Hickok tv-7 - UK Vintage Radio Repair and Restoration Discussion Forum

David Simpson · 31st Dec 2018, 6:07 pm

Does anyone know the actual fsd of the TV-7's M101 Meter's movement, please ? The circuit diagrams in the 96 page "Field & Depot Maintenance Manual" don't reveal the actual uA & any internal shunts or multipliers. Just that external thumping great C103 - 100uF capacitor ! They just refer to the meter as a "Milliammeter (IG)".
By the way, do Hickoks work lower down the Gm graph, similar to cautious Taylors, for their Mutual Conductance Test ? (i.e. more -ve Vg & thus lower Ia than an AVO MK3 uses).
Yes, I understand that M101 is hermetically sealed & a sod to access, so don't expect that many folk have delved inside.

Regards, David

ms660 · 31st Dec 2018, 8:13 pm

According to this it's 200uA with a resistance of 2.365k which I assume includes an internally fitted 1.91k resistor:

http://www.arizona-am.net/misc_files/TV7MeterB.htm

Lawrence.

Kevin Hoyland · 31st Dec 2018, 9:56 pm

Well done Lawrence on finding the information regarding the meter for David.

Regards
Kevin.

David Simpson · 31st Dec 2018, 10:34 pm

Many thanks Lawrence for that helpful link. All the Best for the New Year to yourself, Kevin, and the rest of the Forum Guys.

Regards, David

David Simpson · 6th Jan 2019, 6:20 pm

All sorted. Can be closed Moderators, thank you. David

31st Dec 2018, 6:07 pm	#1
David Simpson Nonode Join Date: Mar 2008 Location: Aberdeen, UK. Posts: 2,853	Hickok tv-7 Does anyone know the actual fsd of the TV-7's M101 Meter's movement, please ? The circuit diagrams in the 96 page "Field & Depot Maintenance Manual" don't reveal the actual uA & any internal shunts or multipliers. Just that external thumping great C103 - 100uF capacitor ! They just refer to the meter as a "Milliammeter (IG)". By the way, do Hickoks work lower down the Gm graph, similar to cautious Taylors, for their Mutual Conductance Test ? (i.e. more -ve Vg & thus lower Ia than an AVO MK3 uses). Yes, I understand that M101 is hermetically sealed & a sod to access, so don't expect that many folk have delved inside. Regards, David

31st Dec 2018, 8:13 pm	#2
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Hickok tv-7 According to this it's 200uA with a resistance of 2.365k which I assume includes an internally fitted 1.91k resistor: http://www.arizona-am.net/misc_files/TV7MeterB.htm Lawrence.

31st Dec 2018, 9:56 pm	#3
Kevin Hoyland Heptode Join Date: Feb 2009 Location: Rotherham, South Yorkshire, UK. Posts: 559	Re: Hickok tv-7 Well done Lawrence on finding the information regarding the meter for David. Regards Kevin.

31st Dec 2018, 10:34 pm	#4
David Simpson Nonode Join Date: Mar 2008 Location: Aberdeen, UK. Posts: 2,853	Re: Hickok tv-7 Many thanks Lawrence for that helpful link. All the Best for the New Year to yourself, Kevin, and the rest of the Forum Guys. Regards, David

6th Jan 2019, 6:20 pm	#5
David Simpson Nonode Join Date: Mar 2008 Location: Aberdeen, UK. Posts: 2,853	Re: Hickok tv-7 All sorted. Can be closed Moderators, thank you. David