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Old 29th Aug 2019, 4:06 pm   #1
HoraceBatchelor
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Default Horace needs help. Bush VHF70.

Hello everyone its been a while. I hope im not going to seem like an idiot asking this.
Last week i got myself a Bush vhf70, in great condition looks wise, other than the expected wear and tear marks that 60 odd years brings. So i decided to spray the front trim an identical gold colour, freshen up the grille cloth and soak the grubby knobs for an hour or two. By doing that the radio is going to look like it is worth every penny of the £15.10.6 it cost originally.

Hardly got going, then stopped in my tracks, I couldn't get the knobs to come off. I'm a strong chap with a vice like grip, but this little Bush guy had me beat. There's only so much pressure you can use when doing a job like this I thought.

So not wanting to damage anything I decided to risk looking like an idiot and ask you guys, because some of you must have had the same problem at least once and known the remedy.

But since that initial attempt i've looked again and come to the conclusion that i may be able to remove the chassis with the knobs in situ. They go through the dial glass, so is it safe to undo the clips that seem to be holding the glass to the cabinet and slide the whole lot out?

But i am aware that if i can get the cabinet empty I will still have the problem of freeing the knobs. Will some sort of freeing agent (wd40) safely do the job?
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Old 29th Aug 2019, 7:30 pm   #2
Nickthedentist
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Default Re: Horace needs help. Bush VHF70.

Hello Horace,

The manufacturers' instructions for dismantling start with pulling off the control knobs, so I suspect there's no way to avoid doing just that.

Have you tried the trick of threading some string under the knobs, and pulling on that? Rather like David describes here: https://www.vintage-radio.net/forum/...89&postcount=6

Nick.
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Old 29th Aug 2019, 7:49 pm   #3
gallowfields
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Default Re: Horace needs help. Bush VHF70.

hi, found the best way was to wrap a handkerchief round the back of the knob twist the remainder and pull .this way even pressure is applied to the rear of the knob
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Old 30th Aug 2019, 9:28 am   #4
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Default Re: Horace needs help. Bush VHF70.

As Nick has posted. The knobs 'pull off'..I presume they are held on with D clips that may have become rusted. It should be safe to apply a little more force but take care with the scale glass.
Data from the original Bush manual. Not a lot of help I'm afraid. John.
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Old 30th Aug 2019, 5:13 pm   #5
HoraceBatchelor
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Default Re: Horace needs help. Bush VHF70.

Just an update on those stubborn knobs. After an afternoon of dogged perseverance, I am delighted to be able to inform you that at approx 4.25 pm the second knob gave up its hold on the on-off switch. Not without a fight i may add...So thanks for your suggestions. And no doubt i will be back to ask for guidance on appropriate caps i will have to change.
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Old 30th Aug 2019, 9:23 pm   #6
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Default Re: Horace needs help. Bush VHF70.

Suggestion....when reassembling the radio, give the control shafts a good clean and apply some grease. This will inhibit rusting and hopefully allow the knobs to come off more easily next time.
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Old 9th Sep 2019, 4:40 pm   #7
HoraceBatchelor
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Default Re: Horace needs help. Bush VHF70.

I know next to nothing about the workings of these radios, or any other radios. I'm just a collector because i like the looks of them. I started collecting at the beginning of this year and i have seven. Polished up and shown on display they look really good. So good i would love to show them off, but it seems this site is not able to cope with anything other than thumbnail size, which is a pity.

But getting back to my latest acquisition " the Bush vhf70". i may not have the knowledge you boys have, but i do like to see what shape my buys are in on the inside. And if nothing seems obviously wrong i will power them up through a lamp limiter as i did with the Bush. It powered up with scale lamps (correct size) aglow after replacing the old ones for new, The 100 watt bulb glowed with the usual red glow as it should, but it did seem a little more of a redness to the glow than i had seen with my other radios.

All i received was a light humming and the occasional crackle as the pointer passed over where stations where. But after approx 15 minutes the 100 watt bulb flashed fully and that was the end of me doing any thing else as safety beckoned.

This maybe a "how long is a piece of string question" but with that limited information could anyone give a stab at what may be the trouble?
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Old 9th Sep 2019, 5:57 pm   #8
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Default Re: Horace needs help. Bush VHF70.

The "thumbnail" is just what you see when the post is viewed in the thread.


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Old 11th Sep 2019, 9:32 pm   #9
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Default Re: Horace needs help. Bush VHF70.

There seems to be a 0.05uF capacitor (C60) from the live wire to the chassis.

If this capacitor fails short circuit, the full 240V mains will appear across the 30 Ohm resistor and the two 3.5V 0.15A bulbs which are in parallel with the resistor. A large current will flow!

That capacitor should be replaced by an X class capacitor rated for 250V AC mains even if it is not faulty.

What size fuse do you have in the mains plug? I use 1 Amp fuses.
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Old 18th Sep 2019, 3:42 pm   #10
HoraceBatchelor
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Default Re: Horace needs help. Bush VHF70.

Thanks Silicon, I will take your advice and grateful. The plug as 3 amp fuse as have all my radios.
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