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etpm@whidbey.com: Nov 14 12:20PM -0800 One of my CNC machines has a circuit board that has failed 3 times now. The control is a FANUC 3T. It is an older control so failing boards don't surprise me. But it is just the one board. This board has many custom hybrid ICs, some other of the shelf ones, 6 EPROMs, and one electrolytic capacitor. I have checked this cap on two boards with my meter and the cap has the stated value and is not shorted. But I don't have a way to check ESR. The failure mode for all the boards is the same. First the turret on this lathe will occasionally index in the wrong direction. After the machine is powered up for a while it will then start to index properly. I can control the turret rotation from a program but when the board starts to fail it will only index in one direction. Furthermore, then turret should always rotate in the direction that is the shortest to the next tool called up, but when the board starts going bad the turret still only indexes in one direction. Unfortunately this is the wrong direction. After this failure other things start going wrong, like the speed control. Changing the boards has always fixed the problem. Note that when I change the boards I have to swap all the EPROMs so that the programming for the machine operation will be the same. Since all the boards seem to fail the same way I was wondering if somehow a failing cap could cause this failure. Even though the cap value reads fine with my VOM, that does not measure ESR. In any case I'm gonna order some caps and see if anything changes but I would like to know if it is probably gonna be a waste of time. Thanks, Eric

John Robertson <spam@flippers.com>: Nov 14 01:03PM -0800 > but I would like to know if it is probably gonna be a waste of time. > Thanks, > Eric   I'd say it is unlikely the capacitor is the problem - normally these are used to smooth the Vcc to the chips. You say there are custom chips on the board, so depending on if you can get schematics or not then you may be looking at the rest of the circuits.   Regular electrolytic caps are rarely used for critical timing, rather they would use a tantalum cap if the value was important.   If you want to check the ESR then Bob Parker's Blue ESR meter kit is not a bad way to go...available here (flippers.com - shameless plug!) and there...   However I don't think the cap is responsible for your problems.   Have you tried simply reseating the chips and connectors to the PCB and any readouts, sensors, etc. in case it may be that simply reseating plugs fixes the problem?   If the problem is only apparent after the machine has been on a while have you checked the temperature of the logic? Chips don't like being more than 50C by and large, and the cooler they run the better. A heat gun and some cold spray may help find the sensitive IC as you say the problem goes away when the system is warm.   John :-#)#

Ralph Mowery <rmowery28146@earthlink.net>: Nov 14 05:35PM -0500 In article <68crset030lbht7eq52p34vogu6lmvqj61@4ax.com>, etpm@whidbey.com says... > one electrolytic capacitor. I have checked this cap on two boards with > my meter and the cap has the stated value and is not shorted. But I > don't have a way to check ESR.   The capacitor probably only costs a few dollars at most. Just replace it and see if the board comes back to life. That is see if the machine acts normally.

etpm@whidbey.com: Nov 14 04:01PM -0800 On Thu, 14 Nov 2019 13:03:28 -0800, John Robertson <spam@flippers.com> wrote:   >gun and some cold spray may help find the sensitive IC as you say the >problem goes away when the system is warm.   >John :-#)# Greetings John, Actually the machine starts to work after it has warmed up for a while. I have tried the whole contact cleaning route several times and it has had no effect on this machine. Today I tried out two boards that I got used from eBay. One worked and the other, whil it indexed then turret OK would not allow programmed speed changes. The speed change fault is mysterious to me and it has happened on another board. The mystery is because of what the fault does. Niormally speed changes while running a program can only happen from programmed speed changes or from the constant surface speed command. But when the board goes bad then the spindle speed can only be controlled by the dial used for speed changes when in jog mode. And that dial normally does not work when running a program. I checked all the parameters and they have not changed. And the EPROMs that hold the ladder programs for the machine are not affected. In fact, I have to change them from board to board. Speaking of EPROMs, I am ordering a GQ-4x4 programmer so I can copy my EPROMs. I am really afraid I will destroy one one of these days. I have lots of 2716 and 27C16 EPROMs that I can erase and re-program. The machine has in it some 2716 and 2516 devices and I was told that the 2516 devices should not be used. I am hoping the programmer can read the 2516 devices. Thanks, Eric

etpm@whidbey.com: Nov 14 04:01PM -0800 On Thu, 14 Nov 2019 17:35:48 -0500, Ralph Mowery   >The capacitor probably only costs a few dollars at most. Just replace >it and see if the board comes back to life. That is see if the machine >acts normally.   Yeah, I am gonna do that. I just won't get my hopes up. Eric

John-Del <ohger1s@gmail.com>: Nov 14 06:32PM -0800 > but I would like to know if it is probably gonna be a waste of time. > Thanks, > Eric   I work on a lot of industrial equipment for two local machine shops, and electros do go.   They bring me the suspected boards but I have them well trained to first heat the boards with a heat gun (without crisping them) and report if the normal operation is restored when heated.   If so, the first thing to get checked is the electros. I pull every one and test them for value, ESR, and dielectric absorption. Testing ESR in circuit on many modern circuit boards is a waste of time.   99% of the time a board that works normally when heated has a lazy electrolytic.   If the electro replacement doesn't fix it, try cooling individual parts to see if you can get it to act up.

Ralph Mowery <rmowery28146@earthlink.net>: Nov 14 11:14PM -0500 In article <ad5da084-f6ed-492e-8d5e-c989be6c3d03@googlegroups.com>, ohger1s@gmail.com says... > eport if the normal operation is restored when heated.   > If so, the first thing to get checked is the electros. I pull every one and test them for value, ESR, and dielectric absorption. Testing ESR in circuit on many modern circuit boards is a waste of time.   Once pulled, you might as well not test them, just replace them.   You may want to test the new ones before you put them in.

Cursitor Doom <curd@notformail.com>: Nov 15 09:40AM On Thu, 14 Nov 2019 18:32:29 -0800, John-Del wrote:   > 99% of the time a board that works normally when heated has a lazy > electrolytic.   Or a dry solder joint somewhere on the board.   > If the electro replacement doesn't fix it, try cooling individual parts > to see if you can get it to act up.   Good call. For which you can use stuff like 'pipe freeze' or 'Arctic freeze' with the fine straw inserted - sold at your local plumbing supplies. Clean the board with IPA afterwards.         -- 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.

Cursitor Doom <curd@notformail.com>: Nov 15 09:45AM On Thu, 14 Nov 2019 18:32:29 -0800, John-Del wrote:     > If so, the first thing to get checked is the electros. I pull every one > and test them for value, ESR, and dielectric absorption. Testing ESR in > circuit on many modern circuit boards is a waste of time.   Why so?       -- 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.

John-Del <ohger1s@gmail.com>: Nov 15 05:26AM -0800 On Friday, November 15, 2019 at 4:45:16 AM UTC-5, Cursitor Doom wrote: > > and test them for value, ESR, and dielectric absorption. Testing ESR in > > circuit on many modern circuit boards is a waste of time.   > Why so?   Too many circuits these days use a small value SMD multi layer chip capacitor bypassing an electrolytic. These chip caps have ESR figures as low or lower than most electrolytics you're likely to run across despite being small value caps.

John-Del <ohger1s@gmail.com>: Nov 15 05:30AM -0800 On Thursday, November 14, 2019 at 11:14:21 PM UTC-5, Ralph Mowery wrote:   > Once pulled, you might as well not test them, just replace them.   > You may want to test the new ones before you put them in.     If you know the board *will* be fixed and put back in service, then yes, by all means replace them. But if I pull an electro during testing and it's good, I put it back and continue working on the board. No sense changing good caps on a board that may have to be replaced, like OP is dealing with.   Lots of these industrial boards use custom ICs, ICs and semis that have been intentionally defaced, and processor ICs for which there is just no data. Sometimes you just have to replace a board.

John Robertson <spam@flippers.com>: Nov 15 08:34AM -0800 > read the 2516 devices. > Thanks, > Eric   Hi Eric,   If those are TI TMS2516 then they are equivalent to regular Intel 2716s. The TMS2716 by TI had a triple supply and A10 was displaced.   TMS2716 vs regular 2716s   https://www.dropbox.com/s/7xaz0b829bhha6b/TMS2716vs2716.jpg?dl=0   TMS2516 (Thanks JRock for hosting):   http://www.jrok.com/datasheet/TMS2516.pdf   I don't know about the dependability of the TMS2516, but I would back up ALL EPROMs just for safeties sake!   I hope your new EPROM reader can handle the 2716s, if not if it can read 2732s then you will get the data twice and you can split off the high and low sections.   John :-#)#   -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."

etpm@whidbey.com: Nov 14 09:10AM -0800 I know, no electronics repair really but there is a lot of varied experience here. I need to vent a basement room. It's about 20'; x 12'. What happens now is moisture laden air goes down the stairs and then drops the moisture in the basement room. I want to keep the room cool so heating to get rid of the moisture is out. So I have been looking at vent fans and pretty much all I see are fans for venting crawl spaces and attics. So what kind of fan should I use? Thewre must be some sort of shutter and a screen but I think those can be added to the outside. And do I need two fans? One at each end of the room? So that fresh air comes in and old air goes out. Or just an exhaust fan? The room is aligned lenghtways sort of north to south. The southern fan would be the exhaust fan and would vent under the front porch. The northern fan, if there is one, would draw air in from the north facing end of the house. I live about 30 miles north of Seattle so I guess weather should be taken into account too. Thanks, Eric

"pfjw@aol.com" <peterwieck33@gmail.com>: Nov 14 09:58AM -0800 First, given your location, all fans will do is relocate outside moisture to the inside, and push inside moisture to the outside. What you need is an effective dehumidifier - which is heat/cool neutral, but does remove moisture - albeit at a cost (electricity).   Second, based on venting to the south, drawing in from the north, you are doing exactly the opposite of what you should do for your purpose, at least in the northern hemisphere. You want to draw air from the warm(est) side of the house, which will be the sunward side, even in Seattle. And you want to vent to the cool(est) side, which will be to the north (no direct sunlight).   Short of deliquescent materials, there is no passive means to remove humidity. Any anyone that suggests otherwise is telling porkies. Some other points:   a) Concrete and stone (typical foundation materials) are, emphatically, not vapor barriers, so unless an effective vapor barrier was installed on the *outside* face of the foundation walls, and beneath the concrete slab, you will have a constant source of moisture at all times, weather notwithstanding.   b) I really hope that you are not intending to do any sort of work involving electronics or you handling electrified equipment in that space. Working over a concrete floor over dirt is, essentially, equivalent to standing in an inch of water. To prove the point, with a decent VOM on AC volts, one probe to the hot side of a receptacle, the other to the floor. As your body, assuming you are otherwise healthy, is not much more than a 10,000 ohm, 1/4 watt resistor, be careful!   c) Cellars (more than 50% below grade) or basements (50% or less below grade) unless designed as such from the git-go are simply not meant to be used as finished, habitable space. And in your climate, even more so. And, if you happen to be in an older house where local stone was used in the foundation walls, drying them out is absolutely not a good idea unless you want your house to start settling, big time. There is a long explanation for this, but typically old foundations were built with a mud/lime mortar with very little Portland Cement involved. The stuff is solid when damp, but when dried out, it shrinks, crumbles and fails. Here in the Philadelphia region, the likes of Dr. Desert Dry and their ilk won't touch older houses for that reason. Again, be careful!   Best of luck - fans are a waste of money if dehumdification is the specific goal. Deliquescent materials have a high first cost, and will have you upsetting your significant other as you will be baking them dry in the oven constantly. But, they do work. Leaving you with machines as quick, relatively efficient means to that end. Invest in the additional condensate pump so you are not constantly emptying the bucket.   Best of luck!   Peter Wieck Melrose Park, PA

amdx <nojunk@knology.net>: Nov 14 12:20PM -0600 > taken into account too. > Thanks, > Eric   Can you add enough positive pressure to the basement to reduce the flow down the stairs? I know that would be drawing cold air into the basement. ¯\_(ツ)_/¯ Get a dehumidifier, you get heat and dry air.   Mikek

Adrian Caspersz <email@here.invalid>: Nov 14 06:34PM > moisture in the basement room. I want to keep the room cool so heating > to get rid of the moisture is out. So I have been looking at vent fans > and pretty much all I see are fans for venting crawl spaces and   Seems you need to block the air coming down the stairs. Is there a door at the top? Can you install another a few feet in like an air lock, and vent out the air in-between with a timer/humidity operated fan?   -- Adrian C

"pfjw@aol.com" <peterwieck33@gmail.com>: Nov 14 10:35AM -0800 On Thursday, November 14, 2019 at 1:20:58 PM UTC-5, amdx wrote:     > Can you add enough positive pressure to the basement to reduce the > flow down the stairs? I know that would be drawing cold air into the > basement. ¯\_(ツ)_/¯   That would involve bringing outside humidity inside. Keep in mind that the average relative humidity in that region is 79%, and the average number of sunlight hours per day (not cloudy) is two (2). It IS humid. All. The. Time.   > Get a dehumidifier, you get heat and dry air.   Dehumidifiers are heat/cool neutral. They use refrigeration to pull the moisture out of the air, but dump the residual heat at the same time. The air feels less clammy, so the perception is that it is warmer. It really is not.   Peter Wieck Melrose Park, PA

whit3rd <whit3rd@gmail.com>: Nov 14 10:40AM -0800 > now is moisture laden air goes down the stairs and then drops the > moisture in the basement room. ...   > So what kind of fan should I use?   A bathroom or kitchen vent fan would be appropriate, but for control, you'd want to run it only when the absolute (not relative) humidity in the basement is higher than the absolute humidity in the make-up air (presumably the outside air), that will filter into the basement.   As an approximate control, you might consider that before dawn, when there's dew on the grass, the outside air humidity will be low; a time switch that runs a fan for a couple of hours in the early morning might work.   A more complex system could be imagined, circulating basement air to an air/air heat exchanger with outside air, to make the 'dew' effect produce droplets into a drain, from the basement air. Drain into a jar, and you can get a measure of the effectiveness. If the basement windows fog up in the mornings now, that's an encouraging indication.

"pfjw@aol.com" <peterwieck33@gmail.com>: Nov 14 11:47AM -0800 Some basic facts about the Pacific Northwest:   a) Average relative humidity, all four seasons such as they are is 79%. By comparison, in Philadelphia, PA it is 54.6%.   b) Most of the time, interior humidity (inside an occupied house) will be much less than outside. Why? Because the hottest months (July & August) average 73 by day, and 55 by night.   c) 152 average rainy days per year.   Put another way, it is a damp climate with a lot of rain.   The air in the house, for 12 out of 12 months, by night, and 10 out of 12 months by day will be *warmer* than the outside, and therefore LESS HUMID, but based only on temperature. What is happening is that the warm air is hitting the cool cellar, and moisture is condensing - as with a glass of ice-water.   Isolating the cellar from the upstairs will not lower the humidity in the cellar, but it will avoid the shock from the warmer air from above. Circulating outside air will, in fact, increase humidity in the cellar. Why? Odds are that the cellar will be marginally warmer than outside, so the latent heat (humidity) will be lower. Cool that down, and the sensible heat will drop like a stone as the relative humidity will jump.   Remember, you are starting from an average of 79% RH.   This is not an easy fix. And a mechanical solution to address the specific issue of humidity is the single practical answer. HOWEVER - if the goal is only to avoid the heavy condensation issue, and dropping overall humidity is not the goal, then isolation of the conditioned areas of the house from the cellar is the single practical solution. Either by installing a functional vapor-barrier and sealed doors, or some other solution. Beware the vapor barrier, however as it will collect condensate which most be managed.   Peter Wieck Melrose Park, PA

amdx <nojunk@knology.net>: Nov 15 08:07AM -0600 > That would involve bringing outside humidity inside. Keep in mind that the average relative humidity in that region is 79%, and the average number of sunlight hours per day (not cloudy) is two (2). It IS humid. All. The. Time.   >> Get a dehumidifier, you get heat and dry air.   > Dehumidifiers are heat/cool neutral. They use refrigeration to pull the moisture out of the air, but dump the residual heat at the same time.     I disagree about heat/cool neutral as it concerns the room temperature.   I tried running a dehumidifier to assist my air conditioning. I found if I reduced the humidity to 40% I could raise the temperature 3* F and even 4* F higher and still have the same comfort. The only convenient place for the dehumidifier was in a foyer, and that foyer got very warm.   While I understand it would be an adiabatic process except for motor inefficiencies, some of the removed heat is stored in the waste water and is put back into the room.     The air feels less clammy, so the perception is that it is warmer. It really is not.   That is just opposite of my experience, give me low humidity Please! I feel much more comfortable and even want a warmer temp if the humidity is low. I run my auto air conditioning in the winter just to lower the humidity. I live in North Florida.   Mikek

"pfjw@aol.com" <peterwieck33@gmail.com>: Nov 14 12:15PM -0800 1234   Server Issues?

Fox's Mercantile <jdangus@att.net>: Nov 14 08:24PM -0600 > 1234   > Server Issues?   UR 5X9 NTX, QSL?       -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Cursitor Doom <curd@notformail.com>: Nov 14 11:42PM On Sun, 10 Nov 2019 18:37:41 -0800, Michael Terrell wrote:   > leaving the remaining part of the capacitor, in circuit. If you measure > the capacitance of a damaged X or Y capacitor, it will be lower than > marked.   Yeah, I guess it would. Anyway, after hacking a hole in the bottom of the motherboard I was able to removed the cap in question from underneath and it looks far worse now I can see it properly. It definitely let go in a big way and now I'm pretty confident it was the source of the loud bang I heard. I've also carefully examined all the other sub-boards and the PCB underneath them and they're all fine. Shards of broken cap were scattered about the area of the explosion. Shame I had to butcher the board to get it out, but there was no other way open to me. I follow what you said about removing that j6 power connector but I just don't have the dexterity I'm afraid. So it was a case of Dremmel to the rescue! :-)

Chris <cbx@noreply.com>: Nov 14 11:34PM OK, thanks to everyone who responded. I'd thought that volume feature would be unique to one manufacturer to be honest - I've never seen it on any other amp. I think now someone mentioned JVC and that *does* ring a bell. It's just that I'd never equated JVC with the best of the amps of that era. Looks like I may have to review my prejudices. The search goes on...

Clive Arthur <cliveta@nowaytoday.co.uk>: Nov 14 05:17PM On 13/11/2019 01:33, Winfield Hill wrote:   >> ... within an hour, the odors are cleared. As incense is >> burned, it draws in the smoke and no odor that I can detect.   > But then, why burn the incense in the first place?   To ward off the twin evil spirits of decaffeinated coffee and alcohol-free beer.   Cheers -- Clive

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