'd mean that I wouldn't have to worry about whether or not this IC was programmed then, right?

[keeney123]

Re: Considering purchasing a Logic Analyzer

If you have a chip number on the IC we could look up the data sheet to see how it works. That would help in troubleshooting the problem. Also, if you can give me the model number of the O-scope I will also look. The service manual should tell you how to calibrate the scope and that will also give you an indication of what has gone bad. You might what to go to this site and see if anyone has your schematics. http://www.keysight.com/owc_discussi...7356&tstart=-2

[Spork Schivago]

Re: Considering purchasing a Logic Analyzer

I was just saying that a gate array can be programmed in the field. If HP was responsible for making this machine you might what to call them to make sure the IC is programmed. Also, if this O-scope is an older model you might also be able to get the schematics from them. The schematic would be useful if there has been more taken out then one chip. I fact the chip may not be damage, you might of taken out a power supply circuit. It would depend on actually what was shorted and how it is connected in the circuit. The schematic would also be useful if you need to repair this thing in the future. If they are unwilling to give you the schematics there must be some company that either sells them of you can get for nothing.

Thanks Keeney123. HP sold the stuff to KeySight who destroyed it back in 2010 or somewhere around there. I've asked for a schematic but they said they have long been destroyed. It'd be nice if I could find one for this oscilloscope module. I guess the triggers on these modules tend to fail. This circuit has something to do with the triggering I do believe. The person who sold it to me showed that the oscilloscope module worked in his logic analyzer, minus the actual triggering function. I have searched high and low for a schematic. I've found the service manual for this module but it doesn't include any schematics, unfortunately.

At this point in time, I think maybe I should first try to replace the caps. I'll just maybe go for 16V MLCC 10nF SMD caps. I'll install the unit in my HP 16702B logic analyzer and try to figure out how to use the triggering function. If it doesn't work, then I'll replace the IC and see if that fixes it. I guess there's a chance the short on the IC just made the caps explode off the board and didn't actually destroy the IC itself.

[stj]

Re: Considering purchasing a Logic Analyzer

old gate arrays usually had an external "boot" eeprom or they had to be "mask" programmed at the factory - they didnt have flash in them then.

[keeney123]

Re: Considering purchasing a Logic Analyzer

I was just saying that a gate array can be programmed in the field. If HP was responsible for making this machine you might what to call them to make sure the IC is programmed. Also, if this O-scope is an older model you might also be able to get the schematics from them. The schematic would be useful if there has been more taken out then one chip. I fact the chip may not be damage, you might of taken out a power supply circuit. It would depend on actually what was shorted and how it is connected in the circuit. The schematic would also be useful if you need to repair this thing in the future. If they are unwilling to give you the schematics there must be some company that either sells them of you can get for nothing.

[Spork Schivago]

Re: Considering purchasing a Logic Analyzer

So what was the 10 nF connected to a crystal? I would imagine the type of cap would be determined where it was used. The only reason you can not program a gate array in the field would be because they do not want you to know how it is program. The gate array as I remember is full of NAND logic they can be programmed burnt in the field to configure almost any Boolean logic circuit.

Thanks for the response Keeney123. So, do you think just replacing this IC won't be enough? It'll need to be programmed? Or do you think there's a good chance that it's actually programmed? Someone, I think STJ, said they thought the part number was more or less an internal part number used by Agilent / HP. To me, that means if I find the same chip with the same part number, there's a good chance it's been programmed the same way or it's simply not programmed at all.


As for what it's actually connected to, I'm not sure, besides the gate array. The Logic / Gate Array had a broken screw grounding out terminals. I can't find schematics for the oscilloscope module. Physically looking at it, it looks like both of the caps just connect to different pins on the IC, through vias. I can't see many traces. I think maybe there's more than just two layers. I could use a DMM and try figuring out where the vias go to if it'd make a difference, like what pin number, etc.

[stj]

Re: Considering purchasing a Logic Analyzer

yea, 7404, crystal, 2 caps, maybe a resistor.
classic clock circuit.

[keeney123]

Re: Considering purchasing a Logic Analyzer

Thought you might like that one. Thanks for the info. I could not remember the values. From old school we made oscillators out of discrete components back in the 70's. First crystal I came in contact with was around 1982.

[stj]

Re: Considering purchasing a Logic Analyzer

very funny.
then i will also rephrase.
crystals use caps in the 5-30pF range

[keeney123]

Re: Considering purchasing a Logic Analyzer

Sorry Stj I will make that 10 nF into 10,000 pF

[stj]

Re: Considering purchasing a Logic Analyzer

crystals use caps in the pF range

[keeney123]

Re: Considering purchasing a Logic Analyzer

So what was the 10 nF connected to a crystal? I would imagine the type of cap would be determined where it was used. The only reason you can not program a gate array in the field would be because they do not want you to know how it is program. The gate array as I remember is full of NAND logic they can be programmed burnt in the field to configure almost any Boolean logic circuit.

[Spork Schivago]

Re: Considering purchasing a Logic Analyzer

You should have plenty fun working with that. People may not see you for days.

Yeah So, I've been trying to get this dang oscilloscope module I bought broken, fixed, to use with my logic analyzer. I contacted China and they found a bunch of the ICs I were looking for. People over on EEVBlog say it's some sort of Logic Array / Gate Array / ASIC and they're programmed during manufacturing and there's no way to program them in the field. So we're hoping the ones China sent me are programmed properly, you know, for this oscilloscope module.

I guess they're kind of like PICs were the pinouts can change. But only when they're making them or something.


Here's a problem I got though. On the back, there's two missing SMD caps. They're 10nF SMD ones that blew off / exploded I think. The IC that I was talking about, it had a screw on the pins and I think that shorted stuff out and made those caps explode. I don't know what voltage SMD caps I should get though. I don't know what type of SMD caps I should get either. I was thinking if they exploded from being shorted out, maybe they're those MLCC SMD caps? I was also thinking maybe I could just order some 15V 10nF MLCC SMD caps and see what happens. From the datasheet, I didn't see any voltages over 5V. The datasheet was just giving a very brief overview of what the chips do though.


Any suggestions?

[Spork Schivago]

Re: Considering purchasing a Logic Analyzer

very expensive last time i looked at scsi2ata adapters, i would just fit a 36gig scsi drive in it.

The SCSI2SD adapter isn't that bad. With shipping, around 69$ http://www.ebay.com/itm/SCSI2SD-3-5-...AAAOSwFnFWBHDt

I couldn't find one that didn't come with the MicroSD card. I'd probably just use one of ours. We have up to 64GB. That should be more than enough, but maybe I'll just take it up to 128GB. I worry that the MicroSD card might ware out a lot quicker than a SCSI2 drive would...

[keeney123]

Re: Considering purchasing a Logic Analyzer

You should have plenty fun working with that. People may not see you for days.

[stj]

Re: Considering purchasing a Logic Analyzer

very expensive last time i looked at scsi2ata adapters, i would just fit a 36gig scsi drive in it.

[japlytic]

Re: Considering purchasing a Logic Analyzer

I think I'm going to be happy with my 16702B when it comes. I was thinking of replacing the 18GB SCSI2 drive with one of those SCSI2SD adapters. They plug into a 50-pin SCSI port and can emulate SCSI 1 or 2 from what I've read and you just use a MicroSD card. They support SDSC, SDHC, and SDXC. The price is a little steep compared to something like a 146GB SCSI Ultra 320 drive but I'd still need an adapter for that to work in this. If the hard drive is bad, I'll probably by the SCSI2SD adapter. If it's good, I'll probably wait a few months before making the upgrade.

In case you didn't know, there are SCSI2CF (SCSI to CompactFlash) adaptors on the market as well.

[Spork Schivago]

Re: Considering purchasing a Logic Analyzer

At the time, I used the latest one downloaded from the latest ubuntu repos (which was for a higher version than 12.04 I am running on the machine I use for electronics stuff). At that time it was the same version as the one on their official download page IIRC. I don't know if it would be latest version now. I haven't needed to use it for a while.

Mostly it worked fine, but sometimes it would stop capturing prematurely. This happened in pulseview and sigrok. I suspect the hardware. I think I found a post about it online saying the same thing. I can try to find it again if you want to know the exact problem.

But aside from that issue, everything seemed OK for what I did. I never used protocol decoding so far because I so far have not needed to. But from the demo capture files included it does seem to work.

Good thing about it being open source, I expect it would be quite easy to implement new decoders.

It's okay about the exact problem, you don't have to look for it. I know they're actively developing it. I had to ask a few questions about the source code and signed up to the mailing list. I just never unsubscribed. It's almost every day now I get a few e-mails with changes to the code. I was under the impression that maybe using the latest from the repository would be a better idea than the version on their site simply because of how knew the code is. I believe there were a lot of changes made upstream (on the github page) that would fix a lot of problems. Thanks for the feedback! Much appreciated!