1936 Marconiphone 365 Radiogram - Page 8 - UK Vintage Radio Repair and Restoration Discussion Forum

Station X · 3rd May 2022, 6:46 pm

Check the resistance between pins 4 and 5 of the valve itself. A low reading indicates that the heater is intact.

kinnego07 · 3rd May 2022, 7:57 pm

Ok, so the filament has gone.

This was the first thing I checked on inspection and all the valves were good then.

Station X · 4th May 2022, 2:14 pm

That's not good. X41's aren't cheap.

AC/TH1 isn't an exact equivalent, but has the same pin out and should work.

kinnego07 · 4th May 2022, 2:55 pm

Oh dear!

I guess age had wearied it and going on full power finished it off. I had tested all valves a couple of times early on so that I could order replacements if faulty.

I think however that the initial problem still exists.

If anyone can help me out with a suitable valve it would be greatly appreciated and a hearty thanks to all who have been following and contributed.

In particular thanks Station X for your patience and endurance

John10b · 4th May 2022, 3:18 pm

I have been following this with great interest, I think station X certainly has shown great patience giving you advice and guidance, as well as others. I hope you are able to source a valve and carry on to a successful outcome.
John

PJL · 4th May 2022, 3:42 pm

It's worthwhile resoldering the heater pins by using a solder sucker on the end of the pins to reveal the wire then applying fresh solder.

kinnego07 · 4th May 2022, 9:39 pm

Thanks John for your reply and interest from the start.

I'm not beaten yet so stay tuned. I'm actively seeking a replacement and as an incentive "her in doors" has promised me a dance to Flying down to Rio. Last dance was about 40 years ago! (it also means that I'm allowed to have the Radiogram in the living room)

Also, thanks PJL for your contributions and I'm ordering a solder sucker this evening.

I have got around ten barn find radios up and running to date but I don't think I can solve this one on my own so keep checking in.

kinnego07 · 11th May 2022, 9:01 am

Update -

It's up and running! Fitted a NOS X41 valve and the set sprang to life immediately. Great sound quality and pulling in normally weak stations loud and clear. All brilliance and bass positions working as they should.

I stripped some of the metallic coating off the old valve and found that the inside had a white film which I have read is a sign that the valve had lost vacuum.

I guess that this was the original problem and that the filament had held up until full power was applied?

So now the gram. Motor is working but slow to start and speed is all over the place. Pick up is working but sound quality is not so good. this may be due to the needle which I found in the bottom of the case. Any advice greatly appreciated.

John10b · 11th May 2022, 2:00 pm

Well done to you and all your helpers for solving the problem.
Did you have a dance ?
Oops sorry you still got to fix record player.
John

kinnego07 · 12th May 2022, 8:40 pm

No dance yet - Have to sort out a dodgy knee and two hips first. And that's only the wife!

The gram speed is not controllable and the turntable stops in automatic mode when changing records. I have cleaned and lubed all that I can without taking it apart (and I'm not doing that)

I washed the speed brake and re lubed it with light oil without improvement

I wonder if the motor is weak?

Analogue man · 13th May 2022, 10:17 pm

Quote:

Originally Posted by kinnego07

No dance yet - Have to sort out a dodgy knee and two hips first. And that's only the wife!

The gram speed is not controllable and the turntable stops in automatic mode when changing records. I have cleaned and lubed all that I can without taking it apart (and I'm not doing that)

I washed the speed brake and re lubed it with light oil without improvement

I wonder if the motor is weak?

I would strip the motor, clean and relube it then with it running in your hand gently tap on all sides with a small hammer to realign the bearings, if this fails then you may well have a weak motor.

kinnego07 · 16th May 2022, 8:00 pm

Thanks for the advice. However, "the motor" is a large metal disc (which turns the turntable) driven by electromagnets? with around 230 V AC running through them. The speed brake acts by means of a lubricated friction pad on a smaller disc which sits at right angles to the large disc.

If I set the speed to play correctly at the beginning of a record the record will be playing fast before the end. When a second record drops the turntable will slow almost to a stop when the needle touches the record.

Station X · 16th May 2022, 8:25 pm

Classic symptom of excessive friction or lack of lubrication in the autochanger mechanism. It takes a lot more power to operate the autochanger than it does to just spin a record. The effect is more pronounced at low turntable speeds as there's less energy stored in the mass of the turntable.

Techman · 17th May 2022, 12:18 am

Quote:

Originally Posted by kinnego07

I have cleaned and lubed all that I can without taking it apart (and I'm not doing that)

You're going to have to do it!

The autochange problem will likely be dried up grease etc. There's no idler wheel to slip on these - it's proper direct drive!

The speed variation will probably be to do with the governor disc not sliding along its shaft freely when the balls/weights spin out and draw it along this shaft and up to the pre-set brake pad, which should be lightly oiled - the same idea as on a wind-up gramophone.

electrogram · 17th May 2022, 11:43 am

Isn't there a capacitor in series with the motor on these, if it has changed in value that could result in a lack of torque. I think there was a thread about this a couple of years ago

kinnego07 · 17th May 2022, 1:52 pm

I'm not looking forward to taking this apart! A car engine yes - but not this.

But if it has to be done....

There is a capacitor can (see attached) and I was wondering if this might be the problem. There are no markings on the can so what would this capacitor be?

I have also attached some photos of the motor, governor and brake. I can't see how the governor could move up and down the shaft as there is a screw fixing it to the shaft. However there is some movement in the springs to which the balls are attached.

It takes very little adjustment of the speed brake to stop the turntable which with my limited knowledge suggests a torque issue?

John10b · 17th May 2022, 2:03 pm

Good luck, my only tip is take plenty of pictures.
John

Techman · 17th May 2022, 2:31 pm

You're getting it a bit round your neck as to how these governors are supposed to work.

The "DISC" isn't fixed to the shaft, it slides along the shaft as the balls spin out when the motor is running. The brake pad must NOT be touching the disc when the motor is at rest. There MUST be a gap between the pad and the disc when the motor is not running. When the motor starts, the balls spin out under centrifugal force and the three springs pull the spinning "DISC" along the shaft until it touches the brake pad which then regulates the speed.

The most common fault is that the disc binds on the shaft and doesn't slide along it due to gumming up. The second problem is that if you're not VERY careful, you can bust those springs and if you do then it's game over for the motor, so be very careful!

The capacitor that's been mentioned is certainly another contender and has been proven to be a problem in the past. It's probably not known what the value is and it may not be marked on it, but it has certainly been ascertained in previous threads as to what it is, so you can do a 'forum search' or someone may be able to advise you or direct you to a thread with the information.

But first do the easy bit as regards checking that the disc slides along the shaft when the motor starts to run.

Edit: remember, GAP, GAP, GAP! There isn't one according to your photos!

kinnego07 · 17th May 2022, 4:20 pm

Thanks Techman for making sense of it all for me.

I know from working at various vintage engines how a governor should work but I just couldn't see how this would work. I could see the balls moving out a fraction or two by movement in the springs.

It must be REALLY gummed up!

I will give it a CAREFUL once over when I get home.

I will conduct a search of this forum re capacitor

electrogram · 17th May 2022, 5:55 pm

Yes, get that governor working properly first. The capacitor issue may be another tin of worms you won't need to open with any luck. Another mechanical problem I have seen on Garrard gram units this age is is that the ball in the turntable main bearing has worn the bottom of the spindle, sometimes to a quite astonishing degree, greatly increasing friction.

3rd May 2022, 6:46 pm	#141
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: 1936 Marconiphone 365 Radiogram Check the resistance between pins 4 and 5 of the valve itself. A low reading indicates that the heater is intact. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

3rd May 2022, 7:57 pm	#142
kinnego07 Tetrode Join Date: Dec 2020 Location: Dungannon, County Tyrone, Northern Ireland, UK. Posts: 76	Re: 1936 Marconiphone 365 Radiogram Ok, so the filament has gone. This was the first thing I checked on inspection and all the valves were good then.

4th May 2022, 2:14 pm	#143
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: 1936 Marconiphone 365 Radiogram That's not good. X41's aren't cheap. AC/TH1 isn't an exact equivalent, but has the same pin out and should work. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

4th May 2022, 2:55 pm	#144
kinnego07 Tetrode Join Date: Dec 2020 Location: Dungannon, County Tyrone, Northern Ireland, UK. Posts: 76	Re: 1936 Marconiphone 365 Radiogram Oh dear! I guess age had wearied it and going on full power finished it off. I had tested all valves a couple of times early on so that I could order replacements if faulty. I think however that the initial problem still exists. If anyone can help me out with a suitable valve it would be greatly appreciated and a hearty thanks to all who have been following and contributed. In particular thanks Station X for your patience and endurance

4th May 2022, 3:18 pm	#145
John10b Nonode Join Date: Nov 2016 Location: Aberaeron, Ceredigion, Wales, UK. Posts: 2,887	Re: 1936 Marconiphone 365 Radiogram I have been following this with great interest, I think station X certainly has shown great patience giving you advice and guidance, as well as others. I hope you are able to source a valve and carry on to a successful outcome. John

4th May 2022, 3:42 pm	#146
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: 1936 Marconiphone 365 Radiogram It's worthwhile resoldering the heater pins by using a solder sucker on the end of the pins to reveal the wire then applying fresh solder.

4th May 2022, 9:39 pm	#147
kinnego07 Tetrode Join Date: Dec 2020 Location: Dungannon, County Tyrone, Northern Ireland, UK. Posts: 76	Re: 1936 Marconiphone 365 Radiogram Thanks John for your reply and interest from the start. I'm not beaten yet so stay tuned. I'm actively seeking a replacement and as an incentive "her in doors" has promised me a dance to Flying down to Rio. Last dance was about 40 years ago! (it also means that I'm allowed to have the Radiogram in the living room) Also, thanks PJL for your contributions and I'm ordering a solder sucker this evening. I have got around ten barn find radios up and running to date but I don't think I can solve this one on my own so keep checking in.

11th May 2022, 9:01 am	#148
kinnego07 Tetrode Join Date: Dec 2020 Location: Dungannon, County Tyrone, Northern Ireland, UK. Posts: 76	Re: 1936 Marconiphone 365 Radiogram Update - It's up and running! Fitted a NOS X41 valve and the set sprang to life immediately. Great sound quality and pulling in normally weak stations loud and clear. All brilliance and bass positions working as they should. I stripped some of the metallic coating off the old valve and found that the inside had a white film which I have read is a sign that the valve had lost vacuum. I guess that this was the original problem and that the filament had held up until full power was applied? So now the gram. Motor is working but slow to start and speed is all over the place. Pick up is working but sound quality is not so good. this may be due to the needle which I found in the bottom of the case. Any advice greatly appreciated.

11th May 2022, 2:00 pm	#149
John10b Nonode Join Date: Nov 2016 Location: Aberaeron, Ceredigion, Wales, UK. Posts: 2,887	Re: 1936 Marconiphone 365 Radiogram Well done to you and all your helpers for solving the problem. Did you have a dance ? Oops sorry you still got to fix record player. John

12th May 2022, 8:40 pm	#150
kinnego07 Tetrode Join Date: Dec 2020 Location: Dungannon, County Tyrone, Northern Ireland, UK. Posts: 76	Re: 1936 Marconiphone 365 Radiogram No dance yet - Have to sort out a dodgy knee and two hips first. And that's only the wife! The gram speed is not controllable and the turntable stops in automatic mode when changing records. I have cleaned and lubed all that I can without taking it apart (and I'm not doing that) I washed the speed brake and re lubed it with light oil without improvement I wonder if the motor is weak?

16th May 2022, 8:00 pm	#152
kinnego07 Tetrode Join Date: Dec 2020 Location: Dungannon, County Tyrone, Northern Ireland, UK. Posts: 76	Re: 1936 Marconiphone 365 Radiogram Thanks for the advice. However, "the motor" is a large metal disc (which turns the turntable) driven by electromagnets? with around 230 V AC running through them. The speed brake acts by means of a lubricated friction pad on a smaller disc which sits at right angles to the large disc. If I set the speed to play correctly at the beginning of a record the record will be playing fast before the end. When a second record drops the turntable will slow almost to a stop when the needle touches the record.

16th May 2022, 8:25 pm	#153
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: 1936 Marconiphone 365 Radiogram Classic symptom of excessive friction or lack of lubrication in the autochanger mechanism. It takes a lot more power to operate the autochanger than it does to just spin a record. The effect is more pronounced at low turntable speeds as there's less energy stored in the mass of the turntable. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

17th May 2022, 11:43 am	#155
electrogram Heptode Join Date: Jul 2008 Location: Hereford, UK. Posts: 719	Re: 1936 Marconiphone 365 Radiogram Isn't there a capacitor in series with the motor on these, if it has changed in value that could result in a lack of torque. I think there was a thread about this a couple of years ago

17th May 2022, 1:52 pm	#156
kinnego07 Tetrode Join Date: Dec 2020 Location: Dungannon, County Tyrone, Northern Ireland, UK. Posts: 76	Re: 1936 Marconiphone 365 Radiogram I'm not looking forward to taking this apart! A car engine yes - but not this. But if it has to be done.... There is a capacitor can (see attached) and I was wondering if this might be the problem. There are no markings on the can so what would this capacitor be? I have also attached some photos of the motor, governor and brake. I can't see how the governor could move up and down the shaft as there is a screw fixing it to the shaft. However there is some movement in the springs to which the balls are attached. It takes very little adjustment of the speed brake to stop the turntable which with my limited knowledge suggests a torque issue? Attached Thumbnails

17th May 2022, 2:03 pm	#157
John10b Nonode Join Date: Nov 2016 Location: Aberaeron, Ceredigion, Wales, UK. Posts: 2,887	Re: 1936 Marconiphone 365 Radiogram Good luck, my only tip is take plenty of pictures. John

17th May 2022, 2:31 pm	#158
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: 1936 Marconiphone 365 Radiogram You're getting it a bit round your neck as to how these governors are supposed to work. The "DISC" isn't fixed to the shaft, it slides along the shaft as the balls spin out when the motor is running. The brake pad must NOT be touching the disc when the motor is at rest. There MUST be a gap between the pad and the disc when the motor is not running. When the motor starts, the balls spin out under centrifugal force and the three springs pull the spinning "DISC" along the shaft until it touches the brake pad which then regulates the speed. The most common fault is that the disc binds on the shaft and doesn't slide along it due to gumming up. The second problem is that if you're not VERY careful, you can bust those springs and if you do then it's game over for the motor, so be very careful! The capacitor that's been mentioned is certainly another contender and has been proven to be a problem in the past. It's probably not known what the value is and it may not be marked on it, but it has certainly been ascertained in previous threads as to what it is, so you can do a 'forum search' or someone may be able to advise you or direct you to a thread with the information. But first do the easy bit as regards checking that the disc slides along the shaft when the motor starts to run. Edit: remember, GAP, GAP, GAP! There isn't one according to your photos! Last edited by Techman; 17th May 2022 at 2:37 pm.

17th May 2022, 4:20 pm	#159
kinnego07 Tetrode Join Date: Dec 2020 Location: Dungannon, County Tyrone, Northern Ireland, UK. Posts: 76	Re: 1936 Marconiphone 365 Radiogram Thanks Techman for making sense of it all for me. I know from working at various vintage engines how a governor should work but I just couldn't see how this would work. I could see the balls moving out a fraction or two by movement in the springs. It must be REALLY gummed up! I will give it a CAREFUL once over when I get home. I will conduct a search of this forum re capacitor

17th May 2022, 5:55 pm	#160
electrogram Heptode Join Date: Jul 2008 Location: Hereford, UK. Posts: 719	Re: 1936 Marconiphone 365 Radiogram Yes, get that governor working properly first. The capacitor issue may be another tin of worms you won't need to open with any luck. Another mechanical problem I have seen on Garrard gram units this age is is that the ball in the turntable main bearing has worn the bottom of the spindle, sometimes to a quite astonishing degree, greatly increasing friction.