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Hello Chaps

Just a quick question. Are the + and - markings on the new coils equivalent to CB and SW respectively on the older coils?

I currently have a CSI electronic distributor installed which may have a fault and I want to try the former Lucas distributor to check if that is the issue. The wiring from distributor to coil etc is different on electronic distributors and I've forgotten the Lucas set-up! The car is a TR3 on positive earth.

Rob

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12 minutes ago, RobTR3 said:

Hello Chaps

Just a quick question. Are the + and - markings on the new coils equivalent to CB and SW respectively on the older coils?

I currently have a CSI electronic distributor installed which may have a fault and I want to try the former Lucas distributor to check if that is the issue. The wiring from distributor to coil etc is different on electronic distributors and I've forgotten the Lucas set-up! The car is a TR3 on positive earth.

Rob

If its positive earth then it would be + lead from coil to the distributor.

Stuart.

Edited by stuart
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1 hour ago, RobTR3 said:

Just a quick question. Are the + and - markings on the new coils equivalent to CB and SW respectively on the older coils?

Stuart is right as to how you should connect it but the pedantic answer to your question, just for the record,  is no they are not equivalent. 

Coils with CB and SW markings were probably made for positive-earth cars. Those with + and - are most likely for negative-earth. The coils are connected as auto-transformers with a common connection to the bottom of each winding. On CB/SW coils that common point will be 'CB' whereas on +/_ coils it will be at '-'.   The manufacturers intend the '+' to be supply and the ' - ' terminal to be connected to the contact breaker, but that will be wrong for a positive-earth car as it results in reversed spark polarity.

 

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There is a subtle difference electrically in connecting the common point to supply instead of to the points, but In practice it doesn't seem to make any noticeable difference to coil performance so as I said, this is just for the record.

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Hi Rob,

is there no end to your electrical genius.

 

Two years ago I took an old but beautiful Hacker 'Harrier' portable radio to the repair shop.

It was not used for about 5 years and when the battery was put in it did not work.  

The shop is usually run by the sons of the owner but on this day the owner (Bernard) was there. He tried to convince me that it wasn't worth while.

I explained that I wanted it repairing and put a figure of up to £150 on the repair.

He grudgingly took it away saying it may takes days to sort out. By the time I got home (an hour later) he was on the phone saying was ready.

He used to work for Marconi (or perhaps GEC) and back in the 60's his job was repairing all the portable radio warranty repairs.

When he took the back of the set he couldn't resist repairing immediately. The fault turned out to be a Collect short to the metal case of the OC81.

He explained that there are no new OC81's and old stock may well have the same fault so he unclipped it from the heat sink and said don;t turn it up too loud.

And for this beautiful story & expertise he charged £20.  I hope he never dies. The last of some clever people.

It worked and still works today and sounds excellent.

 

Roger

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I think I still have a couple of OC81s somewhere in my stash of bits Roger - and OC72s.   I wonder if they still work after five decades ? If I can find them maybe I'll try them someday just to see. 

Someone gave me a portable transistor radio to mend once.  He told me he had opened it up to change the battery and had  'tightened up all the screws' after which it had stopped functioning.  I was a bit mystified by that but when I looked at it I found he had indeed screwed down and broken every one of the soft ferrite tuning slugs in the IF coils ( I suppose they did look a bit like slotted grub-screws.......)

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Too modern for me! I'm still using an old valve Armstrong FM radio receiver in the garage it sounds better than DAB.

Your right Roger finding people who can understand, repair vintage radio's etc is a rare thing now, long gone are the days you could buy a book of circuit diagrams and build/repair it yourself. The old style radio/tv repair shops have nearly all gone.

Andy   

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7 minutes ago, PodOne said:

Too modern for me! I'm still using an old valve Armstrong FM radio receiver in the garage it sounds better than DAB.

 

You are aware that valves are the in-thing with Hi-Fi buffs?  If they can fit an ECC88 into a 'high end' pre-amp it seems to quadruple the price, so your Armstrong is right on-trend. Next thing they will be selling will probably have a cats-whisker detector in it.  

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3 minutes ago, RobH said:

You are aware that valves are the in-thing with Hi-Fi buffs?  If they can fit an ECC88 into a 'high end' pre-amp it seems to quadruple the price, so your Armstrong is right on-trend. Next thing they will be selling will probably have a cats-whisker detector in it.  

Hi Rob

Off topic but I'm a bit of a Hi Fi nerd as well! Valves for me never went out of fashion they still outshine the most expensive transistor offerings despite what the critics might say.

I've never liked the sound of transistors even when run in Class A. At present running a Conrad Johnson Premier 11 valve amp I found broken propping a door open a few years ago, Quad pre amp and Linn deck as it sounds better than my CD player which has a valve in its output stage no doubt to try and make it sound more natural. I've also got pair of Quad II mono blocks and Leaks which I've acquired and restored over the years when no one wanted them. I'd Love a tuner with the old magic eye if I see one at some point.

Good fun tracking down components which are hard to find nowadays at a reasonable price. 

Andy

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I also have a few geranium transistors kicking around, but I don't think I will be employing them any time soon.

Bob.

P.S.

+1 for Leak speakers, I still use a pair of "Sandwich" ones for my main music listening.

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In about 1958/9, when working in the Electronics Laboratory at Evershed & Vignoles (Acton Lane, Chiswick), I obtained the instructions for and built a Mullard 510 amplifier - one could obtain the parts at a shop in Kingston marketplace.  By some subterfuge, I obtained later the circuit diagram for the Leak amplifier (then considered one of the best) and converted my 510, which used the same valves.  Can't say that I detected any improvement in the sound, but I imagine that the 510 was a good design.

Ian Cornish

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Hi Ian

I inherited a book from Mullard (along with other period home electronic books from guys like Briggs, Wharfedale) to promote their valve with amplifier designs such as the 510 for use with EL34 and EL84? valves. I built a pair of mono blocks with EL34's about 30 years ago when you could just about find power supply transformers and high voltage caps etc from visiting radio rallies and had the output transformers wound by Sowters not sure if they are still around now. 

Got me thinking I should dig them out and give them a warming.

Andy  

Wow just checked the web Sowter are still in business amazing that we still have a company that makes such tackle!  

Edited by PodOne
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I have a Seeburg 200 and when I bought it in 1976 it was not working. I used to clean up parts and connections every evening after putting the babies to bed. After a few weeks I mended a broken strip with a small strip of Formica from the kitchen that I was building. This made a connection and suddenly it was playing A Whiter Shade of Pale by Procul Harum,. The strip is still there and I have replaced some valves which are only made in Russia. The sound is very strong and not like the radio in the kitchen. The coin mechanism is an ongoing fix. It only takes shilling coins and it does not always give a credit.

Richard & B.

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I have a few old radios (valve). They worked last time I tried them, but that was probably 10 years ago. I also have a cine amplifier made by Quad. I was given it in the early 1970s, and I used it to play a guitar through. (I was an impecunious student at the time). It uses EF37s and a KT66 as the output (Class A). I would guess it is 1930s or earlier. I tried to contact Quad to ask if they have any info about it, but they did not reply. I remember replacing a choke in the supply in 1974, but I probably last used in in 1977/8. It is on my list to sort out since the rectifier diode was damaged when I moved house around that time.

 

TT

 

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I used to go to an Amateur Radio Club when I was a teenager.

Lots of old men smoking pipers, wearing jackets with leather patches on the elbows, and discussing triodes and red spot transistors.

You lot sound just like them.

 

Charlie.

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 We are just the next generation of those old chaps Charlie.  Soon no doubt there will be old guys in leather-patched hoodies, vaping and reminiscing about the good old days when there were quad-core ARM processors and USB-c was new....

Edited by RobH
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