Should I buy Tektronix TDS 360 or Fluke PM3394A? - Page 1
Forum section: electronics / beginners

author: ThangNguyen
author_rank: Contributor
timestamp: June 21, 2017, 06:09:53 pm
content: Hi,This is my first post here.I would like to buy an oscilloscope for my growing hobby which is robot stuffs. Currently I am using a myRIO (NI's realtime + FPGA controller). This myRIO has 40 MHz clock rate. I decided to buy a 200 mhz oscilloscope. Right now my choice is narrow down to Tek TDS 360 or Fluke PM3394A. There is one thing concern me which make me prefer the Fluke is calibration. The Fluke has auto calibration feature while the Tek does not and it use NVRAM to store all of those information. But another side Tek has 1Gs/s while the Fluke has 200Ms/s. So I still not sure which one should I peak for current work and future, I really need your input.Thank ahead for your time reading and answering my post.

author: edavid
author_rank: Super Contributor
timestamp: June 21, 2017, 06:55:05 pm
content: Quote from: ThangNguyen on June 21, 2017, 06:09:53 pmOf those 2, I would pick the PM3394A, because:1. has useful analog mode2. 4 channels instead of 23. record length 32Kpt instead of 1Kpt (still skimpy)4. better control layout5. service manual availableHowever, if you have the money for a Rigol DS1054Z, that would be a better choice than either of these classics/boat anchors.

author: rustybronco
author_rank: Contributor
timestamp: June 21, 2017, 07:12:18 pm
content: Read this post before you decide if the 1K record length is too skimpy for your needs.https://www.eevblog.com/forum/testgear/first-scope-tektronix-tds220-vs-rigol-ds1052e/msg475389/#msg475389QuoteTo quote a PM I received... "The delayed timebase function on the TDS360 makes up for and is superior to a large record length in most applications."This won't help you with the two channel Vs. four channel issue, but the 1 Gs/s sure beats 200 Ms/s.NVRAM dying is a distinct possibility. I bought a Dallas DS1644-120+ to keep as a spare.The service manual for the TDS360 can be found here.https://doc.xdevs.com/doc/Tektronix/TDS340A/tds340a_service.pdf

author: ThangNguyen
author_rank: Contributor
timestamp: June 21, 2017, 08:07:41 pm
content: @edavid: Thanks for your info. But the bandwidth of Rigol DS1054Z is only 50 mhz. And I need to spend more money too.@rustybronco: Thanks for your info. When you have to change the NVRAM, you have to redo calibration right? As far as I know it cost money for that since I cannot do it by myself.

author: edavid
author_rank: Super Contributor
timestamp: June 21, 2017, 08:38:02 pm
content: Quote from: ThangNguyen on June 21, 2017, 08:07:41 pmYou can upgrade it for free to ~ 150MHz bandwidth.QuoteIf you are very careful, you can read the old NVRAM contents with a programmer and copy to a new one.

author: vltr
author_rank: Contributor
timestamp: June 21, 2017, 09:58:19 pm
content: One thing to remember with that era tek scope is the bad electrolytic capacitors. If it hasn't been recapped you're probably going to want to do that before they go.

author: edavid
author_rank: Super Contributor
timestamp: June 21, 2017, 10:18:29 pm
content: Quote from: vltr on June 21, 2017, 09:58:19 pmTDS300 series doesn't suffer from this problem.

author: vltr
author_rank: Contributor
timestamp: June 22, 2017, 03:35:15 am
content: Quote from: edavid on June 21, 2017, 10:18:29 pmAh very good, I spent waaay too long recapping and rebuilding traces on my 410 it has made me very shy of all the scopes with the same physical design. I'm glad the 300s can go back on the list.

author: ThangNguyen
author_rank: Contributor
timestamp: June 22, 2017, 01:58:48 pm
content: So it still comes back to 1GS/s VS Calibration

author: rustybronco
author_rank: Contributor
timestamp: June 22, 2017, 02:03:18 pm
content: Quote from: edavid on June 21, 2017, 08:38:02 pmIt is possible to do it yourself. "As I know it" you would need an accurate DC voltage source (up to 90V?), two 50 ohm terminations, two 3 foot BNC cables and a fast rise time generator. I suspect the latter device could be made or had rather cheaply.Yes, Calibration is the issue. As someone else suggested, desolder the NVRAM and clone it. Note, it's not without pitfalls.What's the price difference between the two?

author: ThangNguyen
author_rank: Contributor
timestamp: June 22, 2017, 02:26:35 pm
content: I search on eBay and found TDS 360 about $250 while the PM3394A is about $300.

author: rustybronco
author_rank: Contributor
timestamp: June 22, 2017, 02:45:14 pm
content: I paid $125 shipped for my TDS360.http://www.ebay.com/itm/Tektronix-TDS-360-Digital-Oscilloscope-Parts-Repair-75/401298370096?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649Cal expired 10-15. 18 months past.Either model you choose, weigh your ebay choices carefully. You can get stung.$15.68 shipped. (It was a P6117 200Mhz probe)http://www.ebay.com/itm/Tektronix-P6109B-Accessories/161936105201?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649$20.61 shipped.http://www.ebay.com/itm/Tektronix-P6109B-100mhz-voltage-probe-w-detachable-ground-clip/252830868376?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

author: rustybronco
author_rank: Contributor
timestamp: June 22, 2017, 03:17:02 pm
content: Do you need 200 mhz bandwidth?TDS340 100 Mhz 500 Ms/s with options. $65.00 + shipping. 2 channel, has cal stickers on it.http://www.ebay.com/itm/TEKTRONIX-TDS-340-OSCILLOSCOPE/382136330530?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D41375%26meid%3D78a897ec69db4fb7bbd93d74ee118050%26pid%3D100005%26rk%3D5%26rkt%3D6%26sd%3D122550371017http://www.toughdev.com/content/2014/01/exploring-tektronix-tds-340-100mhz-digital-storage-oscilloscope/Cheap-cheap...Just a thought.Please get other opinions on it if you do decide

author: ThangNguyen
author_rank: Contributor
timestamp: June 22, 2017, 03:58:27 pm
content: Good price

author: ThangNguyen
author_rank: Contributor
timestamp: June 22, 2017, 05:49:56 pm
content: I have just ordered thishttp://www.ebay.com/itm/TEKTRONIX-TDS-360-TWO-CHANNEL-DIGITAL-REAL-TIME-OSCILLOSCOPE-200MHZ-1GS-s-H10/272717768527?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649Calibrated 02/2017 Due 02/2019andhttp://www.ebay.com/itm/Pair-of-Tektronix-TPP0201-200MHz-10X-Passive-probe-x2/322537049249?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649I am trying to limit the money I spend for my hobby as possible since I need to buy other parts too. I may sell it later to buy the Rigol.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: June 22, 2017, 11:55:10 pm
content: Keep up on the Dallas NVRAM: the drop in replacements are going obsolete. Looks like Digikey has 10 left of the DS-1644P.

author: ThangNguyen
author_rank: Contributor
timestamp: June 23, 2017, 04:24:57 am
content: @Paul Moir: After look at your post, I search on Digikey and saw 10 available but when I bought it turned 0. Luckily I found on eBay and bought 2 from there.Thanks for reminding me.

author: rustybronco
author_rank: Contributor
timestamp: June 23, 2017, 10:43:13 am
content: More likely than not, those chip's on ebay will be clones.

author: ThangNguyen
author_rank: Contributor
timestamp: June 23, 2017, 12:18:51 pm
content: @Rustybronco: Does the clone work?Is the DS1644P-120 a dip type or power cap type?

author: rustybronco
author_rank: Contributor
timestamp: June 23, 2017, 02:01:38 pm
content: Don't know. I haven't tried the one I purchased off Ebay yet. But it's a nice looking clone!http://www.ebay.com/itm/DS1644-120-Package-DIP-28-Manu-DALLAS-Nonvolatile-Timekeeping-RAM/252854007618?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649QuoteThe one in the TDS360 is a DIP package.

author: edavid
author_rank: Super Contributor
timestamp: June 23, 2017, 03:41:42 pm
content: Quote from: rustybronco on June 23, 2017, 10:43:13 amThat's silly, there's never been a Dallas NVRAM clone spotted in the wild.What you see in the secondary market are old date codes, and possibly remarked date codes

author: rustybronco
author_rank: Contributor
timestamp: June 23, 2017, 05:25:50 pm
content: QuoteThe date code on mine is 1608A3C.https://media.digikey.com/pdf/PCNs/Maxim/M000910I.pdfhttps://media.digikey.com/pdf/PCNs/Maxim/M000843A.pdfhttps://groups.io/g/TekScopes/messages?expanded=1&d=&msgnum=105106QuotePost dated 2014.I could be wrong, but $7.00 USD for a part which normally sold somewhere in the $40 USD range leads me to suspect the EBAY part.(Image added)

author: alm
author_rank: Super Contributor
timestamp: June 23, 2017, 05:29:44 pm
content: Pretty sure I have seen reports of fake NVRAMs in the Keithley 2001 repair topic. So I highly doubt the never spotted a fake Dallas NVRAM comment, unless you want to argue that Maxim-branded DSxxxx parts are somehow different.

author: rustybronco
author_rank: Contributor
timestamp: June 23, 2017, 05:50:19 pm
content: IIRC the DS1644-120+ had a minimum order of 1K. I can't find the link at the moment. I did a far amount of searching before I bought the one that I did.It's anyone's guess at this point.

author: edavid
author_rank: Super Contributor
timestamp: June 23, 2017, 06:18:49 pm
content: Quote from: alm on June 23, 2017, 05:29:44 pmCitation please? Is it clones or fakes we are talking about? And how could you distinguish a fake part from a bad, remarked part?QuoteI was referring to the comment about clones, not fakes, and I was lumping together Dallas and Maxim.But that does raise the point that any part that is marked Dallas is pretty suspicious, since Maxim bought them in 2001. I don't know the history of the package markings though.

author: rustybronco
author_rank: Contributor
timestamp: June 23, 2017, 06:34:30 pm
content: Quotehttp://www.dictionary.com/browse/cloneFake/Clone... dealers choice.

author: alm
author_rank: Super Contributor
timestamp: June 23, 2017, 06:56:28 pm
content: Quote from: edavid on June 23, 2017, 06:18:49 pmTo me a clone is something that as advertised as such. Like an Atlas DS1644 (Dallas DS1644 compatible). Or a Compaq IBM-compatible PC. A fake is something marked as genuine Maxim/Dallas part that contains either a die with inferior specs or something completely different (an LM358 relabeled as AD727). But this distinction is sufficiently vague that it is often used interchangeably. I think in this case it is clear that it referred to something labeled Maxim/Dallas DS1644 that was not labeled as such by either Dallas or Maxim.Citation for the fake NVRAM parts:https://www.eevblog.com/forum/testgear/keithley-2002-8-5-digit-dmm-review-and-teardown/msg673264/#msg673264and a few posts around that one. And yes, that also involved Dallas parts with 2011 date codes.

author: ThangNguyen
author_rank: Contributor
timestamp: June 23, 2017, 07:30:03 pm
content: There is part with not marking at allhttp://www.ebay.com/itm/1PCS-DS1644-120-IC-RAM-TIMEKEEP-NV-120NS-28-EDIP-1644-DS1644-/192155251739?hash=item2cbd58741b:g:4eUAAOSw5cNYUks5