Beware laptop power supplies/Dell/SSB transmitters

[Anonymous]

I have a Dell Inspiron 8600 and a week ago, sometime (?immediately) after I had been transmitting on my marine SSB, on start up the laptop gave the error message that it could not recognise the ac adaptor, was running at one third speed and would not charge the internal batteries. I accessed the Dell forums and found that this is a common problem and is almost invariably due to a faulty mains adaptor. Since I have full accident and extended warranty cover I phoned and was sent a replacement which was delivered next day by courier to the marina office. This cured the problem immediately.

1. Could the SSB radio transmissions have caused the fault? I don't know but I will always disconnect the power adapter and work on internal batteries when transmitting, from now on. I suggest you do likewise, whatever the make of your laptop, as the transmitted power levels from an SSB transmitter are enough to heat food, let alone blow small components.

2. I found that the non-Dell 12V converter that I had bought (and thought I had tested) gives only a limited functionality - the processor runs at one third speed and the internal batteries will not charge when connected via this dc-dc converter. The reason for this is unclear - I have searched the newsgroups and Dell fora and there are various theories; most people think there is an ID chip. Maybe, I don't know. Anyway, with hindsight, I should have paid a little more and bought the offical Dell converter. Indeed, I will probably invest in one now and use the other one for other electronic bits and pieces on board.

 

[jerryat]

Hi David,

Thanks very much for that warning. /forums/images/graemlins/smile.gif I have exactly the same laptop and use it regularly on board, though never when transmitting on HF as it happens. It is often on of course, when receiving HF RTTY and wefax transmissions. I assume you are referring to the Dell ac adaptor that came with your computer.

Your comment re the ac-ac converter (presumably 'Maplin's' type dc-dc adapter?) is very interesting considering the enthusiasm for them from posters on this forum. At present, we charge the laptop (if necessary) prior to using it to download wefax using a 12v-240v inverter, but this, as you will know, cannot be left on while receiving as it completely screws up reception. /forums/images/graemlins/frown.gif

I was just about to buy a dc-dc converter of the Maplin's type, so would be very interested in your assessment of the Dell one if you decide to go that route.

Thanks again, /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif

cheers Jerry

 

[Anonymous]

Hi Jerry, Yes, I was talking about the standard Dell 240V supply 'brick' that had failed. My dc-dc converter is not from Maplin but it is of the same ilk. You will not find any (non-Dell) dc-dc converter with a suitable dc plug for the Inspiron 8600 and I failed to find a source. I eventually came across a kind soul who happened to have a failed standard 240V supply and he cut the lead off for me! I then put an in-line connector on the other end, of a type that matched one of the dc-dc converter's plugs. When I wired it on, I found that the cable is very fancy - two co-axial screens (not two coaxes in one sheath but two concentric screens). The Dell product is probably quite fancy as this cable must have cost a fortune.

I can receive weatherfax with my bog-standard 12-240V square wave inverter running, and the little non-standard 12V dc-dc converter but I have a large whip aerial mounted a long way away - a very nice installation and well-bonded. I am even immune to the water pump, shower pump-out, etc. I'm not sure whether to go down the Dell route. I only need to transmit with the laptop running when I send SailMail or Winlink mail. This only takes a few minutes and all I have to do is pull the lead out the back. Of course if I don't buy the Dell dc supply then I will have to re-charge the laptop battery when I run the generator or invertor. Not a big hassle and it pays to discharge the battery from time to time, I suspect.

If you decide to go down the Dell route before me, then do let me know how you get on but meanwhile, if you buy a Maplin, I would say 99.9% you will be running at 600MHz and have no internal battery charging facility- that's if you can find a connector, even!

Good luck!! David

 

[ChrisE]

I bought one of the Maplins dc-dc convertors which worked fine on my Dell Latitude 400 but not on the Inspiron. I later found out that the Maplin devices come with different output power ratings and the one that I had bought was just below the power needed for the Inspiron hence the messages.

I now have a Latitude D610 which came with its own dc-dc convertor for use on trains and boats and planes. The moral to this story is that the power requirements of laptops vary quite considerably and you need to check it out before you buy.

 

[boatmike]

An interesting post Lemain. You obviously know more about computers than I do!
Perhaps you could confirm that I am doing the right thing. I will be running a Laptop for nav software only. I have a 1500W inverter which I use for general AC supply. I have however "acquired" a second inverter that is only 150W that appears to be able to charge the laptop batteries when running and I was going to wire this in seperately to avoid "spikes" in the supply when I use the microwave etc which of course runs off the big jobbie. I don't have SSB. Am I being over cautious? Is there a better way? Would I be better off with one of these DC-DC transformers do you think?
Any comments welcome.....

 

[fireball]

Power of a laptop

Check the powerout of your AC adaptor - they vary from 120w to 160w+ but this is just the rating of the adaptor ... then check the requirement of the laptop (usually tells you on the bottom) - most laptops seem to be sub 150w so you should be able to run it from the 150w inverter ... if you ahve a USB GPS it will increase your power consumption through the laptop.
One issue I had with my Crapard Hell laptop was the ac adaptor would not work on our 300w stepped inverter ... so I had to find another adaptor, but now the laptop is kn*ckered too ...
Dunno about spikes and stuff from the microwave - we don't have one on board, but it doesn't affect my computer room at home!!
Interested in the Dell situation, cos I've looked at those and considered getting the second battery - should give 5-6hrs of battery running ....

 

[MedMan]

I run my laptop using its original 240v 'brick' plugged into the output from a 400w Inverter that I have on board for a whole variety of purposes.

The argument for a DCC converter is that it should be more efficient i,e, less wasted energy as it is not converting 12v into 240v and then back down to 18v (or whatever your laptop requires and its 'brick' provides). However, I am not totally convinced by this argument. My Inverter is a top-quality Mastervolt product that claims to be super efficient. Your average DCC converter is likely to be much less efficient. It would be very interesting to see some genuine comparative readings of power consumption done in proper controlled conditions.

Your 150w inverter is quite man enough for the job to power your laptop but the unknown factor in the equation is 'how efficient is it?'

 

[TrueBlue]

DC-DC converters

Thoroughly unscientific qualitative tests indicate to me that indeed DC-DC converters of the step-up variety are indeed less efficient than the mains units, from the simple observation that they get hotter... Hotter = wasted power = less efficient.

Quite apart from the efficiency argument, you need thicker cables for low voltage supplies - which in my case means a 30ft. run from the battery bank. No thanks I'll stick to the inverter / inverter route...

BTW I have a couple of alfatronix 24/12 converters which don't get past slightly warm (tepid). I don't understand that.

 

[snowleopard]

bear in mind that a typical yacht ssb puts out 150w of energy and a fair bit of that leaks from connectors an cables inducing radio frequency currents in any wiring within a large radius. on our boat every LED on board flashes when i transmit and two CO alarms have died as a result. it's not surprising something has blown.

to protect yourself, switch off things like computers while transmitting, site anything sensitive well away from the cable runs and be prepared to turn off the autopilot.

 

[steve28]

The power supplies fail on a regular basis and not when they are used with invertors, we replace about 20-30 a year on average and most havnt seen anything but a domestic house socket

I have been keeping serial numbers of the ones we have replaced but no pattern is devolping yet.

steve


Ps we see more dell faulty ones than any others

 

[Ships_Cat]

If you get RF feedback to the power supply then you will certainly be getting it into the computer too and that will be via either or all of the power supply cabling, any cabling to the radio from the computer (eg via a modem) or sometimes through direct pickup by long cables such as to mice, multimedia speakers and keyboards. If so the symptoms are obvious and usually are some or all of the mouse and/or keyboard losing function, and the cursor running all over the screen. If there is hard drive writing the file written to may be corrupted.

Power supplies are far more robust than the computer components to RF so if the computer is ok and especially if none of the above symptoms then you can assume that the power supply failed all by itself.

If you were getting any of the above symptoms then it may be (unless you have found that the computer runs normally with a correct power supply) that the slow running, etc that you are experiencing is a fault in the computer, caused by RF feedback. I have actually never had a computer failure of any type while transmitting (don't recall actually hearing of it either unless there was a gross fault in the radio installation) and we have at times had 500 watt transmitters on board, but our radio installation is such that it does not interfere with anything else on board. It may be (again assuming you have not proven that it runs correctly with a correct power supply or you have been able to correctly test the power supply as being ok - that you probably can only easily do if it is a two wire one) that the computer has just suffered a random fault and everything else is ok.

Regarding the DC-DC convertor as you are talking about ID chips then I assume that the cabling from the Dell convertor to the computer is more than 2 wire, which would be unusual. But if so then that would seem to be the problem. If it is only 2 wire then, as I am sure you know, there are only 2 possibilites - either the voltage is wrong or the power capacity is insufficient. In both cases you should probably have no problems until the computer battery flattens. It is possible that the converter is suffering from RF feedback from the radio, causing it to lose control of voltage, but again, I would think that unlikely if you are not getting the computer symptoms above. If it is, then the RF will be getting into it via its cables - if so, then ferrite cubes on both inlet and outlet sides (similar to that described below for interference radiated by the converter) should cure it. Again, if it is losing control of voltage then one would normally assume that the computer would run correctly until the battery flattened.

I think it was established in a previous thread that converters commonly available in UK (as you know I am elsewhere) from cheap outlets are the Vanson Electronics ones and others have had good experience with them. Their jump converter one (ie switch mode >12v out) is the SDR-70W which does 3.5 A up to 20v and 2.9 above 20v. I have tested these convertors and they are rock solid and maintain correct output voltage even with wide excursions on the 12 v side - certainly up to normal >14v charging voltages).

Jump convertors similar to the Vanson can be quite noisy in the radio (but the Vanson is very good and has suppression on its cables). The RF interference normally escapes out of them via the cables, especially the longer output cable to the computer. It can be almost eliminated by winding 4 turns through a clamp on ferrite cube. Even if the cube clips together it pays to pull it up tight with a cable tie right around it so that good contact is made between the 2 ferrite halves, otherwise the magnetic flux will be weakened.

John

 

[Anonymous]

[ QUOTE ]
we see more dell faulty ones than any others

[/ QUOTE ]That's interesting - it certainly looks like a big issue on the Dell user forum. Many believe that the supplies are 'chipped' but it is equally possible that the internal interface puts a heavy transient load on to test for regulation. The puzzle is why the standard supply fails to a 'brown out' condition. Maybe an internal fuse blows? I nearly kept mine to open up on long winters evenings but SWMBO was not amused at the prospect of our nice boat becoming just an electronics lab. Can't imagine why /forums/images/graemlins/confused.gif

 

[Anonymous]

As I said in an earlier post, the dc cable between laptop and supply is fancy and there are three possible contact surfaces - I don't know if they are all wired though I have found + and -. Actually you can send data down a two wire cable superimposed on the dc. Whether Dell (or anyone else) actually do that, I don't know. It sounds like a strange design if they do!! Thankfully my laptop worked immediately I plugged in the new 'brick' and the dc-dc converter still doesn't run the system at full speed or charge the battery. The brick runs fine from my cheap square wave 12-230V invertor, though, so it isn't a big deal right now.

The big problem in transmitting for me is that I need to connect the laptop to the radio via a serial link if I want to use email via SSB. I can manage without a mouse and external supply but I still have the serial cable. It has been working fine, though, and I think you are quite correct in saying that it is almost certain (in my case) that the fault was not due to RF. But it pays to take care, especially for those who are about to cross the Atlantic and are relying on laptops for comms and weather.

I would say to them "Just because it works today does not mean that there is an adequate safety margin. Unplug all unnecessary cables before you transmit."

 

[Ships_Cat]

It would seem then that the problem with the computer not running correctly with the non Dell DC-DC converter is that it is 2 wire (unless it is some non Dell substitute for the real Dell one).

{Edit: on the unplugging unnecessary cables bit, the cable that will almost certainly always be the culprit for any RF feedback will be the one from the computer to the email modem to the radio - which, of course, you cannot disconnect if sending email. If there is no problem with that cable picking it up, any other cables will be ok too.}

John

 

[PhilipH]

I just received a letter from Dell (30 March) saying that they are recalling certain AC adapters as it is possible some could overheat. Visit www.delladapterprogram.com to find an ID number which will tell if your adapter is affected and if so they will change it.

 

[DepSol]

Thanks just checked mine and I am ok.

Dom

 

[jerryat]

Yep! Me too! Phew!!!!! /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

 

[Guest]

Many moons ago .....

I had a twinhead notebook ..... mono screen, 486sx jobbie - it had a strange power lead with 3 cores ..... my other notebooks of the time all ran fine as all mine now with 12V direct in .... the twinhead refused ...... and I assumed that the 3rd core was a signal or other similar check connection. Anyway - never did get it to power direct without the original adaptor.

 

[rwoofer]

You can get the suitable Dell adaptor on an iGo Juice DC-DC converter. That is what I use on the boat and leave the Dell powersupply at home.

RB

 

[boatmike]

I think that makes pretty good sense and I agree with you.
Actually I went to the boat yesterday and the small inverter is only 100W not 150 as I said previously. It has the usual overload protection that squeals in protest if you pull more power than it wants to provide and switches off.
I have a very strange phenomenon however. The inverter is run from my main power junction box with honking great big oversize cables direct from the battery. This is remote from my chart table so I have run an AC cable to a 3 pin plug at the chart table. When I plug in computer plus "brick" and switch on at the plug the inverter squeals and switches off but if I go to the inverter and switch it off and on again it works OK!
Now I have a good (digital) power management system so I know that with the computer battery on charge I am pulling 2.8 amps at 14.2 volts which is about 40Watts. So why does the inverter not like it? More to the point why is it that I switch on at the chart table and overload protection initialises but if I leave it switched on and turn the inverter off and on again it is OK? I can only think that the problem is caused by a surge on start up till the "brick" settles to a steady state well within the inverters capacity but why oh why does it not do it when switched on and off at the inverter?