Failed bios Amilo L6825 laptop

A friend recently gave me a Fugitsu Amilo L6825 laptop which was completely dead. He asked me to see if i could do a cheap repair or else he would buy a new one and scrap this non working laptop.

When i say dead the laptop had no indicator illumination of lights or disks spinning. My friend told me that he was on the Fujitsu support site and noted that his bios was not the current one as shown on their website. So for what ever reason he decided to update his bios on the laptop. When doing this update he encounted a problem where the laptop switched itself off during the update process. This resulted in the laptop now having a bad corrupt bios. The bios is the first part of software code to run when you switch on a computer. This code  gives instructions for the power on self test (post). This self test checks and ensures that the computer has all the required parts eg disks memory etc and that they function.

The laptop had been running Windows XP and had all his important info  on the hard disk eg emails photos etc. Normally i can recover a bad bios. Most modern computer bioses can be recovered by using a crisis disk whether this be via a floppy or usb disk media. On some computers however when the bios boot tables become corrupt this can be problematic as this normally requires the bios chip to be manually reprogrammed or replaced. My friend said that he had followed the instructions within the bios update utility but half way through the update the laptop switched its self off. As the laptop showed  no signs of life whats so ever i had to open the laptop casing up to get to the bios chip. For a change this laptop was quite easy to work on. The laptop bios was a plcc32 chip part number  A29040AL-70.

The laptop bios chip was also placed in a socket which meant it could easily be taken out. On some motherboards the bios chip can be soldered onto the motherboard which then requires the chip to be unsoldered for reprogramming or replacement. Bios eeprom programmers can be purchased with test clips that can be clipped to the chip but these are quite expensive to buy. For those who don't have an eeprom programmer the bios chips are quite cheap to buy of fleabay. The sellers can  also send the chips pre-programmed with the bios code of your choice. I however have an eeprom programmer which supports this particular chip. I have a usb pro GQ-4x supplied by a company called MCUmall Electronics in Canada.

I was able to use my eeprom programmer to re-program the bios code back on to his existing chip. On completing the bios recovery the laptop was fully recovered. My friend was amazed and very grateful for having his laptop bought back to life. The most important thing was he was able to get his precious data back.

On giving his laptop back to him i gave him that most important advice "If it ain't broken don't fix it".  i couldn't understand why he needed to update the bios in the first place. 

This type of repair can be very expensive and some manufacturer support engineers sometimes replace the motherboard rather than the cheaper solution of repair or replace the chip. In some cases this repair can cost up to or more than the original computer itself.

 

As this was a repair for a friend this cost him just one hours labour.

--Another gadget saved from the ever growing landfill--

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Wireless router problems

I recently had someone having problems with a Netgear RangeMax Dual Band Wireless N Router Model WNDR3300. The problems reported were that the wireless connection was always intermittent. The client workstations would keep on connecting and then in a short time disconnect from the router. The signal bar on the workstations were also constantly going up and down.

After ensuring that the router had the latest firmware it was assumed that the router maybe experiencing some interference which may be effecting the wireless network. The router setup menu was accessed and it was noted that the wireless channel was set on the auto channel.

We then decided to set the channel setting to channel 2. Once the router had been re-booted it was noted that 5 of the 6 workstations now had good wireless signal and a very satisfactory connection.

We then worked on the 6th workstation which was a HP laptop. First of all we checked the HP website to ensure that we had the latest wireless drivers installed. Then we checked for a suitable connection by means of connecting by a hard wired Lan connection.

We noted that the laptop would work via the Lan connection but the browser seemed some what slower in response compared to the other work stations. Our next approach was to check our anti virus software for updates. We then noticed that this laptop had been running without any anti malware / spyware utility.

The laptop was then installed with a free popular anti spyware utility and checked for undesirable infections. When the program completed we noted that it found numerous infections. We opted for our program to delete all infections found. After re-booting the wireless connection on the laptop seemed to have been repaired.

So in the final summary our wireless network seemed all of a sudden not to like the default channel that it was set on. This was rectified by setting the channel to channel 2. It was assumed that some interference was probably being picked up which we were unable to identify. The laptop had been proven to contain malicious malware activity which played havoc on the working of the router and laptop.

For people with similar problems our advice would be to ensure that your wireless network is not prone to interference and the most important advice do ensure that your security anti-virus and anti-malware software are up to date.

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Amstrad DRX180 Sky+ Box

I was asked to look at an Amstrad DRX180 Sky+ PVR satellite box. The problems that the user reported was that the box was giving a "No signal" on tuner 2. This prevented him to record a different channel to the one being watched.

The box was out of warranty and sky in his opinion was charging a lot of money to send an engineer out to have a look at his box. Sky had quoted him for replacement reconditioned box.

I opened the case and immediately noticed a 470uf 16v capacitor quite local to the tuner with a bulging case. The capacitor was un-soldered and replaced with a 470uf 25v capacitor.

Replacement of this capacitor satisfactorily repaired the box. On researching these symptoms further on google it seemed that this type of problem of no signal on tuner 2 was quite common on this particular type of box. Sometimes this was repaired by replacing the hard disk drive. The hard disk on this box seemed ok as once the capacitor had been replaced the recording seemed to work.

The cost of the capacitor was a few pence.
--Another device repaired by replacement of a capacitor costing a few pence--
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Linksys 12v 1A power supply unit causing havoc on DSL line

Recently i was given a Linksys 12 volt 1000mA power supply unit which had been causing havoc to a users dsl connection. The user over a period of a few weeks had noticed his dsl  router connection to randomly re-sync causing the isp's DLM system lowering his connection speed. At first it was thought that there was a line fault as there was sometimes a buzzing noise being heard on the telephone line. The user  reported a fault to his telephone service provider. After a few days the telephone company's engineer had diagnosed the problem to be the user's equipment. I was called to see if i could help.
The fist thing i did was to go into the routers web configuration page to look at his router stats. I noticed that the router had been re-syncing multiple times and the line stats were very bad as well.  The DL noise margin had crept up to 15db and the line attenuation of 36db didn't reflect to the lousy line rate of 800kbps.
To eliminate equipment i first tried a spare replacement belkin router. This immediately improved the line stats and line rate. So it was thought that the Linksys router was probably the cause of his problems and would probably be best to replace.
As the user was going on his annual holiday he asked me to repair or find a replacement router. I opened up the router and could not see anything wrong. Then i tried a replacement power supply and the router immediately was showing a more appropriate line stats.
So the problems was the power brick power supply. I decided to crack open the power supply.

The power supply was very basic consisting of a transformer, a pcb with four diodes and a smoothing capacitor. I tested the transformer on the secondary side which was giving out approx 17V under no load which seemed correct. I then tested the four diodes on the pcb which two tested unsatisfactory. The 2200uf smoothing capacitor also showed a capacitance reading of 83uf with an esr reading of 19.5 which defiantly was a sign of failure.
I replaced all four of the diodes with some spare IN5400 and soldered a new 2200uf 25V capacitor. The casing was glued back and the router and repaired power supply put back on the user's dsl line.
The results were a complete success as the sync rate immediately jumped up to a more respectable 7345kbps and the line noise lowering itself to 7db.
The cost of the the components replaced were under two British pounds and the client recently reported that he has never had his router work so well.

-- Another piece of electronic equipment saved from a journey to the ever growing landfill --
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ESR Micro capacitor test meter

Read this blog contents also at    http://www.punj.co.uk/punjwebfiles/electronics/microesr.html
*Permission granted to post above link by the website owners at http://www.punj.co.uk*
 

Well anyone who dabbles alot in electronics will tell you that it can be very useful to have an esr meter to test for bad capacitors. When the hobbyist then researches to get one of these handy items for the toolkit they can be quite expensive and sometimes quite difficult to understand. So what is esr and its revelances on a  capacitor.

ESR can be explained as follows. A capacitor consists of metal plates, which are filled with a dielectric that separates the plates consisting of an oxide layer on the lining, and the electrolyte. All this is placed in an aluminum at the connection plates. This, in turn, causes resistance to form a pathway deterioration for the alternating current within the capacitor, causing heat, and consequently, accelerates the processes described above. All losses may be summarized in the so-called equivalent series resistance (ESR) - an imaginary resistor in series with the capacitor itself.

When you google esr meter for info on these items you will find quite a few. I found that these meters can be quite expensive and also not very user friendly for the lame hobbyist.

I however came along one such meter which was not only within my tight budget but very user friendly to use.

The esr meter that i found on google and bought was a little device called EsrMicro V4.

This little device was purchased from Russia http://www.radiodevices.info/zakaz_e.php

At the time when i bought this it cost 75US Dollars which included taxes and shipping. If you need one you just fill out the order form and a chap called Mike will email you back on how to complete your order.  I also found Mike very good at communicating with any queries relating to the product or order.

Mike also frequents occasionally at the http://www.badcaps.net/  where he has acquired a very good reputation. Just do a search for esr meter on the site and you will note the very happy customers around the world he has sold these meters to.

The order took 10 days for delivery which is not bad for delivery to the UK. The meter will come without batteries and a very basic manual. 

Using the meter is very easy. You can use the meter probe lead or you can use the meter socket pins to check a capacitor. The meter will give a very clear reading of the esr reading and the capacitance reading.

One very important thing to bear in mind is that you must ensure that when testing existing capacitors that they have been fully discharged. The meter incorporates only a very simple protection by the use of diodes. This minor protection against a capacitor discharging on the meter can quite easily cause major damage to the meter. But comparing this to other meters which can literally cost hundreds of dollars if you ensure that you carryout discharging of your electronic component capacitors this meter will serve you well.

I have now used this meter a few times and can say it greatly helps in the diagnostics of my electronic projects very well.

I will in time post further blogs on how this meter helped and the kind of bad readings of a capacitor which can only be found by using such instruments as this.

 

---Hope this was a good read ---

Read this blog contents also at    http://www.punj.co.uk/punjwebfiles/electronics/microesr.html
*Permission granted to post above link by the website owners*

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