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Cursitor Doom <curd@notformail.com>: Nov 10 01:37PM So I've had this HP RF VNA in mothballs for the last 10 years (and I *know* it's exactly 10 years) which I decided to fire-up. Being as it's been a while, I took it up very slowly with a variac, beginning Friday evening (I checked the service manual first and it's got a linear PSU) and by the time I got to late morning on Sunday I had it up to 230V (which is only 10 less than the local supply) and all seemed well. It had been fine on this for a good hour when out of nowhere there was a **bang** and a funny smell. I was in the shower 30 feet away when it happened but could still hear it from there so it was pretty loud.   [short time later...]   I whipped off the case and made my way to a row of large electrolytics (the usual suspects). These are the big, blue Sprague 'Powerlytics' (TM) That HP were very fond of using back in the day (c.1980) but they have all tested fine for capacity and ESR. That's my prime theory out the window, then. No visible signs inside what could have catastrophically failed, just the unmistakable smell that *something* has. The device still powers up fine and the screen traces are normal, so wtf else goes *bang* and smells toxic?       -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.

Michael Terrell <terrell.michael.a@gmail.com>: Nov 10 05:59AM -0800 On Sunday, November 10, 2019 at 8:37:37 AM UTC-5, Cursitor Doom wrote: > failed, just the unmistakable smell that *something* has. The device > still powers up fine and the screen traces are normal, so wtf else goes > *bang* and smells toxic?   The capacitors on the AC line input crack and adsorb moisture, Then the explode, along with the smell of burning plastic. They are a common failure in older HP test equipment. Once the short clears, the equipment will operate, but not in a safe manor. Most people replace the entire filter, rather than the capacitors. The ones that fail are mostly the same brand. There are a lot of comments about these on https://groups.io/g/HP-Agilent-Keysight-equipment replacement user group for the old Yahoo groups.

Fox's Mercantile <jdangus@att.net>: Nov 10 08:37AM -0600 On 11/10/19 7:59 AM, Michael Terrell wrote: > The capacitors on the AC line input crack and adsorb moisture, > Then the explode, along with the smell of burning plastic. > They are a common failure in older HP test equipment.   I used to repair test equipment at Hughes Aircraft. I was surprised to find that HP used Sprague Black Beauty capacitors in their older equipment. Regardless of the reason it was on the bench, standard procedure was to replace all them.       -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Cursitor Doom <curd@notformail.com>: Nov 10 03:20PM On Sun, 10 Nov 2019 05:59:39 -0800, Michael Terrell wrote:   > will operate, but not in a safe manor. Most people replace the entire > filter, rather than the capacitors. The ones that fail are mostly the > same brand.   Thanks for that, Michael. I think I've found the cap you refer to, straddled across the mains incoming supply, looking rather jaded, bulgy and cracked. I'd have thought they'd have used potted, integrated filters like the Tek scopes of the same era did. I think IIRC I've had issues with these caps before on other equipment. It's buried somewhat in the guts of the device immediately behind the mains socket but I can just about see it. 250V it says on it. Not much headroom with our 240V mains here! How about I just snip it out and not bother replacing it? It's a PITA to get at.       -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.

Fox's Mercantile <jdangus@att.net>: Nov 10 09:24AM -0600 On 11/10/19 9:20 AM, Cursitor Doom wrote: > How about I just snip it out and not bother replacing it? > It's a PITA to get at.   Or you could just throw it in the trash. If it's not worth fixing, it's not worth keeping.       -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Michael Terrell <terrell.michael.a@gmail.com>: Nov 10 07:27AM -0800 On Sunday, November 10, 2019 at 10:20:06 AM UTC-5, Cursitor Doom wrote: > here! > How about I just snip it out and not bother replacing it? It's a PITA to > get at.   They are X or Y rated safety capacitors. I would not omit them. The 250 volt marking is AC volts, not DC. The HP manual should have the specs for the bad caps.

Michael Terrell <terrell.michael.a@gmail.com>: Nov 10 07:29AM -0800 On Sunday, November 10, 2019 at 9:37:30 AM UTC-5, Fox's Mercantile wrote: > capacitors in their older equipment. > Regardless of the reason it was on the bench, standard procedure > was to replace all them.   Just think of all the Ebay sales you could have made to deluded musicians, with those used BB caps! come to think of it, I had a bag of NOS BBs that came from an old shop that went out of business. Maybe I'll dig them out and list them. :)

Michael Terrell <terrell.michael.a@gmail.com>: Nov 10 07:31AM -0800 On Sunday, November 10, 2019 at 10:24:43 AM UTC-5, Fox's Mercantile wrote: > > It's a PITA to get at.   > Or you could just throw it in the trash. If it's not worth > fixing, it's not worth keeping.   Have you seen the 'Nano VNA' handheld units? Under $50 at many places.

Cursitor Doom <curd@notformail.com>: Nov 10 03:34PM On Sun, 10 Nov 2019 07:27:03 -0800, Michael Terrell wrote:   > They are X or Y rated safety capacitors. I would not omit them. The 250 > volt marking is AC volts, not DC. The HP manual should have the specs > for the bad caps.   I have a box full of Wima X and Y caps here (which are supposed to be superior) so sourcing a replacement for this failed Rifa is not an issue. It's getting access that's the thing.         -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.

Michael Terrell <terrell.michael.a@gmail.com>: Nov 10 08:14AM -0800 On Sunday, November 10, 2019 at 10:34:57 AM UTC-5, Cursitor Doom wrote:   > I have a box full of Wima X and Y caps here (which are supposed to be > superior) so sourcing a replacement for this failed Rifa is not an issue. > It's getting access that's the thing.   What's life, without a challenge? :)

Cursitor Doom <curd@notformail.com>: Nov 10 04:19PM On Sun, 10 Nov 2019 07:27:03 -0800, Michael Terrell wrote:   > They are X or Y rated safety capacitors. I would not omit them.   They're "safety capacitors" in respect of the fact that they can be connected across a (reasonably) high energy source; that's all. If they are omitted it's NOT a safety issue. Obviously *if* one is going to connect a capacitor across the mains supply it needs to be X rated, but *leaving out* such a capacitor, x rated or not, is not going to kill or injure anyone.         -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.

mjb@signal11.invalid (Mike): Nov 10 04:15PM In article <qq99r3$lps$1@dont-email.me>, >like the Tek scopes of the same era did. I think IIRC I've had issues >with these caps before on other equipment.   Elsewhere down thread you mention "RIFA" capacitors, sounds like the gold coloured 0.47uF/250V ones that seem to disgrace various 1980's ASTEC branded power supplies (BBC Computer, Apple II computer, ICL One Per Desk and others) all of which work fine for a while, and then crackle-phut-burnt toffee flavoured smoke, but keep on working.   I guess I got lucky, they didn't fail shorted, but they definitely cracked and bulged.     -- --------------------------------------+------------------------------------ Mike Brown: mjb[-at-]signal11.org.uk | http://www.signal11.org.uk

Ralph Mowery <rmowery28146@earthlink.net>: Nov 10 11:23AM -0500 In article <0673dcfc-6859-4f94-9f08-e67a019c0895@googlegroups.com>, terrell.michael.a@gmail.com says...   > Have you seen the 'Nano VNA' handheld units? Under $50 at many places.   I bought one a while back and paid $ 57 for it. They have came down.   While not lab quality, they do work well enough for an expirmenter on a low budget.   Around 20 years or less ago , they would almost have been lab quality. All they would need is a high stable and accurate frequency .   There is lots of stuff comming out of China that works well enough for people like me that don't have a lot of money to buy things with but still like to expirment and learn.   Those little component testers for around $ 20 really get to me. They seem to work really well in most cases as to identifying components and their values.

Clive Arthur <cliveta@nowaytoday.co.uk>: Nov 10 10:24AM On 08/11/2019 17:25, Alex Borroughs wrote: > I've been looking for a cheap, possibly DIY solder smoke solution.   <snip>   Most of my soldering nowadays is done peering down a binocular microscope. If I have to do more than I can manage to hold my breath for, I use a snorkel. Works well.   Cheers -- Clive

jlarkin@highlandsniptechnology.com: Nov 10 07:45AM -0800 On Sun, 10 Nov 2019 10:24:05 +0000, Clive Arthur >microscope. If I have to do more than I can manage to hold my breath >for, I use a snorkel. Works well.   >Cheers   I love my Mantis. It's super 3D, super bright and clear, and has a big working distance.   https://www.dropbox.com/s/wlim2da8cv9q6fj/Bench_Mantis.jpg?raw=1   I can put a rackmount box on the bench and swing the Mantis over/into it.   https://www.dropbox.com/s/gqendd0rnn3k7w0/Mantis_Box.JPG?raw=1     You can also poke a regular camera into the hood   https://www.dropbox.com/s/1qv6gjt9kc0gjy8/Mantis3.JPG?raw=1     I don't worry about solder smoke. I've been soldering since I was 3 years old.                 --   John Larkin Highland Technology, Inc   lunatic fringe electronics

Robert Baer <robertbaer@localnet.com>: Nov 09 02:36PM -0800 Chris wrote: > It had an all black finish. > It was only 60W per channel but punched above its weight in this respect > and produced _the_ most outstanding sound quality. * Up to this point, that reminds me of a Sansui system i had ages ago.   > which hopefully will identify it: a quite small volume knob with a little > red LED on one edge of it which lit-up and physically rotated whenever > the remote control unit's volume button was activated. * Now major description departure; sorry.

Chris <cbx@noreply.com>: Nov 09 11:59PM On Sat, 09 Nov 2019 14:36:15 -0800, Robert Baer wrote:   > * Up to this point, that reminds me of a Sansui system i had ages ago.   No, it wasn't Sansui nor Sanyo nor Sharp nor Pioneer nor Proton as Phil suggested, none of those nor any of the earlier ones in the thread people said it might be. I guess I'll probably never know now it's just too long ago. :(   Thanks for trying to assist, anyway guys.

tabbypurr@gmail.com: Nov 09 06:46PM -0800 On Saturday, 9 November 2019 23:59:06 UTC, Chris wrote: > said it might be. I guess I'll probably never know now it's just too long > ago. :(   > Thanks for trying to assist, anyway guys.   google imagines for japanese amp doesn't get you anything?

Phil Allison <pallison49@gmail.com>: Nov 09 07:17PM -0800 tabb...@gmail.com wrote:   ------------------------   > google imagines for japanese amp doesn't get you anything?   ** Might as well Google "cat" and select images in order to find your missing one.     .... Phil

Chris <cbx@noreply.com>: Nov 10 01:24PM On Sat, 09 Nov 2019 18:46:24 -0800, tabbypurr wrote:   > google imagines for japanese amp doesn't get you anything?   Er, no........

Lucifer <LuciferMorningstar@bigpond.com>: Nov 10 01:02PM +1100 FUTABA F6-STR SINGLE SUPER HET 27.095 MC MADE IN JAPAN

Phil Allison <pallison49@gmail.com>: Nov 09 06:18PM -0800 Mad Troll Lucifer wrote:   ------------------   > FUTABA F6-STR SINGLE SUPER HET 27.095 MC MADE IN JAPAN   ** Hobby radio control switch on 27MHz.   Yawnnnn....       .... Phil

Lucifer <LuciferMorningstar@bigpond.com>: Nov 10 01:08PM +1100 On Thu, 8 Aug 2019 04:12:06 -0700 (PDT), "pfjw@aol.com"   >> >http://www.elcontrol-energy.net/divisioni/misurazione/nanovip/?lang=en   >> Thank you, but the nanovip is very different.   >You miss the point. The mother ship may have archival information on equipment they made in the past.   Thank you but they were no help.

ggherold@gmail.com: Nov 09 08:48AM -0800 On Thursday, November 7, 2019 at 4:53:46 AM UTC-5, Fletcher wrote: > What adhesive to repair nylon halved pencil sharpener gear? > http://img4.imagetitan.com/img.php?image=20_image5623.jpg > If it fails, what online pencil sharpener do you recommend?   Maybe JB Weld. (epoxy with thickener) Or Phil A's idea.   George H.

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