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| Test Equipment Anonymous (TEA) group therapy thread |
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| m k:
--- Quote from: bd139 on June 29, 2022, 01:11:48 pm ---Ok some quick lunch time debuggery today. I have located the 465B failure and for once it's not a tantalum capacitor. Well that's not true, there is one shorted tant but that's not what is killing the 5V rail. It's much much worse! I eventually chased it around and found out that it only borked the power supply if channel 1 was selected. So I traced that down to the channel switch. And yep, it's a tek ASIC has gone short. But it's not an ASIC! Part is labelled Tektronix 160-0204-00 which is actually a 63S141J fuse programmable 256x4 PROM. Manual confirms this. Fortunately it's documented! Now the IC is available for £23 which is a bit much so I am considering what other options I can use here to replace it. The actual original blank PROM is fairly unobtainable and I'd probably fuck it up programming it. Will mull on it for a few days... --- End quote --- Can't you use regular 74-series stuff? |
| Vince:
--- Quote from: mnementh on June 29, 2022, 12:26:00 pm ---The point is it's not the 1980s anymore; floppy is no longer "the convenient choice". There are literally a dozen better ways to do it than floppy, and many of them are still compatible with these old machines. While none of the choices available on these machines are great, floppy is still the worst one possible. And in here, everybody knows about those better ways. mnem *puts on best Rain Man voice* "Floppy drives suck... yes, definitely... definitely suck..." --- End quote --- Yes, I am not stupid, I get that. That was you and Mansaxel's point. But that was not MY original point (it all started from my first remark, remember...), and you were both replying to me as if it was the point to begin with, which it never was. Hence it was completely irrelevant, hence I failed to see the insistence on hammering that point :-// It is exactly as if I had said for example "I find Nixie displays cool ! ", and then people vehemently writing essais on how Nixies are crap and colour graphical LCD touch screens are so much better. Eh ?! What's the point of replying that ? Or say, you saying how cool a Dragon avatar and people saying no it's stupid grow up, Dragons don't exist, read up ! :-// If you find Dragons cool there is no need to justify, what's the point of even discussing the reality of Dragons ?! :-// I could go on and on... Maybe you both misunderstood what I mean when I said I found FDD equiped TE "cool"... I thought it was obvious I meant it in an irrational / vintage interest kind of "cool", like we find our old glowing Tek scopes "cool"... That said, in Dragon's style, I would like to stir it a little and have a bit of fun, and say that... sorry, but for me, right now.... a scope with a floppy is what makes most sense to me ! :-DD I am tired of taking 20 pictures of scope screens hoping one them would be half usable, then go back to my computer desk and download the pics, adjust compression ratio etc. I don't want to have cables running across the floor on my living room either to go from the bench/scope, to my computer/desk., be it serial or GPIB or Ethernet or anything cable. Don't have these cables anyway. No all I want, sorry, just like in the '90s when these scopes were current is.... shove a freaking floppy inside the scope, put my screen capture on it, grab the floppy and take it to where ever in the house my desk/computer might be, then read that freaking screen capture, and call it a day ! A portable medium, any medium, don't care, but a portable one. USB would more practical, but not by much. file sizes are small so even on a floppy it doesn't take too long too write, I don't care one bit. OK my computer, even though it's 15 years old, doesn't have a floppy drive ? I can add one, must have one somewhere. Worse case I just get a cheap old used external floppy drive that you plug into a USB port, and that's all, big deal !! :palm: See ? I can stir it too when I want ! Hey I might morph into a Dragon one day who knows ! :-DD |
| bd139:
--- Quote from: m k on June 29, 2022, 01:21:09 pm --- --- Quote from: bd139 on June 29, 2022, 01:11:48 pm ---Ok some quick lunch time debuggery today. I have located the 465B failure and for once it's not a tantalum capacitor. Well that's not true, there is one shorted tant but that's not what is killing the 5V rail. It's much much worse! I eventually chased it around and found out that it only borked the power supply if channel 1 was selected. So I traced that down to the channel switch. And yep, it's a tek ASIC has gone short. But it's not an ASIC! Part is labelled Tektronix 160-0204-00 which is actually a 63S141J fuse programmable 256x4 PROM. Manual confirms this. Fortunately it's documented! Now the IC is available for £23 which is a bit much so I am considering what other options I can use here to replace it. The actual original blank PROM is fairly unobtainable and I'd probably fuck it up programming it. Will mull on it for a few days... --- End quote --- Can't you use regular 74-series stuff? --- End quote --- Nope - no matching parts :-// |
| xrunner:
--- Quote from: Vince on June 29, 2022, 01:22:08 pm ---Maybe you both misunderstood what I mean when I said I found FDD equiped TE "cool"... I thought it was obvious I meant it in an irrational / vintage interest kind of "cool", like we find our old glowing Tek scopes "cool"... --- End quote --- I understood you Vince. :-+ |
| bd139:
More 465B shenanigans. So I figured I'd just do a short check on the IC and see if it was pin specific. Well it was. Only the A3 line pin 4 was short to ground which is the CH1 select line. Figured the best option here would be to just bend that pin out and see if the rest of the scope works. So here it is giving me the finger: Of course I pulled the shorted tant out of the HV supply as well just to see if that would come up, but without a suitable fuse I'm not willing to power it the HT up in case I blow out the inverter transformer. So next step is to find a suitably priced fuse and stick it in and see what else is broken and if it's worth spending £23 on an IC for :-DD The scope does power up now but without HT. Progress! |
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