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Old 31st Jan 2015, 2:55 pm   #181
Biggles
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Default Re: Ex TV Engineers

I can pick a particular value resistor out of a mixed box without thinking about it too much. It becomes second nature and seems to be a function of the brain's ability to recognise a pattern. That only works with the "old" four colour code. Now when it comes to the multiple banded modern versions, I always check with a meter as my brain doesn't seem to accept the new system. It is difficult to see the gap and consequently work out which end to read from never mind decipher what the bands all mean. Maybe I'm just getting old...
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Old 31st Jan 2015, 3:12 pm   #182
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I agree with you about the resistors Alan. I too find the new code difficult to deal with. Wonder why they had to alter it in the firdt place. It's the same with capacitors, no longer the value, just a strange number to get used to. Oh well I suppose we must bow to progress.
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Old 31st Jan 2015, 3:33 pm   #183
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And SMD's are no easier, no values at all on ceramic capacitors. Fortunately with two magnifiers I can still read the resistors. The additional bands on resistors are for 1% tolerance devices. But I too use my meter for checking.
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Old 31st Jan 2015, 4:21 pm   #184
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I have watched the local TV repair shops steadily disappear. The only one I know of now looks like an abandoned shop with a graveyard of stuff piled in the windows and has looked like that for yonks. I assumed it was just that until I was told by an acquaintance that he had managed to get a repair done there.

What has surprised me on this thread is how many engineers were leaving the trade in the early eighties as I always assumed there was loads of work then. I certainly knew lots of repairmen in the eighties and I don't remember talk of a dying trade but by the late nineties early 2000s it was a different story.

I knew one guy who had a thriving rental business. He packed it in in the early nineties to retire - he'd clearly 'done alright' - but he sold his business on.
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Old 31st Jan 2015, 5:42 pm   #185
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It's not just the repair shops that have gone AWOL. There used to be numerous outlets where you could get spares, and loads of useful junk to make things from. When I was at school there were 3 places in Maidstone where it was possible to get all needs for radio construction, There was a junk shop that used to sell government surplus, and often I would cycle home with a radar unit on the carrier, packed full of goodies you have to scratch around for now. Used to cost me a shilling, or one and sixpence if the bloke was on the make. Then there was always Lisle Street, another story.
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Old 1st Feb 2015, 8:52 am   #186
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I managed to hang on in the trade until I retired in 2004 but it wasn't earning us a living wage, the few rentals we had out helped but we had to susidise our income with the B&B.

Regarding colour codes, I could see the blue and yellow bands OK what I couldn't distingiush was the important last colour, brown or green - which makes a considerable difference. I am sure there must be a number of you with the same problem.

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Old 1st Feb 2015, 10:00 am   #187
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Peter, it must be frustrating not to be able to pick out colour codes. Must admit I now have to use a magnifier for some of the small resistors. Wonder what you think of the modern solder, I find it lacking in performance to what we had years ago. A card of old multicore turned up in a box of junk from a car boot the other day and the difference is quite surprising. It was old enough to have 6d marked on the price. If out in the country I collect pine resin to supplement what they pass for flux these days. The solder we were issued with in the RAF was about the best, seemed to tin anything.

Dry weather better than dry joints.

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Old 1st Feb 2015, 10:49 am   #188
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Quote:
Originally Posted by Heatercathodeshort View Post
Resistor colour codes. We all know how reading codes becomes second nature by recognizing them as one familiar pattern rather than reading the actual colour codes individually. I was led a real dance years ago when I fitted a 15 ohm in place of a 1m grid leak in a sync separator circuit. Lay one of each on your bench and I think you will agree it's a simple mistake to make! John.
Yes indeed - after a few years we just glance at the resistor and we know what the value is. Some values can throw you a bit, like 15r for 1M or 12r for 1k and some very low values with the gold band need checking on the AVO.
I never got to grips with the silly 4-band code, it seemed completely unnecessary to me and I avoid them if I can.
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Old 1st Feb 2015, 12:32 pm   #189
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4-band resistance codes are necessary for instruments.

If resistors are made with the stability to justify 1% specs, then 96 values are needed per decade to cover the range without gaps (this means that any resistor made fits into one value's spec or another, and there is no wastage). The ratio of value between adjacent values is the 96th root of 10 (honest!)

To handle this, the values need three digits and a multiplier. You also get stranger-looking values like 46.4k which for wider tolerance parts is rounded to 47k

What's changed is that the resistors made nowadays are a lot more stable than everyday parts used to be, so there is little price saving in going for 5% 10% and 20% resistors. On top of this, the ultra price sensitive consumer electronics industry has fled Britain, and what's left is making more critical things.

Components have change a lot from when I augmented my pocket money by fixing tellies and jukeboxes. I'm just glad of the improved reliability, though there is justification for the old quip that hunts was the firm which fed and clothed a whole generation of repairman's children. (My upbringing was paid for by car smashes)

Solder, carpet.... been there.

David
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Old 1st Feb 2015, 10:09 pm   #190
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Hi!

Quote:
I'm just glad of the improved reliability, though there is justification for the old quip that Hunts was the firm which fed and clothed a whole generation of repairman's children.
Hunts along with Callins, Suflex and Erie certainly kept me fed and watered in my younger days!

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Old 2nd Feb 2015, 12:42 pm   #191
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I think you can add Daly to the list as well Chris. Used to go O/C frequently. RR used them.
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Old 2nd Feb 2015, 1:09 pm   #192
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We used to have a system called 'Viewline' down here on account of the terrain. There was a UHF receiver on the cliff at Charmouth with a VHF converter and the signal was piped down to charmouth and Lyme Regis by cable, they also had a similar system in Seaton and Beer. The result was we had a lot of dual standard sets working on VHF but 625 lines.

I had a set in for repair one day with an aerial plugged in and saw a test card that I didn't recognition, it said RAE with quite a good stable picture, on investigation I found it originated in Italy! The best bit of TV DXing I have ever done. I have only ever worked as far as Spain on 2M and that was with side band.

Mike.

I have never had occasion to use 'modern' solder although I have tried to unsolder components fitted with it, dilution with some 'proper' solder makes it easier to work with. At the rate I use it I probably have enough tin/lead in stock to see me out.

Peter
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Old 2nd Feb 2015, 2:01 pm   #193
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I didn't know they know they converted UHF like that Peter. Those 625 line sets were primed to pick up a bit oF DX via sporadic E. I've a picture of a Spanish Test Card, on VHF, but most of my TV DXing was done on UHF. I used to take the sound down to 5.5MHZ, then it was possible to watch Dutch TV in colour when we only had BBC2. In the early days a lot of their programmes were in English with Dutch subtitles. Used to pick up French 819 line serices occasionally, that was pushing the line TB a bit but interesting at the time. I think 819 lines went out when they started colour.
Your comments on modern solder are interesting. The stuff just doesn't flow, does it. I bit of pine resin helps, but we have to wonder.
Mike. G4BIY.
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Old 2nd Feb 2015, 3:31 pm   #194
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When I worked in the domestic TV trade the company ran a "Relay" system in Ilkley, which was originally band 1, thus BBC1 was on CH2 and ITV down converted to CH5. Then BBC2 came along and this was squeezed in on CH "RI" in colour, say CH 3.5. The system was then upgraded to Band 3 and expanded to cover more of Ilkley.
Then came the UHF Filler station in Wharfedale, and that virtually killed the relay overnight. One wonders what happened to all the new Thorn wideband amps and that high grade coax. The old band 1 amps were valve and those out of range of a mains supply were "line powered" at 50V AC. You could still get a "tickle" if not careful.
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Old 2nd Feb 2015, 4:32 pm   #195
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Interesting about the relay system Wendy. Perhaps all those wideband amps turned up at a radio rally. I used to be a trader at those, had loads of electrical bits and bobs. You might have seen me at Leicester.
I wonder if we ever spoke on the air. Your callsign seems to indicate seventies or thereabout.
Would be the old 2m AM days. I used to speak to stations in Yorkshore, but never kept the old logbooks. Still, you never know.
Mike G4BIY.
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Old 3rd Feb 2015, 1:27 am   #196
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Now I think about it Mike we did have up converters on the viewline to drive UHF sets but there were some dual standard sets that were quite easy to operate on 625 VHF straight off the line.

I can remember quite frequently picking up 819 line transmissions when I lived in Kent, you could lock the line at half speed which gave you two pictures but no sound of course. When conditions were good you could get a BBC transmission on all five channels.

Where we moved to in Kent when I got married which was at the bottom of Wrotham Hill but still fairly high and flat, I could get a picture on every ITV channel by swinging a beam round in the workshop, in fact two on Ch11, Chillerton Down and Mendlesham, one vertical and one horizontal.

Those were the days.

Peter
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Old 3rd Feb 2015, 10:23 pm   #197
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Hi Mike. I was licenced in 1967. and of course 2M am.. I was based in Otley and a member of Otley radio society G3XNO. I don't think I ever went to the Leicester rally. The Band 3 amps were made by Thorn and were about 4" in diameter, about 9 " long with all discreet transistors. The Band 1 valve amps were by Teleng.
Ref 2M am... I was on 145.575, but I still maintain... The Liner 2 killed 2M am and home construction, no one wanted to talk on am anymore.
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Old 4th Feb 2015, 10:51 am   #198
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I 'retired' from the trade in 2002/3. The writing had been on the wall since around 1998 but it was like a switch being thrown by 2000. Add to this the ever increasing shop rates, £200 in 1973, £5000+ in 2002. Why do local Councils take money off you in the form of business rates with one hand and then try to put you out of business with crazy parking/stopping restrictions with the other ?
It happened very quickly. I was driving to the shop one weekday, met the trail of traffic on Carters Bridge Raynes Park caused by readjustment of the traffic light sequence to justify a London Congestion charge and thought to myself, 'I don't want to do this anymore'. It was as simple as that. The shop premises were placed in the hands of the local estate agent that very morning and by the evening I felt a great weight had been removed from my person. Thirty seven years and loved it all other than the last 18 months.
To be honest I wish I had wound it up a couple of years ealier but glad I had the guts to end it when I did, rather than grind on probably being discovered dead at the workbench at the age of 70. A few of my friends in business did just that and it was a sad business clearing their workshop and premises. Very Happy Days 99% of the time. Regards, John
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Old 4th Feb 2015, 12:08 pm   #199
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John.. I suppose the company I worked for was indirectly to blame for the demise of the TV repair shop. The supermarkets and other "outlets" were crying out for "cheap" TV's and other brown goods, and if we didn't supply then others would. That meant the end of sales of the 12" monos and 14" colour sets, and the supermarkets were offering no argument replacements when they went faulty.

Our policy was to sell "container" loads only, where as Nikkai were selling to the independent shops. It's still going on now, but larger screens, tablets and other stuff, most unrepairable anyway.

In a few years there will be no one to remember this stuff, as we shuffle off to the great solder pot in the sky.
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Old 4th Feb 2015, 1:15 pm   #200
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Hi Wendy. I agree with you about the old AM days, but in other respects things seem to be going down hill. I no longer operate on HF due to high noise level, loads of Tellys and other little bits plugged in 24/7, all spewing out noise. Overhead wires make great antennas for these beasties.
I was licenced in 72, and ran 10 watts from a Pye Cambridge. The antenna was a double 8 el on 2m, rotatable from the bench. Mobiles would make their way down the old Norwich Road, and then I would swing the beam around and blow their socks off.
I can no longer have antennas that do any good at this QTH, so a modest ground plane on the garage keeps me in touch with local repeaters.
It's a shame about the home construction, but there are diverse reasons, one being the lack of suitable components. I notice that even the humble Jfet 2n3819 is no longer manufactured, and anything that might handle RF is really a switching device. Also our homes tend to get smaller, and there's no room for a shack, so valve equipment, which many of us find easier for homebrew takes up far too much room. I was offered an AR88 for restoration, but doubt if it would have fitted on the bench.
I wonder too about youngsters learning radio in this digital age. I used to build standard superhet radios and knew what every part did, but am unable to cope with digital. My first transmitter was while in Germany. It was an old reacting detector radio with a crystal pickup fed into the suppressor grid. Played Glen Miller to most of the camp. Naughty, but interesting in those times.
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