EEVblog #677 - Mailbag - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: October 28, 2014, 10:27:26 am
content: Mailbag MondayDave opens his mail.Spoilers & Links:HP 4260A LCR Universal Bridgehttp://cp.literature.agilent.com/litweb/pdf/04260-90011.pdfiPod Blood pressure monitorOld computer hardwareIntel 1Mb Bubble MemoryPICop development board:http://www.bloguetronica.com/2014/07/placa-de-desenvolvimento-picop.htmlTEM Products SMD IC and LED thermal productsPowerPeg:http://tem-products.com/index.php/powpeg.html/Stepper Motor Controller:http://tem-products.com/index.php/motion-control.htmlTSL1401CL LineScan Camerahttps://www.tindie.com/products/AP_tech/tsl1401cl-linescan-camera-/

author: mux
author_rank: Regular Contributor
timestamp: October 28, 2014, 10:32:25 am
content: I'll just pre-emptively, before even watching the video, complain that the video is too short so that that's over with. We all know somebody is going to say it, might as well be me.Alright, let's see what's what and who's who! *switches to the video*

author: max666
author_rank: Frequent Contributor
timestamp: October 28, 2014, 02:20:28 pm
content: Awww no postcards any more, I liked watching the postcards. The format is called mailbag after all.Impossible to please everybody, isn't it Dave?

author: Pedram
author_rank: Regular Contributor
timestamp: October 28, 2014, 02:55:22 pm
content: these Thermal Connectors are nicebut they are overpriced. $1.4 each ?? too expensive.

author: simingx
author_rank: Contributor
timestamp: October 28, 2014, 03:45:13 pm
content: Hi Dave, I see you've finally gotten around to opening my packageThe 4260A did work once upon a time, but it's been sitting around way too long... guess the years finally took their toll on itI don't remember the Mode and Range dials being out of alignment though, guess it got bashed around somewhat in transit...Hope to see the teardown video soon, I know you'll love it O0

author: German_EE
author_rank: Super Contributor
timestamp: October 28, 2014, 04:58:58 pm
content: Those power pegs are an interesting idea, I have never been a fan of multiple vias on a PCB installed underneath a chip in an attempt to promote heat flow. One thing though, with the power peg installed in the hole how do I solder the chip to the board/peg?

author: SeanB
author_rank: Super Contributor
timestamp: October 28, 2014, 05:40:01 pm
content: I ould guess if you are reflowing it you make the power peg a press fit, and install it with a jig before solder past application, probably using a spacer that holds it while supporting the board. Then the paste is applied over it, and then place and reflow as normal and it will wick into the hole and the component. You probably would be better off though having the board side not being a round pin, rather a polygon shape so that you can press fit it into a controlled range of hole diameters and which allows solder to wick through the holes during reflow. You probably would also want some dimpling on the mounting shoulder for the same reasons, so that hot gas and trapped flux can escape before the solder wicks through to hold it. That probably would be easy to do with a die set that forges the part out of a slug cut from rod, and then you do the machining in a CNC to get the end flat and do the thread for the screw. After that you wash, tumble polish then do the plating to protect them.

author: wilgil
author_rank: Contributor
timestamp: October 28, 2014, 08:12:27 pm
content: That 4 input 'scope behind Dave is still upside down...my OCD is killing me....Maybe he could gift it to a good home (I have a suggestion) where it will be cared for and put the correct way up on said good home's workbench...

author: eV1Te
author_rank: Regular Contributor
timestamp: October 28, 2014, 08:44:52 pm
content: I really like the Power Pegs, I will definitely have them in mind the next time I am considering though hole TO220s or similar with a standing heat-sink.As I understand you screw the heat-sink into the peg after everything has been soldered. But since they are tiny, how much momentum can you use on the screw? How do you prevent the screw from shaking loose (Loctite?)?

author: DrSchweizer
author_rank: Newbie
timestamp: October 28, 2014, 10:08:37 pm
content: Just some additional information on Eritrea. It is ruled by Isayas Afewerki a former guerilla fighter, dictator and head of the only allowed party. The country was founded 1993 and is also called 'Africa’s North Korea'. The UN actually rates it as worse than North Korea. So not a place to go to.

author: jancumps
author_rank: Unknown
timestamp: October 28, 2014, 10:29:19 pm
content: Quote from: wilgil on October 28, 2014, 08:12:27 pmThat's because he lives in Australia. I'm from Belgium, Europe. The scope is showing correct for me....

author: Dave
author_rank: Super Contributor
timestamp: October 28, 2014, 10:36:20 pm
content: Those thermal pegs are quite nice, but one thing concerns me about them: Can the solder joints withstand the mechanical stress created by those pegs? Imagine you have 6-10 transistors on a board, all connected to the same heatsink, each with its own powerpeg. The heatsink will certainly have a different thermal expansion coefficient than FR4 - something will have to give.

author: EEVblog
author_rank: Unknown
timestamp: October 28, 2014, 10:50:34 pm
content: Quote from: DrSchweizer on October 28, 2014, 10:08:37 pmYikes

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: October 28, 2014, 11:21:05 pm
content: Dave you pronounced Eritrea correctly, I've got a friend on the Eritrean ski team (alpine skiing).

author: Rutger
author_rank: Regular Contributor
timestamp: October 29, 2014, 12:52:08 am
content: Dave, in the previous mailbag (or the one before) you received an cool EEVBlog clock. Can you please hang the clock on the opposite wall of the web cam (above the small desk), so the world can see the local time and live action.

author: Bud
author_rank: Super Contributor
timestamp: October 29, 2014, 01:54:04 am
content: Quote from: DrSchweizer on October 28, 2014, 10:08:37 pmAnd people of both Eritrea and North Korea just live their lives and do not give a f@ck about UN ratings.

author: Bud
author_rank: Super Contributor
timestamp: October 29, 2014, 02:02:44 am
content: Quote from: Dave on October 28, 2014, 10:36:20 pmI agree, would also be concerned about the mechanical stress on the die if the peg is soldered to an IC.

author: Bud
author_rank: Super Contributor
timestamp: October 29, 2014, 02:03:55 am
content: Quote from: German_EE on October 28, 2014, 04:58:58 pmWhy is that? Works for me very well.

author: Bored@Work
author_rank: Super Contributor
timestamp: October 29, 2014, 05:59:42 am
content: Quote from: wilgil on October 28, 2014, 08:12:27 pmYou don't understand. That is Dave's canary. As long as it is upside down everything is ok. If the oscilloscope is suddenly upright we know that Dave is held hostage by Ben Heck and we need to send in the clowns to rescue him.

author: nitro2k01
author_rank: Frequent Contributor
timestamp: October 29, 2014, 06:23:33 am
content: Quote from: Bud on October 29, 2014, 01:54:04 amWhile they may not care about the ratings themselves, they would certainly care about the poverty, starvation and political oppression that prompted those ratings in the first place.

author: Smokey
author_rank: Super Contributor
timestamp: October 29, 2014, 07:07:17 am
content: Quote from: Bud on October 29, 2014, 01:54:04 amThat is an interesting opinion. Did you enjoy being able to express your opinion publicly? Maybe you can explain to the people of Eritrea what it's like to be able to express yourself without the risk of going to jail forever.http://en.wikipedia.org/wiki/Eritrea"in September 2001 the government closed down all of the nation's privately owned print media, and outspoken critics of the government have been arrested and held without trial, according to various international observers, including Human Rights Watch and Amnesty International. In 2004 the U.S. State Department declared Eritrea a Country of Particular Concern (CPC) for its record of religious persecution."..... yes I apologize for quoting wikipedia...

author: EEVblog
author_rank: Unknown
timestamp: October 29, 2014, 11:52:56 am
content: Quote from: Rutger on October 29, 2014, 12:52:08 amAh, I want to get my Time Circuit clock working again for that, thanks for the reminder.

author: Towger
author_rank: Super Contributor
timestamp: October 29, 2014, 07:03:33 pm
content: Quote from: wilfred on October 29, 2014, 12:43:21 pmFitted to the C5 ;-)

author: JackOfVA
author_rank: Unknown
timestamp: October 30, 2014, 11:19:42 am
content: I have a 4260A and the similar General Radio analog RLC meter (1650A and also a 1650B) in my collection, along with both GR and HP digital RLC meters.There's still a place for the analog instruments, however, compared with the inexpensive digital meters in that (a) external voltage bias for capacitance measurement and current bias for inductance can be applied and (b) it is possible to vary the AC voltage applied to the part under test.The 4260A unfortunately limits external bias voltage to 6V but the GR meters can use external bias up to 30V or perhaps higher -- it's been a while since I looked at the manual. And the 1650B permits DC current to be passed through the inductor under test as well, up to 50 mA or so. The 1650B also has a front panel potentiometer that adjusts the applied AC voltage.While lab grade digital RLC meters permit external bias and adjustable drive (although some make this an extra cost option), these features are not often found on the simpler RLC meters.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: October 30, 2014, 12:31:41 pm
content: Quote from: wilfred on October 29, 2014, 12:38:18 pmIt's for us Northern Hemisphere folks. From our perspective, it's the only scope in his lab that's NOT upside down.

author: Rutger
author_rank: Regular Contributor
timestamp: October 30, 2014, 02:03:43 pm
content: Quote from: EEVblog on October 29, 2014, 11:52:56 amThe BTTF clock sounds cool, but I don't think we will be able to read the digits from that distance an analog clock would better.

author: womai
author_rank: Contributor
timestamp: October 30, 2014, 07:38:02 pm
content: I did a short search and it seems the 4260A is more like 1966 vintage, not from the 80s.http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1966-09.pdfIMHO that fits the overall design of the unit, just looks the way they did it in the 60s.

author: EEVblog
author_rank: Unknown
timestamp: October 30, 2014, 08:28:10 pm
content: Quote from: womai on October 30, 2014, 07:38:02 pmYeah, that feels right to me. I was going by the date in the manual. The 80's is when they must have archived it.

author: arekm
author_rank: Unknown
timestamp: October 31, 2014, 06:13:03 pm
content: For Cree LEDs it's better to use copper plates (+ small isolation) instead of typical pcb and "power pegs".Example, noctigons, sinkpads, maxtoch:http://budgetlightforum.com/node/21547http://budgetlightforum.com/node/33488

author: TEMProducts
author_rank: Newbie
timestamp: October 31, 2014, 10:01:52 pm
content: Hello everyone! A few responses here...Quote from: German_EE on October 28, 2014, 04:58:58 pmThe pegs do not press fit. This would cause stress in the FR4. They slip-fit in a 2.5MM via.Simply add a dab of flux, tack in place, allow to cool, and paste/reflow as usual. Action of capillarity holds the peg in place when the solder is molten.I will try to make a video soon.Quote from: eV1Te on October 28, 2014, 08:44:52 pm1.0 inch pounds of torque MAX. Use a clutch driver, or screw by hand.http://tem-products.com/TCAP-4325-TR_Datasheet.pdfAs long as the screw is fully engaged in the Peg, the screw will actually break before the thread strips. 0-80 screws are delicate!PowerPeg is made of copper, so friction is enough to hold the screw in place when fully tightened. I have never seen one come loose (and I have used them in every way imaginable). However loctite can be used, and does not effect the thermal interface.Additional screws from PCB to heatsink are recommended to relieve mechanical stress from the thermal connector. PowerPeg is tough, but not invincible!Quote from: Dave on October 28, 2014, 10:36:20 pmThe effects of thermal expansion of copper are negligible over short distances. For example: with a temperature change of 100C the length of the peg will change 0.000068 inches.PowerPeg is precision machined to have matched thickness allowing many pegs to be attached to a single heatsink.Quote from: Pedram on October 28, 2014, 02:55:22 pmIn the past two years we have made only one batch of 1200 pegs. The small quantity is the reason for the high price.These pegs were (partially) hand made. They are precision machined from copper alloy and plated with nickel, then 24 kt gold.The next batch will be larger. I forsee the price under $0.80.

author: JuiceKing
author_rank: Regular Contributor
timestamp: November 01, 2014, 12:39:47 am
content: The HP 4260A is an amazingly compact and convenient analog bridge. Direction lights tell you which way to crank and it automatically finds D and Q. I believe it was the first product from the YHP group and they poured a lot of passion into it. Check out the HP Journal article that came out when it was launched.Sent from my iPad using Tapatalk HD

author: simingx
author_rank: Contributor
timestamp: November 01, 2014, 10:24:38 am
content: Quote from: JuiceKing on November 01, 2014, 12:39:47 amLinked for your conveniencewww.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1966-09.pdfThe HP Journals makevery goodreading... the theory of operation is described in much detail, rather than nowadays where it is just given a cursory description, as everything is done in software

author: TheWelly888
author_rank: Frequent Contributor
timestamp: November 01, 2014, 03:00:33 pm
content: Dave - I work on blood pressure monitors as part of my job in the local hospital so I would like to point out that they do not use "vacuum pumps" as you described it, they are actually compressors to inflate the cuff, the air is then released slowly ( at a set rate of about 5 - 10 mmHg per second ) through a slow release valve.I'm looking forward to the teardowns of the gear.

author: TEMProducts
author_rank: Newbie
timestamp: November 23, 2014, 07:58:49 am
content: This video shows how PowerPeg thermal connectors integrate easily with typical PCB assembly techniques.Simply tack the peg in place, stencil, and re-flow as usual. Capillary action holds the peg in place while the solder is molten.

author: EvilGeniusSkis
author_rank: Regular Contributor
timestamp: November 24, 2014, 09:51:21 pm
content: Quote from: EEVblog on October 29, 2014, 11:52:56 amI'm surprised no one has sent you the chips yet.

author: TEMProducts
author_rank: Newbie
timestamp: August 07, 2015, 02:38:48 pm
content: Anyone who was interested in the The PowerPeg thermal management system, it is entered in the 2015 Hackaday contest.Theres tons of interesting information on the project page.https://hackaday.io/project/6874