Ekco BPT-333 Jewellery Case transistor radio

[Vintage_RC]

I recently acquired one of these late 1950's radios untested but visually in generally good condition. I like these early lift up lid transistor radios as the 1960's pop culture has not yet affected the styling and in fact it looks just like a typical 1950's valve portable only smaller. This particular set has the iconic Ediswan "top hat" transistors. The battery connector had been cut off and the ends of the leads had the insulation removed so goodness knows what voltage might have been applied. Anyway I optimistically connected it to a current limited 6V DC supply and somewhat to my surprise it burst into life on both MW and LW. Sensitivity seems good as it was able to pick up all the stations I would expect during the daytime including RTE and RTL on LW. I have attached a few pictures but this leads me to a question. If you look at the close up of the top chassis mounting you will see two studs moulded into the case which go through lugs on the chassis and have nuts securing the chassis. There is a single stud at the other end. Hopefully you can see that a thick varnish of some sort has been applied as a thread lock. Although the set works I would still like to remove the chassis to inspect and photograph it as I do with all my equipment. So the question is how do I remove this varnish completely to allow removal of the nut without risk of breaking the stud out of the plastic case?

[dazzlevision]

I find a very small amount of Acetone (nail varnish remover) does the trick, but keep it away from any plastic!

[Ed_Dinning]

If no heat sensitive parts in the immediate area then a hot soldering iron and quickly undo.

Ed

[Vintage_RC]

Thanks for the suggestions, in this case I don't think heat would be wise as the studs are moulded into the plastic case and heat would immediately reach the plastic. It would help if I knew what sort of varnish had been used 60 years ago, I've got some cellulose thinners, I might try applying a very small amount and see what happens to the varnish. On the other hand I could do the sensible thing and forget about removing the chassis!

[snowman_al]

I have never seen one of those before, nice find.

Pick as much of it off as you can with a jewellers screwdriver.
Test the chippings with the thinners or nail varnish remover.
Use a cotton bud to apply your chosen fluid a little at a time, either will melt the plastic.

[FIXITNOW]

it should be standard Tamper evident seal varnish RS still do this (196-5245) its made to just break away if tampered with so should just flake off with the point of any suitable tool

[McMurdo]

Nice little thing, makes a change from the vidors and ever readys, I've never seen one either. I can imagine a chap in the drawing office, inking the tracks on that circuit board on some giant sheet of paper.

I'd see if the red stuff is brittle, if so, scrape it off using the end of your mini nippers, and if necessary add a dot of white spirit or similar to the thread. My main worry would be cracking the stud from the moulding . I resort to heat only if it's the gooey hot-melt stuff which hopefully hadn't yet been invented.

[60 oldjohn]

Best done at room temperature, not in a frozen shed. The plastic hopefully being less brittle.


John.

[Vintage_RC]

Good idea regarding chipping the varnish off, I'm out most of today but will see if it is brittle and chips off easily this evening or tomorrow. It's a lovely little set with a very pleasant audio quality, I wonder if it was the first Ekco transistor set, it was released in 1958.

[TonyDuell]

If you do get the nut off without damage, you can probably clean up the threads on nut and stud with the appropriate tap and die. I do that on the screws in HP9800 series calculator keyboards (the screws go into tapped bushes in a very brittle plastic moulding in those machines)

[ajs37]

my experience of this 'lock-tite' precursor is that it is so brittle, you don't need to do anything - just remove the nuts and it breaks up and does no damage.
Nice radios these - I have a couple (they are not rare) and do seem to work very well without much fettling
Cheers
Andy

[Vintage_RC]

I got back to inspecting the Ekco jewellery case transistor portable again today. A friend of mine saw the radio and said the varnish used to lock the retaining bolts looked like shellac which is dissolved by alcohol. As was said earlier here the varnish was likely to be brittle (which shellac is) and I chipped off most of it and cleaned the threads with IPA. After unsoldering the speaker leads the bolts were easily removed and the chassis was free. I took a series of photos some of which I have attached. The six Ediswan "top hat" transistors are clearly visible, many of the capacitors are Hunts black ones (wrapped with a white paper sleeve). The set works fine so I don't intend to start removing any components but are any of the components (such as some of the caps) known to be troublesome? The set only runs on 6V so nothing is under any great stress.

[Nuvistor]

Nice radio a really good condition, if the radio works well and the quiescent current drawn by the radio is correct I would not change anything.

[Vintage_RC]

Quiescent current is 19mA which seems about right and it has a pleasant tone, albeit with a bit of background hiss. The hiss is not offensive and most noticeable on weak stations, as you would expect for germanium transistors of this era. As an aside, the cost in 1958 was 20 guineas or £21. According to the Bank of England inflation calculator that is equivalent to £482 in 2018, makes you realize what a serious purchase what was probably a second radio was back then and how cheap electronic goods are today.

[60 oldjohn]

Originally Posted by Nuvistor

Nice radio a really good condition, if the radio works well and the quiescent current drawn by the radio is correct I would not change anything.

Mine worked first time when I first bought it, and its still working today. Without changing anything.


John.

[TrevorG3VLF]

I have had trouble with Ediswan transistors, their legs fall off!
They were used in equipment out of doors and there may have been condensation to activate corrosion. A valve or two would have kept them warm and cosy.

['LIVEWIRE?']

Reading Alan, G6PUB's post # 14, I would have thought, based on average wages then and now that today's equivalent price would be more like £600 to £650*, as I doubt the average adult male wage in '58 would have been more than about £14 or £15 p.w., whereas today it's said to be around £450 p.w. at least. Whatever the figure, though, the fact that a transistor radio cost around 1.5 week's wages meant that things were repaired when they broke down, unlike today's throwaway culture. Mind you, electronic goods made in the 50s, 60s & 70s were/are usually easier to repair than most modern gear! On that note, it's a while since I've seen anything with Ediswan transistors, but I second Trevor G3VLF's sentiments about them
* My Fidelity Coronet at 10gns(£10.50) cost me almost 4 weeks wages. As a 15 year old my take-home pay was, from memory, £2.15s. (£2.75) p.w. then.

[poppydog]

Originally Posted by TrevorG3VLF

I have had trouble with Ediswan transistors, their legs fall off!
They were used in equipment out of doors and there may have been condensation to activate corrosion. A valve or two would have kept them warm and cosy.

I've had several of those top hat transistors where the leadouts have rotted out, when I've looked for replacements for some reason they seem to command silly money on the usual internet auction sites

[60 oldjohn]

Originally Posted by poppydog

I've had several of those top hat transistors where the leadouts have rotted out, when I've looked for replacements for some reason they seem to command silly money on the usual internet auction sites

Not only on the ones mentioned, If one disturbs the legs on the Newmarket transistors they are lightly to break at the seal, leaving nothing to attempt to solder to.


John.

[G6Tanuki]

That's really rather a lovely radio to have brought back to life. And yes it would have been murderously-expensive for an upper-working-class/lower-middle-class worker to buy in the very-late-50s/early-60s!

It's also intriguing that the designers chose to fit a then leading-edge transistor radio into what was then a rather dated style of packaging/case. It might have made 'sense' back then for a manufacturer not to do anything too avant-garde style-wise when releasing these new-fangled-and-untested transistors on to the deeply-conservative UK radio-buyer market - but the Japanese, Hong-Kong and US radio-companies were only too happy to style their radios in a rather more exciting way - the Bush MB60/TR82 [styled by David Ogle] was there, soon to be followed by the TR130.