TY80F EHT rectifier. (Actually a TY86F). - UK Vintage Radio Repair and Restoration Discussion Forum

Tractorfan · 19th Oct 2011, 8:14 pm

Hi,
Browsing t'internet last night while looking for info about an EY82, I was reminded of the TY80F that was designed specifically for certain models of Ferguson TV.
Why was this special valve necessary and what was so peculiar about the TV that a special valve had to be designed? Also, what was different about this valve?
They even came with a sticky label for the benefit of future engineer's visits.
Thanks in advance.
Cheers, Pete

Heatercathodeshort · 19th Oct 2011, 8:20 pm

The TY86F was produced by Mullard for the Ferguson 306T 17" receiver of 1956. The original LOPT's heater winding produced excessive voltage that led to early failure of the EY86 EHT rectifier. The EY86 is 6.3v and the TY86F is 7.5v Later LOPT's were downrated to correct heater supply. Regards, John.

Tractorfan · 19th Oct 2011, 8:23 pm

Hi,
Thanks for that. Ah, it was just excessive heater voltage then. I meant TY86F, my mistake, sorry.
Cheers, Pete

Herald1360 · 19th Oct 2011, 9:11 pm

I saw those too and wondered what they were, but there was some info in r-type.org which gave the heater volts as 7.5 which explained the "T", so I just thought "he'll be lucky to shift those" and moved on.

I suppose if you buy enough, a special valve works out cheaper than adding a resistor to solve a design "oops".

Peter.N. · 19th Oct 2011, 10:51 pm

I learn something every day on here, I never came across one of those in all my years in the trade.

Peter

Sideband · 20th Oct 2011, 8:15 am

Likewise!!! and I've repaired T306's and T308's in the past. A really huge CRT in the 308 as I recall.

SB

ms660 · 20th Oct 2011, 12:50 pm

I seem to remember from my TV days that some EHT valve base assemblies had a series resistor built in for the heater...am I remembering right?

Lawrence.

Sideband · 20th Oct 2011, 1:12 pm

Yes they did. Usually a couple of ohms or so....maybe a bit less.

SB

ms660 · 20th Oct 2011, 1:20 pm

Thanks SB, I thought so..usually covered in black spikey dust.

Lawrence.

Heatercathodeshort · 20th Oct 2011, 8:57 pm

Yes there were resistors fitted including the 306T! Must have been a design slip up and Ferguson were a big customer of Mullard so sticking a higher voltage heater assembly into an EY86 was no sweat. It would have been an unbelievably nasty job to pull the cabinet off and fit a higher value resistor in the EHT valve holder. Stink of melted Nylon with subsequent arcing! J.

Ronaykay · 23rd Jun 2014, 12:20 pm

Ronaykay
I was an engineer with Boyd's (part of the GUS group) at that time....All 306's in stock had to be modified due to the design error, initially by increasing the series resistor, later by fitting the TY86F Good TV though.

19th Oct 2011, 8:14 pm	#1
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,184	TY80F EHT rectifier. (Actually a TY86F). Hi, Browsing t'internet last night while looking for info about an EY82, I was reminded of the TY80F that was designed specifically for certain models of Ferguson TV. Why was this special valve necessary and what was so peculiar about the TV that a special valve had to be designed? Also, what was different about this valve? They even came with a sticky label for the benefit of future engineer's visits. Thanks in advance. Cheers, Pete __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

19th Oct 2011, 8:20 pm	#2
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: TY80F EHT rectifier The TY86F was produced by Mullard for the Ferguson 306T 17" receiver of 1956. The original LOPT's heater winding produced excessive voltage that led to early failure of the EY86 EHT rectifier. The EY86 is 6.3v and the TY86F is 7.5v Later LOPT's were downrated to correct heater supply. Regards, John.

19th Oct 2011, 8:23 pm	#3
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,184	Re: TY80F EHT rectifier Hi, Thanks for that. Ah, it was just excessive heater voltage then. I meant TY86F, my mistake, sorry. Cheers, Pete __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

19th Oct 2011, 9:11 pm	#4
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: TY80F EHT rectifier I saw those too and wondered what they were, but there was some info in r-type.org which gave the heater volts as 7.5 which explained the "T", so I just thought "he'll be lucky to shift those" and moved on. I suppose if you buy enough, a special valve works out cheaper than adding a resistor to solve a design "oops". __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

19th Oct 2011, 10:51 pm	#5
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: TY80F EHT rectifier. (Actually a TY86F). I learn something every day on here, I never came across one of those in all my years in the trade. Peter

20th Oct 2011, 8:15 am	#6
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,578	Re: TY80F EHT rectifier. (Actually a TY86F). Likewise!!! and I've repaired T306's and T308's in the past. A really huge CRT in the 308 as I recall. SB __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

20th Oct 2011, 12:50 pm	#7
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: TY80F EHT rectifier. (Actually a TY86F). I seem to remember from my TV days that some EHT valve base assemblies had a series resistor built in for the heater...am I remembering right? Lawrence.

20th Oct 2011, 1:12 pm	#8
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,578	Re: TY80F EHT rectifier. (Actually a TY86F). Yes they did. Usually a couple of ohms or so....maybe a bit less. SB __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

20th Oct 2011, 1:20 pm	#9
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: TY80F EHT rectifier. (Actually a TY86F). Thanks SB, I thought so..usually covered in black spikey dust. Lawrence.

20th Oct 2011, 8:57 pm	#10
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: TY80F EHT rectifier. (Actually a TY86F). Yes there were resistors fitted including the 306T! Must have been a design slip up and Ferguson were a big customer of Mullard so sticking a higher voltage heater assembly into an EY86 was no sweat. It would have been an unbelievably nasty job to pull the cabinet off and fit a higher value resistor in the EHT valve holder. Stink of melted Nylon with subsequent arcing! J.

23rd Jun 2014, 12:20 pm	#11
Ronaykay Retired Dormant Member Join Date: Jun 2014 Location: Forfar, Angus, Scotland, UK. Posts: 7	Re: TY80F EHT rectifier. (Actually a TY86F). Ronaykay I was an engineer with Boyd's (part of the GUS group) at that time....All 306's in stock had to be modified due to the design error, initially by increasing the series resistor, later by fitting the TY86F Good TV though.