Philips V5A wavechange knob. - UK Vintage Radio Repair and Restoration Discussion Forum

PJL · 17th Jun 2011, 8:07 pm

I have a truly stuck wavechange knob. Can someone advise if the screw is threaded into the knob or into a hole in the shaft?

Tried oil, heat, levering, hammering...I am running out of ideas. If it's threaded into the shaft I'll have to try to drill it out.

Darren-UK · 17th Jun 2011, 8:24 pm

It's threaded into the shaft.

Be careful drilling though, if you end up drilling straight through the shaft you'll go through the other side of the knob too - probably wrecking it. The knob is a hollow moulding and quite fragile.

If you do have a mishap, I have a knob (and grubscrew) here which you can have.

PJL · 17th Jun 2011, 8:39 pm

That was quick! Thanks Darren, my fears are confirmed and of course thanks for your very generous offer. The radio is in a terrible state but I'll post a success story when done.

geofy · 17th Jun 2011, 8:47 pm

Try Plusgas Formula A dismantling lubricant, leave for 24 hours after soaking, if this doesn't work nothing will!

Alistair D · 17th Jun 2011, 9:15 pm

Maybe some freezer spray on the screw head to try and shrink the threads a little.

Al

PJL · 17th Jun 2011, 10:25 pm

It's looking like I will have to saw the knob off and go for Darren's spare. My suspicion is the threaded pin extends through the shaft and out the other side and into the knob on the opposite side. Drilling out the pin to the shaft will not free the knob. Drilling all the way through will then wreck the shaft.

Darren-UK · 18th Jun 2011, 12:36 am

The knob is a hollow moulding, as opposed to a solid lump. Moulded into the underside of the knob is a boss into which the shaft locates. This boss is fragile, has an entry hole for the grubscrew but there's no diametrically opposite hole. If there was, the grubscrew could be turned right through the knob with no means of tightening it.

It's therefore logical to assume the tapped hole in the shaft is blind. Unfortunately I no longer have the wavechange switch itself so cannot confirm.

I'll post a picture of the underside of the knob in the morning as it may prove useful for other members at some point.

Darren-UK · 18th Jun 2011, 3:14 pm

Right, now I've dug the knob out I can be a bit more accurate. The tapped hole in the shaft is straight through - not blind.

The grubscrew goes through the shaft and clamps onto the solid bakelite of the knob's boss diametrically opposite it's entry hole. Overtighten and the knob, or rather its boss, will likely fracture.

Images attached.

PJL · 18th Jun 2011, 7:35 pm

Thanks so much for all the effort Graham. Drilling out is not an option then.

I hate to do it, but I think wrecking the knob is the only option. There are some black caps and rotten insulation that I can't reach without removing the RF chassis. The Philips black caps have so far proved to be in worse condition than the normal types.

Darren-UK · 18th Jun 2011, 9:05 pm

I'm at something of a loss to see how it could be drilled out anyway, given that the knob is so close to the side of the cabinet. The only thing which would allow you to get close enough to the cabinet to drill at 90deg to the shaft would be a pin chuck, but you'd still be twiddling away at Christmas with one of those.

One other thought, is it possible to disconnect the wavechange switch from the RF chassis from inside the radio? If it is, you could remove the chassis and leave the switch in situ. From memory though, it's awkward to access but it might be possible with the power supply chassis removed.

17th Jun 2011, 8:07 pm	#1
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Philips V5A wavechange knob. I have a truly stuck wavechange knob. Can someone advise if the screw is threaded into the knob or into a hole in the shaft? Tried oil, heat, levering, hammering...I am running out of ideas. If it's threaded into the shaft I'll have to try to drill it out.

17th Jun 2011, 8:24 pm	#2
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Anyone got a Philips V5A? It's threaded into the shaft. Be careful drilling though, if you end up drilling straight through the shaft you'll go through the other side of the knob too - probably wrecking it. The knob is a hollow moulding and quite fragile. If you do have a mishap, I have a knob (and grubscrew) here which you can have.

17th Jun 2011, 8:39 pm	#3
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Anyone got a Philips V5A? That was quick! Thanks Darren, my fears are confirmed and of course thanks for your very generous offer. The radio is in a terrible state but I'll post a success story when done.

17th Jun 2011, 8:47 pm	#4
geofy Retired Dormant Member Join Date: Jun 2006 Posts: 1,798	Re: Anyone got a Philips V5A? Try Plusgas Formula A dismantling lubricant, leave for 24 hours after soaking, if this doesn't work nothing will! Attached Thumbnails Last edited by geofy; 17th Jun 2011 at 8:55 pm.

17th Jun 2011, 9:15 pm	#5
Alistair D Nonode Join Date: Jan 2010 Location: Edinburgh, UK. Posts: 2,008	Re: Anyone got a Philips V5A? Maybe some freezer spray on the screw head to try and shrink the threads a little. Al __________________ I won't tell you how I discovered that.

17th Jun 2011, 10:25 pm	#6
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Anyone got a Philips V5A? It's looking like I will have to saw the knob off and go for Darren's spare. My suspicion is the threaded pin extends through the shaft and out the other side and into the knob on the opposite side. Drilling out the pin to the shaft will not free the knob. Drilling all the way through will then wreck the shaft.

18th Jun 2011, 12:36 am	#7
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Anyone got a Philips V5A? The knob is a hollow moulding, as opposed to a solid lump. Moulded into the underside of the knob is a boss into which the shaft locates. This boss is fragile, has an entry hole for the grubscrew but there's no diametrically opposite hole. If there was, the grubscrew could be turned right through the knob with no means of tightening it. It's therefore logical to assume the tapped hole in the shaft is blind. Unfortunately I no longer have the wavechange switch itself so cannot confirm. I'll post a picture of the underside of the knob in the morning as it may prove useful for other members at some point.

18th Jun 2011, 3:14 pm	#8
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Philips V5A wavechange knob. Right, now I've dug the knob out I can be a bit more accurate. The tapped hole in the shaft is straight through - not blind. The grubscrew goes through the shaft and clamps onto the solid bakelite of the knob's boss diametrically opposite it's entry hole. Overtighten and the knob, or rather its boss, will likely fracture. Images attached. Attached Thumbnails

18th Jun 2011, 7:35 pm	#9
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Philips V5A wavechange knob. Thanks so much for all the effort Graham. Drilling out is not an option then. I hate to do it, but I think wrecking the knob is the only option. There are some black caps and rotten insulation that I can't reach without removing the RF chassis. The Philips black caps have so far proved to be in worse condition than the normal types.

18th Jun 2011, 9:05 pm	#10
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Philips V5A wavechange knob. I'm at something of a loss to see how it could be drilled out anyway, given that the knob is so close to the side of the cabinet. The only thing which would allow you to get close enough to the cabinet to drill at 90deg to the shaft would be a pin chuck, but you'd still be twiddling away at Christmas with one of those. One other thought, is it possible to disconnect the wavechange switch from the RF chassis from inside the radio? If it is, you could remove the chassis and leave the switch in situ. From memory though, it's awkward to access but it might be possible with the power supply chassis removed.