Recommendations to replace my old SENCORE SC61 oscilloscope  - Page 1
Forum section: electronics / testgear

author: Voxman
author_rank: Contributor
timestamp: August 08, 2020, 03:40:45 pm
content: Hello Everyone!Asking for advice on retiring my old Sencore SC61 oscilloscope that has served me well but takes up WAY too much room on my very limited workbench area. I’m just now setting up my test bench again after being out of this hobby for a long time.I’m overwhelmed by the number of choices offered these days and although I’m well acquainted with the features on my old Sencore, the new scopes out there seem to have way more features than I’ll ever use. My test/repair needs are pretty basic... I just need the scope to measure AC volts, P-P, RMS, frequency, and DC volts. Most of the work I’m doing is consumer audio amplifiers and musical instruments amplifiers (vacuum tube amps). I’m so used to the Sencore’s features that allow me to see any of the test measurements in the LCD readout displayed at the top of the scope face.I’d really like to find a scope that displays these basic measurements. Although I see a lot of digital storage scopes, I don’t think I’ll ever use that feature so if it saves me some money by not adding that type of scope to potential list, that’s fine. Also I don’t think I’ll need anything more than a 2 channel scope in the 60MHZ range. I did see a mention or 2 about scopes not being able to handle high voltages (450VDC+) which is a concern for my testing since I work on vacuum tube amplifiers. Please keep that in mind when recommending a new scope.I’d like to stay under $250 for this scope but will consider scopes above this price if they hit the mark.I’ve included a photo of the Sencore so folks who are not familiar with this dinosaur can get an idea what I’m used to and it’s various features.Thanks and much appreciation for any recommendations and adviceGary

author: Grandchuck
author_rank: Super Contributor
timestamp: August 08, 2020, 04:25:40 pm
content: Welcome Gary:Something like this?https://www.globaltestsupply.com/product/rigol-ds1052e-digital-oscilloscope?msclkid=f5fc36fb0f71113271be69d5de4853b6&utm_source=bing&utm_medium=cpc&utm_campaign=GTS.%20-%20Rigol%20(USA)%20(PS)%20(B)&utm_term=4580909045826440&utm_content=RIGOL%20-%20INSTRUMENTSThere are so many ways to go. I am sure others will chime in. You might find yourself using some of the "advanced digital" features a lot, once you learn about them.Anyway, take your time and do lots of reading about the features.

author: AVGresponding
author_rank: Super Contributor
timestamp: August 08, 2020, 04:29:42 pm
content: That's a bobby-dazzler! Shame it's too big.If size is a serious concern how about a used Fluke Scopemeter? Battery power means no worries about where you can clip your scope ground to.Though the CAT III ratings apply to a 600V limit on mine (PM99-2), the scale goes out to 1kV/div, with a 300V limit on the scope inputs meaning 3kV at the probe tips using the supplied 10:1 probes.I'd imagine (not a lawyer or an expert on glowing glass) that would be enough for B+ on most stuff? CRT voltages would be another matter ofc.EDIT: Welcome to the forum!

author: Voxman
author_rank: Contributor
timestamp: August 08, 2020, 05:19:51 pm
content: Thanks so far for the recommendations! I’ll keep checking back to see what else is being offered as a solution.One question I do have about the current gamut of scopes being offered by Asian manufacturers.... do most of these scopes in the $250 range display the measurements on screen as I’m used to having on my Sencore? I get the feeling most if not all do automatically calculate the basics and display them on screen but I wanted confirmation from users in the know.Thanks for the helpful advice!Gary

author: No.15
author_rank: Contributor
timestamp: August 08, 2020, 05:54:25 pm
content: I have no recommendation because I am a noob but I know I have amps with B+ in the 1000v + range (845)don't know how often you run into those, but it might be a considerationNot to common I guess in the amp world.(next to a 12ax7)

author: Grandchuck
author_rank: Super Contributor
timestamp: August 08, 2020, 06:36:56 pm
content: Gary, if you want to learn more about this type of oscilloscope you can peruse the manuals. Here is a link for the one mentioned before:https://physicscourses.colorado.edu/phys4430/phys4430_sp20/datasheets/Rigol_DS1052E_Oscilloscope_Manual.PDFOn page 2-92 of that manual, Automatic Measurements are explained. I think that might help you decide.

author: bdunham7
author_rank: Super Contributor
timestamp: August 08, 2020, 06:53:53 pm
content: Most of the budget scopes discussed here have a pretty good set of measurements and cursors. Some are easier to use than others, but unless you get an ultra-cheapie, I'm not aware of any that don't do this. As far as voltage issues go, just get an appropriate set of 100X probes and you'll be fine.$250 is a pretty low price point and you can get a lot more scope if you stretch just a bit. The Rigol DS1052E is $259 (and you can get an EEVBlog discount from TEquipment or Saelig just for asking) and will work, but the Siglent SDS1202X-E at $379 is what I'd recommend for you.Are you selling the Sencore? It may actually be quite valuable on eBay.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: August 08, 2020, 11:13:24 pm
content: Since you are in a similar position to myself, I though I would share my story.....I just retired an HP 1980 100 MHz scope with lots of functions including freq and rise time etc....(price 18K in 1985), this thing actually had "autoscope" in 1985. It does even more than your Sencore.I bought an Agilent 54810 (a bit upgraded, new SSD instead of HD) from someone on the forum for $400 including HP probes.The new scope is just fine but not as easy to use at lower freq as my CRT scope. Lots of functions. Love the screen. FFT is nice but not as good as a real spectrum analyzer. Screen kinda works like a windows computer, since it runs on windows, you use a mouse and can use a keyboard a little.It is always a challenge when you change instruments to get used to using the new one. From what I have seen the criticisms of various newer scopes about using various functions is a matter of preference. The more functions the bigger the menu and all menus are not arranged with the same logic.However the Agilent 54810 might be too big for you. I can never keep enough test equip close enough to the work. Space is always a problem.The comment about selling the Sencore is appropriate. It may be worth more than you would guess. I think audiophooles love that thing.Add the cash to your budget.For very high volts I use a sniffing loop rather than a direct connection when I can. I try to avoid old HV stuff since most of it is really over the hill. Got military volt meters for that also.You can always get a used high voltage probe, you probably already have one.Wally

author: 0culus
author_rank: Super Contributor
timestamp: August 08, 2020, 11:39:26 pm
content: Quote from: Voxman on August 08, 2020, 03:40:45 pmWow that thing is a real beast. I've never seen one before. Have you considered getting a rolling cart of some kind for your scope so you can not having it on your bench? Some people swear by Danger Freight welding carts for this. The reason I say so is that if you're primarily probing around in tube amps, the problem is that modern scopes really were never designed for that sort of use since vacuum tube electronics is super niche nowadays. Older units were build at a time when those sorts of things were much more commonplace, and were designed and rated accordingly, as your Sencore unit seems to be. Even the plugins for my Tek 585A aren't rated for 2 kV peak AT the inputs.

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 09, 2020, 01:05:07 am
content: At 450V you'll likely also need some differential probes, which adds a bit of cost. The cheaper ones go for about $150.

author: fastguido
author_rank: Regular Contributor
timestamp: August 09, 2020, 04:26:34 pm
content: That is one reason I have hung on to my SC61, high input voltage spec. I only pull it out when I need to measure higher voltages. I do wish is was smaller, takes up a lot of real-estate.

author: bdunham7
author_rank: Super Contributor
timestamp: August 09, 2020, 05:56:09 pm
content: Quote from: 0culus on August 08, 2020, 11:39:26 pmIt doesn't work like that. The scope depends on you using the HV-capable 10X probes that came with it.

author: 0culus
author_rank: Super Contributor
timestamp: August 09, 2020, 07:36:12 pm
content: Quote from: bdunham7 on August 09, 2020, 05:56:09 pmOh I see it now. It even says on the vertical controls, read direct with 10x probes.

author: Martin72
author_rank: Super Contributor
timestamp: August 09, 2020, 10:29:48 pm
content: Hi Voxman,First of all, you shouldn´t give away your scope after buying a new one - Analog scopes still got advantages against digital ones.Then, 250 bucks....hm-hm, in that range you should have a look at used rigol ds1054Z models.It´s not only the 4 channels ( which you won´t need) it´s got more than a DS1052E model, so look at it, very recommendable.Try to get some as cheap as possible, because for your measurings up to 450vdc you will need a differential probe today.Take a look to the micsig differential probes, god value for money.Martin

author: tautech
author_rank: Super Contributor
timestamp: August 09, 2020, 11:26:39 pm
content: Quote from: Martin72 on August 09, 2020, 10:29:48 pmActually not.100x probes are not expensive and you can get at least a couple for the cost of a differential probe.It seems from previous posts the OP's SENCORE uses HV rated 10x probes and while many are rated to 600V the derating vs frequency can make them unsuitable to be used anywhere near their rating whereas 600V is a walk in the park for a 100x probe that is no more bulky than an ordinary 10x probe.It would seem the OP has been doing fine with HV rated 10x probes so unless he needs further isolation 100x probes will work fine for his use.

author: Voxman
author_rank: Contributor
timestamp: August 10, 2020, 06:18:23 pm
content: I’ve often thought of getting a Harbor Freight welding cart to use as a roll-about cart for the SC61. The cart seems almost ideal for it except for the area for the welding tanks on back! They also offer a welding cart with drawers too but it’s too expensive for my budget right now.Seeing some conversations about the probes for measuring high voltage. I’m using the 10X probes that came with it and haven’t had any issues so far. Also using a Sencore Powerite PR-57 for an isolation transformer. It is a very versatile power supply and has saved my butt a few times. It’s a little pricey in the used market but apparently techs see the value in it. I used one long ago when I used to service guitar amps and high fidelity components. Oh those were the days!Thanks for your adviceGary

author: Martin72
author_rank: Super Contributor
timestamp: August 10, 2020, 08:10:36 pm
content: QuoteWe use the differential probes to avoid high potentials on the scope, it´s a safety thing.