1954 Radio Rentals 208 5 valve MW/LW table radio - UK Vintage Radio Repair and Restoration Discussion Forum

howard · 25th Sep 2008, 3:05 pm

Hello again,

This little RR set in a white urea-formaldhehyde case I got from eBay for £15. It didn't work very well on arrival, its bulbs were missing, it hummed a bit and it wasn't picking up County Sound on 1566 khz MW. Someone had already replaced all but one of its wax capacitors and I just replaced the last one, a Hunts 1500v mouldseal.

I put in two new 6.3v 0.115a bulbs obtained from Mike Lewis and they hardly lit up at all and strangely, one was brighter than the other. I swapped all the valves over from my RR 216 which works quite well but this set still wasn't working well so Ron Bryan took a look at it for me.

Ron found that the 150 ohm resistor in circuit with the bulbs had been replaced by two 25 ohm resistors ..... they were duly replaced with the correct value resistor and the bulbs starting working and the HT improved too. A close look at the dimmer bulb revealed that it had two filaments in it, so it wasn't surprising that it was dim so that was replaced with another (Mike always sends me an extra bulb or two just in case one doesn't work). As the set was humming a bit the 16+16+16uF smoothing caps were tested individually and one was duff so a temporary 22uF electrolytic was tacked in and that stopped the hum. The HT to the valves was now good yet the set still wasn't very sensitive so the valve heater voltages were all checked and that on the UCH42 measured at just 8 volts, when in fact it should be around 14 volts. So I found a brand new UCH42 in my spares box and fitted it and away she went picking up everything loud and clear except for County Sound on MW .... the heater voltage on that one measured 14.5 volts.

Ron then realigned the set. The 470 khz IF frequency was found to be fine so he proceeded to realign medium wave. While setting the 200m/1500khz point, it was found that it was necessary to unscrew the adjuster C5 on the side of the tuning capacitor rather a long way out (the same problem occurred on my RR 216). The capacitance of the 420pf capacitor C9 was checked for drift and that measured 421pf ..... so no problem there then ! So the adjuster C5 was locked in place with some wax. LW was realigned with no problems. I ordered some more capacitors and resistors from JustRadios in Canada on Monday morning including 450v 16uF electrolytics (they are somewhat cheaper over there) and they arrived just 3 days later and I permanently fitted one to bypass the duff one in the smoothing capacitor.

This little set really does work well, it's considerably more sensitive than Ron's DAC90A and mine too which have the same valve complement, no doubt due to it having a good sized ferrite rod aerial. For instance it picks up RTE radio on LW as strong and clear as any radio in my collection, a good achievement for a 1954 AC/DC valve set. It sounds a bit bright but it's a cute little set in its white case with black and white loudspeaker cloth and I'm delighted with it.

Howard

Leon Crampin · 25th Sep 2008, 3:33 pm

Nice job, Howard as usual.

Just as a general point of interest, I wonder if the designers of this set understood the consequences of putting the ferrite rod partly above the hottest parts of the set. (I see there is a heat shield over the dropper but the rod could have been positioned more to the left as seen in the pictures).

Ferrites change their permeability quite a bit with temperature and it would be interesting to check the alignment cold, then hot. I suspect the tracking might be quite a bit out...

Leon.

geofy · 25th Sep 2008, 4:00 pm

Nice set Howard,

looks like an Elac or Goodmans speaker, a small cap across the primary of the O/P transformer might take the top edge off.

Just happened to watch the 'Bargain Hunt' tv program (on my 34 year old Hitachi colour set) where a very similar looking Philips radio was bought for £20 and sold at auction for £25 !

Anyone on the forum ?

Geof

JoshWard · 25th Sep 2008, 5:11 pm

Lovely little set! I have one of these sitting on the shelf beside me but since the last time I used it the sound has gone very very quiet and high pitched but seeing as I havent done any work on it yet it has done quite good service

.
I am very fond of Radio Rentals sets, they are just so well built it always amazes me and they give very good results.
Maybe I can make mine look as fine as yours one day

howard · 25th Sep 2008, 7:49 pm

Quote:

Originally Posted by Leon Crampin

...............Just as a general point of interest, I wonder if the designers of this set understood the consequences of putting the ferrite rod partly above the hottest parts of the set. (I see there is a heat shield over the dropper but the rod could have been positioned more to the left as seen in the pictures). Ferrites change their permeability quite a bit with temperature and it would be interesting to check the alignment cold, then hot. I suspect the tracking might be quite a bit out... Leon.

Hello Leon,

Here's a top view of a scrap Radio Rentals 216 chassis which is more or less the same as the 208 and the aerial isn't quite over the valves and there is not a lot of room for it to move to the left.

https://www.vintage-radio.net/forum/...1&d=1222368565

If it was positionned further back it would be heated by the dial bulbs. I guess it could have been fixed to the case but then these sets were designed to be dismantled as quickly as possible. The set does drift during warm up but no worse than a mid 1950s Bush.....

I guess the asbestos heat shield could be considered a slight health risk, but I've no idea what material could be used to replace it with.

Howard

PS: I've shifted the RR 208 aerial to the left into the same position as the one in the RR 216 as it had shifted a bit.

howard · 25th Sep 2008, 7:54 pm

Quote:

Originally Posted by geofy

Nice set Howard,

looks like an Elac or Goodmans speaker, a small cap across the primary of the O/P transformer might take the top edge off.................Geof

Hello Geof,

It's an Elac loudspeaker but it doesn't sound that bad, small sets like this tend to sound a bit bright although the Bush DAC90A sounds much more mellow.

Howard

mark pirate · 25th Sep 2008, 9:24 pm

Nice little set Howard, i like RR sets, seem to go on forever

i have just discovered another one in my grand loft clearout (the 37 sets that were up there are now in my garage awaiting packing up for moving) will try it tomorrow, as was working well when stored away a couple of years ago

Mark

25th Sep 2008, 3:05 pm	#1
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	1954 Radio Rentals 208 5 valve MW/LW table radio Hello again, This little RR set in a white urea-formaldhehyde case I got from eBay for £15. It didn't work very well on arrival, its bulbs were missing, it hummed a bit and it wasn't picking up County Sound on 1566 khz MW. Someone had already replaced all but one of its wax capacitors and I just replaced the last one, a Hunts 1500v mouldseal. I put in two new 6.3v 0.115a bulbs obtained from Mike Lewis and they hardly lit up at all and strangely, one was brighter than the other. I swapped all the valves over from my RR 216 which works quite well but this set still wasn't working well so Ron Bryan took a look at it for me. Ron found that the 150 ohm resistor in circuit with the bulbs had been replaced by two 25 ohm resistors ..... they were duly replaced with the correct value resistor and the bulbs starting working and the HT improved too. A close look at the dimmer bulb revealed that it had two filaments in it, so it wasn't surprising that it was dim so that was replaced with another (Mike always sends me an extra bulb or two just in case one doesn't work). As the set was humming a bit the 16+16+16uF smoothing caps were tested individually and one was duff so a temporary 22uF electrolytic was tacked in and that stopped the hum. The HT to the valves was now good yet the set still wasn't very sensitive so the valve heater voltages were all checked and that on the UCH42 measured at just 8 volts, when in fact it should be around 14 volts. So I found a brand new UCH42 in my spares box and fitted it and away she went picking up everything loud and clear except for County Sound on MW .... the heater voltage on that one measured 14.5 volts. Ron then realigned the set. The 470 khz IF frequency was found to be fine so he proceeded to realign medium wave. While setting the 200m/1500khz point, it was found that it was necessary to unscrew the adjuster C5 on the side of the tuning capacitor rather a long way out (the same problem occurred on my RR 216). The capacitance of the 420pf capacitor C9 was checked for drift and that measured 421pf ..... so no problem there then ! So the adjuster C5 was locked in place with some wax. LW was realigned with no problems. I ordered some more capacitors and resistors from JustRadios in Canada on Monday morning including 450v 16uF electrolytics (they are somewhat cheaper over there) and they arrived just 3 days later and I permanently fitted one to bypass the duff one in the smoothing capacitor. This little set really does work well, it's considerably more sensitive than Ron's DAC90A and mine too which have the same valve complement, no doubt due to it having a good sized ferrite rod aerial. For instance it picks up RTE radio on LW as strong and clear as any radio in my collection, a good achievement for a 1954 AC/DC valve set. It sounds a bit bright but it's a cute little set in its white case with black and white loudspeaker cloth and I'm delighted with it. Howard Attached Thumbnails

25th Sep 2008, 3:33 pm	#2
Leon Crampin Octode Join Date: Nov 2005 Location: Surrey, UK. Posts: 1,870	Re: 1954 Radio Rentals 208 5 valve MW/LW table radio Nice job, Howard as usual. Just as a general point of interest, I wonder if the designers of this set understood the consequences of putting the ferrite rod partly above the hottest parts of the set. (I see there is a heat shield over the dropper but the rod could have been positioned more to the left as seen in the pictures). Ferrites change their permeability quite a bit with temperature and it would be interesting to check the alignment cold, then hot. I suspect the tracking might be quite a bit out... Leon.

25th Sep 2008, 4:00 pm	#3
geofy Retired Dormant Member Join Date: Jun 2006 Posts: 1,798	Re: 1954 Radio Rentals 208 5 valve MW/LW table radio Nice set Howard, looks like an Elac or Goodmans speaker, a small cap across the primary of the O/P transformer might take the top edge off. Just happened to watch the 'Bargain Hunt' tv program (on my 34 year old Hitachi colour set) where a very similar looking Philips radio was bought for £20 and sold at auction for £25 ! Anyone on the forum ? Geof

25th Sep 2008, 5:11 pm	#4
JoshWard Octode Join Date: Dec 2005 Location: Near Stowmarket, Suffolk, UK. Posts: 1,962	Re: 1954 Radio Rentals 208 5 valve MW/LW table radio Lovely little set! I have one of these sitting on the shelf beside me but since the last time I used it the sound has gone very very quiet and high pitched but seeing as I havent done any work on it yet it has done quite good service . I am very fond of Radio Rentals sets, they are just so well built it always amazes me and they give very good results. Maybe I can make mine look as fine as yours one day

25th Sep 2008, 9:24 pm	#7
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: 1954 Radio Rentals 208 5 valve MW/LW table radio Nice little set Howard, i like RR sets, seem to go on forever i have just discovered another one in my grand loft clearout (the 37 sets that were up there are now in my garage awaiting packing up for moving) will try it tomorrow, as was working well when stored away a couple of years ago Mark