HMV 1621 Radiogram - UK Vintage Radio Repair and Restoration Discussion Forum

georgebruce · 4th Apr 2020, 1:20 pm

I am working on a HMV 1621 Radiogram. When I originally switched it on I noticed that the Stylus was broken and the only Valve that did not light up was DH77 6AT6. There was no response from the radio in either Waveband but the turntable did spin. I ordered a new stylus and a Used DH77 and fitted both.
Switched on and DH77 still does not Light Up and nothing from the Radio. The Record Player is operational but I only hear the music at the actual stylus.
Any advice would be greatly appreciated.

Michael Maurice · 4th Apr 2020, 8:10 pm

You could have a broken pin on the valve holder or a bad connection to the heater pins.

The heater pins are 3 & 4

Station X · 4th Apr 2020, 9:29 pm

Check that the valve's heater is intact by measuring the resistance between pins 3 and 4 with the valve removed from the set. Open circuit/infinite resistance denotes a faulty valve. Valve pins number clockwise from the gap when looking from UNDERNEATH.

http://www.r-type.org/exhib/aaa0863.htm

If the valve is OK, then with the set powered up check that you have 6.3VAC between tags 3 and 4 of the valve holder. If not check the wiring to these pins.

If the voltage at the pins is OK, then you have dirty valve pins, dirty contacts in the valve holder or loose contacts in the valve holder. Spray some Servisol 10 contact cleaner on the valve pins and insert it into the valve holder several times. Loose contacts should be GENTLY nipped up with a a pair of thin nosed pliers.

georgebruce · 5th Apr 2020, 8:58 am

Thanks guys, quick update, I now notice that Valve ECC85 B719 would appear to be faulty and have ordered a replacement. Will let you know how I get on with the tests above.

Techman · 5th Apr 2020, 12:32 pm

It's highly unlikely that all these valves will be faulty!

Particularly with the DH77 you won't be able to see any light in this valve unless viewed in complete darkness and even then you may struggle.

You need to start doing some proper fault finding and stop with all the guesswork!

You remember the story of the man who's car wouldn't go, so he replaced a part and the car still wouldn't go, so he replaced another and it was still the same. In the end he'd replaced every single part that he could identify and the car still wouldn't go and he'd spent more than the cost of just taking it to a proper garage for a diagnosis and probable repair in the first place.......

Edit to say - the ECC85 will only cause a problem with VHF/FM radio and NOT the rest of the gram, so you're completely wrong on that one - time to start some proper fault finding and stop pointless guessing!

Michael Maurice · 5th Apr 2020, 2:17 pm

First things first.

Do you have multimeter and know how to use it?

Have you replaced the capacitor between the anode D77 and the output valve?

If not you need to remove the output valve and measure the resistance of the primary of the power supply. It might be open circuit.

If it is, then you’ll have to have it rebuilt.

None of us know of your skill level, we’re happy to help you but you need to know how to make these measurements.

To make things more difficult, there are no diagrams for this model.

What I and others do is look at the valve line up and use the data from those valve types to work out what voltages should be present and where.

I hope this helps

georgebruce · 5th Apr 2020, 4:15 pm

Gents, Point taken,
I do have a multi and can use it, I have not replaced the capacitor.
I am just back on the gram and still on the first checks DH77 looks fine but 0 VAC between tags 3 and 4 of the valve holder so i will now check wiring to same.

georgebruce · 6th Apr 2020, 2:41 pm

Found a bad joint on the wire from pin 3 to frame (it had been broken at some time and only twisted back on) resoldered same and got 6.0 VAC between 3 & 4. Reassembled unit and powered up, DH77 lit up like all the rest and the record player now operates perfectly with better sound quality than i expected.
Still no response from the Radio.
Thanks for your help.

Techman · 6th Apr 2020, 4:03 pm

Good news! You've done well. You can now see how much better it is to do proper fault finding rather than just replacing random parts on a whim. It's an old myth that if it doesn't work then it must be a valve. Valves in these type of sets don't just suddenly go out and fail, they generally fail slowly and gradually with performance gradually reducing over time - the ECC85 that you mentioned is a good example, as the VHF/FM radio will gradually reduce in performance as the valve ages, so if VHF wasn't very good before the fault you have now, then a replacement valve 'may' liven things up on that band, but it won't help the rest of the radio section of the gram.

The big question is....did the radio ever work, or did you obtain the gram with it not previously working?

The fault may well be a very simple one. When you change wavebands between long, medium and VHF, is there a nice 'crunch' sound from the speakers with the volume turned up?

A nice crunch is good, no crunch is bad!

georgebruce · 6th Apr 2020, 4:59 pm

I got the gram as is so do not know if it was working before, i am getting a nice crunch when changing wavebands.
The reason i mentioned the ECC85 was because there is a crack in the glass and it is white inside.
Thanks again.

paulsherwin · 6th Apr 2020, 5:41 pm

If it is white inside then the vacuum has been lost - we refer to this as having 'gone to air'. It definitely needs replacement in that case.

Michael Maurice · 6th Apr 2020, 6:18 pm

You should still get reception on MW/LW/SW. You need to work out the resistors that go to the radio section valves' anode and screen grid.

If you give us a line up of the valves we can point you in the right direction.

Any wax and Hunts capacitors must be changed before you do anything else.

georgebruce · 6th Apr 2020, 6:39 pm

Will do but it might be a few days as i am busy this week.

Station X · 7th Apr 2020, 12:18 pm

Quote:

Originally Posted by georgebruce

Gents, Point taken,
I do have a multi and can use it, I have not replaced the capacitor.
I am just back on the gram and still on the first checks DH77 looks fine but 0 VAC between tags 3 and 4 of the valve holder so i will now check wiring to same.

Excellent! Proper fault finding. Some newbies will happily change components on a "poke and hope" basis before they even think of getting a meter out and making some basic tests.

Station X · 7th Apr 2020, 12:39 pm

I note that this radiogram uses separate radio and amplifier/power supply chassis. If they're connected by plugs and sockets it may be worth cleaning these.

The HMV 1622 is very similar, but uses different valves in the amp/psu. The service info for the receiver could be useful as the valve line up is the same as the 1621 and voltage readings are given.

https://www.service-data.com/product...30/3735/m12730

4th Apr 2020, 1:20 pm	#1
georgebruce Diode Join Date: Apr 2020 Location: Ballater, Aberdeenshire, UK. Posts: 6	HMV 1621 Radiogram I am working on a HMV 1621 Radiogram. When I originally switched it on I noticed that the Stylus was broken and the only Valve that did not light up was DH77 6AT6. There was no response from the radio in either Waveband but the turntable did spin. I ordered a new stylus and a Used DH77 and fitted both. Switched on and DH77 still does not Light Up and nothing from the Radio. The Record Player is operational but I only hear the music at the actual stylus. Any advice would be greatly appreciated.

4th Apr 2020, 8:10 pm	#2
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,224	Re: HMV 1621 Radiogram You could have a broken pin on the valve holder or a bad connection to the heater pins. The heater pins are 3 & 4 __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

4th Apr 2020, 9:29 pm	#3
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: HMV 1621 Radiogram Check that the valve's heater is intact by measuring the resistance between pins 3 and 4 with the valve removed from the set. Open circuit/infinite resistance denotes a faulty valve. Valve pins number clockwise from the gap when looking from UNDERNEATH. http://www.r-type.org/exhib/aaa0863.htm If the valve is OK, then with the set powered up check that you have 6.3VAC between tags 3 and 4 of the valve holder. If not check the wiring to these pins. If the voltage at the pins is OK, then you have dirty valve pins, dirty contacts in the valve holder or loose contacts in the valve holder. Spray some Servisol 10 contact cleaner on the valve pins and insert it into the valve holder several times. Loose contacts should be GENTLY nipped up with a a pair of thin nosed pliers. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

5th Apr 2020, 8:58 am	#4
georgebruce Diode Join Date: Apr 2020 Location: Ballater, Aberdeenshire, UK. Posts: 6	Re: HMV 1621 Radiogram Thanks guys, quick update, I now notice that Valve ECC85 B719 would appear to be faulty and have ordered a replacement. Will let you know how I get on with the tests above.

5th Apr 2020, 12:32 pm	#5
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: HMV 1621 Radiogram It's highly unlikely that all these valves will be faulty! Particularly with the DH77 you won't be able to see any light in this valve unless viewed in complete darkness and even then you may struggle. You need to start doing some proper fault finding and stop with all the guesswork! You remember the story of the man who's car wouldn't go, so he replaced a part and the car still wouldn't go, so he replaced another and it was still the same. In the end he'd replaced every single part that he could identify and the car still wouldn't go and he'd spent more than the cost of just taking it to a proper garage for a diagnosis and probable repair in the first place....... Edit to say - the ECC85 will only cause a problem with VHF/FM radio and NOT the rest of the gram, so you're completely wrong on that one - time to start some proper fault finding and stop pointless guessing!

5th Apr 2020, 2:17 pm	#6
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,224	Re: HMV 1621 Radiogram First things first. Do you have multimeter and know how to use it? Have you replaced the capacitor between the anode D77 and the output valve? If not you need to remove the output valve and measure the resistance of the primary of the power supply. It might be open circuit. If it is, then you’ll have to have it rebuilt. None of us know of your skill level, we’re happy to help you but you need to know how to make these measurements. To make things more difficult, there are no diagrams for this model. What I and others do is look at the valve line up and use the data from those valve types to work out what voltages should be present and where. I hope this helps __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

5th Apr 2020, 4:15 pm	#7
georgebruce Diode Join Date: Apr 2020 Location: Ballater, Aberdeenshire, UK. Posts: 6	Re: HMV 1621 Radiogram Gents, Point taken, I do have a multi and can use it, I have not replaced the capacitor. I am just back on the gram and still on the first checks DH77 looks fine but 0 VAC between tags 3 and 4 of the valve holder so i will now check wiring to same.

6th Apr 2020, 2:41 pm	#8
georgebruce Diode Join Date: Apr 2020 Location: Ballater, Aberdeenshire, UK. Posts: 6	Re: HMV 1621 Radiogram Found a bad joint on the wire from pin 3 to frame (it had been broken at some time and only twisted back on) resoldered same and got 6.0 VAC between 3 & 4. Reassembled unit and powered up, DH77 lit up like all the rest and the record player now operates perfectly with better sound quality than i expected. Still no response from the Radio. Thanks for your help.

6th Apr 2020, 4:03 pm	#9
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: HMV 1621 Radiogram Good news! You've done well. You can now see how much better it is to do proper fault finding rather than just replacing random parts on a whim. It's an old myth that if it doesn't work then it must be a valve. Valves in these type of sets don't just suddenly go out and fail, they generally fail slowly and gradually with performance gradually reducing over time - the ECC85 that you mentioned is a good example, as the VHF/FM radio will gradually reduce in performance as the valve ages, so if VHF wasn't very good before the fault you have now, then a replacement valve 'may' liven things up on that band, but it won't help the rest of the radio section of the gram. The big question is....did the radio ever work, or did you obtain the gram with it not previously working? The fault may well be a very simple one. When you change wavebands between long, medium and VHF, is there a nice 'crunch' sound from the speakers with the volume turned up? A nice crunch is good, no crunch is bad!

6th Apr 2020, 4:59 pm	#10
georgebruce Diode Join Date: Apr 2020 Location: Ballater, Aberdeenshire, UK. Posts: 6	Re: HMV 1621 Radiogram I got the gram as is so do not know if it was working before, i am getting a nice crunch when changing wavebands. The reason i mentioned the ECC85 was because there is a crack in the glass and it is white inside. Thanks again.

6th Apr 2020, 5:41 pm	#11
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,947	Re: HMV 1621 Radiogram If it is white inside then the vacuum has been lost - we refer to this as having 'gone to air'. It definitely needs replacement in that case.

6th Apr 2020, 6:18 pm	#12
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,224	Re: HMV 1621 Radiogram You should still get reception on MW/LW/SW. You need to work out the resistors that go to the radio section valves' anode and screen grid. If you give us a line up of the valves we can point you in the right direction. Any wax and Hunts capacitors must be changed before you do anything else. __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

6th Apr 2020, 6:39 pm	#13
georgebruce Diode Join Date: Apr 2020 Location: Ballater, Aberdeenshire, UK. Posts: 6	Re: HMV 1621 Radiogram Will do but it might be a few days as i am busy this week.

7th Apr 2020, 12:39 pm	#15
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: HMV 1621 Radiogram I note that this radiogram uses separate radio and amplifier/power supply chassis. If they're connected by plugs and sockets it may be worth cleaning these. The HMV 1622 is very similar, but uses different valves in the amp/psu. The service info for the receiver could be useful as the valve line up is the same as the 1621 and voltage readings are given. https://www.service-data.com/product...30/3735/m12730 __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.