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Note that each grumble was written at the time I was annoyed and of course the passage of time may have put right the wrong if any was there to be righted... Even though lots of these grumbles are now many years old I'm leaving them in place just in case the perpetrators haven't pulled their socks up yet and still need reminding of their failings. Some are historically interesting and these I've left for general information. |
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The hard drive is the most important
bit of a modern computer. If a motherboard fails a new one will
get things going easily, memory or processor chips just plug
in and other bits and pieces are never difficult to replace. To the average member of the public
it may not even be imagined what's in store, or more accurately
what isn't in store! Lately I've had a couple of hard drive failures that caused me real grief. The first was a Fujitsu drive that had half failed. It was just able to part with the customer's data, after a fashion, before finally biting the dust. A new drive was obtained under warranty
and fitted. Next came the long-winded process of loading an operating
system, drivers for graphics, sound, modem and motherboard then
applications programs and printer, scanner, and Internet stuff
etc. The next month another computer crossed
the threshold. This time, a "Time" machine used in
a small engineering supply business. It wouldn't boot up and
dismay was expressed when I diagnosed a faulty hard drive and
that it was too far gone to retrieve any data. Not long afterwards a third machine
arrived. Not really a third. It was the first machine making
a second visit to the workshop. This is a serious matter as it generally means, if interface and cables are OK (and they were), that the drive has lost its partition information. In this state all the data is usually present, but without partitions it is unreadable through DOS or Windows. There are a number of possible solutions. The one I adopt is to run a proprietary data recovery program. This clever program can read any data present on the drive and is able to extract it and transfer it to a second hard drive. To work properly the drive must be in good working order and the easiest recoveries are made when a partition has merely been accidentally deleted. In the case of the Fujitsu drive in this example, not only was the partition lost but the drive would appear then disappear in the BIOS screen without any logical reason. FDISK would sometimes find it then a moment later it wouldn't. Sometimes switching a faulty drive from master to slave or removing a parallel device, such as the CDROM, can help. In this example it didn't. Next I tried the drive on a different computer. If it's an interface fault the slight differences in the hardware can make a dead drive come alive. It worked. I now had an active drive, with no partitions admittedly, but at least it was visible to the data extraction program. The program ran and presented me with all the data held on the drive, including files deleted early in its life. I decided to extract the important data first then, when that was safe, try copying the whole drive to a second of the same size, 20Gbyte. The first exercise worked albeit with more than a few hiccups but the second started to go slow… very slow. In its default setting with multiple reads, designed to extract the last ounce of data, the predicted completion time was nearly a year and getting worse! By resetting to only a single read the completion estimate dropped to a manageable couple of hours. I finally got a directory structure from which the data could be selected. I decided to have a shot at retrieving the lot, about 5Gbytes. Not a good idea. 24 hours later the job was complete but lots and lots of read errors recorded. These will result in truncated files or fragments of files and were distributed pretty uniformly over the drive. I removed the two drives from my workshop computer. The Fujitsu destined for replacement yet again, and the new IBM to be installed in my customer's computer. I booted it up. No luck. The system files were corrupt for a start. I copied fresh system files and made the drive active. I again set the computer to boot and was rewarded with a Windows screen and very few error messages. So far so good. Unfortunately the special program for re-inserting long file names in place of the truncated DOS ones failed to get very far. Clearly it couldn't handle the files that had been truncated. I re-installed Windows 98 and a selection of application programs. Things didn't look too bad. Even the Internet worked and e-mail messages were all there. Not quite everything worked however. When an attempt was made to add clipart to a blank page the computer stopped working. Not completely. A couple of things were possible. The mouse pointer moved around and a CTRL-ALT-DEL produced a list enabling one to close down the offending program. I reloaded Office 2000… both disks. This took a very very very long time. Many hours later I tried to add clipart. I was rewarded with exactly the same results. No justice for all the time I'd spent. I decided to "repair" the programs. After some difficulty this was done. I tried clipart and again the same near-dead computer. Although the Office start-up menu claims to be able to repair an installation, if certain specific files are corrupt it has great difficulty and cannot complete the job. I deleted all the office stuff. This was done through a mixture of its built-in uninstaller and brute force methods. The uninstaller, like the repair feature will not work properly if certain files are corrupt. Once it had gone I reloaded both disks. Again the dreaded half-dead computer. What next. Well let's try some intelligent guesswork. When the thing half-died I looked at the running programs in the screen arising from CTRL-ALT-DEL. Nothing much of interest except there was something called ARTGALRY. That's something similar to clip art I imagined. I looked for anything called ARTGALRY and found a folder of that name complete with lots of files starting with the same name. I copied them one by one from my workshop computer. Gradually things started to happen. This time when I selected clip art I got a message instead of a half-dead computer. I copied a named file said to be corrupt into the appropriated folder and then got things to go a little further. Another error message. Another copied file and suddenly clip art worked! How many more corrupt files are there still in the machine? Anyway, with an IBM hard drive instead of a Fujitsu maybe I won't see this computer again for a long time! Oh, I just remembered. Groan. A replacement Fujitsu hard drive will be appearing some time in the near future. I asked my supplier about their experience with hard drives. We've had five Fujitsu drives returned with similar dates to yours (August 2001). Maybe it's a bad batch? What can I do with the replacement when it arrives? Constructive suggestions appreciated. By the start of October 2002 all the Fujitsu hard drives I'd fitted in computers had failed. I understand that the company is having to cough up well in excess of $20,000,000 to meet their warranty commitments. Thankfully the replacements are not made by Fujitsu! The last replacement for a duff Fujitsu 20gig was a Maxtor 30gig. I understand that the main control chip didn't work properly. Was it being asked to work within its spec or was it just badly designed? If the latter does the chip manufacturer have to foot the bill? Anyway, if you see a second-hand Fujitsu drive offered on ebay........ I contacted Fujitsu and suggested they were reckless in supplying a replacement hard drive knowing full well it was likely to fail in the same way as the original and said I was going to sue them for the cost of the work needed to put right my customer's computer. I've since discovered that this is the stance taken by a US lawyer acting for disgruntled Fujitsu customers in the States. As more of the saga is revealed I have read that Fujitsu knew of the problem and had identified it to be caused by a large processing chip supplied by a third party. However, whilst the arguments were proceeding between the two, sales of drives destined to fail, still went on. What a mess! The sum of money involved if litigation is successful is great enough to create real damage to whichever company ends up carrying the can. In addition, if ever the users of systems emplying the Fujitsu drives, sold by the large chains, ever get together further actions may be brought. Interestingly, one does not have to have had a contract with the manufacturer to bring an action. In UK law, end users are protected, in that if damage to a computer is caused by a faulty component, and the value of the computer is higher than say £300 for example, then the manufacturer of the component is automatically introduced as being liable to pay damages if an action is successful. One might suggest that there is no damage to the computer caused by a failed hard drive. Clearly a user would not agree as once a new drive is fitted he would soon discover, that after switching on, all he would see on the screen would be the words "INSERT SYSTEM DISK" or similar. The damage is complete loss of all his software. Re-installation would cost quite a lot of money. A tiny Tiny computer arrived this week with very intermittent operation to read about it click here |
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The Company with the red vans,
I've heard tell, is losing money. I received a parcel a few weeks ago
marked "Fragile". On the 25th March another radio was
despatched to Thorney Hill. Where's my radio I wondered? A recorded announcement said that my
call couldn't be taken because ALL the operators were talking
to customers. I tried ringing on Saturday but an announcement said that Parcelforce didn't work at the weekend and I could call back between 9 and 5 or something, Monday to Friday. Surely for such a large company an odd operator or two could be found to answer questions? Even BT can manage a couple of people to answer queries in the evenings! Isn't it strange? These companies must be worth loads and loads of money and their bosses must be picking up small fortunes in wages but they can't provide a proper out-of-working-hours service for their customers. (Elsewhere I explain about BT and their 2 night-time operators for the whole country....) I really don't understand how WE have let some public services go to seed without complaining. I can remember small suburban railway stations in years gone by. They had lots of waiting rooms with coal fires, lots of staff, even someone living in a house on the platform so there'd always be someone on call, a busy ticket office, lots and lots of passengers all day long, cheap fares, a cup of tea for a penny (that's half-a-P), bustling platforms and full trains with coaches full of warm sulphury air and steam hissing out of joints. I first noticed the slide, when after many years of motoring, I got on a train ten years ago in a Big Southern Station. The platform was deserted. Unsure of the right train, I sat in my seat near the engine. It was cold. I waited. I waited a long time and by then all the passengers had got off and wandered away when a man in a uniform appeared. Oh good I thought..it's the driver. He came up to the deserted drivers cab, opened the door and looked in. He slammed the door and started walking away. I opened the window and called out. "Is this the train to Woking or somesuch place". "Yes", he said but we can't find the driver so its cancelled, you'll have to wait an hour for the next train". Nowadays you'd be lucky to find anyone to ask. Most of the stations round here are unmanned. There's a ticket collector on the train; sometimes. Prices are astronomic. What governments, intent on managing money, seem to have overlooked is that these public services are "SERVICES" not a means of providing investors with a good return for their money. You can't have both. They are mutually exclusive. Improve the service and you reduce the return. Reduce the service and you improve the return. What's more important the service or the financial return to an investor? To whom does one complain? Your local MP? Well admittedly he or she is likely to be home more since parliament decided that working for a week was really too much and reduced their working week, first to four days and now three days. More time for their constituents? I think not. More time to carry out those company director's duties that many MPs have adopted? Possibly; I don't know. Occasionally I look in on the "Parliament TV Channel". You can often count the people there on the fingers of one hand! Maybe the only time the place is full is when they're voting themselves a pay rise, and that wouldn't be a Monday or a Friday? What about "economies of scale"? Fragment a business like rail or post or telephones, or duplicate the providers, and you make it so much harder to provide a service. If you have two delivery vans serving exactly the same area for exactly the same service you have twice the costs. So two deliveries a day have to be reduced to a single delivery. Two cable companies providing the same cable TV service over the same area means twice the costs; so to keep the same service you end up with half the TV programs or, because one can't have blank screens for half the time... twice as many repeats. I understand a French Company now owns our local water company. By no stretch of the imagination can a French Company care less about service in the wilds of Dorset! Making money? I imagine so. Anyway, back to my true story.... I switched on my computer and logged
onto Parcelforce. "Type in the number of the parcel",
it stated. I logged onto the Parcelforce website
again I was invited to fill in a form I called Parcelforce again but ALL the operators were STILL talking to customers I gave up again I wondered what the people who rang
the national Parcelforce number, wanting to enquire about posting
parcels, had done. I remembered somewhere I had a special
e-mail number for Parcelforce. I waited and waited and eventually…. It had a label on the end saying, "THIS
WAY UP". Nothing that can't be put right thankfully. I thought about making a claim about the radio that arrived in "kit form". I contacted Parcelforce using the special e-mail address. I needed "three bits of evidence" before a claim would be contemplated, I was told. This required me to contact the sender. He didn't reply. I tried again. He still didn't reply. I tried again and he said he was sorry but he'd been busy. "Can I have proof of posting and a letter giving me the right to claim on your behalf", I asked? I waited and waited and waited.... No luck. I asked my son-in-law who is a really good solicitor. "You don't need to have the sender's permission because there was no contract and anyway the sender was your agent as you paid him to send the parcel". Alas to no avail.. the 30 days from posting date had, by then, expired! I wonder if anyone will think about
picking up the discarded "Parcelforce" name. It sounds
a jolly good name. It has a good ring about it. 13th June 2002; Consignia have just announced a loss of £1.1 billion pounds, which I assume is really £1,100 million. The USA, presumably because many years ago, somebody very important made a mistake counting zeroes and inadvertently called a thousand million "a billion" adopted the wriong definition of this sum. The UK governments over the years, because politicians are usually rank amateurs at their jobs, adopted the error. Then subsequently the Press, never very good at accuracy, re-inforced the original bungle. So in Britain we are stuck with the error! A billion is a million million not a thousand million. In Europe, at least in countries with strong economies, there is still a distinction. The "milliard" is a thousand million. Unfortunately, in the interests of harmony, I suspect the "billion" is also now being undermined on the continent as well as in the UK. Anyway I'm getting away from the point, which is that "Consignia" have come to realise that their new name is not going to re-vitalise their industry and have announced a change to "Royal Mail plc". I don't like the "plc", which smacks of political correctness, another modern idiocy! The spokespeople (another idiocy), in admitting the name change as a contributor to the loss, made no mention of mass mangement sackings. Presumably there are different rules for different people? We shall see. I'd already heard that Consignia were changing their modus operandi. One of the bosses must have looked into the business of special discounts for major users. Horror of horrors it wasn't profitable! Ditch them was the end result. The conclusion seems to be that a huge number of vans will be made surplus to requirements; no doubt with their drivers? It's the first time I've heard of deliberately losing business to improve one's profits. Once lost it will be very difficult to retrieve the volume shippers of parcels. Surely those companies picking up the new business will now lower the rates for their other services and then whittle away at what's left to ailing "Royal Mail"? Consignia's main attraction was that their rates were very competitive? If I were a manager in their business I'd do my darndest to keep the customers and concentrate on reducing the overheads. Their advertising leaves a lot to be desired! Adverts should be "to the point" and not leave one with a message that needs decoding as is the current stupid practice across the advertising industry. I've noticed that some of their staff are first rate. I've also noticed that some of their staff are absolute rubbish. My last parcel took, not 48 hours to reach me but 96 hours. Why? Because a stand-in delivery person (the latter category) couldn't find me by the time he'd decided to go home, and it was left for their excellent regular driver (the former category) to bring it with the apology. I shall watch what happens to the company with interest. If someone would like to explain why the cost of sending a letter with two or three next-day deliveries per day.... and inclusive of Christmas day even, has jumped from an old penny to nearly 6 shillings (or 60 old pennies) I'd be interested. Even the jump from twopence-halfpenny (about one P) to 27P since I went to school defeats my logic! More (mid-2003)Things are settling down now. Initially the postman said that he would bring me parcels if they had stamps on them, but I've noticed that some don't.. they have a pre-printed label. Our postman has only a small van. The other day in mid-July 2003 there was a knock at the door and there was a trolley on which was a huge american radio with legs. It was earlier than our usual delivery because the postman couldn't get to his letters. The radio was in the way so he brought it first. It seems to me to be heavier than the rules say a parcel should be and at £10 its not as expensive as it might have been and it also arrived a day or two earlier than the standard delivery rules said. That's the way to win back business and I'm sure it's more interesting for the postman to deliver old radios than the usual consignment of junk mail. |
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I'm forever asking people why they don't take a particular piece of equipment back to the supplier or the last repairer. Admittedly sometimes it's a day or two over the warranty period; but frequently the thing is still under warranty and they find it easier to come to me than mess around sending something back. I obviously don't charge enough! The really annoying thing is... I often feel guilty if (a) I can't fix it or (b) if it's something the designer or manufacturer did or didn't do that made it fail. Not only do I get newish things like TV sets brought to the workshop, but also new computers. In fact if I didn't supply the computer I should charge a lot of money to make up for the lost profit on the sale. Yesterday I was handed a VCR which had been put away 4 years ago. It was almost new when it first went wrong.. or more precisely it had failed immediately after they bought it secondhand from a reputable local dealer. It chewed tapes on day one. It went back to be fixed... twice. The second time, I was told, it had been fitted with "a major new component", and she, "wouldn't have any more trouble". It still chewed tapes however and it had been consigned to the loft and a new VCR purchased. That was 4 years ago. Now a close relative needed a VCR and it had been retrieved and I had been asked to fix it. I initially examined it to see which "major new component" had been fitted 4 years ago. The only part that seemed to have been touched was the mode switch. I could tell because the end solder tag had been broken off and the soldering didn't look factory fresh. The VCR was a Hitachi VT-M930. This series of models are pigs to work on. The mode switch is not easy to remove and there is no locating notch so, when refitting it, you have to fiddle around with a probe looking for a hole in the cam under the chassis whilst peering at the thing with a magnifying glass to align little black numbers with a little black arrow (on a black background). All a bit hit and miss I thought as I fiddled with it trying to get the gears to mesh, after having dismantled the switch, and having resoldered it to its mini-circuit board. Dismantling the switch is different from other makes as one has to cut it open. Others you just unclip, wipe with switch cleaner, retension, and reassemble. Not this however, as having refurbished it, one has to superglue it back together making sure the glue doesn't run inside and seize it up. I refitted the carriage, jiggling it to click its gearwheel into place. I switched it on and was rewarded by the thing going straight into the Play position, making lots of whirring noises then trying to eject and finally switching off. I tried to insert a dummy cassette but the mechanism was limp and it wouldn't go in. Presumably the mode switch gearwheel had slipped its teeth during refitting and was indicating the wrong mode. I went off in search of the maintenance manual and turned to the page showing "refitting of the mode state switch", or whatever name Hitachi had chosen for it.. I removed the carriage, partly prised off the switch to disengage its gearwheel, and following the instructions in the manual, double checked the position of the ident hole in the cam. After trying even more carefully than before to get the gears aligned without them rotating into the wrong position I finally had it back in place and the complete thing reassembled again. This time a dummy cassette poked into the front set a motor whirring and it went in. But without doing anything further the VCR went into play, then without having touched anything, it misbehaved once more and half attempted to eject and I couldn't get the cassette out by using the buttons. Each time it I tried it seemed to do a random selection of movements and ended by giving up and switching itself off. Pressing eject had no effect. I groaned and, not to be beaten by a mere inanimate object, repeated the exercise of dismantling, fiddling and reassembling. When I had finished, with power not applied it looked perfect (as it had on the other two occasions). The mode switch pointer was indicating the correct state and I could feel the right amount of springiness as I offered up a cassette. I plugged it in and as the display lit and whirring noises began I just happened to notice a little green logo appear momentarily. It was the cassette loaded logo. I was still holding the casssette however and as I tapped the top of the carriage the logo came on then went off. Now I recalled there was a stock fault with this series. A dry jointed sensor. I had in fact checked before and turning the VCR over I could see that, at first sight, soldering to both sensors looked fine but under a strong magnifier one could see there was the tiniest indication of a meniscus around the circular solder tag. One of the legs of the sensor wasn't wetted. I removed the old solder and was able to make the logo come on and go off at will. This was the fault that had plagued the VCR, probably from new. Not a dry joint as such, at least not the fatigue variety due to old age. It was more likely a manufacturing defect. Contamination or poor tinning of the sensor leads? If it's a stock fault it presumably would apply to all the models made. There's certainly no heat involved at the sensor. The fault must make itself evident once the tiniest amount of oxidation has affected the unsoldered sensor leg. I resoldered it using plenty of heat and all was well! |
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My son wanted a nice desk in his bedroom so he didn't have to do his homework on the floor. A reasonable request. He could also use it for his computer, which also presently resides on the floor. He hasn't got much furniture. After wandering round the various emporia, MFI was graced with our order for a new desk. Now to those of you who aren't up-to-date on matters such as this let me explain. Once upon a time there were very big stores that you could visit to see all sorts of furniture. You picked out what you wanted and within a few minutes numerous packages would arrive and you could load them into your car. Once you got home you could assemble your chosen furniture and within the day be using it. Not any more you can't. Unless you are very lucky you cannot walk out with your purchase. You supply all the details to a person sitting at a computer. That is if you can actually find anyone. Details are keyed in, you are relieved of your money and a vague promise is made about delivery. If you are lucky you will get a firm delivery date, usually 4 weeks after leaving the store. So it was with Jeremy's desk. Ordered on Jan 1, delivery was promised on the Jan 28 On Jan 27 the phone rang. "Hello", said someone, pronouncing my name in such a strange way I didn't think they wanted me. "Are you expecting a desk to be delivered tomorrow"?. "Yes", I said, "we've been waiting a month for it". "Well it's not coming", she said. "There's a part missing and you can't have it until sometime in March"! "That's not good enough", I said. "I'm not prepared to wait another month or more, I'd like an alternative of similar quality. I'm very annoyed", I said. "It's no use complaining to me", she said, "I'm only the girl at the call centre". "Well put me through to someone in authority at MFI", I said, "I want to complain". "I can't", she said, "I'll get someone to call you back". They never did! In the meantime, I rang the local store that had taken the order. "The desk will be with you tomorrow morning", was the response after some key-clicking. "Are you sure?", I asked. "Yes, definitely, you're drop 2. That'll be early tomorrow morning". I brightened up. My complaint must have been dealt with. I thanked the young lady at the store after being re-assured all was well. Later that day I felt uneasy. I looked at the invoice. "Call so and so number to check your delivery it stated". I rang and after keying in lots of digits from the invoice I was informed that the delivery would indeed be, "tomorrow, quite early". Again I felt relieved. Later that day I again became uneasy. I rang the store again. This time I mentioned the call-centre telephone message. "Ring them back and double check", they said. "No", I replied, "in any case I don't have their number. You check and call me back". The chap rang back. "You can't have the desk tomorrow", he said, "there's a bit missing". "Is it a vital bit?", I asked. "The top", he replied, "It's manufacturer's delay" (If you think about it the logic doesn't stand scrutiny). "That's a vital bit", I responded. "It'd be no use without the top". "When can I have our desk", I asked? "Sometime in March", he responded. "In that case", I said, "I'd like a refund. I'm not happy". "Certainly", he said. I won't be dealing with MFI again. If more people complained and cancelled orders I'm sure suppliers' would take notice. As it is they're quite happy to take your money and provide sloppy service! So at whom does one shout? Post script..... Although I wanted to make a desk from some pieces of worktop my wife and son went off to Bournemouth or Poole or somewhere to Staples to buy a new desk. They picked one out but the salesman said they couldn't have it because it had no fittings. It had a top and legs, but no screws and things with which to put it together. Not to outdone however my wife asked if there was another store locally? After ringing around, "Southampton" said they had a desk and it had all its fittings! So even though it was late Sunday afternoon they diverted 30 odd miles to Southampton and bought it. They had to unpack it from its giant case to get the bits into the car but it slipped in with millimetres to spare..... We put it together the next day and now Jeremy doesn't have to work on the floor any more. Funny though... when we'd finished making it there were loads of screws and metal bits left over. Enough for at least one more desk. You just can't get the staff these days!! |
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If you have a digital camera you
will eventually need a card reader. With USB devices the golden rule is
to first load the software THEN plug in the device. However… I un-installed everything and tried
again. Later I looked at the contents of the
CD that came with the reader. First I un-installed all the old versions. What next? I re-booted…. I rebooted…. Now… I looked in "My Computer"
and there, at last, was the "Removable Disk" icon! Was the CD missing the driver for the
SDDR-31? How do manufacturers' get away with
selling us products like these! The last time I wrote a "strong"
letter of complaint to someone that upset me |
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I removed a 330kohm resistor from a TV power supply the other day. It's fairly common for these sort of things to fail because the voltage rating of a resistor is just as important as any other parameter and some designers don't understand this. As the basic HT supply from the mains rectifier bridge powering a chopper circuit is 330 or thereabouts a resistor connected to this should have a commensurate voltage rating. I measured the suspect resistor and it measured the best part of several megohms. I took from my resistor collection several new 330kohm 2 watt devices suitably voltage rated. The resistors were strung together on what was essentially part of a bandolier... that's the way some are supplied so they can be used on automatic insertion equipment. I detached the end resistor and automatically checked it on my multi-meter. It read 32.3 ohms. I looked at it carefully. It was exactly the same as all the others in the strip. Orange-orange-yellow bands or 330kohms. I switched the meter on and off as it sometimes gives odd results in ohms when the batteries are going down. I checked it again and it still read 32.3 ohms. I removed the remainder of the resistors, 4 in all and measured them. They all read about 330kohms as you'd expect. I measured the first one again and it still read 32.3 ohms. Why? Can anyone explain this? |
| I hate having to do TV repairs on customers' premises but sometimes that's the only option. I was called to fix a Hitachi TV last week. Partial frame failure was the symptom and after checking for dry joints and finding none I had a good look at the area around the frame output chip. A 2,200uF capacitor had been getting hot and its sleeve had shrunk leaving a quarter of an inch of bare aluminium can showing. As I hadn't brought a component of this value with me I swapped it with another capacitor of the same value nearby. If the fault changed from frame to something else I could nip back to the workshop and collect a new capacitor, or otherwise bash on with my fault finding. I swapped the two capacitors and switched on the set. For a moment or two the full frame appeared then the set went off with a "pop". Fair enough I thought and popped back for a new capacitor. Twenty minutes later I'd fitted the new capacitor and was rewarded by a full picture for a few moments then the set went off with a "pop". I scratched my head and looked at the two capacitors. I touched one and found it was red hot! I removed it and shone my torch at the circuit board. I'd fitted it with the negative terminal adjacent to the black marker on the board. I'd also fitted the replacement frame capacitor with its negative terminal adjacent to its black marker as well. Wait a minute. The main circuit board wasn't one but two boards butted up to each other. On one the black markers were adjacent to negative terminals and on the other adjacent to the positive terminals. I could tell because of the way other capacitors were orientated. After fitting a second new capacitor the right way round, and holding my breath while turning on the set, I was rewarded with a full picture and no "pop". On the workbench with proper illumination, instead of the customer's floor in semi-gloom, I would have noticed the discrepancy. Why on earth did Hitachi change their rules half way through designing a set??? |
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I don't know whether this is feasible or not but if it is it's a very worrying problem or at least it will be for some people if it's true. A friend of mine recently had a "set to" with BT. The problem was his phone bill which was more than a trifle high. Phone calls to the Pacific area abounded. He has one of those cordless phones for which you can buy spare handsets. They have a button which lets you tune in the handset to the best channel. My son borrows mine so he can make phone calls when he's at home. He lives about 2 or 3 hundred yards away. The thing works well at this range and is better than his mobile phone which doesn't get a good signal round here. You can use two phones for one base unit. The question is...whose base unit? What if there was another of these phones nearer than mine? Would the handset link with the stronger signals? Being FM, the capture effect will neatly link the stronger signals. What if I were to take my handset into the nearest village and look for a dial tone? When in use the only indication is a red light on the base unit. Is this why my friend's phone bill was so high? Has he got a neighbour with relatives in Australia??? Can anyone shed light on this? |
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Although I sell new computer systems
I don't like selling printers. Well the next day… a nice Printer Man called and swapped the black printer for a new white one. |
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The local recycling centre is now
employing a chap to test TV and VCRs for sale. I must say I'd
rather pick one off the pile, untested and cheaper rather than
get one that's been passed as OK at a premium. I suppose there's
logic to this. If a VCR is powered up and appears to perform
all its functions it may have been ditched because of a poor
quality picture due to worn heads. Some of the newer VCRs have
mighty expensive heads so I'd rather pick one, that for example,
has a cassette stuck in it. At least if the VCR is unrepairable
I get a free cassette as a consolation. I picked up a nice looking Nicam Toshiba the other day with a pre-recorded tape in it. When I got it on the bench and examined it I found the detachable power supply in a metal case was missing its securing screws and on its end was marked "Toshiba 857B". Clearly it had been somewhere for repair and had either been deemed too expensive or too difficult. The owner had then deposited the thing at our local tip. I checked that the power supply was plugged into the circuit board and connected a mains lead. No display and a dead machine. I removed the power supply and detached its covers. There were some obvious problems. Several small components were charred. I removed these and fitted new parts. One was awkward as its markings were burnt but I figured it looked like 2.2kohm resistor. I fitted this value rather than a 2.2ohm which would have been my second guess. But as there were no results I decided on a bit of detective work. I didn't have its circuit diagram unfortunately so I looked at other sources. My Willow Vale CD told me that the same chopper control chip was used in the V204 and V254 models and Practical TV fault reports mentioned these models several times and gave me pointers to potential problems. I had already changed the two small electrolytics in the primary side of the power supply so next I got out my eyeglass and looked at the multitude of surface mounted resistors on the underside of the circuit board. I found a chunky 4.7 ohm that read around 1kohm so I hunted around and found a similar sized device of 5.1ohm on a scrap hard drive. After fitting this still no results! I thought about the problem for a few moments. I'd checked all the diodes and the odd transistor and all the remaining devices measured OK. I looked at the U4146B chopper chip. I didn't have a spare and my collection of old VCRs kept for parts didn't yield one. Here I use the Willow Vale CD. Typing in the part number and checking the "used on" option gave me a list of potential sources for a suitable spare part but no joy. Nothing for it but order a new one. It was expensive but not unduly so at £7.28 plus VAT. A new one arrived and I removed the old one. Next I used a trick known to most but not all repairers (probably not the ones working for large firms). Place the two chips side by side and measure between pairs of pins using the diode test feature of a multimeter. Often a near dead short across a pair of pins is a dead giveaway but sometimes a double reading of around 1.2 volts has changed to a single diode drop of 0.6 volt indicating a suspect chip. In this case I found two adjacent pins short circuit on the old chip and 0.6 volts on the new. So far so good. I fitted the new chip. Powering up still revealed no display and no functions. Back to the drawing board. Was the 2.2kohm resistor really 2.2ohms? I didn't want to risk the £7.28 plus VAT so I looked further. When I checked Practical TV, not for fault reports but for a proper article on the VCR, I found two issues carrying details of the Toshiba V3. Not quite the model I had but close enough to tell me that the 2.2kohm resistor was a current sensing component and it was 2.2kohm not 2.2ohm. Nothing else of any benefit was revealed in the articles. I was just about to consign the VCR to the back of the bench, where it would probably lie until the next skip arrived, when I thought I'd give it one more look. I removed the power supply and examined it with my eyeglass and the multimeter set to ohms. Everything read OK so this time I powered it up on the bench rather than in the VCR. The primary side looked OK. Nothing really amiss. I was sure the thing was oscillating but a scope check would show this if I had the enthusiasm to find my isolation transformer (needed because the primary side of the power supply is at mains potential and connecting an oscilloscope ground to it would not be a good idea). I looked at the output of the chopper transformer. Grounding the metre probe to the primary ground produced an inkling of an AC voltage. I connected the probe to the metal case, but looking at the various rectifier diode cathodes, I found no indication of any DC outputs from the secondary side. Just then I noticed a flick of the meter. I looked at the circuit board again. The metal case was soldered to the output ground circuit or was it? One chunky solder joint at the lower edge certainly was but closer examination of the second solder joint at the top revealed that the track had broken away and no connection! Some manufacturers use convenient metal screens to connect separate areas of circuit ground together, and here Toshiba (or Thorn.. whoever designed the power supply) had used this dubious practice. I say dubious because countless times one finds cracked solder joints at the interface between metalwork and circuit board. This happens due to metal fatigue in the solder from repeated differential heating and cooling. This example however was probably caused by rough handling rather than metal fatigue. I cleaned away solder resist and soldered the case to the board. Switching on produced DC voltages at the output connector and refitting the power supply to the VCR produced a display. I pressed "eject" and the commercial cassette sprang out. I pushed it in again and I noticed the display tended to go brighter at times and dimmer at other times, very dim! Then the penny dropped. The VCR had been taken to a repairer, probably with the complaint that the display was dim and they had tackled the primary side of the chopper power supply rather than the secondary side. From the amount of damage, all of it a little unusual, it looked as if someone had been poking around inside either with the power on or without first discharging the main smoothing capacitor carrying 315 volts. Eventually after putting more faults on the machine than he could cope with he had given up and returned it to the customer. The real fault was a low value smoothing capacitor on the secondary side of the chopper transformer. A very small 220uF 10 volt component had fallen in value to a couple of hundred nF and was also leaky. Replacing this produced a lovely bright display and cleared up what was, almost certainly, the original complaint. Looking at the miniscule 220uF capacitor you realise they're not going to have the reliability of the larger older ones. In a hot environment the tiny things just don't have the propensity to stay cool. I only wish the last owner had parted with the handset and handed it with the VCR to Dave at the tip (as many do). I must suggest next time I pop in that he refuses to accept VCRs without their original handsets! |