Computers and equipment resetting

Continued

I suspect a mains interference problem, as the shop has one wall of refrigerators, a half tonne of air-conditioning and a railway line (electric) a block away.

I have fitted clip on ferrite suppressors to all the UPS power leads, but this does not seem to have helped. I am looking for other ideas and a possible supplier of inexpensive line conditioning or low frequency filtering equipment, standard surge suppressors with EMI / RFI filtering only filter from about 100kHz and up. I suspect low frequency switching transients. So far the only items I have been able to locate are in the thousand dollar plus price range, and this is a bit too much to trial, especially if it doesn't work.

The UPS log does not show any untoward power problems, but then if it is a transient problem the UPS may not be "triggered" by the transient.

It may also be an earth loop problem.

All suggestions welcome.

One problem, is I don't know what equipment brands are available to you.

Here in the US, I would start with Sola or Topaz for line conditioners.

You might try a less expensive line isolation transformer rather than a full line conditioner.

If the transformer helps noticeably, then you can evaluate the value of a full line conditioner.

Another option, would be to build up a line filter. Corcom used to make filters that went down to the 10 KHz range. I built one into a box with outlets on it and have used it many a time to prove a line noise problem.

Do the network cables run close to any mains?
For that matter, are they as far away from light fixtures as possible?

A noisy ballast transformer can throw off a lot of RF noise.

Yes, I would go ahead and put in a new CMOS battery on the one system.

Another thing I suggest you do, is stand back and observe the operation for a period of time.

I had one PC system that was "acting" up for months on end with no solution in sight.
Turns out the user would set things on top of the keyboard, and the custom software locked up when the keyboard buffer got full. Until I observed the process for a half hour, there was no clue as to the source of the problem.

How environmentally sealed are the scale / scanner and keyboard?

Could the clerks be cleaning things in a manner that gets cleaner inside things, or dripping down the cables?

Are the PCs up off the floor and protected from floor cleaning?

On the power side, you might want to canvas the local electricians and see if any of them has a good power line monitor. Many can record spikes, dips and transients. Renting one for a week would help prove the need for a line conditioner.

Since it has been in the PC news, don't forget to inspect the filter caps on the new motherboards. Look for bulges or leakage on all of them.

When all else fails, drop back and look over the situation from another perspective.

Good luck,

Chas

what's the POS software being used? Is it SAMS 4? often times SAMS 4 POS works great with Windows 98 but stinks with XP. Even with their updates. One thing to check is the polling between registers. XP SP2 is great but SP2 can break stuff like POS software where Windows runs in the background. The BIOS reset thing, follow The Chas's advice. He's the guru of hardware.

If this is IBM POS then I would say the problem might be with the POS server. If you have internet access anywhere on any of the computers [presumably all are networked together, I'd say maybe infection is the culprit.

Check your local phone book and find an instrument rental. A line monitor can be as low as about$30. a week. This will enlighten you
and might even scare you, so I'd say that a broadband filter would give the best coverage.

Are there any environmental hazards around? I had once a client whose office was next to a police station and one of the PCs was somehow in the line of the transmission beam from some sort of a radio transmitter. Once the PC was moved a couple of meters, the obscure problems sorted themselves out and disappeared...

Hi-
The suggestions I had have already been covered, so I have nothing to add that might help your computer problem, but I thought I might lend you a little board help. :-) (Just to keep in mind in case you have anymore problems in the future.) I see that you did not wish to reject a couple of the answers you received.
You can add more than one comment to your original post, rather than commenting on a reply itself, simply add your comment to your own post and indicate who (which helper) you are replying to, that way you can keep a running commentary with those that are trying to lend a hand and avoid rejecting their answers until the problem is solved, or not solved.
Of course that doesn't apply to the few silly people here that give answers like "Eat some chicken soup first, then start your computer.." LOL
HTH,
ED.

Being in AU the electrical authority should come out and provide a recorded box for Power Measurements. Up Here I've used this service quite often when required.

At one place we had a computer fail on a daily basis and it nearly drove me nuts. I had tried everything that I could think of and then some that paper tape when rolled out flat didn't so much as produce a serious spike or drop or any transients. So I was at a loss until I walked outside and saw a dentist beside where the computer was failing. Apparently their X-Ray machine needed some serious maintenance as it was leaking radiation and killing the computer on the other side of the wall.

Not to sure that it did the user too much good either. :D

But if you can disconnect the network cable from the problem machine if even for a short Test Time it might point you in the right direction. In these Supermarket type environments I've seen LAN cable wrapped around 3 Phase Power cable to keep it in place, it played havoc with the network but at least the lead stayed in place. :)

If it is necessary could you try a Shielded Fly Lead to replace the existing one and have it well off the floor for safety reasons.

I also agree with Chas here change out the CMOS Battery it's cheap and may save you a lot of wasted time and effort, it's just not worth the expense in not changing it and while you have it out check the socket to make sure that it isn't faulty. While rare it's possible.

Col

Chas,

Thanks for your answers. Tried new CMOS battery, no different, am going to pull computer to check on bench and leave old one to tide over.

Built low pass filters, as you suggested, ~ 5k bandwidth. Used old PSUs, they have quite good filters already, and threw in some extra capacitance. Don't know result yet.

Please re post an answer so I can award points.

Hi Col,

Thanks for your reply, see also comment above to Chas.
I've looked around and the only possibility is a restaurant next door - microwave oven?

Herb

Hi MJD420,

The UPS installed has an input voltage logging function and this shows that the mains is within spec. Does not show transient noise, though.

I have check with a rental co. but they only have U beaut line loggers, at about $300 per week. If all else fails I'll try and get the power company involved.

Herb

Hi Toivo,

Thanks for your reply, see comments to Col, above.

Also if this is the problem I'd have massive difficulties in moving the computers, they are in serving counters.

Herb

To Electricdragon,

Thanks for your tip about comments, I'm doing it now. The only problem I envisage is that I don't think there is any notification that comments have been added to the question, as there is when the answer is rated.

Herb

I would recomend you get an electritian to ISOLATE the computer systems off the regular circuts.I would also recomend a UPC with a transfer system that works when the power goes out. this means you don't have to shut down the store when the power goes out.

i can see how everyone jumping to conclusion bad power in supermarket but i read your wonderfully thoughtout question couple times and i think you may have multiple failures. unless there is something else guiding you to that theory that you haven't mentioned...
the ups's should be working. the computer would only get its defaults if the thing reset.
i'd wonder if power just went out except you checked the ups logs for that...
so i would also start with a new battery on that one. but i'd bet a movie ticket that mobo is bad. all parts suspect until this dang 'globalilzation' settles in, if you ask me.
re: the scanner. if they both now work after your swap, then how can that be power? or a faulty unit? that sounds more like an resource conflice (interrupt) conflict. you mentioned you needed more slots on one, just go over the basics see what is on there what i/o base and interrupts may not be plug and play and that pos equipment...
sounds like you are mostly rocking and keep up the good work. you are a natural. getting stuff working and then figuring out what it was is how i do it and i bet how lots of us do it...

This question was closed by the author