New to me Oscilloscope - Page 1
Forum section: electronics / beginners

author: larrybl
author_rank: Regular Contributor
timestamp: April 30, 2021, 06:28:23 pm
content: I'll be picking this up Sunday, any suggestions on checking it out before powering up? No variac or isolation transformer available.

author: fordem
author_rank: Regular Contributor
timestamp: April 30, 2021, 06:39:22 pm
content: Verrry nice - my first scope was a used heathkit - you can grab the manual here...https://www.audioservicemanuals.com/h/heathkit/heathkit-io/26846-heathkit-io-4105-manualMaybe take a look at the initial test section of the manual, there are a series of resistance tests intended to catch assembly mistakes, they should catch any major defects.

author: larrybl
author_rank: Regular Contributor
timestamp: April 30, 2021, 07:03:25 pm
content: Thanks for the manual!

author: james_s
author_rank: Super Contributor
timestamp: April 30, 2021, 08:55:28 pm
content: Just plug it in and flip the switch, be ready to yank the power cord if there is smoke or scary noises. I'd bet it will just power up and work more or less, might need to have the switches cleaned.

author: larrybl
author_rank: Regular Contributor
timestamp: April 30, 2021, 08:59:00 pm
content: I'll take my time, may pull the top cover for a visual inspection and make sure no rodents or pugs are in it.

author: larrybl
author_rank: Regular Contributor
timestamp: May 02, 2021, 06:58:16 pm
content: I have the scope, and a LOT of re-sorting. All for free, Friend paid $20 at a yard sale for all this. He just gave it to me.

author: james_s
author_rank: Super Contributor
timestamp: May 02, 2021, 08:36:54 pm
content: Looks like a lot of good random bits, that would have been the basis of a really nicely equipped lab in the 80s-90s. It's pretty old stuff but still serviceable and it's hard to beat the price.

author: larrybl
author_rank: Regular Contributor
timestamp: May 02, 2021, 08:48:20 pm
content: He said the guy that had it was into Ham Radio. I'll run to town later this week (after I see if it works) and see if I can find some probes for it.

author: james_s
author_rank: Super Contributor
timestamp: May 02, 2021, 08:51:35 pm
content: I don't even know where you'd find scope probes locally anymore. You can get a set of P6100 probes for around $15 shipped from various ebay sellers, they're quite good as far as inexpensive probes go.

author: larrybl
author_rank: Regular Contributor
timestamp: May 02, 2021, 10:39:14 pm
content: There is a L&M Electronics store in town that is like what Radio Shack used to be. As for a quick test I could run a thin wire from the (1V P-P 60hz) connector to the center pin of the input B&C connector. What do you think?

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: May 02, 2021, 11:15:38 pm
content: This is a low freq low impedance input device.To be safe, just use a capacitor between the 60 Hz and the center pin of the BNC, like maybe 10 micro farads.I don't know what probe would work, but that would be in the manual., just check before you order any probe so you don't waste your money.The capacitance of the probe is usually the factor you use to match it to the scope. But this might call for a direct 1:1 probe.

author: fordem
author_rank: Regular Contributor
timestamp: May 03, 2021, 12:06:37 am
content: Quote from: larrybl on May 02, 2021, 10:39:14 pmYou'll be fine - that would be the equivalent of an X1 probe - see AC Calibration pg76/77 of the manual.By the way - the input connector is BNC - Bayonet Neill–Concelman - not B&C.

author: larrybl
author_rank: Regular Contributor
timestamp: May 03, 2021, 02:45:07 am
content: Free Oscilloscope first power up and check out. Might try and see the points action on the 1978 Roper tractor in the back ground.

author: Jwillis
author_rank: Super Contributor
timestamp: May 03, 2021, 07:51:21 am
content: Awesome find . Deflection yoke needs a little twist . Careful of the high voltage .

author: Gyro
author_rank: Super Contributor
timestamp: May 03, 2021, 08:48:31 am
content: I'll never forget the excitement of building my heathkit scope. Nice find.Quote from: Jwillis on May 03, 2021, 07:51:21 amActually, it's the tube itself that needs to be rotated (after first loosening the neck clamp). The instructions will be in the manual. Don't overtighten the clamp afterwards.EDIT: Keep it away from the points on your Tractor - The high back EMF from the coil will kill it stone dead!

author: fordem
author_rank: Regular Contributor
timestamp: May 03, 2021, 11:06:37 am
content: Quote from: Jwillis on May 03, 2021, 07:51:21 amI believe most scopes, at least the ones I've opened up, use electrostatic deflection, so no yoke to twist.Now remove that capacitor, set the input for DC coupling, and you should get a nice clean square wave.

author: CaptDon
author_rank: Super Contributor
timestamp: May 03, 2021, 05:01:10 pm
content: Oscilloscopes don't have yokes!!

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: May 03, 2021, 05:13:18 pm
content: This thing will be great for Audio Freq, which are sometimes hard to see easily on digital scopes.

author: james_s
author_rank: Super Contributor
timestamp: May 03, 2021, 07:27:50 pm
content: Quote from: CaptDon on May 03, 2021, 05:01:10 pmMost CRT based digital scopes had yokes, but yes, all analog scopes use electrostatic deflection instead. Better ones have a rotation coil with a pot to rotate the trace but more basic models typically you loosen some screws and just twist the entire tube.

author: larrybl
author_rank: Regular Contributor
timestamp: May 03, 2021, 08:04:31 pm
content: Need to tighten up the BNC connector, and read the manual to adjust the screen. There may be a POT for that.

author: james_s
author_rank: Super Contributor
timestamp: May 03, 2021, 09:50:45 pm
content: I don't see a rotation coil on there, this is a very simple scope and not the sort likely to have a feature like that. I suspect you loosen up the screw on either side of the strap holding the neck and then just gently rotate the entire tube before cinching up the screw. Careful not to crank it too tight, you don't want to crack the tube. Also might be prudent to wear safety glasses when you have the cover off as that tube doesn't look like it has any form of implosion protection.

author: JDubU
author_rank: Frequent Contributor
timestamp: May 03, 2021, 10:08:12 pm
content: Quote from: james_s on May 03, 2021, 09:50:45 pmThe CRT rotation adjustment is on page 74 of the manual:https://www.audioservicemanuals.com/h/heathkit/heathkit-io/26846-heathkit-io-4105-manual

author: larrybl
author_rank: Regular Contributor
timestamp: May 03, 2021, 10:15:18 pm
content: Yep, got it sorted and the BNC tightened up. I'll do a little dusting before putting the case back on.

author: james_s
author_rank: Super Contributor
timestamp: May 03, 2021, 11:17:46 pm
content: Looking good, that's a nice clean classic scope. Gives me a warm fuzzy feeling, I can almost smell it just looking at the picture, old electronics like that all seem to have the same scent of warm dust.

author: larrybl
author_rank: Regular Contributor
timestamp: May 04, 2021, 12:15:36 am
content: My local electronics store did not have a probe. (they used to). I did pick up a few things while there.

author: CaptDon
author_rank: Super Contributor
timestamp: May 04, 2021, 12:37:05 am
content: I always forget that what the other posters mentioned, that digital storage scope with C.R.T.'s do tend to have yokes. All of my TDS C.R.T. models do. of course the TDS with LCD don't. Looking at the picture of the original posters scope and being familiar with the model I realized it was electrostatic all the way and it may or may not be equipped with a rotation coil. We have some oddball TEK scopes at work, 2430 I think that are digital storage with analog electrostatic C.R.T.'s. Sadly, I don't like them since they suffer the same aliasing as a pure digital scope. We have a need for medium bandwidth pure analog scopes. We do diesel fuel injector PWM at 100khz but the injection waveforms themselves are long at sometimes 20ms. When we slow the sweep to see multiple injections then the 100khz will alias and look way whacked out on digital scopes. The pure analog scope shows the nice smooth loop control of the 100khz exactly the way we tune it and you can see the nice PWM control of the boost, hold1 and hold2 phases of the injection cycle. Cheers folks!!! I love scopes, been using them since the OS8 military units.

author: larrybl
author_rank: Regular Contributor
timestamp: May 04, 2021, 12:46:54 am
content: Well the manual says this is a 5Mhz scope, so Audio is about it for this. I decided to try and see what the Capacitance checker signal looked like on my DDM.I placed the 10uf cap in the ddm to see the signals.First picture is with (Time set to 2ms and Volts set to 0.02)Second is with (Time set to 200ms and Volts set to 0.01)Third I changed the settings on the DDM.I may get the 150 electronica kit out and build a couple oscillator / audio circuits to play with.

author: james_s
author_rank: Super Contributor
timestamp: May 04, 2021, 03:05:52 am
content: Quote from: larrybl on May 04, 2021, 12:15:36 amThat place reminds me of Active Electronics, now long gone. I'm envious that there's still anything like that around, enjoy it while you can. I'm surprised they didn't have a probe, but you can order a pair of P6100 probes from a US seller if you want them fast, Jameco stocked them last I looked.

author: larrybl
author_rank: Regular Contributor
timestamp: May 05, 2021, 02:12:52 am
content: Little O-Scope project will be on hold. I have a rescue mission tomorrow to save a 1966 Cub Cadet Garden Tractor. I expect this to be about 9 Month restore project.

author: james_s
author_rank: Super Contributor
timestamp: May 05, 2021, 05:50:48 am
content: That's a neat little tractor. Reminds me a bit of the Jacobson tractor my grandmother had when I was a kid.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: May 05, 2021, 12:06:55 pm
content: Some of my best Zen time is accomplished from the seat of a tractor. Enjoy.

author: larrybl
author_rank: Regular Contributor
timestamp: May 05, 2021, 09:08:17 pm
content: Thanks! this will be # 12 or so. I enjoy doing ground up restores. I purchase these for a few hundred dollars when I find them, then make them show quality. Here are a few I have done.

author: james_s
author_rank: Super Contributor
timestamp: May 05, 2021, 09:47:17 pm
content: Those are beautifully done. That newer Craftsman looks identical to the one we had when I was a kid. My friend and I drove it all over the neighborhood once on a summer day while my parents were at work.