Re: Tektronix 3001GPX power up & boot

Jim Ford

Hi, Jeff.

That 3001GPX appears (from TekWiki) to be a more portable version of the Prism (or is it Prison?!) system logic analyzer/DSO that I used at a former employer back in the late 1990's. In the early 2000s, I consulted for the same company and took out some of my pay in the form of test equipment, including 2 Prism systems. I ended up selling them on eBay, but I'll try to remember how those things worked.

Mid 2000s I bought a TLA711, AFAIK the next generation Tek logic analyzer/DSO system, and used it for a while before the realtime clock battery died. In that case, it did indeed refuse to boot up. So I wouldn't be surprised if your 3001GPX does the same.

BTW, the Prism system had the General Purpose logic analyzer pods called GPX and 2 optional HSM (High Speed Module) pods with IIRC 10 channels each and 2 optional DSM probes. The HSM was interesting and useful because it had 2 thresholds per channel. Handy for checking for bus contention where one transceiver was trying to pull signals high and another was trying to pull them low. I've not seen that capability elsewhere before or since. You'd have a one and a half bit signal on the screen, almost like analog. And speaking of analog, that's where the DSM came in. It's a DSO with IIRC 400 MHz BW and 8-bit resolution, automatically sync'd to the GPX and HSM pods. Why is that signal chattering between states? Hook up the DSM and look at the waveform. Aha! Slow risetime because something is capacitively loading the bus. Etc.

Let me know if you have any questions. I'll see if I can dust off the brain cells.

Good luck with the 3001GPX!

Jim Ford

------ Original Message ------
From "Jeff Dutky" <jeff.dutky@...>
Date 5/22/2022 3:35:52 PM
Subject Re: [TekScopes] Tektronix 3001GPX power up & boot

Several of updates:

1) I verified that the hard drive option (Opt. 1M) is actually installed (which I already suspected from the "Opt. 1M" tag on the back, along with a tag indicating that the hard drive is a Seagate ST-151, rather than the later IDE version, and because the boot screen says that it loaded the software from hard disk, and says that it parked the heads when I put it in standby).

2) I let the instrument try to boot from the software on the hard drive for 25 minutes, with not change in the boot screen messages, and no apparent progress.

3) I've been reading through the service manuals, and it doesn't look like there is a way to make the boot process show verbose messages. In fact, there doesn't appear to be any diagnostic guidance for a failure to boot. My only option seems to be to boot from the diagnostic floppy (which I have images of, but I have not created a floppy from them yet).

4) I also see that there is a battery to keep the clock-calendar memory, which I assume needs to be replaced. It doesn't sound like the battery backed NVRAM holds other information (e.g. calibration constants) so maybe it won't be a big deal after I replace the battery. Would a dead battery keep the machine from being able to boot? I am skeptical.

5. All of the power on self tests pass, and I have a steady image on the CRT, which tells me that a lot of things are working correctly. The fact that I'm not seeing error messages from reading the hard disk seems to suggest that it is also working correctly. Do I need to have the probe pods connected for this to boot?

-- Jeff Dutky

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