Next Year's project

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Ray P
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#1 Next Year's project

Post by Ray P »

I sorted out a project for next year last evening - always wanted to get hold of an old valve radio to restore and enjoy. I was browsing ebay a few days ago and the name of one of the old radios caught my attention and last evening I won the auction and picked up one of these for £42, apparently still in good working order;

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https://www.radiomuseum.org/r/raymond_f17f_1.html

Made in around 1947, apparently using lots of WWII surplus stuff. I checked and the valves can still be obtained so it should be a viable project but I'll probably look to pick some collective brains when I get started - I seem to recall Jack (Nick) helped Steve C with his restore.

I need to look out a manual/schematic next.
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#2 Re: Next Year's project

Post by Cressy Snr »

It's good fun restoring old wireless sets.
My Baird set is used nearly every day and has not missed a beat since I (with Nick's help) rescued the AF section and power supply, from the scrapheap)
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#3 Re: Next Year's project

Post by jack »

That's a lovely set - a Raymond F.17 from just after WWII - 1947.

I love Bakelite too - nice radio to work on - see https://www.radiomuseum.org/r/raymond_f17f_1.html
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Mike H
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#4 Re: Next Year's project

Post by Mike H »

Image Watching.


I did exactly this for a neighbour back in 2001. It was an Ekco AC-85, we thought from about 1934 -ish. It inspired me to make my own set from scratch: http://livinginthepast-audioweb.co.uk/i ... =ac85clone

One problem you might have is any electrolytic capacitors are going to be in a bad state, and possibly dangerous. Certainly the values and 'performance' will be crap due to age. In the Ekco the PSU dual elec (16uF + 8uF) had already been replaced previously, for this reason, with a strange white paper-enclosed rectangular shaped wax like block, god know from what era but seemed to work OK. First thing that became immediately apparent once working, was the grid coupling capacitor to the power OP pentode was leaky, so the valve was hard on, in fact drooping the HT. Everything worked much better when replaced with a modern one. :D

Something else you must check for. As a test, measure Voltages, then unsolder the grid coupling cap, turn on and measure the Voltages again to check for any difference. If different, e.g. HT is higher, and/or op pentode anode current is lower, then original cap is junk.

If you keep using the pentode at the wrong higher current, it will probably expire. I remember my dad was often having to buy new op pentodes for an old set we had when I ws a kid, I now know why. :D

Also get datasheets for all the valves so you know what to check them out against. I had to replace 3 in the Ekco. One (the input mixer & oscillator) I couldn't get so had to use an equivalent, which had slightly different pin numbering, so socket needed rewiring.

The Valve Museum is a good source of info, certainly helped me.

Other biggest problem was rust and corrosion.

HTH
 
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Ray P
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#5 Re: Next Year's project

Post by Ray P »

Thanks for the advice and encouragement chaps.

The seller has shipped it today so I shouldn't have to wait too long to get a feel for what I've taken on. I'll post some pictures when it arrives.

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Ray P
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#6 Re: Next Year's project

Post by Ray P »

I've had a notification from UPS that they'll be delivering it today so some pictures soon. It'll be hard to resist the temptation to get stuck in but I have to finish my DSD decoder, 6C33C amp and 300B HPA projects first!
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#7 Re: Next Year's project

Post by Ray P »

Oh, and I've downloaded the manual/schematic from the radio museum website. The document is dated February 1947.
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Mike H
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#8 Re: Next Year's project

Post by Mike H »

Fab. :thumbleft:

Image Yep, piccies!


"apparently still in good working order"

Nevertheless you might want to replace the mains lead with something more modern and with a fused plug before turning it on.

When I got given the Ekco its mains lead went straight in the bin, much too dodgy looking. Never mind the 2-pin plug on the end. Amazing that we used to rely on this sort of stuff years ago. Well amazing that there were't more electrical fires. :D
 
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#9 Re: Next Year's project

Post by jack »

Apart from the obvious (out-of-spec caps & resistors, dried electrolytics, crumbling rubber insulation) etc...

...just be aware that a lot of these sets have a "live" chassis. When working on them, best to use an isolation transformer. Always do a first power-up on a variac... (or a chain of 3 x 40W incandescent light bulbs when you can switch the bulbs out one-by-one)...

Replacement mains filter caps etc. for these are normally available from Ask Jan First (Jan Wuesten) who is excellent and completely trustworthy & reasonably priced.
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Mike H
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#10 Re: Next Year's project

Post by Mike H »

jack wrote: Wed Nov 21, 2018 1:52 pm ...just be aware that a lot of these sets have a "live" chassis.
Not if it's got a kosher mains transformer. The Ekco did.

However, good point, many of the old sets were made to also operate on DC mains, in which case, yes transformer wouldn't work so instead the circuit is connected directly into the mains supply, with a single rectifier diode included for where the supply is indeed AC instead.
 
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#11 Re: Next Year's project

Post by jack »

Mike H wrote: Wed Nov 21, 2018 2:15 pm
jack wrote: Wed Nov 21, 2018 1:52 pm ...just be aware that a lot of these sets have a "live" chassis.
Not if it's got a kosher mains transformer. The Ekco did.

However, good point, many of the old sets were made to also operate on DC mains, in which case, yes transformer wouldn't work so instead the circuit is connected directly into the mains supply, with a single rectifier diode included for where the supply is indeed AC instead.
Many British sets of that era had no transformer as they were expensive (post-war and all that) - they just used a heater chain, DC or AC. Further, some of them had resistive mains leads that acted as droppers - these were termed "line cord" and were quoted in ohms-per-foot.

As it happens, I believe this set has a transformer, but the chassis still won't be earthed.
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Mike H
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#12 Re: Next Year's project

Post by Mike H »

Yes my dad had a small American set (about the size of a small loaf) with a resistive "mains cord", as originally it was meant for 120V; to adapt it for use in England, simply bung a resistive lead on.

:D

Ray's link: https://www.radiomuseum.org/r/raymond_f17f_1.html

Says, "Alternating Current supply (AC) / 200-250 Volt" so pretty much implies transformer.

But only Ray can verify this. :D
 
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#13 Re: Next Year's project

Post by Ray P »

It's waiting for me at the local UPS service point, which is less than a quarter of a mile away but its raining persistently!
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#14 Re: Next Year's project

Post by Mike H »

'Course it is. :D
 
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#15 Re: Next Year's project

Post by Ray P »

Bad news! The seller did a poor job with the packaging and it has suffered significant damage as a result. There are two areas where the bakelite case has been badly broken but by far the worst thing is that the gass display has been shattered - I think this part will be irreplacable and certainly not repairable. I've not looked inside. I think this radio is now only fit to be a source of spares for another similar model. I've contacted the seller to request a return and refund.

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