Floating Earth on Whole House - Normal?

[Harry Bloomfield]

Having said that, I've been playing with 'sensitive electronics', without 'taking any precautions', for decades, starting in the days when they were much more susceptible to static discharges than they are today, and have never knowingly 'lost' a semiconductor because of that!

Electrostatic damage can show up much later, I understand.

 

[Harry Bloomfield]

I tend to agree and I too have been very blase about them but I do know of the odd failure here and there.

The only precaution I took, was to make I briefly touched some earthed metalwork, close to the item, before doing the work.

 

[JohnW2]

Electrostatic damage can show up much later, I understand.

From what I understand of the mechanism of electrostatic damage to semiconductors ('immediate' destruction of junctions), I find that rather hard to believe - and, in any event, it's incredibly rare that I have come across 'late failure' of any semiconductor devices, even though some of the ones I've 'handled' were handled over 50 years ago!

 

[JohnW2]

The only precaution I took, was to make I briefly touched some earthed metalwork, close to the item, before doing the work.

I did that occasionally, but even that probably pretty rarely. Even to this day, I do keep ICs stored in an anti-electrostatic manner, and when I'm doing things with them usually sit them with their pins on some metallic or foil surface.

 

[SUNRAY]

I did that occasionally, but even that probably pretty rarely. Even to this day, I do keep ICs stored in an anti-electrostatic manner, and when I'm doing things with them usually sit them with their pins on some metallic or foil surface.

I have little plastic drawers full of revovered components, ICs are very roughly sorted into analogue, ttl, cmos. When I want one I tend to rummage through, usually with long nose pliers or tipping onto the bench, the straighten the selected chip with the pliers and insert it into the breadboard or holder.
I'm not saying I don't have failures but then I don'y know the history of most of them.

 

[Harry Bloomfield]

I did that occasionally, but even that probably pretty rarely.

It has become a deeply ingrained habit for me, to discharge myself, every time I approach my bench.

Even to this day, I do keep ICs stored in an anti-electrostatic manner, and when I'm doing things with them usually sit them with their pins on some metallic or foil surface.

Polystyrene tile material, covered with cooking foil, with thousands of chips on them. I always touch the foil, before the chip.

 

[Harry Bloomfield]

I have little plastic drawers full of revovered components, ICs are very roughly sorted into analogue, ttl, cmos. When I want one I tend to rummage through, usually with long nose pliers or tipping onto the bench, the straighten the selected chip with the pliers and insert it into the breadboard or holder.

I used to recover lots of chips, back in the day, when they were so very expensive and difficult to source, but not so much these days, unless I am stuck for one. I would clamp the scrap pcb vertically, in the vice, then apply a hot air gun to the solder side, and twang the board, to send the solder flying. The second stage, if needed, was to put a screwdriver, under the side of the chip, to lever it, and reheat again.

 

[JohnW2]

Polystyrene tile material, covered with cooking foil, with thousands of chips on them.

Same here - or scraps of 'conductive foam' if/when I have some around.

I always touch the foil, before the chip.

As I've said, I'm inclined to think that I 'ought to' do that, but probably rarely do!

 

[JohnW2]

I'm not saying I don't have failures but then I don'y know the history of most of them.

I have the same uncertainty about the history of many of the ICs I use but, as I said, I have experienced incredibly few "IC failures" over the decades (other than in the early days, when audio power amp chips had no short-circuit protection on the outputs - I was always blowing them up, but through no-one's fault but my own )

 

[SUNRAY]

I have the same uncertainty about the history of many of the ICs I use but, as I said, I have experienced incredibly few "IC failures" over the decades (other than in the early days, when audio power amp chips had no short-circuit protection on the outputs - I was always blowing them up, but through no-one's fault but my own )

My major IC failure back in the early 80's was audio power amps and voltage regulators... In CB radios and CB powersupplies. There were so many I kept a stock of them: about 4 or 5 audio amp chip types and in particular I kept a quantity of full sets of devices for the whole range of Bremi power supplies (which somehow had the 'Best power supplies' reputations. I always assumed the CB amps failing was due to the 'experts' who wired the extension speakers in and well how is a set of 25W boots supposed to work on a 3A PSU?

I do store EPROMS correctly and described above and quite frankly it's virtually impossible to not touch the conductive foam or foil first but other than that I don't take precautions.

 

[JohnW2]

My major IC failure back in the early 80's was audio power amps and voltage regulators...

Indeed. When I wrote ....

... other than in the early days, when audio power amp chips had no short-circuit protection on the outputs ...

I was talking about early-/mid-70s in my case but, as I said, the failures were all my own fault, and nothing to do with static electricity. However, you remind me that a similar problem arose with voltage regulators back then, and I think again for the same reason -a lack of 'short-circuit protection' (plus doing silly things!)

 

[Harry Bloomfield]

However, you remind me that a similar problem arose with voltage regulators back then, and I think again for the same reason -a lack of 'short-circuit protection' (plus doing silly things!)

Which reminds me, I have a linear variable 30amp PSU to repair yet again. Rather weirdly, it blows it's 723 reference IC, on overload, rather than it's output transistors. I never managed to fathom why.

 

[fourtytwo]

Which reminds me, I have a linear variable 30amp PSU to repair yet again. Rather weirdly, it blows it's 723 reference IC, on overload, rather than it's output transistors. I never managed to fathom why.

Could be something wrong with the current shunt, bad connection etc OR depending on how the output of the 723 is connected to the o/p base the lack of a current limiting resistor as the o/p transistors will take a lot more base current w/o damage than the poor little 723 can cope with!