Gecophone ST1501 - UK Vintage Radio Repair and Restoration Discussion Forum

keithinuk · 27th Jan 2013, 11:32 am

Hi again,

I picked up this telephone the other day and was hoping someone would know if I can still use it. It has no lead and the dial needs a part, but that's no problem to fix.

I would like to use it as an extension 'phone if possible, as I don't think my 'phone system will work with the old pulse-dial 'phones.

It's from the 1950's I gather and would be nice to put it to use again.

OscarFoxtrot · 27th Jan 2013, 1:30 pm

Circuit diagram is here
http://www.britishtelephones.com/gec...res/ks7533.jpg

The telephone was intended for DC ringing on a PAX, as such the phone does not have a ringing capacitor and the bell might not work on AC.

Nickthedentist · 27th Jan 2013, 1:33 pm

It does not appear to have an ASTIC (coil) either.

What are the two components shown bottom left of the diagram (marked 30 & 100 Ohms)?

keithinuk · 27th Jan 2013, 1:43 pm

It's the internal bell and a coil I think.

AC/HL · 27th Jan 2013, 3:44 pm

Quite an oddball. A dial, so for an auto exchange, but the mic and earphone are in series so no sidetone suppression.
DC ringing, the bell coil and the 100 ohm (lamp?) look to be wired in parallel. Must be for a special application.

keithinuk · 28th Jan 2013, 5:50 pm

As it seems to be a PAX DC mains phone, it looks like I will have to modify and add the parts it needs to make the phone work again.
I will start looking for parts.

keithinuk · 8th Feb 2013, 8:54 pm

Could someone answer this for me, to rewire this Gecophone, you have to remove a wire from the capacitor, dose that mean you don't need a 2uf capacitor?
I know useless, well the 332L I got should be easier to do, as it was made for a GPO line and was reworked in 62.

Nicklyons2 · 9th Feb 2013, 12:25 am

Hi, I managed to get one of these 'phones to work quite well on a standard BT line. The bell set is too low impedance for direct connexion, I used a small mains transformer from an old batt/mains radio, sort of mains to 10Vac, you might need to experiment a bit. The primary was just fed from the BT plug pin 3 ringer cap feed or you could put a 2.2uF internally and keep the phone as '2 wire'; the secondary just fed the bell directly. The dial connexions are shown on that diagram, if you wish to add one. If you're still on BT the chances are D.C. loop (pulse dialling) will still work. The lack of ASTIC wasn't much of a problem, I found; the sound quality on modern landlines is so good the extra enhancement this provided on the lines of the 1930s isn't so important - although you do hear yourself quite well! I've got some dials I think if you want to try it,
Nick

27th Jan 2013, 11:32 am	#1
keithinuk Retired Dormant Member Join Date: Mar 2011 Location: Hertfordshire, UK. Posts: 208	Gecophone ST1501 Hi again, I picked up this telephone the other day and was hoping someone would know if I can still use it. It has no lead and the dial needs a part, but that's no problem to fix. I would like to use it as an extension 'phone if possible, as I don't think my 'phone system will work with the old pulse-dial 'phones. It's from the 1950's I gather and would be nice to put it to use again.

27th Jan 2013, 1:30 pm	#2
OscarFoxtrot Heptode Join Date: Apr 2011 Location: Edinburgh, UK. Posts: 805	Re: Gecophone ST1501 Circuit diagram is here http://www.britishtelephones.com/gec...res/ks7533.jpg The telephone was intended for DC ringing on a PAX, as such the phone does not have a ringing capacitor and the bell might not work on AC.

27th Jan 2013, 1:33 pm	#3
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,844	Re: Gecophone ST1501 It does not appear to have an ASTIC (coil) either. What are the two components shown bottom left of the diagram (marked 30 & 100 Ohms)?

27th Jan 2013, 1:43 pm	#4
keithinuk Retired Dormant Member Join Date: Mar 2011 Location: Hertfordshire, UK. Posts: 208	Re: Gecophone ST1501 It's the internal bell and a coil I think.

27th Jan 2013, 3:44 pm	#5
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Gecophone ST1501 Quite an oddball. A dial, so for an auto exchange, but the mic and earphone are in series so no sidetone suppression. DC ringing, the bell coil and the 100 ohm (lamp?) look to be wired in parallel. Must be for a special application.

28th Jan 2013, 5:50 pm	#6
keithinuk Retired Dormant Member Join Date: Mar 2011 Location: Hertfordshire, UK. Posts: 208	Re: Gecophone ST1501 As it seems to be a PAX DC mains phone, it looks like I will have to modify and add the parts it needs to make the phone work again. I will start looking for parts.

8th Feb 2013, 8:54 pm	#7
keithinuk Retired Dormant Member Join Date: Mar 2011 Location: Hertfordshire, UK. Posts: 208	Re: Gecophone ST1501 Could someone answer this for me, to rewire this Gecophone, you have to remove a wire from the capacitor, dose that mean you don't need a 2uf capacitor? I know useless, well the 332L I got should be easier to do, as it was made for a GPO line and was reworked in 62.

9th Feb 2013, 12:25 am	#8
Nicklyons2 Octode Join Date: Jan 2013 Location: Barnsley, South Yorkshire, UK. Posts: 1,517	Re: Gecophone ST1501 Hi, I managed to get one of these 'phones to work quite well on a standard BT line. The bell set is too low impedance for direct connexion, I used a small mains transformer from an old batt/mains radio, sort of mains to 10Vac, you might need to experiment a bit. The primary was just fed from the BT plug pin 3 ringer cap feed or you could put a 2.2uF internally and keep the phone as '2 wire'; the secondary just fed the bell directly. The dial connexions are shown on that diagram, if you wish to add one. If you're still on BT the chances are D.C. loop (pulse dialling) will still work. The lack of ASTIC wasn't much of a problem, I found; the sound quality on modern landlines is so good the extra enhancement this provided on the lines of the 1930s isn't so important - although you do hear yourself quite well! I've got some dials I think if you want to try it, Nick