Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 14556629 times)

0 Members and 25 Guests are viewing this topic.

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 14483
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4475 on: December 07, 2017, 09:08:49 am »
Another great example of productive block is, with my 8800A i knew a power supply was shorted but it took me this long to think that it might be  a tantalum. First 3 tants i pulled were dead as doornails and their all being replaced shortly, quick question can 220u 6V tant be replaced with a much cheaper electrolyic on the AC converter board? The only reason they used tant that i can think of is size.

P.S. The 8800A has to have the worst possible connector for extender cards, fragile receptacle met with a tight fit and limited space, i miss the card edges of earlier models  :-DD
Quick answer is yes, many of us here do that as a temp measure. I don't think it's a size issue, more of stability and reliability then anything else.

Sent from my SM-J510FN using Tapatalk

All i know is i ain't gonna pay 5 bucks a shot for 3 of them when a good electrolytic set would only cost me 50 cents and are alot less likely to burst into flames or randomly short like the old ones.
I think that a lot of times that happens is because the normal rated voltage is to close to the caps max rating and so its been driven hard all the time. I would say that the ideal is double running voltage if possible and never drop the caps voltage rating below a third higher at the worst case. Dont forget that electrolytics are prone to drying out and thus failure and also they are not anywhere as stable value as well as thermal wise.
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline neo

  • Super Contributor
  • ***
  • Posts: 1694
  • Country: us
  • The specialist.
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4476 on: December 07, 2017, 09:12:44 am »
Well there is polymer tantalum at only 80 cents a piece, any good?  :-//
A hopeless addict (and slave) to TEA and a firm believer that high frequency is little more than modern hoodoo.
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 23018
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4477 on: December 07, 2017, 09:17:20 am »
Watch it when replacing tants with electrolytics. Not all capacitors and use cases are equal. If it’s supply decoupling, electrolytic is fine. If it’s anything else, forget it; the tant is in there for a reason.

To replace supply decoupling caps I tend to just buy tants now. They’re not that expensive from local suppliers for me. If you have to use an electrolytic, use a low ESR one and solder a 100nF ceramic across it as well. Electrolytics are only reasonable up to a few hundred KHz.

If you’re feeling cheap, the surface mount tants are cheaper and can usually be soldered across the old TH tant’s pads.

I bought a whole reel of 10uF 25v tants for £10. That’s about 400 on there. And AVX ones no less.
« Last Edit: December 07, 2017, 09:20:37 am by bd139 »
 

Offline neo

  • Super Contributor
  • ***
  • Posts: 1694
  • Country: us
  • The specialist.
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4478 on: December 07, 2017, 09:19:30 am »
Watch it when replacing tants with electrolytics. Not all capacitors and use cases are equal. If it’s supply decoupling, electrolytic is fine. If it’s anything else, forget it; the tant is in there for a reason.

To replace supply decoupling caps I tend to just buy tants now. They’re not that expensive from local suppliers for me. If you have to use an electrolytic, use a low ESR one and solder a 100nF ceramic across it as well. Electrolytics are only reasonable up to a few hundred KHz.

It's on the ac converter, i presume as a smoothing capacitor due to size but i don't know. My options are either electrolytic or polymer tantalum, a solid tant is 5 bucks a piece at this value.
A hopeless addict (and slave) to TEA and a firm believer that high frequency is little more than modern hoodoo.
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 23018
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4479 on: December 07, 2017, 09:21:12 am »
What is the component ID? Will look it up on the schematic.

Edit: assuming C13, C14 and C26
« Last Edit: December 07, 2017, 09:23:19 am by bd139 »
 

Offline Mr. Scram

  • Super Contributor
  • ***
  • Posts: 9810
  • Country: 00
  • Display aficionado
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4480 on: December 07, 2017, 09:23:25 am »
I must say that poking around in a device while it's connected to mains makes you pay a little more attention to what you're doing than usual. That bare piece of metal with mains on it front and center made me quite aware of where my hand would go if the probe or screwdriver slipped.

Maybe it'd be a good idea to tape that one up next time.
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 14483
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4481 on: December 07, 2017, 09:23:43 am »
Well there is polymer tantalum at only 80 cents a piece, any good?  :-//
You might find the answer to that question here?

Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline neo

  • Super Contributor
  • ***
  • Posts: 1694
  • Country: us
  • The specialist.
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4482 on: December 07, 2017, 09:25:45 am »
I must say that poking around in a device while it's connected to mains makes you pay a little more attention to what you're doing than usual. That bare piece of metal with mains on it front and center made me quite aware of where my hand would go if the probe or screwdriver slipped.

Maybe it'd be a good idea to tape that one up next time.

Yes, knowing that something can kill you makes you hyper aware of what your doing. The fun is in the risk though.
A hopeless addict (and slave) to TEA and a firm believer that high frequency is little more than modern hoodoo.
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 23018
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4483 on: December 07, 2017, 09:27:23 am »
What is the component ID? Will look it up on the schematic.

Edit: assuming C13, C14 and C26

Found them. Those should remain tants. They are quite critical. They are in parallel to give high capacitance and low ESR for half of the AC converter amp. You may get away with electrolytics here if they are much higher capacitance. Around 470uF. Problem is they may be too big to fit the board.
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 14483
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4484 on: December 07, 2017, 09:28:34 am »
I must say that poking around in a device while it's connected to mains makes you pay a little more attention to what you're doing than usual. That bare piece of metal with mains on it front and center made me quite aware of where my hand would go if the probe or screwdriver slipped.

Maybe it'd be a good idea to tape that one up next time.

Yes, knowing that something can kill you makes you hyper aware of what your doing. The fun is in the risk though.
What like Russian Roulette is under until the hammer falls on a live chamber? Play safe each and every time whenever possible is my motto.  :popcorn:
« Last Edit: December 07, 2017, 09:35:14 am by Specmaster »
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline neo

  • Super Contributor
  • ***
  • Posts: 1694
  • Country: us
  • The specialist.
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4485 on: December 07, 2017, 09:33:59 am »
I must say that poking around in a device while it's connected to mains makes you pay a little more attention to what you're doing than usual. That bare piece of metal with mains on it front and center made me quite aware of where my hand would go if the probe or screwdriver slipped.

Maybe it'd be a good idea to tape that one up next time.

Yes, knowing that something can kill you makes you hyper aware of what your doing. The fun is in the risk though.
What like Russian Roulette is under the hammer falls on a live chamber? Play safe each and every time whenever possible is my motto.  :popcorn:

Yes always play safe, never said other wise. I just said the fun is in the risk, doesn't imply you have to throw caution to the wind it's just  a statement of opinion.

What is the component ID? Will look it up on the schematic.

Edit: assuming C13, C14 and C26

Found them. Those should remain tants. They are quite critical. They are in parallel to give high capacitance and low ESR for half of the AC converter amp. You may get away with electrolytics here if they are much higher capacitance. Around 470uF. Problem is they may be too big to fit the board.

Polymer tantalum it is then.
A hopeless addict (and slave) to TEA and a firm believer that high frequency is little more than modern hoodoo.
 

Offline Mr. Scram

  • Super Contributor
  • ***
  • Posts: 9810
  • Country: 00
  • Display aficionado
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4486 on: December 07, 2017, 09:39:27 am »
Yes, knowing that something can kill you makes you hyper aware of what your doing. The fun is in the risk though.
Well, I've shocked myself properly when I was rather young, so I'm properly innoculated. That's how it works, right?

Honestly, I sometimes feel that experience has left me more careless than it should, because it made mains seem painful rather than deadly. Thankfully my reasoning skills also have a say in the matter.
 

Offline neo

  • Super Contributor
  • ***
  • Posts: 1694
  • Country: us
  • The specialist.
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4487 on: December 07, 2017, 09:43:00 am »
Yes, knowing that something can kill you makes you hyper aware of what your doing. The fun is in the risk though.
Well, I've shocked myself properly when I was rather young, so I'm properly innoculated. That's how it works, right?

Honestly, I sometimes feel that experience has left me more careless than it should, because it made mains seem painful rather than deadly. Thankfully my reasoning skills also have a say in the matter.

Lets see.... I've been shocked by 120V AC least a dozen times, burnt the tips of my fingers on one hand with one of those, and HVDC at least as many.

Let me say, if getting shocked inoculates you it would be by making you comfortably numb and not any acceptable means because 300VDC still hurts like heck.
A hopeless addict (and slave) to TEA and a firm believer that high frequency is little more than modern hoodoo.
 

Offline Mr. Scram

  • Super Contributor
  • ***
  • Posts: 9810
  • Country: 00
  • Display aficionado
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4488 on: December 07, 2017, 09:43:52 am »
Yes always play safe, never said other wise. I just said the fun is in the risk, doesn't imply you have to throw caution to the wind it's just  a statement of opinion.

Polymer tantalum it is then.
If it isn't a bit dangerous, it isn't fun!

The strange part is that we do things every day that are statistically much more likely to kill us, but we consider those utterly mundane or even excruciatingly boring.
 

Offline Mr. Scram

  • Super Contributor
  • ***
  • Posts: 9810
  • Country: 00
  • Display aficionado
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4489 on: December 07, 2017, 09:45:52 am »
Lets see.... I've been shocked by 120V AC least a dozen times, burnt the tips of my fingers on one hand with one of those, and HVDC at least as many.

Let me say, if getting shocked inoculates you it would be by making you comfortably numb and not any acceptable means because 300VDC still hurts like heck.
This was 230V AC too, so 320V peak voltage. It sure gives you a proper tickle.
 

Offline neo

  • Super Contributor
  • ***
  • Posts: 1694
  • Country: us
  • The specialist.
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4490 on: December 07, 2017, 09:47:22 am »
Yes always play safe, never said other wise. I just said the fun is in the risk, doesn't imply you have to throw caution to the wind it's just  a statement of opinion.

Polymer tantalum it is then.
If it isn't a bit dangerous, it isn't fun!

The strange part is that we do things every day that are statistically much more likely to kill us, but we consider those utterly mundane or even excruciatingly boring.

To truly live you must first know that you could die in an instant. Even with something labeled as mundane or excruciatingly boring, if you know the risks it becomes a lot more interesting. If only because you pay attention to it.

Yes i might be slightly nuts, aren't we all? Yes i might be slightly nuttier than the rest of you, no argument  :-DD

The one i burnt my fingers on came complete with unconsciousness and pearly gates.
« Last Edit: December 07, 2017, 09:49:31 am by neo »
A hopeless addict (and slave) to TEA and a firm believer that high frequency is little more than modern hoodoo.
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 14483
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4491 on: December 07, 2017, 09:57:33 am »
Lets see.... I've been shocked by 120V AC least a dozen times, burnt the tips of my fingers on one hand with one of those, and HVDC at least as many.

Let me say, if getting shocked inoculates you it would be by making you comfortably numb and not any acceptable means because 300VDC still hurts like heck.
This was 230V AC too, so 320V peak voltage. It sure gives you a proper tickle.
415V is far worse, thankfully you don't often come across that often in a piece of kit.
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 14483
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4492 on: December 07, 2017, 09:59:42 am »
Yes always play safe, never said other wise. I just said the fun is in the risk, doesn't imply you have to throw caution to the wind it's just  a statement of opinion.

Polymer tantalum it is then.
If it isn't a bit dangerous, it isn't fun!

The strange part is that we do things every day that are statistically much more likely to kill us, but we consider those utterly mundane or even excruciatingly boring.

To truly live you must first know that you could die in an instant. Even with something labeled as mundane or excruciatingly boring, if you know the risks it becomes a lot more interesting. If only because you pay attention to it.

Yes i might be slightly nuts, aren't we all? Yes i might be slightly nuttier than the rest of you, no argument  :-DD

The one i burnt my fingers on came complete with unconsciousness and pearly gates.
Bloody good job St Peter had that day lost the key to those gates then
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline Mr. Scram

  • Super Contributor
  • ***
  • Posts: 9810
  • Country: 00
  • Display aficionado
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4493 on: December 07, 2017, 10:16:12 am »
415V is far worse, thankfully you don't often come across that often in a piece of kit.
There's always worse and always someone with a better story  ;D
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 14483
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4494 on: December 07, 2017, 10:32:25 am »
415V is far worse, thankfully you don't often come across that often in a piece of kit.
There's always worse and always someone with a better story  ;D
Hmm, I'm not a very good storey teller but theres plenty of those on this forum, always manages to raise a smile a two on here  :-+
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline djos

  • Supporter
  • ****
  • Posts: 991
  • Country: au
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4495 on: December 07, 2017, 10:49:28 am »
415V is far worse, thankfully you don't often come across that often in a piece of kit.
There's always worse and always someone with a better story  ;D
Hmm, I'm not a very good storey teller but theres plenty of those on this forum, always manages to raise a smile a two on here  :-+

I learnt my HV caution when working on 21" Sun CRT monitors in the 90's after not discharging the flyback transformer on one properly and accidentally subjecting myself to waaaaaay too many volts - my left arm was paralysed for several hours after that.  :palm:

Offline bd139

  • Super Contributor
  • ***
  • Posts: 23018
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4496 on: December 07, 2017, 11:07:20 am »
I wouldn't pick a fight with a Trinitron.

Actually really the biggest hazard of those is implosion. I emptied a lab out of those monitors many years ago when they got replaced with shitty TFTs and Sun Ultra 5's. Someone dropped one in the skip a bit hard and it took the case off. We decided that the obvious thing to do was to get a chunk of wood and knock the gun with it. Kaboom! Never heard anything like it. You can hit the front of the tube with a sledgehammer and it'll just hiss at you. If you hit the back, different story!

That actually scares me more than the odd mains zing.
« Last Edit: December 07, 2017, 11:10:04 am by bd139 »
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 14483
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4497 on: December 07, 2017, 11:12:07 am »
I wouldn't pick a fight with a Trinitron.

Actually really the biggest hazard of those is implosion. I emptied a lab out of those monitors many years ago when they got replaced with shitty TFTs and Sun Ultra 5's. Someone dropped one in the skip a bit hard and it took the case off. We decided that the obvious thing to do was to get a chunk of wood and knock the gun with it. Kaboom! Never heard anything like it. You can hit the front of the tube with a sledgehammer and it'll just hiss at you. If you hit the back, different story!

That actually scares me more than the odd mains zing.
Isn't that because the front is massively think but the rear and especially around the neck is thin like valves?
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 14483
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4498 on: December 07, 2017, 11:23:40 am »
Anyone looking for a good basic DMM manual switcher as a general chuck in the toolbox type of unit for not a lot, should take a look at this, I've got 2 of them and they are really pretty good, 6,000 count and true RMS etc and pretty accurate for a cheap meter, free postage as well, not bad eh for £6.90

http://www.ebay.co.uk/itm/like/173007052771

Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 23018
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #4499 on: December 07, 2017, 11:36:01 am »
Anyone looking for a good basic DMM manual switcher as a general chuck in the toolbox type of unit for not a lot, should take a look at this, I've got 2 of them and they are really pretty good, 6,000 count and true RMS etc and pretty accurate for a cheap meter, free postage as well, not bad eh for £6.90

http://www.ebay.co.uk/itm/like/173007052771

That's not a bad price actually for that. Better than those horrid DT830's in bang-for-buck metrics.

Isn't that because the front is massively think but the rear and especially around the neck is thin like valves?

Yep I suspect it is. The neck is pretty thick still, just I think it acts as a lever if you hit it side on.

Found a video:

 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf