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Old 8th Jun 2019, 8:23 am   #21
stitch1
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Default Re: Bush RG73 advice please.

Going back to your question.
Quote:
Originally Posted by ekjdm14 View Post
.... 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?)
You have probably already saved it from landfill it always feels wrong to scrap something but most of just don’t have the space to keep something this size.
I would offer it on here for anyone who wants to collect and restore it, if there’s no takers then scrap it guilt free.
We used to call this ‘Christmas treeing’ no idea why.

John
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Old 8th Jun 2019, 12:20 pm   #22
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Default Re: Bush RG73 advice please.

That (non-original) BSR UA6 autochanger is well worth saving. These were made between early 1953 and up to mid-1956.
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Old 8th Jun 2019, 12:42 pm   #23
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Default Re: Bush RG73 advice please.

That's an interesting turn of phrase John, considering the non-originality and the fact that I have a schematic at my disposal I'm thinking along the lines of a "resurrection" before anything else. Then if/when it's working (or at least diagnosed what it needs to work) will probably offer it up for someone who would appreciate it for what it is.

There must be more like me, who get a kick out of seeing the lengths to which people went to keep their set of choice working. Trouble is, they're probably already tripping over cool old sets like myself!

Laurence, that's interesting to note about this press-board and printed "veneer" as this one, although battered, abused and "fluffy" round the edges isn't terribly warped or peeled that I noticed, it seems it may have had a dry life although there is evidence of coal-fired society as it's utterly black inside! The more I think on this set the more I'm talking myself into preserving it!
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Old 8th Jun 2019, 8:28 pm   #24
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Default Re: Bush RG73 advice please.

if its covered in black coal dust it will need alot of warm water sponging out on the inside, looks like its gonna be a HELLUVA lot of work! See you tomorrow, Laurecne
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Old 8th Jun 2019, 10:53 pm   #25
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Default Re: Bush RG73 advice please.

Looking at the pictures, I would say it was the radiogram version of a PB 12?
https://www.radiomuseum.org/r/bush_pb12.html
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Old 9th Jun 2019, 12:16 pm   #26
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Default Re: Bush RG73 advice please.

I'm not so sure, looking at the schematics it's closer to the PB73, it has holders for 6 dial lamps and the radio/'gram switch is not on a push button but a separate switch (plugged into where the switch would have been on the back of the PB73 chassis.

It'd be a humongous task to bring it back to original condition in any sort of presentable way, but for my part if I can clean it up and get it playing that's "my" half of the battle, will upload some cabinet photos at some point and ask about whether anything can be done for it.
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Old 9th Jun 2019, 3:08 pm   #27
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Default Re: Bush RG73 advice please.

Ooohh look what a little bit of Wilko Teak oil has done! I just slapped some of this over the cabinet without even cleaning it up and it's made a world of difference, the photos don't even do it justice. I'm pleasantly shocked, even the remaining light marks on the top (looks like a tyre was sat on it) will probably come out with a little careful abrasive work.

That's my mind made up, there's some very tatty/damaged '70s stuff in the conservatory that I also had for parts & they will be dismantled and relegated to the garage whilst the RG cabinet comes indoors and the set receives some attention.
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Old 9th Jun 2019, 3:21 pm   #28
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Default Re: Bush RG73 advice please.

Glad to hear it! looking much better already, it may only be paper type veneer but they got the Walnut figuring look of the finish looking quite authentic.
Steve.
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Old 12th Jun 2019, 3:41 pm   #29
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Default Re: Bush RG73 advice please.

OK well I've just started to do a few checks on the chassis & it appears the power transformer is OK but, typically, output is open on its primary. At least the secondary checks out haha

Thankfully the service data includes it's impedance so I can search out a temporary substitute, but it's looking like time to bite the bullet and invest in some rewinding equipment since I have at least 3 OPT's in need of surgery now as well as a potential power transformer for a Philips B4X11A and others.

Wonderful. Still what do I expect for a fiver?
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Old 12th Jun 2019, 5:09 pm   #30
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Default Re: Bush RG73 advice please.

Right, stripped the OPT to see where it was damaged & noticed there was a break right at the end of the winding. A little microsurgery later has a turn unwound from it and re-soldered in place, however I do think there's some pretty badly shorted turns since it now seems to measure in the region of 6 ohms (there does appear to be a burned spot in the waxed paper on one edge, halfway through the winding).

Will have to sanity check my readings as spec is 700R so will have to make sure I didn't have the wrong range selected but I'm thinking a replacement is on the cards for testing at least. I wonder what shape the output valve is going to be in though, hopefully the OPT has been the "fuse"!
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Old 24th Apr 2020, 7:30 pm   #31
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Default Re: Bush RG73 advice please.

Reopened by request.
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Old 24th Apr 2020, 11:48 pm   #32
ekjdm14
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Default Re: Bush RG73 advice please.

Thanking you Sir

Spent a good 5 hours this evening (as timed by SWMBO so I know it's at least that long!) re-assessing this radiogram & doing some repair work. As the SAC35 it's not magically cured itself over it's rest period, no surprises there. Refreshing my memory, the OPT primary on this set was near-short (6.2R) with evidence of charring in one corner of the winding, without having a valve tester the condition of the non-standard output valve remains to be seen but it has a filament at least.

I hasten to note, I said "repair work" as opposed to "restoration" for good reason. This set is so far from original and has seen so much repair work previously, so I've decided to carry on in the same vein and have replaced waxies with modern ceramic and poly equivalents (there were far more waxies than I'd first thought, a few well hidden under the other side of the phenolic tag board that took a while to carefully hinge outward to access!) EDIT- also had to replace the output cathode bias resistor as that was burned open, hope the valve isn't cooked.... Donald Stott's DAC10 post reminded me of this! Interestingly it is specced out as a 200R in the Mfr's data, but the dead one was a 400R & only suitable replacement I had measures 510R, I wonder if it was a random replacement though or a "supporting mod" for the EL37 (replacing specced EL33)

The electrolytics, all late '40s/early '50s Hunts and Radiospares replacements, appear OK for now so have been left in place. Some rewiring completed and another semi-suitable "OPT" repurposed from an old audio-gen that had similar DC resistances to spec.

Just before leaving off for tonight I've stuck it on the variac & brought it up without valves, rectifier heater good, valve heaters good, Raw HT good & lamp windings good even if only one of the two present bulbs (out of 6 specified!) actually worked. On that note, knowing what I do now there's no way the 4 removed were in any way to reduce current to compensate for the extra valve filament draw since not only are they on a lower tap of the filament winding but also they're only lit one at a time according to the band selected.

Still, mains transformer shows no signs of having suffered/got hot so hopefully it's coping fine. I believe at this point I'm ready to drag the variac into the conservatory (where the cabinet lives), insert the valves, plug the speaker in and bring her up tentatively with meters on the HT and possibly an ammeter in series with the filaments to confirm their hunger. I still like the make-do and mend nature of this bitsa set!

Last edited by ekjdm14; 25th Apr 2020 at 12:17 am.
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Old 25th Apr 2020, 1:56 pm   #33
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Default Re: Bush RG73 advice please.

Phew it's hot in the conservatory today! Chassis currently hooked back up the the 'speaker and controls, just came indoors for a cool-down and sanity check & then will be back out into Death Valley with a box of valves, a variac & crossed fingers
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Old 25th Apr 2020, 2:48 pm   #34
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Default Re: Bush RG73 advice please.

Second cool-off break & this time it's for myself AND a 6uF/500WV cap!

I tried to bring it up as slowly as possible on the variac to allow the electrolytics a chance to reform but this one at least was slow on the uptake. Going to allow it to cool and try one more time before replacing it, but we have audio and activity back to behind the EBC33. No sign of activity on the tuner side as far as I could tell before I cut power but was only up to about 195V and there's also a potentially flaky Radio/Gram switch to consider.

All in all though, very happy to have as much as I do thus far especially as the audio output was my biggest worry with the set. I think it'll sound really nice when it works
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Old 25th Apr 2020, 3:18 pm   #35
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Default Re: Bush RG73 advice please.

Again into the house to cool, and the 'lytic has still not decided to behave so it'll go bye-byes BUT we have reception! At least, long wave we have one station and 2 areas of QRM and just a few bits of hash on MW but it's a start & might (will definitely!) improve on full line voltage with a new smoother & an actual long wire instead of the built in loop.

Volume and clarity was even fairly decent considering the mains xfmr. doing duty as OPT, a little more tinkering and I can probably call this resurrected. Would like to get the SW bandspreads functioning as a little evening DX is my cup of tea & on something as elderly as this, even more so. Also will test the cartridge as I'd like the TT to play some old junk records on.

Onward and upward as they say!
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Old 25th Apr 2020, 6:50 pm   #36
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Default Re: Bush RG73 advice please.

Bit more progress, smoother replaced & radio has run for a while with no sign of trouble except for noisy pots. With a bit of solder strung across the width of Death Valley, *ahem* I mean the conservatory, I've picked up a few stations on 31m and 25m earlier and also RTE1 on LW, still not much to be heard on MW though.

Also reconnected the turntable and to my surprise it actually all worked (after a fashion) including the auto cycle and size detection, without so much as removing the platter! OK the speed selection is very touchy and off-speed due to the motor grommets being sagged out. But, as I dared to speculate last year during initial overview, the crystal turnover cartridge does indeed have a good robust output and will do just fine for junk old records.

Off to string a temporary wire down the garden and see how she performs while monitoring things but I daresay she's alive again.
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Old 25th Apr 2020, 8:53 pm   #37
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Default Re: Bush RG73 advice please.

Last post on this for now unless any further developments, have rigged the motor up to correct turntable speed and given the platter and idler some lube & that side of things has been literally blasting out Johnny Cash for the last hour or so with plenty of volume.

Only criticism of the sound I have is a lack of bass, but that could well be down to a wrong cap value in the tone control circuit or an effect of the subbed OPT "solution". Haven't managed to get a decent wire down the garden this evening but even with the solder lash up I'm getting Russian, German, French, Indian? and the usual CRI stations on 31m & some even quite clear all things considered. The switches and pots will definitely need cleaning & it'd benefit from an alignment which might well wake up MW and 19/16 metres which are devoid of much at all apart from Absolute radio & radio Stoke on about 200 metres.
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Old 28th Apr 2020, 2:52 pm   #38
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Default Re: Bush RG73 advice please.

OK slight update on this, tone cap replaced with closer to correct value (best i could do without pulling the chassis again, will do a better job today) & there was far better response from the tone control. Strung a wire down the garden & with a bit of trimming last night was getting Radio Thailand WS English absolutely booming in from Udon Thani on the 31m band.

Really need to get the chassis on the bench again and do a full alignment but was fairly impressed with the amount of stations pulled in on 31m, although the other bands are pretty quiet at the moment but not tested it against another known-good performing transistor set to see if it's just the location of the wire or something else external stopping any joy on those, I do feel it's one of the many yet to be undone bodge repairs in the chassis.
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Old 2nd May 2020, 12:55 am   #39
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Default Re: Bush RG73 advice please.

Chassis now back on the bench for more "correct" repairs. (previously I'd simply added new caps in series with the waxies to prove whether the OPT sub would work acceptably well.)

Now the caps have been replaced properly with correct values as-per schematic, tone compensation circuit returned to standard, some flaky wiring in the volume/input circuits replaced & the output valve's cathode bias resistor changed to better suit the EL37. This had been previously changed since the factory spec (with EL33 output) is 200R but incumbent when I began work was a very conservative 400R wirewound (incidentally this as well as the OPT was burned out!)

For testing purposes I'd been going with about 380R as it was something I had to hand similar to what was already there & the set did work OK but not the best volume so a little measurement was done & I've settled on 150R at the moment. Valve seems happy without red-plating and volume is much more like I'd expect.

I did have a minor disaster while working on the set, in that the 50pF coupling cap to the detector lost a lead flush to the body... Fortunately been able to carry on in the "make do and mend" fashion and make a replacement from a couple of 100pF in series. Other than that, it's seemingly working pretty well and pulling in stations even on a 5 foot random bit of wire in my notoriously RF-noisy work room so fingers crossed it'll be improved still further when back on the long wire.

Have a bit of tidying up & lead dress niggles to attend to tomorrow, go through the coil deck & w/c switches & then will get it aligned and back into the cabinet permanently with any luck. Have some 300mA 6.5v bulbs on order so will get my scale lighting back up to scratch too soon

Then it's back to the SAC35 project & learning the necessary to build a solid-state "valve"!
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