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What's 1960 got to do with it? This is 2011!
You queried the lack of OA81. The OA91 that IS available on that site will be an admirable replacement for the OA81, should you need to replace it again.
And going by the number, it'll fit in a smaller socket...
In message , Terry Casey writes
Except that every time you buy from a spammer, a fluffy little kitten dies
You were very keen to leap on the O/P as a spammer, I've seen that nick around elsewhere on usenet and don't see any reason to believe it he's a spammer.
The suggestion that the components are merely suitable for art projects is a little odd though ...
Its a commercial posting
Its spam
Spam is not allowed in uk.diy
It was a recommendation (albeit unsolicited), you benefit from the occasional one yourself ...
Christ on a bicycle man, it was in 1960 that I replaced the diode, OK!! This was a 1940's Ministry of Supply radio that I remembered from when I was a tiny as working and then not working. After that we went to Radio Rentals. Later, I found the MoS radio in the loft and fixed it up so I could listen to Radio Luxembourg on the q/t. That radio has been in a landfill since about 1966.
Since then I've had astonishingly little need for diodes for AM radios and so was unaware there was a replacement. After all, it was small enough then, around the same size as an OC71 or OC44.
That would probably be because he's a spammer.
If he had turned up and stated "I've got a load of old tat electronics that I'm trying to flog" his offence would have been ignored, after all we ignore others here who mildly flog their commercial tat and services. Even if I do disagree with what they do.
However he was blatantly spamming and in the worst possible way - pretending to be a disinterested third party recommending someone else's web site. That's plain dishonesty and it's a knowing act since he tried to disguise the origins of the post by using Google.
Scum like that need taking out and LARTing.
So you have some evidence that links him to the site? Surely a spammer would post to more than one group?
Superficially the message fits the "drive-by spammer" pattern, but the guy has posted to this group before, I think he genuinely thought it might interest a few people, and in a small way, it did ...
Had you bothered to check any of the OP's posting addresses, you would have discovered that they all resolve to a town in the Midlands, which is approximately 110 miles distant from Benfleet in Essex, the location of Partridge Electronics.
Whereas posts from people who are clearly incapable of admiiting that they're wrong, or of apologising for their mnistake, clearly are.
You can rest assured that the reason that Usenet in general is dying on its feet has little if anything to do with spam.
You should be so lucky.
Nigel
In message , Nigel Hopkins writes
IF that's actually true, I bolloxed up there and apologies to all concerned, however, it read like spam to me
Now who are these people "who are clearly incapable of admiiting (sic) that they're wrong, or of apologising for their mnistake (sic)"
your turn
No - it's not a valve! It's a germanium diode but, in the early days of semiconductors, Philips/Mullard used valve numbering with the initial 'O' (standing for zero volt heater) for diodes and transistors with the second letter 'A' for diode and 'C', intended for a triode valve, used for the three electrode transistor. [1]
Thus the 80 and 90 serial numbers are not related to B9A & B7G valvebases - which I assume you were alluding to - because they are wire ended components.
You were right in a way though, as the OA91 is about the size of a match head, making it about a quarter of the size of the OA81.
[1] The valve system denoted different types of valve and function but this could not easily be expanded to semiconductors so a new, but similar, system was implemented later on. Amongst other things, it differentiated between germanium 'A' and silicon 'B' devices, so AA119 would denote a germanium diode, etc.30
Small it may have seemed at the time but, when the 'vest pocket radio', as our Amercan cousins referred to them, started to flood the country from Japan a couple of years later, it was suddenly huge!
The diode was always at the bottom corner of the PCB next to the battery and they were frequently broken when the ham-fisted attempted to replace the battery.
I can tell you from experience that a replacement OA80 (same size as OA81) would get the radio working again - but you couldn't get the back on the case again because it was too long!
An often overlooked point...
You need to be carefull about substituting modern power transistors into old designs.
The old transistors had cutoff frequencies around 1MHz, and the designs didn't concern themselves with higher frequencies.
Sometimes, substituting modern devices which have significant gain at much higher frequencies can cause high frequency instability, which you may then need to damp down.
I'm perfectly aware of that. It was a joke....
Yes, I know...I was there...!
And GPO Telephones had "Valve, Electronic" as a part description.
Owain
In message , Nigel Hopkins writes
You are making the fundamental assumption that he only has access to one persona at one location - or is that one step too far for you
Even I have several in several countries
Do I need to explain further or will you accept someone else's post in this threadlet?
What I SHOULD have done, was to check his email addy for other postings, which I didnt
I've apologised - time for you to do so too
Well, I did check for a smiley there before I replied ...
That makes two of us (at least!)
Having looked through their entire catalogue, it looks as if they have supplies of many obsolte items which are no longer available, probably, from any other source and SOME of their prices are quite reasonable.
A quick Google for polystyrene capacitors, for example, brings up a number of sources with prices an order of magnitude higher ...
Of course, if someone is desperate to get their hands on the last remaining component in the world at any price ...
Certainly they could be very useful to anybody restoring vintage equipment.
I really think they should put a health warning on their stock of ancient electrolytic capacitors though, pointing out the need to re-form them before use ...
I used to have a Saturday/holiday job working for Technical Tading in Brighton. They had branches in other places (TCR London, Worthing and others I forget). I did sales of hi-fi (Quad down to Sinclair PWM!) but also had a lot to do with handling, testing and relabelling secoindhand valves. I think they used to advertise on page 3 of Practical Wirelsss, big lists of valves, if anyone remembers..you might!
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