TDS 784C option HD (hard disk) disappeared - Page 1
Forum section: electronics / testgear

author: james_s
author_rank: Super Contributor
timestamp: March 22, 2017, 05:46:54 am
content: So last night I hooked up a GPIB adapter and cleared the error log on my TDS 784C. While I was in there I enabled option 2C just for the heck of it, re-enabled the write protect and rebooted, congratulated myself that 2C was now showing in the list of options but something seemed a bit off about the list. Went back and checked an older screenshot that I had and sure enough, HD was missing from the list. Checking the file utilities confirmed that the hard drive is not listed anymore. What the heck? I just used the hard drive a few days earlier, I honestly don't know if it was listed when I powered up and connected the GPIB interface, I wasn't paying attention to that. Is it possible that I somehow disabled the hard drive?Thinking the drive failed, I removed the PCMCIA drive and popped it in an old laptop, the drive enumerates in Device Manager but doesn't show up anywhere as a disk. So I tried a CF card in a PCMCIA to CF adapter and that mounts as a drive in the laptop but put it in the scope, power it up and still no option HD. Opened the lid on the scope and had a look around, everything looks fine, all the cables connected, power it up and I can hear the drive spinning. Not sure what to try next, anyone know if the drive is a standard FAT format? Should a CF card in an adapter work? Is there any diagnostic function for the hard drive built into the scope? I've looked around and it seems there's almost zero information about this feature.

author: Jwalling
author_rank: Unknown
timestamp: March 22, 2017, 10:16:23 am
content: I know that the drives should be formatted FAT16. There's no diagnostics for it as far as I know. If the scope can't read from the drive for whatever reason, the HD option won't be displayed. I would try formatting the drive FAT16 in the laptop and see what happens.Does it spin up and stay spinging? No clicking over and over indicating a disk problem?FWIW, I've seen flash drives in these as well. A Sandisk SDP3B PCMCIA card.http://www.ebay.com/itm/like/321925209610?lpid=82&chn=ps&ul_noapp=trueI do know that these scopes are very finicky about the drives they support. Later D versions used a standard laptop 2GB 2.5" drive.

author: james_s
author_rank: Super Contributor
timestamp: March 22, 2017, 03:36:07 pm
content: Thanks for confirming this. Yes the drive spins up and keeps spinning, doesn't make any unhealthy noises. It shows up in device manager on the PC but isn't recognized as I drive. I can't even see it in the disk manager to create a partition.Maybe I'll try one of those Sandisk cards, they're pretty reasonably priced.

author: cncjerry
author_rank: Unknown
timestamp: March 22, 2017, 04:19:33 pm
content: This goes back a ways, but don't they use an LED to detect something when the drive spins up?

author: james_s
author_rank: Super Contributor
timestamp: March 22, 2017, 04:52:58 pm
content: I remember there were some Quantum 3.5" drives where the head arm would get stuck on the rubber stop as it aged and became sticky, I actually fixed at least one of those with that problem. They did exhibit a similar symptom, spin up but get stuck in a loop waiting for the seek to complete. I don't want to open this PCMCIA drive until I'm positive that it's bad though as there is some inherent risk in popping the lid.

author: cncjerry
author_rank: Unknown
timestamp: March 22, 2017, 05:11:48 pm
content: Quote from: james_s on March 22, 2017, 04:52:58 pmwait, you would state that you are afraid to take something apart on this forum?Note to moderator: ban this person.

author: james_s
author_rank: Super Contributor
timestamp: March 22, 2017, 06:00:39 pm
content: Hey now, I never said I was afraid to take it apart, in fact I fully intend to do so, I just want to be positive that the drive is in fact dead before I conduct an autopsyI simply know from experience that taking the cover off a hard drive occasionally kills them due to contamination. I've done it before and succeeded in fixing a few drives but I've also completely killed a few that were mostly working until I opened them. Seems that generally you can open a drive without issues but running it with the cover off screws with the airflow and causes the heads to crash. I'm not really comfortable using a drive that has been opened for anything critical, although I did run one I fixed for several years before trading away the 286 it was in.

author: cncjerry
author_rank: Unknown
timestamp: March 22, 2017, 06:04:56 pm
content: Wait, that's a hard drive? I thought it was a diskette drive.Taking the cover off a hard drive outside a cleanroom you might as well just drop it in the trash. the heads fly a few microns above the disk these days making a dust particle look like the Rock of Gibraltar.

author: james_s
author_rank: Super Contributor
timestamp: March 22, 2017, 06:16:00 pm
content: Yes it's a 170MB hard drive in the form of a double thickness PCMCIA card, the floppy diskette drive is working just fine.That's the conventional wisdom, but speaking from experience you *can* take the lid off a hard drive, tinker with it, put it back together and have it work, a clean room would be preferable but I have done this several times on my kitchen table and the drives worked after I resurrected them. The key is to not power the drive with the lid off, and minimize the the time the lid is off, minimizing the amount of dust that gets in there. There is a small filter inside the drive that will catch any dust specks that do get in so long as that happens before the heads sweep over them. It's not something you'd want to do on a working drive that you care about because there is risk, but it's not quite as dire as some would have you think. For a while a friend of mine was doing some amateur data recovery at home, he transplanted the platter from a defective drive into an identical working drive and did manage to successfully recover the data. which was not valuable enough to pay for a professional service.

author: andy2000
author_rank: Frequent Contributor
timestamp: March 23, 2017, 05:45:34 am
content: Some of those old PCMCIA hard drives seem to be a little non-standard. I've got a few that will only work in very old laptops (486 era). In more modern laptops, they aren't detected properly.I'm using a PCMCIA to compact flash adapter in my 784D, so that might be worth a try.

author: Jwalling
author_rank: Unknown
timestamp: March 23, 2017, 10:07:24 am
content: Quote from: andy2000 on March 23, 2017, 05:45:34 amI've seen that work as well, but once again, these scopes are very fussy as to which CF media they are compatible with as well.Wish I had kept notes on which ones work.Do you know the model number of the one you're using?

author: james_s
author_rank: Super Contributor
timestamp: April 18, 2017, 07:57:22 am
content: I finally got the Sandisk 256MB PCMCIA SSD I ordered from China. It's a used pull in good shape as advertised. I popped it in the scope and option HD came up and works perfectly, yay!So apparently it was nothing more than a failed hard drive, just an odd coincidence that it died when it did. The scope boots much faster now, I'd thought it seemed like it was slower than when I first got it. Apparently it was waiting for the dead hard drive to respond then finally giving up. This scope is now fully working and has become my primary scope.

author: Jwalling
author_rank: Unknown
timestamp: April 18, 2017, 10:18:10 am
content: Quote from: james_s on April 18, 2017, 07:57:22 amGood deal!Did you use the Sandisk SDP3B I mentioned above, or is it another model number?

author: james_s
author_rank: Super Contributor
timestamp: April 18, 2017, 03:28:52 pm
content: I'm not actually sure what the model number is, I probably should have made a note of that before I installed it. It's one of these:http://www.ebay.com/itm/301896421019Maybe I should buy a bunch more and resell them as replacement hard drives for Tektronix DSOs