Recent content by GanjaTron

Yet another update, this time with good news. I finally managed to read the ROMs as an MCM68764/68766 with pulled-up CS1 in my 29B (the 288 still wasn't happy). These EPROMs are the only ones I'm aware of that cram 64kb into a 24pin package, which makes them convenient drop-in replacements for...

Quick update: Burning new 2532s changed nothing. Infact, I now realise the "garbage" pattern is actually identical every time it powers up. That seems to rule out an issue with missing reset. I now also realised I was probably barking up the wrong tree -- I was looking at the VT640 board with...

Thx for the explanation, Doug. I checked on the web and saw similar reports elsewhere, tho I never had issues with EPROMs myself. Then again, most of my stuff doesn't use the older types. The VT100 and maybe the AIM65 are an exception with their 25xx ROMs. And yeah, EPROMs are cool; I remember...

BTW: is this issue specific only to EPROMs? --Roland

Thx, Doug, will try that. I'm pretty sure I have spare 2532s around. I also discovered I *do* have a batch of 4116s that I had sitting around for another project that's now stalled indefinitely (ahem), so I could infact replace the whole set and take it from there. I now realised that the...

Hi Monty, hi everyone, hope you're enjoying the waning Easter break. I just wanted to confirm that I finally did get my MFM working -- with Jos' invaluable help. Thanks, Jos! It turned out that the DS12885 RTC was indeed faulty -- or fake. Whatever. No more silly endless password prompts...

You can get neat plots with gnuplot on these in Tek 401x mode. 😋 https://forum.vcfed.org/index.php?attachments/dsci3321a-jpg.1044408/ --Roland

Hi everyone, hope you're enjoying your Easter break. Quick update: the VT100 suddenly turned comatose; just garbage on screen, and no beep. According to the docs, the keyboard LEDS L1..L4 *may* indicate an error code from POST. L2 is consistently lit, which would indicate a checksum error in...

Hi Monty, yeah, it's been a while! :) Jos is still on to it. I understand he now concluded the DS we've got now aren't fakes, but there appears to be an issue with the GALs. Will keep you posted when we know more. TBH I've been pretty much absent from my Tek and SGIs lately. Job woes and...

Thx, Jos. No idea how to spot fakes, though I did notice the DS12885 labelling is rather indistinct compared to that of the other chips. Not sure if that's anything to go by, tho. I remember Dallas chips as having a cool and instantly recognisable clock symbol next to the DS logo, but...

Hi Jos, yeah, you beat me to that one. ;^) I used the DS12885 you sent me, which I understand is a DS12887 without internal battery. I connected the battery as provided on the PCB. I can confirm that Monty's R14 calls (HEXDEC, VLIST) work. No luck with the RTC tho; resetting the powerup string...

Hi Monty, thanks for the hints, I'd only skimmed the docs so far, wasn't aware the R14 pack offered hex-dec conversion -- which is always useful. As a matter of fact, I never get a working prompt when booting with the RTC battery installed. Instead I get a crazy CAL"!*@&#^" followed by a...

Hi Jos, hi Monty, I now assembled my MFM and it appears to work. I get the message that the R14 isn't compatible with the 4052 (at least not with my v5.1 firmware), which I understand is expected, followed by the usual prompt. But when I boot with the RTC battery installed, I'm stuck on a...

Hi Monty, thanks for the info on the Elastibands -- good to know! I guess they're only an option for a one-time recovery then. Thanks also for the info on the Flash drive; will have to think about "pimping" my 4052, also with Jos' MF Option ROM. I'll set aside some time to actually do...

Hi Monty, glad they helped, chaotic as some of those notes are in retrospect! I remember it took me -- on and off -- about 5 years (!) to hunt the complete 4052 docs down; they simply weren't in circulation back when I got the clunker. If anything, all I found were incomplete excerpts. A big...