Test Equipment Anonymous

I did something similar ages ago. Dropped a scope probe on a Tek 465 power supply. Blew a chunk out of the ground ring

Nothing like a good wake up though - glad you didn't get hurt!

my pride is hurt.

in the interest of full disclosure......

had no business probing around in that thing anyway.

once the breaker was reset and my retinas recovered from the arc flash, saw there was a 2200 mfd 10v cap with a bulging vent end that had been clearly visible all along. replaced it and the supply is fixed.

DOH!

Keep your eyes open for a differential probe, no bangs after that, provided you remember to use it of course

yes. a diff probe would be an excellent idea.

but laziness and stupidity might still win out.

should have grabbed the fluke 97 scopemeter for messing around in a switching supply.......but that would mean digging it out of its box and sticking fresh batteries in.

waaaaaay to much work. better to be embarrassed afterward rather than do the right thing first.

swmbo will probably put this on my monument...... "lazy AND stupid, rip"

Isolation transformer is a suitably cheap substitute for working on SMPS. Probably safer as well.

bd139 wrote: ↑Sat Oct 29, 2022 7:35 pm Isolation transformer is a suitably cheap substitute for working on SMPS. Probably safer as well.

read that as you are suggesting that i float the scope on the isolation transformer.

or did you mean to float the power supply on the transformer?

or maybe it would not matter?

if a war breaks out, my plan is to delete this post and deny any involvement.

Float the supply not the scope.

Specmaster wrote: ↑Sat Oct 29, 2022 3:39 pm Thanks for that info, I took a chance on some AAA alkaline batteries yesterday, and they arrived today, and have just ordered some Ni-MH D cells rated @ 1000mAH from their range as well to fit in a LED torch ready for the threatened power cuts this winter. If they are good at not leaking, afterwards they could go into the analogue bench meters

If you are worried about being in the dark because of power cuts, or you just uses torches a lot, you could consider getting a torch with a Cree LED and a Li-ion battery.

Don't go for the ebay £5-£10 "5000 lumen" wonders - they are crap. See what's recommended these days on the Budget Light Forum. It's probably still Convoy and a few others. Cost, probably £15 give or take, from Aliexpress. You need a battery, £5 to £8. Ebay wonder batteries are rubbish, usually stripped out of laptop packs and with a capacity of 1000, mAh, if you are lucky. These seem OK but I haven't bought from them.

https://www.18650.uk/

Then you also need a charger, or some torches have a built in charger and charge using USB.

I've got four or five Convoy torches. When there's a power cut, this place is lit up like a Christmas tree, but in the other houses in the street there's just the odd guttering candle. I use the torches quite a lot anyway. They also make very appreciated gifts.

nixiefreqq wrote: ↑Sat Oct 29, 2022 5:56 pm just clipped a scope probe ground lead on what i though was chassis ground in a switching power supply.

it was not.

BOOM!

no pictures. (you can't take pictures in a dark basement......now which breaker is that?)

I suddenly feel so much smarter now.

nixiefreqq wrote: ↑Sat Oct 29, 2022 6:38 pm my pride is hurt.

Mine's been dented so often that I can now call it 'patina' and intimate that it attracts a buyer's premium.

bitseeker wrote: ↑Fri Oct 28, 2022 9:43 pm I'm going to subscribe to this thread to get a feel for how it's behaving.

Update: So far, it's been working fine. Note that when subscribing to a topic the notification will only occur once when there's a new post. Another notification will not be sent, even if there are more new posts, until you've viewed the topic. So, it won't spam you in the meantime.

bitseeker wrote: ↑Sun Oct 30, 2022 12:44 am

bitseeker wrote: ↑Fri Oct 28, 2022 9:43 pm I'm going to subscribe to this thread to get a feel for how it's behaving.

Update: So far, it's been working fine. Note that when subscribing to a topic the notification will only occur once when there's a new post. Another notification will not be sent, even if there are more new posts, until you've viewed the topic. So, it won't spam you in the meantime.

That's exactly as you'd expect. Another electronic and a shooters forum I frequent do that too, only flick you one message when a new reply and any subsequent are posted.

Happy Halloween all you freaks!



mnem
"There are worse things which stalk the night than demons and witches, young pup... I am one of them." ~gwand-dwagon Eddurds

nixiefreqq wrote: ↑Sat Oct 29, 2022 7:03 pm in the interest of full disclosure...... had no business probing around in that thing anyway.

once the breaker was reset and my retinas recovered from the arc flash, saw there was a 2200 mfd 10v cap with a bulging vent end that had been clearly visible all along. replaced it and the supply is fixed. DOH!

Hindsight is always 20/20 vision.

mnem
*toddles off to ded*

bitseeker wrote: ↑Sun Oct 30, 2022 12:44 am

bitseeker wrote: ↑Fri Oct 28, 2022 9:43 pm I'm going to subscribe to this thread to get a feel for how it's behaving.

Update: So far, it's been working fine. Note that when subscribing to a topic the notification will only occur once when there's a new post. Another notification will not be sent, even if there are more new posts, until you've viewed the topic. So, it won't spam you in the meantime.

Nope, it still ain't working for me, the only notification I get is on the forum itself, just below the search bar on the top right-hand corner, and there are nearly always several notifications, this morning there were 5 waiting for me.

3-element 5050 LEDs driven at approx 80ma total. Cells still at 3.8V after running all night.

mnem
KISS principle, sez I.

Specmaster wrote: ↑Sun Oct 30, 2022 10:23 am Nope, it still ain't working for me, the only notification I get is on the forum itself, just below the search bar on the top right-hand corner, and there are nearly always several notifications, this morning there were 5 waiting for me.

Since groups.io is also misbehaving for you, try flushing your cookies and cache. :fingers-crossed: (no, we don't have that smilie, yet )

Cerebus wrote: ↑Sun Oct 30, 2022 12:31 am

nixiefreqq wrote: ↑Sat Oct 29, 2022 6:38 pm my pride is hurt.

Mine's been dented so often that I can now call it 'patina' and intimate that it attracts a buyer's premium.

Is that PAT-in-a or PA-teen-a?

Supply chain woes:

I've just received an email from CPC - Farnell saying that part of my recent order has been further delayed and I can expect to receive the two 10 µF 35V surface mount electrolytic capacitors I ordered in August 2023. Grrrh!!

There are other suppliers, but they are likely to be similarly affected and there's the minimum order/handling charge which is crippling for a couple of items.

There's ebay, which can work out well for small quantities, but it's notoriously risky for ICs and electrolytic capacitors.

I particularly wanted definitely genuine, top brand, top spec parts for this project.

I'm sure there's a way through, but Grrrh!!

Gah, car wouldn't start this morning, flat battery, RAC called, and they are reporting about 4 hours and 30 minutes response time, meaning that they are likely to arrive at around the same time as I have a doctor's appointment round the corner. What are the chances of them coming at the same time?

If it is the battery, I have a 4-year warranty on it, and it was purchased on 19/9/2019 so its only 3 years old, let's see what they say when they test it.

Why does everything happen all at once, on top of this, I only had a bathroom refit a couple of months ago and as part of that, they replaced the pull switch for the bathroom light, which was replaced within a week after the new one failed, and now that new has again failed

The original one made by my old company (Crabtree Electrical) had been in use since the house was built, 32 years ago, why don't the HA use decent quality bits, it is cheaper in the long term as witnessed by the old switch lasting 32 years

Zenith wrote: ↑Mon Oct 31, 2022 11:37 am I've just received an email from CPC - Farnell saying that part of my recent order has been further delayed and I can expect to receive the two 10 µF 35V surface mount electrolytic capacitors I ordered in August 2023. Grrrh!!

Hey at least they told you. Usually they just send you an empty bag which was supposed to contain them with "2" written on it to make it look like the staff were actually not on their mid afternoon methadone dip.

Specmaster wrote: ↑Mon Oct 31, 2022 12:23 pm Gah, car wouldn't start this morning, flat battery, RAC called, and they are reporting about 4 hours and 30 minutes response time, meaning that they are likely to arrive at around the same time as I have a doctor's appointment round the corner. What are the chances of them coming at the same time?

If it is the battery, I have a 4-year warranty on it, and it was purchased on 19/9/2019 so its only 3 years old, let's see what they say when they test it.

Why does everything happen all at once, on top of this, I only had a bathroom refit a couple of months ago and as part of that, they replaced the pull switch for the bathroom light, which was replaced within a week after the new one failed, and now that new has again failed

The original one made by my old company (Crabtree Electrical) had been in use since the house was built, 32 years ago, why don't the HA use decent quality bits, it is cheaper in the long term as witnessed by the old switch lasting 32 years

Mine has the original battery in it. 8 years old now. I don't drive it though.

On that, after a page or so of rampant scribblings and HP 12C prodding (this thing is current favourite toy) and going through service history and invoices on my car I've decided it's time to let it go. The total cost of ownership is too high and utility is too low to consider keeping it. I added the sum of all expenses together, took off the current value and divided it by the number of miles I've done and it comes out at £0.39/mile just for incidental costs of it existing. Add fuel at current costs at £0.15/mile and it's just not worth it. In context I'd have to use it more to reduce the cost but I don't need to.

To put it in perspective I need to go to Stroud in a couple of weeks. 200 mile round trip at .39 .15 + 200 * is £108. The train there is £50.60 and I get to sit on my arse and read a book at the same time. I am aware I'm going to miss radio rallies but eBay is working out far more productive at the moment.

Same with an upcoming trip to Edinburgh. £166 on the train. 4:40 each way. By car 7h each way and £440.

Nope it's going. Will get a trash bike for local use and use the busses.

Well surprise surprise, RAC arrived just over 2 hours from the time I called them, verdict, battery was dead, not holding its charge, the dealer also concurred with that and swapped it out for another new one, the same. The original had 4-year warranty, but they said that the new one only has the remaining 1-year warranty from the initial purchase date. Strange that I would have thought if the maker was proud of their products I'd get a new 4-year one, oh well it is what it is, at least it should last another 3 years at least.