Bush RG73 advice please.

[ekjdm14]

Hi all, I've just acquired the above set (Bush RG73 Ca.1940) for the princely sum of five pounds.

The set is incomplete (missing at least a couple of pots, maybe the wavechange switch, though the valves appear present, and correct) and looking at the dust it doesn't appear "got at" in at least recent (30+?) years, and is cosmetically rather tatty with numerous scratches/dings and a control torn out of the side. I bought the set mainly as a potential source of parts but before I go destroying it I'd rather ask the experts whether it's actually worth saving/restoring.

Obviously I'm not talking about monetary worth since I got it cheap and even working such a bulky unit isn't likely to be valuable, I'm rather thinking of it's historical value, significance and/or rarity. So, faced with a shortage of space and a ratty large cabinet what would YOU do, strip the chassis/dial glass, speaker and Garrard changer and send the cabinet on it's way or would you pass it on to someone who would restore the set (or even restore it to some degree yourself?)

I'll get some pics uploaded if it stops raining so I can get it out of the car.

Thanks,

[ekjdm14]

By the way, the parts I wanted were in order to bring a Bush SAC35 back to life if that has any bearing on replies.

Auction photos attached

[music-centre]

Seems a shame to scrap it, must be a pretty rare set I would have thought, I can't remember seeing another? Is there that amount of parts that would be useful to fix the SAC35 with its earlier valve series?

Of course I always think it's a shame to scrap them though, why I haven't got any room I guess
Steve.

[ekjdm14]

Exactly the same thoughts here, it's always a shame. Having just had a closer look inside I now note that the speaker is not original too, it's been replaced with a permanent magnet BSR item with the original field coil left connected and screwed to the inside of the cabinet so a little more "got at" than I originally thought.

I'm hopeful that the output transformer may be of use although not really checked yet, it is on the chassis though thankfully so still there.

If I can make enough room to convince SWMBO that it fits in the conservatory then it'll go in there & I'll try and give it a better look over and decide what to do then, I do like the way it looks but it's so tatty and non-original I just don't know. I suppose if I discovered the speaker replacement was a wartime "make do & mend" kind of thing it'd appeal more to me since I like that sort of history!

[music-centre]

It would be interesting to know which Bush model table radio it was based on (if it was) does it have more than one shortwave band?
Steve.

[ekjdm14]

Yes definitely more than one, I think it has about 5 SW bandspreads. That's it's main redeeming feature for me TBH as I do like seeing what I can pull in of an evening given a chance. That and the lovely old TT in it, I like the look of it a lot even if it does have a tracking pressure measurable in ounces!

Will try and liberate the chassis and bring it indoors if I can get away with it!

[ekjdm14]

OK so the chassis is now indoors & on closer inspection it's becoming less hard on me to consider breaking up the set. The cabinet is not solid wood or even veneered ply but basically a wooden frame skinned with hardboard type material with a walnut print. The chassis has been modified quite extensively at some point with evidence of something transformer-shaped having been removed from the chassis previously (audio output transformer is still present on chassis and date code is September 1949 so presumed original despite RMorg's assertion that the set was from 1940, presumably it ran for a few years post-war while newer sets were expensive to develop). Quite a few late 50's-early 60's looking grey Radiospares branded electrolytics under the chassis. Main reservoir can is a TCC with a date code of 1948. Turntable is a BSR Monarch of some description & surprisingly free-spinning. All but two of the 8 scale lamps are missing in action, band-wise there's LW, MW, 4 SW bandspreads and then one London preset and another with it's legend missing that I presume is also a preset as no scale for the leftmost two.

About the best thing I can say for this set is that it was obviously loved for someone to keep on repairing it in the inventive way's I've seen, there's a cute bayonet lamp holder adaptor for power & at least the valves are there.

All in all, an ideal candidate for plugging it in & having it either work or smoke! I have kind of taken pity on it though so I might just give it a little more respect when I get to it. Pictures to follow after dinner!

[Wellington]

Originally Posted by music-centre

It would be interesting to know which Bush model table radio it was based on (if it was).

PB73, I suspect.

I was wondering if the radiogram version would have enhanced output circuitry, push-pull perhaps, but it appears not.

[ekjdm14]

Yes, I think you're right it looks like the table model would've been the PB73. A few pictures now & a couple of other notes, the rectifier has been replaced with an MU14 which I believe draws half an amp more filament current then the original DW4/350, not researched any other differences & the output has been swapped from EL33 to an EL37 which again draws another 500Ma filament. So, we have a very bitsa/got at set but possibly the power transformer was upgraded also as there's no signs it was distressed.

Can anyone confirm/otherwise that the RG73/PB73 were built into the late forties/early fifties, or perhaps what I have could after all be an example of the spirit of wartime ingenuity/post-war thrift with someone creating a working set from a selection of parts maybe from scrap sets?

The plot is certainly thickening, I rather hope this is a homebrewed "bitsa" from the post-war era since character appeals greatly! Anyway, photos...

[ekjdm14]

More pics

[ekjdm14]

Et more...

[ekjdm14]

last couple! And now i also note the rest of the valves are incorrect also, certainly not swapped in the last 30 or so years though from the dust and coal-fire crust around the lot before i shifted everything.

[music-centre]

Originally Posted by Wellington

PB73, I suspect.

I was wondering if the radiogram version would have enhanced output circuitry, push-pull perhaps, but it appears not.

Yes, well spotted, PB73 its got to be, another set I cant remember seeing for sale although there is a thread on the forum about one.

Searching for the PB73 just now a console model also came up.

https://www.radiomuseum.org/r/bush_sug73.html

Steve.

[ekjdm14]

There seem to have been a few variants with the same chassis, and thanks to Wellington for spotting that it's the PB73 as the service DVD contains Factory, Trader AND ERT sheets for that model so at least I have something to "go at" even though it is so far from standard. From glancing at the factory pics I think the missing part from the chassis whose "shadow" that I thought looked transformer shaped, was probably a square multi-section capacitor replaced by the 2 RS and 1 Hunts underneath the chassis.

Power transformer looks original, although it is rather cleaner looking than the rest of the chassis so could conceivably have been upgraded. Kids are so noisy right now so can't collect my thoughts, but I think with the valve complement in place currently it could have worked.

One thing for certain, output transformer specs are way different to the SAC35, primary about twice the impedance so at least the temptation to rob that is gone!

[ekjdm14]

Ah, just noticed I've made an error & there are two correct/original valves in place. The EF39 and EBC33. Plus, the X61M seems to my eyes at least a plausible replacement for an ECH33 so I'm beginning to convince myself that this was built/repaired by someone who knew what they were about but didn't have a lot of money.

Service sheets are from '41 although the '48 cap and '49 output transformer look original so a reasonably long-running model line.

[AC/HL]

Wartime shortages?

[Nickthedentist]

The deck is a UA6 from c. 1953 I believe. It may not be original, but it's in damn fine condition, including the mat as far as I can tell.

[ekjdm14]

Originally Posted by Nickthedentist

The deck is a UA6 from c. 1953 I believe. It may not be original, but it's in damn fine condition, including the mat as far as I can tell.

Probably much like the rest of the set, non-original. Yes the mat seems very nice indeed at first look, pliable and not cracking that I can tell. Only signs of age so far on the TT are the disc size detector arm has stuck down when I moved it, and the tonearm has 2 grooves worn into it from the clip that holds it. You know, this is one I'd even give the cartridge a chance of having output.

Just had a quick look at what's going to be required to see if it works, there only appear to be about 6 or 7 waxies (the rest appear to be ceramic tubular and disc) and 3 crusty electrolytics underneath and then the reservoir/smoothers. Wiring is mostly cloth and in reasonable condition, even the parts that are rubber insulated & mains cord is tolerably flexible and intact for testing purposes. Will give the transformers a quick ohm-out before committing but I think it's got to be worth swapping those few and giving it a date with the variac to see if it has any life before making any decisions.

[ekjdm14]

One final thought, now that I've started reading the factory data. Perhaps the fact that 4 of the scale lamps are missing was to "make up" for the increased filament current draw of the replacement valves? 6.2v 0.3a bulbs, 4 missing = -1.2A which ought to be just enough to keep the mains transformer happy.

Either serendipity or somebody really knew what they were doing when they replaced those valves!

[BUSHVHF]

interesting this post, my mum and dad had one of these before i was born and they told me that they bought it in the late 40s when first married but it was made in the "utility furniture" fashion, a sort of fibreboard with a paper type "veneer" of figured walnut on the cabinet, as the houses then were all coal fires (no central heating for "average people") the houses were bitterly cold and damp and over the next 5 years the fibreboard warped on large open spaces like the lid and the "paper" printed veneer separated and they soon got rid of it, as proper plywood was only being brought in in the mid 1950s for furniture and cabinet production. Looks like this one is one of those "utility" made things!!! laurence