Plugging in power to other side..

[syzygy]

My hands were never steady.. which makes probing stuff on electronics interesting. But the vision thing is new and I guess I'm just getting out of the denial stage of grief about it. Age. Sigh. I really should invest in some tools for magnification.

What on earth are you waiting for? Would you try to use an IC and not have a data sheet but instead just try and guess at what the pins do? If you can't see the probe markings you are simply not giving yourself much of a chance to fix any of these boards. Be thankful you can see *with* magnification.

I just looked at my orders and four years ago, I bought these: https://www.amazon.com/Magnifier-In...le-Professional-Electronic/dp/B075R5HSMM?th=1

I have two powerful, easily positioned *bright* lamps.

I use a small fan when soldering (sorry no fume hood).

I have not wanted/needed to go to a microscope (hate the idea of decreased depth perception) but I will if I need to do that, e.g., https://www.amazon.com/MOYSUWE-10-i...lpcontext&ref_=fplfs&smid=A26A6QJMZTDWZT&th=1

Not trying to hijack your thread but for crying out loud, make some choices.

​

 

[Chuck(G)]

That Locisne headband magnifier looks interesting, but my Optivisors go back nearly 30 years. Real high-qualtiy glass lenses. Optivisors are what the medicos use at the local hospital.

I might try that Amazon one just for curiosity; for $15 it's not a big gamble.

For a time, I wondered about the high-power headsets that dentists and surgeons use. The indication that I get is that the magnification is so high that it takes a lot of practice to use. Maybe next year.

 

[falter]

What on earth are you waiting for? Would you try to use an IC and not have a data sheet but instead just try and guess at what the pins do? If you can't see the probe markings you are simply not giving yourself much of a chance to fix any of these boards. Be thankful you can see *with* magnification.

I just looked at my orders and four years ago, I bought these: https://www.amazon.com/Magnifier-In...le-Professional-Electronic/dp/B075R5HSMM?th=1

I have two powerful, easily positioned *bright* lamps.

I use a small fan when soldering (sorry no fume hood).

I have not wanted/needed to go to a microscope (hate the idea of decreased depth perception) but I will if I need to do that, e.g., https://www.amazon.com/MOYSUWE-10-i...lpcontext&ref_=fplfs&smid=A26A6QJMZTDWZT&th=1

Not trying to hijack your thread but for crying out loud, make some choices.

Easy...

I've had perfect near vision until very recently. Sometimes it takes a little while for it to click in that something physically has changed. I do have some magnification gear just not quite what Chuck has. Even under magnification the X1/X10 markings weren't super easy to see.

 

[syzygy]

That Locisne headband magnifier looks interesting, but my Optivisors go back nearly 30 years. Real high-qualtiy glass lenses. They're what the medicos use at the local hospital. For a time, I wondered about the high-power headsets that dentists and surgeons use. The indication that I get is that the magnification is so high that it takes a lot of practice to use. Maybe next year.

Sounds like you have a piece of good old equipment - wonder what something similar, if available, would cost now.

It is decent and I am happy with it (actually used it today). I would say that I don't really need the 3 lower powered lenses and wish they had 5x and 7x instead. Also, I have never used the LED. As I mentioned, I use some nice bright lamps. One thing I am very impressed with is that the lenses have not (yet) gotten scratched up, which is what I worried about.

I miss having a large, swing out, and illuminated magnifier that is attached to the bench. Alas, it is not too practical in my current situation.

 

[syzygy]

Easy...

I've had perfect near vision until very recently. Sometimes it takes a little while for it to click in that something physically has changed. I do have some magnification gear just not quite what Chuck has. Even under magnification the X1/X10 markings weren't super easy to see.

Sorry if I was being too harsh and you make a point. I was just trying to encourage you to maximize the possibility of success with what you are trying to do. It becomes easy to get used to these new "helpers" once you start using them. It is anything but throwing in the towel (not that you said that, but such is a common reaction, which I also have felt), in fact, it is actually acting like you have more rounds to fight.

 

[falter]

Sorry if I was being too harsh and you make a point. I was just trying to encourage you to maximize the possibility of success with what you are trying to do. It becomes easy to get used to these new "helpers" once you start using them. It is anything but throwing in the towel (not that you said that, but such is a common reaction, which I also have felt), in fact, it is actually acting like you have more rounds to fight.

All good. I appreciate the encouragement. I'm a bit slow with adaptation - Dave pleaded with me to get and use a scope for years before I finally did, because I found the thing so intimidating. Plus with all the personal events this year I've not really had time to dig into anything repair wise very often.. hoping as things calm down for Xmas I can finally concentrate on my lengthening repair list.

 

[daver2]

Falter,

Just take things one step at a time.

When I was a 'youngster' learning how to use an oscilloscope I was given a selection of different voltage batteries and told to measure the DC voltage on each. Some of them were flat (so you couldn't go off the markings). That taught me how to set a ground reference, set up the Y sensitivity correctly and measure DC voltages accurately.

Next I was given an NE555 oscillator. The guy who ran the electronics club randomly adjusted the frequency and we had to work out what the frequency was.

Basically, the things got more and more complicated until I became quite proficient and moved on to repairing things.

Too often people try and take short cuts and skip all the learning.

Some of the 'lessons' were about good (and bad) measurement techniques - where is the safety earth connected, ground loops etc. It is amazing how many things you can observe with an oscilloscope that do not actually exist in reality (it is faulty measuring techniques)!

Dave

 

[daver2]

Of course, the 'fun' learning started when repairing televisions.

Some (old) televisions had 'live' chassis.

The oscilloscope had an earthed ground clip.

If you accidentally connected the oscilloscope ground clip to the TV chassis you had brown pants!

We generally ran with the oscilloscope safety earth disconnected at the mains plug and a hefty life insurance policy!

You also need to watch for things like this in vintage computer power supplies. If the mains safety earth is connected to anything other than 0V/ground, be wary of where you connect an earthed oscilloscope ground clip to.

Dave

 

[Hugo Holden]

That Locisne headband magnifier looks interesting, but my Optivisors go back nearly 30 years. Real high-qualtiy glass lenses. Optivisors are what the medicos use at the local hospital.

I might try that Amazon one just for curiosity; for $15 it's not a big gamble.

For a time, I wondered about the high-power headsets that dentists and surgeons use. The indication that I get is that the magnification is so high that it takes a lot of practice to use. Maybe next year.

There is not as much useful crossover as you might think. I have mainly used optical devices, lighting head lamps, microscopes etc in Ophthalmology, but little of that has any great application in a electronics workshop. Occasionally I have taken something into work for examination with a slit lamp or binocular microscope, but not often.

However there is one optical medical tool very handy in a workshop, that is the Otoscope. These have a short viewing range, provide a light source and are hand held. The new generation ones used white LED's. They were designed for a GP or ENT specialist to examine the Tympanic membrane and external ear canal. But they are excellent as a small tool to pick up, to examine local areas on pcb's, tiny markings on components etc. Otoscopes are relatively cheap on ebay now.

When the eye's auto-focus mechanism fails, which it does gradually with age, its called Presbyopia. If a person is over 55 to 60 and Presbyopic with reasonable distance vision, typically reading or near glasses are required unless there is some Myopia present which can mask over some of the the effects of Presbyopia. (A two diopter myope for example has a situation where the focal point of their eyes are 1/2 of a meter from the eye, regardless of their age and how advanced their presbyopia is). Many people can get away with cheap readymade near glasses for near work, unless there is a large refractive difference between the eyes or significant astigmatism. Then its better to have them made by the Optometrist.

 

[Chuck(G)]

When the eye's auto-focus mechanism fails, which it does gradually with age, its called Presbyopia. If a person is over 55 to 60 and Presbyopic with reasonable distance vision, typically reading or near glasses are required

Unless you're a geezer like yours truly, who long ago had cataract surgery. There, the eye's focus is pretty much fixed. One of the pre-surgery question is "Where should we place the focus--near or distant?" I enjoy being out-of-doors and don't want to be hampered by eyewear, so I chose "distant". And indeed-distant objects are perfectly in focus. And I have a bowl of reading glasses in varying strengths. To read the screen of my computer right now, it's a +2 diopter correction, for example.
Of course, illumination matters, not only to see the zits on your work, but also because of the depth-of-field improvement it effects.
I'm surprised that you didn't mention the endoscope--that fiber-optic snake with a light source and a camera at one end. Very useful to see into tight spaces and around corners. And of course, at one's periodic colonoscopy...and inspection of clogged sewer lines, etc.

 

[Hugo Holden]

There are endoscope like tools used in mechanic's workshop. They were handy if the cable that opened the bonnet broke and you can use one to hook a wire onto the bonnet release mechanism. I have never required one in my electronics workshop though...yet.

As you say higher light levels do help and a smaller pupil helps increase the depth of field of focus. Most of the eye's ability to adjust to light levels comes from the Retina though, which can adjust over levels of a factor of 10,000. The surface area of the pupil only varies by a factor of 30. As we age though the pupil gets smaller. It prompted one author to write: " Youthfulness and excitement dilate the pupil and old age & boredom constrict it". If you look at young people's eyes in low-ish level lighting, you will find they have very large pupils.

Unfortunately disease conditions like dry AMD reduce the retina's ability to see in low light levels and result in photo-stress delay, where it takes the retina a longer time to recover sensitivity after being exposed to bright light.

 

[Hugo Holden]

....PS: Belladonna (Atropine) dilates the pupil and it also can moderately de-focus the vision (which can help, typically if the woman had used it and the man on their date was not an oil painting). For this reason, historically at least, it had been used as a sort of cosmetic, to make a woman appear more youthful and attractive, since large pupils are associated with youth & beauty. It had the potential to improve the odds of attraction for both parties. Except that in some cases, in people with very narrow angles (the drainage area where fluid exits the eye) it could induce a sudden onset attack of angle closure glaucoma.

Also, on the topic of retinal adaptation to low light levels, the process can take as long as 20 minutes, almost tracking the time frame of the loss of light you get with a sunset (another evolutionary feature) . In the old days, the projection systems in the Cinema were not very bright and they would bring the punters in before the show and turn down the lights slowly, to dark adapt them. In the days before Triac light dimmers were invented, they used magnetically saturable transformers.

 

[falter]

Of course, the 'fun' learning started when repairing televisions.

Some (old) televisions had 'live' chassis.

The oscilloscope had an earthed ground clip.

If you accidentally connected the oscilloscope ground clip to the TV chassis you had brown pants!

We generally ran with the oscilloscope safety earth disconnected at the mains plug and a hefty life insurance policy!

You also need to watch for things like this in vintage computer power supplies. If the mains safety earth is connected to anything other than 0V/ground, be wary of where you connect an earthed oscilloscope ground clip to.

Dave

New anxiety discovered. Thanks Dave haha

I do have a situation like this.. I have a MITE printer and the safety earth is not connected to anything at all inside the chassis. No idea where it belongs or if it does.

 

[syzygy]

Unless you're a geezer like yours truly, who long ago had cataract surgery. There, the eye's focus is pretty much fixed. One of the pre-surgery question is "Where should we place the focus--near or distant?" I enjoy being out-of-doors and don't want to be hampered by eyewear, so I chose "distant". And indeed-distant objects are perfectly in focus. And I have a bowl of reading glasses in varying strengths. /-/.

What you called the "pre-surgery" question is an issue that I have discussed at great length with several relatives and close friends. You made an informed choice, others don't get to that as easily. For example, someone who has worn glasses for most of their adult life and also does a *great* deal of reading, needs to know that correcting far distance at the expense of presbyopia may not be what they want at all, but I fear for some, the treat of no more glasses for distance is too compelling. Getting a new lens to replace the clouded one is the main thing. I am constantly amazed by how the technology has improved such that these procedures are now so common place.

As I am sure @Hugo Holden knows, there is even a "monovision" procedure where one eye is corrected for near and the other for far. The visual system beyond the retina is so bloody amazing that for many, as I read, this works out well. I guess my point is to ask the questions to the medical professionals and keep asking them until you understand and are comfortable with making an informed (and evidence-based) choice.

BTW, one of the reasons that I use the product that I mentioned is that they are worn in a similar fashion as eyeglasses, which I am much more comfortable with than a full headband apparatus.

 

[syzygy]

....PS: Belladonna (Atropine) dilates the pupil and it also can moderately de-focus the vision (which can help, typically if the woman had used it and the man on their date was not an oil painting). For this reason, historically at least, it had been used as a sort of cosmetic, to make a woman appear more youthful and attractive, since large pupils are associated with youth & beauty. It had the potential to improve the odds of attraction for both parties. Except that in some cases, in people with very narrow angles (the drainage area where fluid exits the eye) it could induce a sudden onset attack of angle closure glaucoma.
/-/

I don't disagree at all. In fact the word "belladonna" in Italian means, literally, pretty (bella) woman (donna). You may not know that, just a few months ago, the USFDA approved pilocarpine drops for the treatment of presbyopia. I am sure this will be beneficial for some individuals, but I can't help but wonder if this becomes something of a "boutique" drug that gets over-used. I worry about that kind of thing in this age where so many complicated pharmacological treatments are advertised on the media and we get numb (and dismissive) to the package inserts. Makes me long for the days when the big regulation was comercials not showing the actual consumption of the frosty mug of beer, but every possible aspect up to that point.

 

[syzygy]

Falter,

Just take things one step at a time.

When I was a 'youngster' learning how to use an oscilloscope I was given a selection of different voltage batteries and told to measure the DC voltage on each. Some of them were flat (so you couldn't go off the markings). That taught me how to set a ground reference, set up the Y sensitivity correctly and measure DC voltages accurately.

Next I was given an NE555 oscillator. The guy who ran the electronics club randomly adjusted the frequency and we had to work out what the frequency was.

Basically, the things got more and more complicated until I became quite proficient and moved on to repairing things.

Too often people try and take short cuts and skip all the learning.

Some of the 'lessons' were about good (and bad) measurement techniques - where is the safety earth connected, ground loops etc. It is amazing how many things you can observe with an oscilloscope that do not actually exist in reality (it is faulty measuring techniques)!

Dave

I hear you loud and clear on"too often people try to take short cuts and skip all the learning" Here is a different perspective. I am not an EE and have absolutely no formal EE training - just a pure and fun-loving hobbyist. My first O-scope was something like this one - toy like and I had to assemble some of it. I used it for two years and while obviously limited, it actually did work and taught me a great deal (apart from how cool it is to look at wave forms). Finally, I bit the bullet and shelled out for a better one - this one in fact, and I got it after learning of a short-term 50% off sale and it was cheaper than that listed price. I love it and it works. Being a battery-operated hand-held I don't have to worry so much about blowing it up with mains ground issues (correct me if I am wrong) and space is not an issue. In any event, I don't mess with mains power except in the rare occasion of installing a safety outlet or something and there I have a non-contact voltage detector and an understanding and great respect for turning breakers off and verifying that safety procedures are in use (and watching a dozen utube vids).

My point is that I don't want to become an expert in oscilloscopes, I want to build, or fix, the thing I am working on. Every time I use my scope, I spend a good 10-20 minutes relearning how to use the thing. I have on several occasions, declined kind offers of receiving a large, expensive, old scope because it is way over my head (and space limits). I even considered, but discounted turning an old XP into a scope. Still, I am (mostly) getting things done with the modest scope I have (am using it today).

Went through a similar process with logic analyzers, eventually buying a cheap knock off (not proud of that) and use older versions of established software, because I finally got to the point where trying to solve some I2C problem was too much of a pita and those things work great and the software knows about a ton of protocols. I was amazed at how easy that made the task. Same for the scope. The next time I use the logic analyzer, I will likely spend an hour figuring out how I did it the last time - i.e., relearning.

So yes, you are 100% right when you say..

Just take things one step at a time.

Even if those are baby steps - edited to add: and even if you take one step back for every few forward

 

[falter]

I'm of a similar mind. I have no use for a scope outside of trying to fix vintage computing gear, and the use is so infrequent that anything I learn is long forgotten by the time I get back to it. What I'm trying to do now is figure out how to set it up for the specific application I have, amd then write up a procedures checklist, sort of like they have on airliners, so I can quickly get set up again when the next thing breaks.

 

[daver2]

That is exactly what you want to do.

Dave

 

[Chuck(G)]

I've said it before and I'll repeat myself. For a tyro, a good old analogue scope is probably the best way to learn. DSO's have lots of options and controls, but that obscures the basic function--and there are real-time things that analogue scopes are just better at. You can usually find a very good used one for not a lot of money. I still haul out my Tek 465 when I want to do a quick look-see.

 

[daver2]

Most repairs follow a set 'pattern', so once you have written down the procedure for doing certain things - you just follow it.

1. Set the ground reference for all signal measurements.

2. Measuring a DC voltage (Voltage rails).

3. Measuring power rail ripple and noise.

4. Measuring regular periodic signals (e.g. clocks).

5. Measuring irregular signals.

1 to 4 can be proceduralised and learned. 4 may require a little bit of mathematics to convert from frequency to period - but this is relatively simple.

5 is the more difficult - because it needs some thought regarding how to trigger the oscilloscope.

Happy to post a teach-in...

Dave