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[sigma7]

Periodically we see requests for component-level troubleshooting help, and we get only so far requesting voltmeter measurements before many (appear to) give up. It isn't surprising given the amount of time it takes.

Now that there are inexpensive logic analyzers, perhaps it is time to have a standard recommendation list for what to buy to make component level troubleshooting more practical and efficient. Or perhaps the inexpensive options are still not good enough, I don't know. Hence the question:

Can you recommend a particular brand/model of inexpensive logic analyzer that would be suitable to suggest to inexperienced but enthusiastic Lisa troubleshooters?

I suppose a list of ones that are NOT suitable would be useful too.

Thanks for your suggestions!

[sigma7]

Perhaps other forums have gone through or started this process already... please post a link if you know of any!

[sigma7]

The $20 SparkFun TOL-18627 looks like a contender, anyone have experience with it?

It looks like there is a plethora of listings for things looking like that on AliExpress... perhaps all the same, perhaps not?

If not that, perhaps this list has some possibilities:

https://sigrok.org/wiki/Supported_hardware#Logic_analyzers

Worldwide availability would be important aspect.

[bmwcyclist]

I haven't gotten any deeper than using a volt/ohm meter until I got myLisa.

A close friend of mine has one of these, but I haven't had time yet to check to see if it tests any chips at the LISA has.

https://8bit-museum.de/hardware-projekte-chip-tester-english/

On his recommendation, I have purchased one of these but again on the limited time I have I don't fully know how to use it yet.

diymore LCR Meter Transistor... https://www.amazon.com/dp/B0CGRRN7SW?ref=ppx_pop_mob_ap_share

[sigma7]

A close friend of mine has one of these, but I haven't had time yet to check to see if it tests any chips at the LISA has.

https://8bit-museum.de/hardware-projekte-chip-tester-english/

It looks like the list of supported ICs covers nearly all of the chips in the Lisa.

However, since the Lisa's chips are soldered in, removing them to troubleshoot a problem is (I think probably) more work than isolating a problem with in-circuit test equipment and removing only the primary suspects, at which point swapping them with new parts is practical.

So although potentially useful, I would prioritize some other equipment first for Lisa troubleshooting.

[AlexTheCat123]

I personally use the LA2016 and it works really well. It's a 200MHz logic analyzer with 16 channels, but they also sell other versions of it with different sample rates and channel counts if you need something a bit different. It comes in at about $160, so not as cheap as the Sparkfun one that @sigma7 linked to, but well worth the money in my opinion. The software is quite nice too, and you can download it and try it out before you buy the logic analyzer itself.

[bmwcyclist]

It looks like the list of supported ICs covers nearly all of the chips in the Lisa.

However, since the Lisa's chips are soldered in, removing them to troubleshoot a problem is (I think probably) more work than isolating a problem with in-circuit test equipment and removing only the primary suspects, at which point swapping them with new parts is practical.

So although potentially useful, I would prioritize some other equipment first for Lisa troubleshooting.

Could these be used to check the chips without removal?


https://a.co/d/hDUvoY0


.

[sigma7]

Could these (IC clips) be used to check the chips without removal?

DIP clips (and the like) can be convenient for connecting to a chip in-circuit, but what you can find out from those connections depends on the equipment you are connecting to the clip.

Using them to connect a logic analyzer or oscilloscope can help reveal what is happening when the circuit is operating (or malfunctioning).

However, connecting a chip tester to a part still in-circuit is normally not useful as it can't tell whether the readings it is making are coming from the chip itself or the rest of the circuit it is connected to. Hence the requirement to remove the part to reliably test it.

In some circumstances one can locate failures by comparing in-circuit readings between a good board and a bad board, but this is not always possible and needs a greater knowledge of a particular circuit's components than typical troubleshooting.

[stepleton]

Could these be used to check the chips without removal?

It would be nice to be able to clip a gizmo onto a chip and have it apply its own gentle probing to measure whether the chip was bad. Such a gizmo exists: the Huntron Tracker, is the example I know about. These devices seem to be somewhat magical and seriously expensive. As sigma7 mentions, they also seem to need a good board to compare against.

I don't know for inexpensive logic analysers, but for amusement's sake I can share that I bought a big old Pentium-powered 136-channel Tektronix TLA714 from eBay last year, and I've also got the giant 64-pin IC clip ready to chomp down onto the 68k "Texas cockroach" as soon as the need arises. This lumbering fin-de-siecle beast is good for recording a lot of signals for a short amount of time, and mine's been very useful for debugging an old PERQ workstation (an ongoing job!). But for troubleshooting a Lisa, it is probably preferable to have a modern device with fewer channels but a longer memory.

[AlexTheCat123]

I don't know for inexpensive logic analysers, but for amusement's sake I can share that I bought a big old Pentium-powered 136-channel Tektronix TLA714 from eBay last year, and I've also got the giant 64-pin IC clip ready to chomp down onto the 68k "Texas cockroach" as soon as the need arises.

Yeah, I've also got a TLA714 as well as an HP 16702A, and they've got a whole lot of channels, but the memory depth is a huge limitation as you said. So I rarely end up using them, despite the fact that they have some really advanced features that the small modern ones lack, like the ability to decode instructions on a variety of different CPU buses. And the UIs can be pretty tough to use on some of the older ones too. But they sure look cool!

[sigma7]

The $20 SparkFun TOL-18627 looks like a contender, anyone have experience with it?

It looks like there is a plethora of listings for things looking like that on AliExpress... perhaps all the same, perhaps not?

As far as I can tell, these are clones of the lower end units of the USBee series, that were made by CWAV Inc. through 2015.

"Due to these challenges CWAV, Inc., makers of the USBee Test Pods, has chosen to go out of business effective September 10, 2015."

Apparently some software issues arose, which didn't go well... https://www.eevblog.com/forum/testgear/warning-about-usbee/.

They also have some similarities with early Saleae logic analyzers, but the specifications don't line up as well. Regardless, Saleae no longer has an inexpensive version.

So I'm thinking the sparkfun unit and similar aren't a good choice.

Still looking for widely-available low-cost and supported suggestions.

[TorZidan]

I personally use the LA2016 and it works really well. It's a 200MHz logic analyzer with 16 channels, but they also sell other versions of it with different sample rates and channel counts if you need something a bit different. It comes in at about $160, so not as cheap as the Sparkfun one that @sigma7 linked to, but well worth the money in my opinion. The software is quite nice too, and you can download it and try it out before you buy the logic analyzer itself.

I bought the LA2016 analyzer from AliExpress for ~$110 last year, and it is still around that price:
https://www.aliexpress.us/item/2251832588359410.html . It looks legit and works well.
The UI (on Windows) is not very intuitive. You would be quite lost the first time.

[AlexTheCat123]

The UI (on Windows) is not very intuitive. You would be quite lost the first time.

I wonder if the software is really different on Windows or something? I've always used it on Mac and I've found it to be pretty darn intuitive!

[sigma7]

The SparkFun TOL-18627 looks like a contender, anyone have experience with it?

Not seeing anything else widely available and inexpensive, I purchased a SparkFun TOL-18627 to try out.

The board has a Cypress CY7C68013A-56, so it is similar to the CY3689 FX2LP evaluation board with (what looks like) some filtering/protection on the digital inputs.

I'm guessing the 8 input 24 MHz USBee and Saleae logic analyzers were built around the eval board; I don't know which of those was first, but it appears some individuals made logic analyzers from the eval board too. eg. https://www.instructables.com/FX2LP-CY7C68013A-USB-Dev-Board-Logic-Analyzer/ and https://hanixdiy.blogspot.com/2011/03/cy7c68013a-usb-logic-analyzer.html