Mullard H.S.V.T. Cards for "Magic Eye" Indicators? - UK Vintage Radio Repair and Restoration Discussion Forum

Chris55000 · 13th Aug 2019, 4:40 am

Hi!

Can anyone give me a definitive list of which Mullard H.S.V.T. cards were produced specifically to test "magic–eye" indicators?

I don't think there were more than a dozen in the entire range of 1200 or so cards produced by Mullard for this machine, and I'm given to understand that card 940, for the EM34, was the first specific "magic–eye" card to be released for the machine!

There are, I believe, a few of these valves (6AD6/6AF6, the 12.6V "1629" and the Russian Replacement 6e5s (which has it's target–anode on pin 6), that never got a H.S.V.T. card designed – I wonder if the numbers in the 941–950 series could be used for them?

(Yes I'm aware that looking at the brightness of the things is the most obvious way of determining their condition!)

Chris Williams

Chris55000 · 13th Aug 2019, 4:52 am

PS!

The quirky Mullard/Philips EFM1/EFM11, that had it's deflector anode operated from g2 of the pentode section of this, I believe, never got a card, presumably because Mullard said (or assumed) these indicators had all gone long before the H.S.V.T . went on Mullard's drawing–boards!

Chris Williams

GMB · 13th Aug 2019, 9:26 am

It seems that the 940-950 range was originally allocated to magic eyes, and then one or two later ones were added in. These are the ones I have found:

940 EM34,6M2,64ME,6CD7
941 EM1
942 UM34
943 EM80,EM81,65ME,6BR5
944 6M1,Y61,Y63,6E5GT
945 ME91
946 ME41
948 EM71
949 10M2,UM35
950 AC/ME

1113 EM84
1114 UM80,Y119

1132 EM85

1145 EM87

There are no cards for the DM ones.

Chris55000 · 13th Aug 2019, 11:01 am

Hi!

Member GMB, thank you for clarifying which ones I need for "magic-eye" valves - Mullard obvioualy didn't envisage more then 10-11 of them when they chose card-range 940-950 for them!

DM70/DM71 indicators need a B8D sub-min to B7G adaptor making as well as a special card - the H.S.V.T. obviously is configurable for battery valves as all the other conventional types have a card for them, so I would suggest a "DM70" card (No. 947 perhaps?) would need punching for:-

Filament:- 1.4V, pin 5 earthed
Grid: –8V
Anode:- 67.5V

Chris Williams

PS!

I'll look at the other types I mentioned in my first-post and see what I can design for them! I've just remembered - a card-set for the Continental "EAM86" used in valved Tandberg R to R machines wouldn't go amiss either - this would be a two-card set as the EAM86 has an independent diode-anode!

Chris55000 · 23rd Aug 2019, 9:55 am

Hi!

I've managed to get hold of card 940 to test the EM34, of which I have a number, including one with no base, but I will be in a position to buy more if I can find them!

I'm now working out the punchings for an EAM86 Tandberg indicator - I think the EM84/EM87 card and an EB91 card will do as starting-points!

Chris Williams

GMB · 23rd Aug 2019, 10:43 pm

Just email me for accurate PDF card images if you want to make your own cards (unless they are in my missing list of course).

13th Aug 2019, 4:40 am	#1
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,864	Mullard H.S.V.T. Cards for "Magic Eye" Indicators? Hi! Can anyone give me a definitive list of which Mullard H.S.V.T. cards were produced specifically to test "magic–eye" indicators? I don't think there were more than a dozen in the entire range of 1200 or so cards produced by Mullard for this machine, and I'm given to understand that card 940, for the EM34, was the first specific "magic–eye" card to be released for the machine! There are, I believe, a few of these valves (6AD6/6AF6, the 12.6V "1629" and the Russian Replacement 6e5s (which has it's target–anode on pin 6), that never got a H.S.V.T. card designed – I wonder if the numbers in the 941–950 series could be used for them? (Yes I'm aware that looking at the brightness of the things is the most obvious way of determining their condition!) Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

13th Aug 2019, 4:52 am	#2
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,864	Re: Mullard H.S.V.T. Cards for "Magic Eye" Indicators? PS! The quirky Mullard/Philips EFM1/EFM11, that had it's deflector anode operated from g2 of the pentode section of this, I believe, never got a card, presumably because Mullard said (or assumed) these indicators had all gone long before the H.S.V.T . went on Mullard's drawing–boards! Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

13th Aug 2019, 9:26 am	#3
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,092	Re: Mullard H.S.V.T. Cards for "Magic Eye" Indicators? It seems that the 940-950 range was originally allocated to magic eyes, and then one or two later ones were added in. These are the ones I have found: 940 EM34,6M2,64ME,6CD7 941 EM1 942 UM34 943 EM80,EM81,65ME,6BR5 944 6M1,Y61,Y63,6E5GT 945 ME91 946 ME41 948 EM71 949 10M2,UM35 950 AC/ME 1113 EM84 1114 UM80,Y119 1132 EM85 1145 EM87 There are no cards for the DM ones.

13th Aug 2019, 11:01 am	#4
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,864	Re: Mullard H.S.V.T. Cards for "Magic Eye" Indicators? Hi! Member GMB, thank you for clarifying which ones I need for "magic-eye" valves - Mullard obvioualy didn't envisage more then 10-11 of them when they chose card-range 940-950 for them! DM70/DM71 indicators need a B8D sub-min to B7G adaptor making as well as a special card - the H.S.V.T. obviously is configurable for battery valves as all the other conventional types have a card for them, so I would suggest a "DM70" card (No. 947 perhaps?) would need punching for:- Filament:- 1.4V, pin 5 earthed Grid: –8V Anode:- 67.5V Chris Williams PS! I'll look at the other types I mentioned in my first-post and see what I can design for them! I've just remembered - a card-set for the Continental "EAM86" used in valved Tandberg R to R machines wouldn't go amiss either - this would be a two-card set as the EAM86 has an independent diode-anode! __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! Last edited by Chris55000; 13th Aug 2019 at 11:10 am.

23rd Aug 2019, 9:55 am	#5
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,864	Re: Mullard H.S.V.T. Cards for "Magic Eye" Indicators? Hi! I've managed to get hold of card 940 to test the EM34, of which I have a number, including one with no base, but I will be in a position to buy more if I can find them! I'm now working out the punchings for an EAM86 Tandberg indicator - I think the EM84/EM87 card and an EB91 card will do as starting-points! Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

23rd Aug 2019, 10:43 pm	#6
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,092	Re: Mullard H.S.V.T. Cards for "Magic Eye" Indicators? Just email me for accurate PDF card images if you want to make your own cards (unless they are in my missing list of course).