Thanks Paul,
I have one pulse injector probe, and a hp logic probe, but no the current probe :(
Anyway I think that isn´t useful for search for shorted parallel connected capacitors, they are shorts for pulse generator, no?
Look that

https://www.hackster.io/news/little-bee-is-an-open-source-current-and-magnetic-field-probe-3c86cd9fa835




-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de Paul Amaranth
Enviado el: domingo, 20 de diciembre de 2020 21:44
Para: TekScopes@groups.io
Asunto: Re: [TekScopes] TEK176 fixing a shorted wet tatalum capacitor

Two methods I've used:

Get a milliohmmeter that can read down to 0.001 ohm. I've used an HP 3456A for this. Hook one lead to the power ground and then use the other probe to trace along the positive power rail.
When you hit a resistance minimum you're at the shorted part.

Easier and add 10 points for using a really cool tool: Get an HP 547A current probe. Hook up a pulse generator to the power rails. Use the probe to follow the path of the current pulses around the board. When you go through a component you've found the shorted part. This generally takes me longer to hook up than to find the shorted part. You also don't have to turn the board over and it works with multilayer boards since it's a noncontact device.

You used to be able for find them for $50-80 or so, but they've gotten scarce lately and the prices have gone up. I have a low priority project to duplicate the functionality. The sensor tip is the big problem; the electronics are pretty straightforward.

Paul

On Sun, Dec 20, 2020 at 10:36:54PM +1300, donald collie wrote:

I am told that one method is to spray all the tantalums with "freeze"
until they are all frosted, apply power, and look for the first one to
burn off the frost - there`s your culprit. Cheers!...Don C.

There is some trick to find wich capacitor is shorted, (very
shorted), in a low impedance system like that with all capacitors in parallel?

--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows

I am told that one method is to spray all the tantalums with "freeze"
until they are all frosted, apply power, and look for the first one to
burn off the frost - there`s your culprit. Cheers!...Don C.

There is some trick to find wich capacitor is shorted, (very
shorted), in a low impedance system like that with all capacitors in parallel?

I am told that one method is to spray all the tantalums with "freeze" until
they are all frosted, apply power, and look for the first one to burn off
the frost - there`s your culprit. Cheers!...Don C.

There is some trick to find wich capacitor is shorted, (very shorted), in
a low impedance system like that with all capacitors in parallel?

Abe books has one in good condition

https://www.abebooks.com/servlet/BookDetailsPL?bi=22701080646&;searchurl=sortby%3D17%26tn%3DSemiconductor%2BDevice%2BMeasurements&cm_sp=snippet-_-srp1-_-title3

Harvey,

What I currently do is, apparently, fix broken scopes. I've bootstrapped myself up to a point were I have enough reliable equipment that I can triangulate on almost any measurement (with the exception of observing bandwidth rolloff, but that will change in a couple weeks when my TinaSA arrives). I'm going through the calibration process on my 475A using cobbled together equipment. I have a cheap old signal generator, and I calibrate it's output amplitude using a Tek DMM916 and a 2236. The signal generator isn't really good above about 1 MHz, so that's a significant limitation for the 475A calibration process, but I think I'm doing pretty well emulating what the PG506 and SG502 would do at lower frequencies. I'm also working on a DIY calibration source that will produce square waves at several frequencies with amplitudes ranging from 5 mV to 50 V, which would make some of the work I've been doing with with the signal generator and the 2236 a little easier.

Oddly, I feel that the multiple instruments give me greater confidence in what any one of them tells me. I've got three relatively nice DMMs that I've been using the make comparative measurements, as well as a programmable power supply, and the cheap signal generator. Combine those with some TCXOs and I feel as if I can actually make some pretty good measurements of voltage, resistance, and frequency. From there I should be able to bootstrap myself into at least a couple decimal places of accuracy. For the kind of things I'm doing, I'm not sure I care about anything more than that.

What I want to be doing in the short term is investigating and documenting the display protocol for an old laptop that has a gas plasma display, so that I can then replace the innards of the laptop with a Raspberry Pi. Also, I'm working on building a 6809 microcomputer, and a homemade minicomputer using 74181 ALU slices. I've also got a couple other old pieces of equipment of my father's and grandfather's that I'd like to spend some time fixing up.

It's all just hobby stuff that has interested me ever since college, and the pandemic has given me enough extra hours in the week to actually pursue it. I suspect that I don't need much more than a 200 MHz scope to do most of this work, though I'm sure a logic analyzer would be a nice addition. At some point I expect to buy a modern Chinese DSO (probably a Siglent 1204xe), but the old (70s and 80s era) analog scopes are what really interest me, both because of my history with them, and because it feels "closer to the metal" than a DSO. I know too much about the limits of discretely sampled signals to really trust a DSO, and maybe not enough about analog amplifiers to know where my trust in analog scopes should stop.

-- Jeff Dutky

On Dec 20, 2020, at 4:13 AM, Dave Daniel <kc0wjn@gmail.com> wrote:

Do an author/title search on bookfinder.com. There are some copies listed there. Prices are all over the map.

DaveD

On Dec 20, 2020, at 02:04, sdturne@q.com wrote:

Hi all,

I am looking for an original copy of the Tektronix Measurement Concepts series book entitled "Semiconductor Device Measurements" by John Mulvey to add to my library. I do know of the scan available on TekWiki but this scan suffers legibility issues, so I would prefer to find a printed version.

If you have one you are willing to sell, please contact me off list.

Thanks!

Sean