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GanjaTron
August 22nd, 2008, 03:01 AM
Hi folks,

got my hands on a TekTronix 4052 (with one of those weird DVST screens). It powers up, but nothing else happens other than the screen glowing all green, the "power" and "busy" lamps lighting up, and the "I/O" lamp flickering faintly. After a few minutes "I/O" and the screen go dark, before coming back on again after another pause. The cycle repeats with two or three clicks from the speaker. There's absolutely no reponse to any keypresses.

I removed the motherboard and reseated all socketed chips, but to no avail. Haven't done any checks with an oscilloscope yet. Although I have a pile of documentation for it, I don't have any schematics at hand.

There's little info on the web for this system, expect on Jon Stanley's website (http://www.electronixandmore.com/articles/teksystem.html). Jon had to replace the ROMs, of which he had spares. Alas, I don't have the luxury of spares, and without a known good ROM dump I have no way of checking the validity of my ROMs.

Anyone here have any hints or could supply me with a set of schematics?

Thanks,

--Roland

Frankie
October 26th, 2008, 12:52 PM
EPROM's don't last forever, and eventially you have to reburn them which I think is why your Tektronix isn't working. Have you tried contacting the guy to that website to see if he can reburn your EPROM's for you? Or if you have a EPROM burner, have you asked him to email you an image copy?

GanjaTron
October 27th, 2008, 11:58 AM
Have you tried contacting the guy to that website to see if he can reburn your EPROM's for you? Or if you have a EPROM burner, have you asked him to email you an image copy?

Hi Frankie,

I did contact Jon, but he's currently in college and doesn't have access to his Tek. I have a burner so I could make my own EPROMs... <b>but</b> as far as I can after a close inspection of the motherboard(s), the Tek doesn't have EPROMs. It appears to have PLAs and mask programmed ROMs. Not sure if those are prone to failure. I've yet to check mine with a scope for any activity at all, which is kinda difficult since you can only test the board in situ while somehow getting around the monitor assembly above it.

--Roland

GanjaTron
October 27th, 2008, 12:06 PM
Have you tried contacting the guy to that website to see if he can reburn your EPROM's for you? Or if you have a EPROM burner, have you asked him to email you an image copy?

Hi Frankie,

I did contact Jon, but he's currently in college and doesn't have access to his Tek. I have a burner so I could make my own EPROMs, but as far as I can see after a close inspection of the motherboard(s), the Tek doesn't have EPROMs. It appears to have PLAs and mask programmed ROMs. Not sure if those are prone to failure, and if they were I'd be screwed anyway.

I've yet to check mine with a scope for any activity at all, which is kinda difficult since you can only test the board in situ while somehow getting around the monitor assembly above it. In any case, I'd have little to go on without a hardware manual. Jon might have one, but it's gonna be a while before he can check. If someone here has one, I'd certainly appreciate it.

--Roland

NathanAllan
November 20th, 2009, 07:50 PM
I also contacted Jon and he's been emailing back and forth with me, I'm working to diagnose this 4052.

Bump to wake up a great and related thread.

GanjaTron
November 21st, 2009, 12:02 PM
Well, glad to see somebody out there's got a similar challenge on their hands. :)

Nothing really new on my end, and still no service manual. I found one on eBay in the States but I'm not about to shell out a ridiculous 50 EUR (incl. shipping) for a manual which may not even solve my problem. The Tek's been sitting stripped down in my office since April, garnering strange looks from colleagues. No luck so far.

I checked the bus for activity with a scope some time ago, and there's a repeating pattern, so it's not entirely dead. It looks like it's stuck in some loop, apparently resetting with each cycle (lasting a bit over a second), with all signals briefly collapsing and a clicking coming from the speaker. Either the ROMs contain crap and send the Tek into Lala-Land or it's misconfigured and expecting some hardware add-on it doesn't have.

Nathan, got a service manual at hand? ;)

Regards,

--Roland

NathanAllan
November 22nd, 2009, 03:02 PM
I do have the service manual!

There's a photocopied one that's very blurry and the entire thing on microfilm (*from* Tektronix, so it's historical, too!). Hopefully I can go to the community college and scan them in and make some high-res copies of it.

Another thing I will be doing is making mid-res scans and posting them online for people. The original films just have to stay with me, I can't let those go :)

When I find a place to do it for me (if not the college) I'll let you and everyone else know. My little shop is about to start a server and I'll grant access via FTP to the files when they get made.

GanjaTron
November 23rd, 2009, 12:40 AM
Hi Nathan,

now *that's* good news! They'll charge a fee for the microfilm transfer no doubt, but I'd be happy to make a contribution via Paypal. Let us know when it's ready.

Regards,

--Roland

GanjaTron
January 15th, 2010, 06:08 PM
Hi Nathan,

hope you got the new year (decade?) off to a good start. Any luck with that manual on microfilm?

Regards,

--Roland

dave_m
January 15th, 2010, 08:58 PM
Roland,
Have you seen this thread on the 4052 at /genre/other called "Saving ROM data from Tek 4052". There is some info on the ROMs and PLA.

GanjaTron
January 19th, 2010, 02:12 AM
Hi Dave,

thanks for pointing that out. Boy, if the ROMs really are shot (tho I'm not even sure they are) I guess it's really a write-off. I'll drop something in that thread to hopefully confirm I indeed have a ROM problem.

--Roland

MikeS
January 19th, 2010, 07:34 AM
Hi Dave,

thanks for pointing that out. Boy, if the ROMs really are shot (tho I'm not even sure they are) I guess it's really a write-off. I'll drop something in that thread to hopefully confirm I indeed have a ROM problem.

--RolandI'd think that if it was a bad ROM or two that'd be a pretty easy problem to fix if you can get someone to dump a set of good ones to compare yours to. The OP in that other thread plans to do that, maybe you can get together. I'd also think that it would likely work with the patch chips removed; maybe you can persuade him to pull them out and see (in case they're the problem).

Bad ROMs are not as rare as one might think.

MikeS
January 19th, 2010, 04:40 PM
In case you didn't see it, check that other thread again; looks like the images are already on line, thanks to Al Kossow's tireless efforts and whoever supplied them in the first place; since you've got a burner/reader it should be easy to compare them to yours.