730A Philips radio to get working. - UK Vintage Radio Repair and Restoration Discussion Forum

Dick Glennon · 2nd Feb 2020, 5:36 pm

Hi again, A special thanks to everyone for all the help down the years. I have a philips 730A that has been crying out for restoration for 30 odd years ,bought for 50 pence. At last I have picked up courage to have a go. I have just one valve, the 1821, therefore I would be very grateful if someone reading this could give me equivalent numbers for the valve lineup. I have the electrical and radio traders service chart. The valve line-up is 1and2=s4vb, 3and4=244V, 5=PM24A,and 6=1821. I want to see what I might have in other working sets that would work in this one. Ialso would like to verify the following values of condenser no,s 6,15,16,26 and 27, and which are electrolitic. That will do for now ,but rest assured I will have many more questions. Thanks again Dick.

HamishBoxer · 2nd Feb 2020, 6:25 pm

The service sheet is top right on this website if you need it.

Simon Gittins · 2nd Feb 2020, 8:43 pm

A site for valve equivalents is The Valve Museum
This gives sensible equivalents as:
S4VB CV1677
244V TE244
PM24A CV1167 NR43 (I notice that the Trader sheet gives this valve as PM22A)
1821 CV1443 UU5

Capacitor values are in microfarads
C6 1.5µF
C15 1.0µF
C16 1.0µF
C26 3.0µF
C27 4.0µF

As to whether they are electrolytic types or not (and also the output valve type), hopefully someone with another example of the set can answer that. C26 and C27 could be either but I would expect the others to be paper types.

I see that the EXT LS sockets are across the primary waiting to bite!

cathoderay57 · 3rd Feb 2020, 2:18 pm

According to my databooks the 1821 rectifier is directly heated with a 4v 1A filament & max anode voltage/current 250v/60mA. An exact equivalent is the DW2. The UU2 also has identical characteristics but is indirectly heated. My concern with substituting a UU5 is the 2.3A heater current, over twice that of the 1821. While it would undoubtedly work, I would be worried about the stress on the heater winding of a geriatric mains transformer. Recommend look out for a DW2 or UU2 if a replacement is needed. Substitutes for S4VB are tetrodes MS4, MS4B and pentodes S4VA, MS/Pen, SP4. Cheers, Jerry

Dick Glennon · 9th Feb 2020, 11:37 am

Hi again, I have looked at the underside of the chassis, and I see nothing but bare and perished wires everywhere. There are also some loose wires both bare and (covered) which worries me. I was thinking of replacing the bare wires with covered multicoloured wires for ease of identification. I have lots of 0.56mm diam. Wire which I could use if it would take the current it would encounter. The wires that are there are 1mm diam. Also there is conflict with service sheets regarding the values of resistors. There are no markings on them. More questions later. Thanks for all help so far, Regards, Dick.

Herald1360 · 9th Feb 2020, 11:45 am

Apart from heater and possibly mains wiring there's nowhere in a typical valve radio where current higher than 100ma will need to be carried. 0.56mm dia (0.25sq mm) wire is good for an amp or more.

David G4EBT · 9th Feb 2020, 12:27 pm

There are two data sheets available for this set, as you might have gathered - Trader Sheet 647, and an ERT sheet. Useful to have the two, of which the ERT sheet is clearer, and gives full details of the three 'condenser' blocks, which will need rebuilding. Blocks 'A' and 'B' each have six capacitors in them - Block 'C' just has the two smoothing caps in it. Quite low value too - 3uF and 4 uF. (Replace with 3u3 & 4u7).

Quite a challenging set to restore. Given that the set is in its 90th year, as a first step it's worth checking the continuity of the mains and OPT transformers, the smoothing choke, anode choke, coils and speaker speech coil. For me, any problems there would be a game changer. It's one thing re-building the condenser blocks (little cost, lots of time), it's quite another thing if the mains or OPT need rewinding. At least being a TRF, there are no IFTs to complicate life. Nor is the speaker mains energised with a field coil that could be, (often are) open circuit.

Hope that's of interest.

Good luck with the restoration Dick.

Simon Gittins · 9th Feb 2020, 1:28 pm

Another possibility is fitting sleeving over the existing wiring, that way you only have to cut one end of each wire.

PJL · 9th Feb 2020, 1:42 pm

The capacitor cans can be opened using a hot air gun to melt the solder. It all takes time but these are simple sets and work well. It's worth checking the output and mains transformers before you get going.

Dick Glennon · 15th Feb 2020, 6:50 pm

Hi again,I have checked the mains transformer and the output transformer and the ht smoothing choke, and all are good. When I put the ohm meter on the primary of the output transformer I am getting a scratching sound from the speaker, could this mean that the speech coil is ok. What other coils etc. Would I need to check so as to be able to start repair/restoration. If there is any part that cannot be repaired I would like to know as my big outlay would be the valves. Ido not want to buy them and then find out that something else to get the set working cannot be repaired. Thanks again, Dick.

Simon Gittins · 15th Feb 2020, 7:01 pm

Quote:

Originally Posted by Dick Glennon

When I put the ohm meter on the primary of the output transformer I am getting a scratching sound from the speaker, could this mean that the speech coil is ok.

That's a very good sign that the output transformer and speaker are working.

You certainly could check other coils for continuity as well if you want to know whether an expensive component has failed.

Sideband · 15th Feb 2020, 7:22 pm

Quote:

Originally Posted by Dick Glennon

Hi again,I have checked the mains transformer and the output transformer and the ht smoothing choke, and all are good.

Hi Dick. You say you've checked them and all are good.....how have you checked them? In particular the mains transformer.....resistance checks don't necessarily prove that the transformer is good....one shorted turn will not show up on resistance checks but will cause the transformer to overheat. The only way to be reasonably certain that the mains transformer is OK is to apply power to it. I generally leave the pilot lamps connected but remove all the valves including the rectifier. If the rectifier is a metal type (not a valve), then it has to be disconnected. Any capacitor across the mains should also be disconnected (as it will probably fail spectacularly). Only then apply power and see if the pilot lamps work (make sure they are good to start with). You can then check the output voltages of the transformer. Leave it connected to the mains for a few minutes....the transformer should remain cold....if you get this far chances are all is good. Leave it on for around half an hour and the transformer will probably be warm to the touch. Great! The transformer's a goodun!

If however after applying mains, the transformer gets hot within half a minute of so then it's duff.....but make sure there is nothing connected to it that might be causing a problem.

Sideband · 16th Feb 2020, 9:36 am

Quote:

Originally Posted by Dick Glennon

Hi again, I have looked at the underside of the chassis, and I see nothing but bare and perished wires everywhere. There are also some loose wires both bare and (covered) which worries me. I was thinking of replacing the bare wires with covered multicoloured wires for ease of identification.

It is quite normal for these classic radio's to have bare and insulated wires. Leave the bare wires....replacing these with bright multicolured wires will look completely out-of-place and there is a very real danger of making an error. Obviously if there are any insulated wires that are perished, then these can be either resleeved or replaced with similar coloured wire to maintain looks. It's a very simple circuit but requires care and patience to restore correctly.

Here is the link to my 274A which uses very similar construction and wiring. I also explain how I restored the block capacitor. As you see, I kept everything as original-looking as possible.

https://www.vintage-radio.net/forum/...ad.php?t=11743

Dick Glennon · 16th Feb 2020, 2:47 pm

Hi again,I do remember what I thought was an on/off volume control higher up on the cabinet. This was put up for safe keeping along with one of the other knobs but I have not been able to locate either yet. Would I be right in thinking that this is also R 7 on the ERT sheet called as S 1. Sorry about the silly questions, Regards, Dick.

Sideband · 16th Feb 2020, 5:16 pm

R7 is really a gain control since it controls the gain of the RF amp but essentially used as a volume control (the effect is roughly the same). S1 is the mains switch ganged to the control.

This is a very desirable set... one of the classics known as 'Superinductance' in its 89th year. I hope you can restore it successfully.

lloydwells · 16th Feb 2020, 10:03 pm

Its an early Philips the wiring will be uninsulated they all are it's not a concern seems an easy set to work on I've just restored two 930As and various other old Philips sets mains transformers and output transformers never seem to be any trouble here's a link to the Philips service data with wire positions on.

http://www.nvhr.nl/frameset.htm?&ContentFrame

Dick Glennon · 28th Feb 2020, 3:06 pm

Hi again, I just would like someone to verify that s1 is also part of r7 . There was a switch further up on the side of the set as if s1 was switched from it . Should there be an on/off as part of r7. There are loose wires that might indicate that switching was done from further up the side. Also the dial bulb(6v 3watt) has blown. I have one 6 v 8 watt same size, would it be too strong. Regards Dick.

cathoderay57 · 28th Feb 2020, 8:56 pm

The Trader Sheet or manufacturer's data sheet normally gives rating for the dial bulb. Even 3W seems a bit high. Normally they are 0.3A = 1.9W. I'd recommend not using an 8W bulb. It's worth paying attention to Post #12 and powering up the mains transformer under no-load conditions. If all is well then disconnect the HT caps from the rectifier cathode then pop the rectifier in and see how many volts are on the cathode. The 1821 rectifiers don't survive well and if not you'll also need to budget for a replacement or equivalent DW2 or UU2. Cheers, Jerry

Sideband · 28th Feb 2020, 9:19 pm

Quote:

Originally Posted by Dick Glennon

Hi again, I just would like someone to verify that s1 is also part of r7 . There was a switch further up on the side of the set as if s1 was switched from it . Should there be an on/off as part of r7. There are loose wires that might indicate that switching was done from further up the side. Also the dial bulb(6v 3watt) has blown. I have one 6 v 8 watt same size, would it be too strong. Regards Dick.

As I said, the on/off switch is ganged (ie connected to) R7 so yes they are part of the same control. As for 'loose wires' how about putting up some good close pictures? You should be able to see where the other ends of the wires are connected and then from the circuit, where/what they should connect to.

PJL · 28th Feb 2020, 11:26 pm

If the wires with failing rubber insulation are solid wires then my approach is to lift one end, scrape off the remaining gunk, and fit a new sleeve. The capacitors in the cans will be paper, I use the cheapest PCB mount 1uF (or 0.5uF) polyester caps I can find and parallel them up to makeup the larger values using vero board. Some slightly later Philips sets used wet electrolytics but I don't think they are used here.

2nd Feb 2020, 6:25 pm	#2
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,935	Re: 730A philips radio to get working. The service sheet is top right on this website if you need it. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

2nd Feb 2020, 8:43 pm	#3
Simon Gittins Heptode Join Date: Jan 2006 Location: Cornwall, UK. Posts: 506	Re: 730A philips radio to get working. A site for valve equivalents is The Valve Museum This gives sensible equivalents as: S4VB CV1677 244V TE244 PM24A CV1167 NR43 (I notice that the Trader sheet gives this valve as PM22A) 1821 CV1443 UU5 Capacitor values are in microfarads C6 1.5µF C15 1.0µF C16 1.0µF C26 3.0µF C27 4.0µF As to whether they are electrolytic types or not (and also the output valve type), hopefully someone with another example of the set can answer that. C26 and C27 could be either but I would expect the others to be paper types. I see that the EXT LS sockets are across the primary waiting to bite!

3rd Feb 2020, 2:18 pm	#4
cathoderay57 Nonode Join Date: Oct 2017 Location: Bristol, UK. Posts: 2,384	Re: 730A philips radio to get working. According to my databooks the 1821 rectifier is directly heated with a 4v 1A filament & max anode voltage/current 250v/60mA. An exact equivalent is the DW2. The UU2 also has identical characteristics but is indirectly heated. My concern with substituting a UU5 is the 2.3A heater current, over twice that of the 1821. While it would undoubtedly work, I would be worried about the stress on the heater winding of a geriatric mains transformer. Recommend look out for a DW2 or UU2 if a replacement is needed. Substitutes for S4VB are tetrodes MS4, MS4B and pentodes S4VA, MS/Pen, SP4. Cheers, Jerry Last edited by cathoderay57; 3rd Feb 2020 at 2:40 pm.

9th Feb 2020, 11:37 am	#5
Dick Glennon Hexode Join Date: Oct 2006 Location: Edenderry, Republic of Ireland. Posts: 428	Re: 730A philips radio to get working. Hi again, I have looked at the underside of the chassis, and I see nothing but bare and perished wires everywhere. There are also some loose wires both bare and (covered) which worries me. I was thinking of replacing the bare wires with covered multicoloured wires for ease of identification. I have lots of 0.56mm diam. Wire which I could use if it would take the current it would encounter. The wires that are there are 1mm diam. Also there is conflict with service sheets regarding the values of resistors. There are no markings on them. More questions later. Thanks for all help so far, Regards, Dick.

9th Feb 2020, 11:45 am	#6
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: 730A philips radio to get working. Apart from heater and possibly mains wiring there's nowhere in a typical valve radio where current higher than 100ma will need to be carried. 0.56mm dia (0.25sq mm) wire is good for an amp or more. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

2nd Feb 2020, 5:36 pm	#1
Dick Glennon Hexode Join Date: Oct 2006 Location: Edenderry, Republic of Ireland. Posts: 428	730A Philips radio to get working. Hi again, A special thanks to everyone for all the help down the years. I have a philips 730A that has been crying out for restoration for 30 odd years ,bought for 50 pence. At last I have picked up courage to have a go. I have just one valve, the 1821, therefore I would be very grateful if someone reading this could give me equivalent numbers for the valve lineup. I have the electrical and radio traders service chart. The valve line-up is 1and2=s4vb, 3and4=244V, 5=PM24A,and 6=1821. I want to see what I might have in other working sets that would work in this one. Ialso would like to verify the following values of condenser no,s 6,15,16,26 and 27, and which are electrolitic. That will do for now ,but rest assured I will have many more questions. Thanks again Dick.

9th Feb 2020, 12:27 pm	#7
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,763	Re: 730A philips radio to get working. There are two data sheets available for this set, as you might have gathered - Trader Sheet 647, and an ERT sheet. Useful to have the two, of which the ERT sheet is clearer, and gives full details of the three 'condenser' blocks, which will need rebuilding. Blocks 'A' and 'B' each have six capacitors in them - Block 'C' just has the two smoothing caps in it. Quite low value too - 3uF and 4 uF. (Replace with 3u3 & 4u7). Quite a challenging set to restore. Given that the set is in its 90th year, as a first step it's worth checking the continuity of the mains and OPT transformers, the smoothing choke, anode choke, coils and speaker speech coil. For me, any problems there would be a game changer. It's one thing re-building the condenser blocks (little cost, lots of time), it's quite another thing if the mains or OPT need rewinding. At least being a TRF, there are no IFTs to complicate life. Nor is the speaker mains energised with a field coil that could be, (often are) open circuit. Hope that's of interest. Good luck with the restoration Dick. __________________ David. BVWS Member. G-QRP Club member 1339.

9th Feb 2020, 1:28 pm	#8
Simon Gittins Heptode Join Date: Jan 2006 Location: Cornwall, UK. Posts: 506	Re: 730A philips radio to get working. Another possibility is fitting sleeving over the existing wiring, that way you only have to cut one end of each wire.

9th Feb 2020, 1:42 pm	#9
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: 730A philips radio to get working. The capacitor cans can be opened using a hot air gun to melt the solder. It all takes time but these are simple sets and work well. It's worth checking the output and mains transformers before you get going.

15th Feb 2020, 6:50 pm	#10
Dick Glennon Hexode Join Date: Oct 2006 Location: Edenderry, Republic of Ireland. Posts: 428	Re: 730A philips radio to get working. Hi again,I have checked the mains transformer and the output transformer and the ht smoothing choke, and all are good. When I put the ohm meter on the primary of the output transformer I am getting a scratching sound from the speaker, could this mean that the speech coil is ok. What other coils etc. Would I need to check so as to be able to start repair/restoration. If there is any part that cannot be repaired I would like to know as my big outlay would be the valves. Ido not want to buy them and then find out that something else to get the set working cannot be repaired. Thanks again, Dick.

16th Feb 2020, 2:47 pm	#14
Dick Glennon Hexode Join Date: Oct 2006 Location: Edenderry, Republic of Ireland. Posts: 428	Re: 730A philips radio to get working. Hi again,I do remember what I thought was an on/off volume control higher up on the cabinet. This was put up for safe keeping along with one of the other knobs but I have not been able to locate either yet. Would I be right in thinking that this is also R 7 on the ERT sheet called as S 1. Sorry about the silly questions, Regards, Dick.

16th Feb 2020, 5:16 pm	#15
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,577	Re: 730A philips radio to get working. R7 is really a gain control since it controls the gain of the RF amp but essentially used as a volume control (the effect is roughly the same). S1 is the mains switch ganged to the control. This is a very desirable set... one of the classics known as 'Superinductance' in its 89th year. I hope you can restore it successfully. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

16th Feb 2020, 10:03 pm	#16
lloydwells Heptode Join Date: Aug 2016 Location: Dumfries, Scotland, UK. Posts: 549	Re: 730A philips radio to get working. Its an early Philips the wiring will be uninsulated they all are it's not a concern seems an easy set to work on I've just restored two 930As and various other old Philips sets mains transformers and output transformers never seem to be any trouble here's a link to the Philips service data with wire positions on. http://www.nvhr.nl/frameset.htm?&ContentFrame

28th Feb 2020, 3:06 pm	#17
Dick Glennon Hexode Join Date: Oct 2006 Location: Edenderry, Republic of Ireland. Posts: 428	Re: 730A philips radio to get working. Hi again, I just would like someone to verify that s1 is also part of r7 . There was a switch further up on the side of the set as if s1 was switched from it . Should there be an on/off as part of r7. There are loose wires that might indicate that switching was done from further up the side. Also the dial bulb(6v 3watt) has blown. I have one 6 v 8 watt same size, would it be too strong. Regards Dick.

28th Feb 2020, 8:56 pm	#18
cathoderay57 Nonode Join Date: Oct 2017 Location: Bristol, UK. Posts: 2,384	Re: 730A philips radio to get working. The Trader Sheet or manufacturer's data sheet normally gives rating for the dial bulb. Even 3W seems a bit high. Normally they are 0.3A = 1.9W. I'd recommend not using an 8W bulb. It's worth paying attention to Post #12 and powering up the mains transformer under no-load conditions. If all is well then disconnect the HT caps from the rectifier cathode then pop the rectifier in and see how many volts are on the cathode. The 1821 rectifiers don't survive well and if not you'll also need to budget for a replacement or equivalent DW2 or UU2. Cheers, Jerry

28th Feb 2020, 11:26 pm	#20
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: 730A philips radio to get working. If the wires with failing rubber insulation are solid wires then my approach is to lift one end, scrape off the remaining gunk, and fit a new sleeve. The capacitors in the cans will be paper, I use the cheapest PCB mount 1uF (or 0.5uF) polyester caps I can find and parallel them up to makeup the larger values using vero board. Some slightly later Philips sets used wet electrolytics but I don't think they are used here.