First Project in Radio = Philips 838HU Advice /Guidance - Page 3 - UK Vintage Radio Repair and Restoration Discussion Forum

Radioski · 15th Dec 2016, 2:43 pm

Regarding the discussion about open circuit mains switches above, remember that the switch contacts can tarnish and appear high resistance to your average multimeter (which is applying a low voltage). Testing with a insulation tester (i.e. Megger) will give a different result because they apply a much higher voltage. In any case when you connect it up to the mains this will usually burn the contact buildup off and make the switch function correctly.

Dunc100 · 18th Dec 2016, 11:38 pm

Back again with an update and tap your brains.

The replacement electrolytic caps arrived before I'd removed the cans off the chassis.
I had to desolder the end of C4 off the base of C1 to get access to the nuts, but once I'd admitted to myself that I had to do that the can came off easily.

Now to try to remove the base. I've read this thread
https://www.vintage-radio.net/forum/...d.php?t=107115

But is there a way to remove the liquid before I start dismantling?
I'm thinking about drilling a small hole in the base.

60 oldjohn · 19th Dec 2016, 12:02 am

As suggested in the other thread #2, use a Plumbers pipe cutter of the wheel type available on the net to make a clean cut. Most capacitor only contain the electrolyte in between the lairs and after 50years it will have dried up. Saying that wash it out before restuffing to prevent any residue corroding the wires on the new capacitors.

John.

kalee99 · 19th Dec 2016, 12:11 am

Sadly most of these electrolytics in pre war Philips sets are not the dry type. But are filled with a horrible oil which leaks out of the vent if you upend the capacitor. Makes a horrible mess on the bench & may be toxic

I found out the hard way.
Paul.

60 oldjohn · 19th Dec 2016, 12:24 am

Paul, Have they a removable plug in the side of them?

John.

kalee99 · 19th Dec 2016, 12:40 am

Hi,
The ones I encountered did indeed have removable plugs in the side but I did not spot the vent hole in the top & they leaked out all over the place during the night. My fault for going to bed & leaving them lying on the bench

Live & learn
Paul.

Dunc100 · 19th Dec 2016, 2:43 pm

Mmmm well there is certainly no plug in the side of his one. I've also turned it upside down and nothing came out. I was worried that it would leak out so I left it in a plastic tub following removal. Still no liquid to be seen, just heard as it sloshes in the can.

PJL · 19th Dec 2016, 6:28 pm

Boric acid and fairly harmless although by now it will have degraded.

'LIVEWIRE?' · 19th Dec 2016, 8:16 pm

Quite a while ago, I removed the reservoir & smoothing electrolytics from a model 274A, since when they have been left in various places, including lying on their sides, with no sign of leakage. It could be, of course, that these have dried out - they are about 83 years old after all. There is still quite a bit of work to do on this radio, which includes replacing the aforementioned capacitors with suitable modern ones hidden under the chassis. The old ones will be refitted in their oroginal positions for the sake of correct appearance, but left disconnected.

60 oldjohn · 20th Dec 2016, 8:29 pm

This is the actual capacitor mentioned, I had the pleasure of cutting it open for Dunc100. I have never seen anything like it, and yes it had some oily liquid in it. The insides just unscrews.
John.

TonyDuell · 20th Dec 2016, 8:33 pm

I assume the can connects to the elctrolyte ('oily liquid') which is the -ve 'plate'. The finned thing is the anode or positive plate, an oxide film is electrolytically formed on it as the dielectric.

It seems a pity this thing can't be restored by re-filling it (boric acid, if that is what the electrolyte is, is sold by pharmacies for use as an eye wash, it is that harmless) and re-forming the dielectric. Has anyone ever tried to do that?

Al (astral highway) · 20th Dec 2016, 8:43 pm

Quote:

Originally Posted by pwdrive

... so back then it was a case of an earth lamp, it had a picture of an angel ascending to heaven placed above it.

That's a nice way of reminding the operator of the danger! Nice share, Lawrence, love it!

Dunc100 · 20th Dec 2016, 10:36 pm

Many thanks to John for cutting this can open for me. We were both rather surprised to see the fins come out of the can.

John was kind enough to give me a solder tag that will fit great. A small thing but I'm sure it's going to make putting things back together a lot easier.

John has a fantastic collection, just wish I had more time to enjoy it. Another visit is needed, I'm sure John won't mind.

60 oldjohn · 20th Dec 2016, 11:00 pm

Quote:

Originally Posted by Dunc100

John has a fantastic collection, just wish I had more time to enjoy it. Another visit is needed, I'm sure John won't mind.

Sure, You have my number, you're welcome.

John.

'LIVEWIRE?' · 20th Dec 2016, 11:23 pm

That can is exactly the same type as those fitted to the 274A. I did think of cutting those open, rmoving the original contents, and fitting modern electrolytics inside them. Still may do that.

15th Dec 2016, 2:43 pm	#41
Radioski Triode Join Date: Feb 2015 Location: Newtown, Powys. UK. Posts: 18	Re: First Project in Radio = Philips 838HU Advice /Guidance Regarding the discussion about open circuit mains switches above, remember that the switch contacts can tarnish and appear high resistance to your average multimeter (which is applying a low voltage). Testing with a insulation tester (i.e. Megger) will give a different result because they apply a much higher voltage. In any case when you connect it up to the mains this will usually burn the contact buildup off and make the switch function correctly.

18th Dec 2016, 11:38 pm	#42
Dunc100 Retired Dormant Member Join Date: Dec 2016 Location: Driffield, East Riding of Yorkshire, UK. Posts: 19	Re: First Project in Radio = Philips 838HU Advice /Guidance Back again with an update and tap your brains. The replacement electrolytic caps arrived before I'd removed the cans off the chassis. I had to desolder the end of C4 off the base of C1 to get access to the nuts, but once I'd admitted to myself that I had to do that the can came off easily. Now to try to remove the base. I've read this thread https://www.vintage-radio.net/forum/...d.php?t=107115 But is there a way to remove the liquid before I start dismantling? I'm thinking about drilling a small hole in the base.

19th Dec 2016, 12:02 am	#43
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,988	Re: First Project in Radio = Philips 838HU Advice /Guidance As suggested in the other thread #2, use a Plumbers pipe cutter of the wheel type available on the net to make a clean cut. Most capacitor only contain the electrolyte in between the lairs and after 50years it will have dried up. Saying that wash it out before restuffing to prevent any residue corroding the wires on the new capacitors. John.

19th Dec 2016, 12:11 am	#44
kalee99 Rest in Peace Join Date: Dec 2004 Location: Newcastle Upon Tyne, Tyneside, UK. Posts: 420	Re: First Project in Radio = Philips 838HU Advice /Guidance Sadly most of these electrolytics in pre war Philips sets are not the dry type. But are filled with a horrible oil which leaks out of the vent if you upend the capacitor. Makes a horrible mess on the bench & may be toxic I found out the hard way. Paul.

19th Dec 2016, 12:24 am	#45
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,988	Re: First Project in Radio = Philips 838HU Advice /Guidance Paul, Have they a removable plug in the side of them? John.

19th Dec 2016, 12:40 am	#46
kalee99 Rest in Peace Join Date: Dec 2004 Location: Newcastle Upon Tyne, Tyneside, UK. Posts: 420	Re: First Project in Radio = Philips 838HU Advice /Guidance Hi, The ones I encountered did indeed have removable plugs in the side but I did not spot the vent hole in the top & they leaked out all over the place during the night. My fault for going to bed & leaving them lying on the bench Live & learn Paul.

19th Dec 2016, 2:43 pm	#47
Dunc100 Retired Dormant Member Join Date: Dec 2016 Location: Driffield, East Riding of Yorkshire, UK. Posts: 19	Re: First Project in Radio = Philips 838HU Advice /Guidance Mmmm well there is certainly no plug in the side of his one. I've also turned it upside down and nothing came out. I was worried that it would leak out so I left it in a plastic tub following removal. Still no liquid to be seen, just heard as it sloshes in the can.

19th Dec 2016, 6:28 pm	#48
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: First Project in Radio = Philips 838HU Advice /Guidance Boric acid and fairly harmless although by now it will have degraded.

19th Dec 2016, 8:16 pm	#49
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: First Project in Radio = Philips 838HU Advice /Guidance Quite a while ago, I removed the reservoir & smoothing electrolytics from a model 274A, since when they have been left in various places, including lying on their sides, with no sign of leakage. It could be, of course, that these have dried out - they are about 83 years old after all. There is still quite a bit of work to do on this radio, which includes replacing the aforementioned capacitors with suitable modern ones hidden under the chassis. The old ones will be refitted in their oroginal positions for the sake of correct appearance, but left disconnected.

20th Dec 2016, 8:29 pm	#50
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,988	Re: First Project in Radio = Philips 838HU Advice /Guidance This is the actual capacitor mentioned, I had the pleasure of cutting it open for Dunc100. I have never seen anything like it, and yes it had some oily liquid in it. The insides just unscrews. John. Attached Thumbnails

20th Dec 2016, 8:33 pm	#51
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,222	Re: First Project in Radio = Philips 838HU Advice /Guidance I assume the can connects to the elctrolyte ('oily liquid') which is the -ve 'plate'. The finned thing is the anode or positive plate, an oxide film is electrolytically formed on it as the dielectric. It seems a pity this thing can't be restored by re-filling it (boric acid, if that is what the electrolyte is, is sold by pharmacies for use as an eye wash, it is that harmless) and re-forming the dielectric. Has anyone ever tried to do that?

20th Dec 2016, 10:36 pm	#53
Dunc100 Retired Dormant Member Join Date: Dec 2016 Location: Driffield, East Riding of Yorkshire, UK. Posts: 19	Re: First Project in Radio = Philips 838HU Advice /Guidance Many thanks to John for cutting this can open for me. We were both rather surprised to see the fins come out of the can. John was kind enough to give me a solder tag that will fit great. A small thing but I'm sure it's going to make putting things back together a lot easier. John has a fantastic collection, just wish I had more time to enjoy it. Another visit is needed, I'm sure John won't mind.

20th Dec 2016, 11:23 pm	#55
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: First Project in Radio = Philips 838HU Advice /Guidance That can is exactly the same type as those fitted to the 274A. I did think of cutting those open, rmoving the original contents, and fitting modern electrolytics inside them. Still may do that.