Featured
Latest
Share:
Notifications
Clear all

Forum 1

B&W TV 60's Pye VHF tuner

8 Posts
3 Users
0 Reactions
103 Views
irob2345
(@irob2345)
Posts: 741
Honorable Member Registered
Topic starter
 

This quite compact VHF tuner was used by Pye Australia in the T18, T19, T20 and most T21 chassis.

Pye EAF 236 1

Very early versions of this tuner were 10 channel, most were 13 channel. My T18 has a 10 channel version.

Pye sourced this tuner from the UK, subsequently changing over to a locally sourced turret tuner from Astor. This worked for both companies - Pye made yokes and Astor made tuners for both brands.

Anyone seen this before?

Pye EAF 236 2

Who was HDF?

Anyone have a schematic?

Anyone know where to get the rare and unusual RF amplifier bottle, 6FC7?

 

 
Posted : 14/01/2025 10:04 am
Nuvistor
(@nuvistor)
Posts: 4652
Famed Member Registered
 

@irob2345 HDF, High Definition Films Ltd, one of the many Pye companies. They also made early UHF tuners under licence from HOPT of Germany.

 

Frank

 
Posted : 14/01/2025 12:54 pm
irob2345
(@irob2345)
Posts: 741
Honorable Member Registered
Topic starter
 

Thanks Frank. Would never have guessed that's what HDF stood for!

Back in the 60s most techs got very good at putting the index ball back and tightening the nut on the back of the rotor. Very common failure.

The older of the two Pedigrees I picked up has one of these tuners. It had that same fault, as does this one.

This one was fitted to the newer of the two sets, the 24" square corner one. as a means of holding the knobs in place - the correct tuner was left lying in the bottom of the case - fortunately!

23 inch vs 24 inch comparison
 
Posted : 15/01/2025 9:07 am
Cathovisor
(@cathovisor)
Posts: 6684
Famed Member Registered
 

Bit of history of HDF: https://tvstudiohistory.co.uk/itv-studios-in-london/highbury-studios/

The valve is a direct equivalent to the ECC89 and Langrex have 42 of those in stock.

(This reminds me that I need to get an output bottle for my Healing 403E)

 
Posted : 15/01/2025 10:21 am
irob2345
(@irob2345)
Posts: 741
Honorable Member Registered
Topic starter
 

Thanks for that link to HDF history. And the ECC89 cross to the 6FC7, didn't know that.

Looks like Pye UK must have used an existing shelf company (HDF) when they decided to make tuners. Fascinating story! HD kinescopes in the early 50's!

I can't see a Healing 403 in my Oz TV circuit compilation, only a 400 and a 405. These were late 50s 21" TVs.

Or was there a UK Healing TV?

In any case, if you are looking for a 6DQ6, a 6CM5 (EL36) is a good substitute.

That HDF tuner caused an unexpected problem in the Pedigree.

Because the controls were on the top of the set, the tuner was immediately underneath the (metal) channel knob. With the valves buried inside the tuner case, much heat would be conducted up the tuner shaft, which became so hot it couldn't be used without considerable discomfort!

So here is a pic of the old knob, and the clever fix Pye came up with.

Pedigree old and new CSK

Not needed for electrical insulation of course, as one might think looking at it, all Oz TVs have mains transformers and so the metal knob was safely grounded!

I will use the old knob on the newer all SS Pedigree, it doesn't even get warm!

 
Posted : 16/01/2025 9:09 am
Cathovisor
(@cathovisor)
Posts: 6684
Famed Member Registered
 

Posted by: @irob2345

can't see a Healing 403 in my Oz TV circuit compilation, only a 400 and a 405. These were late 50s 21" TVs.

I should have been clearer: the 403E to which I referred is in fact the famous "Scales" radio, of which my example was photographed for this years' BVWS calendar. I bought one at a HRSA auction in Sydney just after the Olympics finished as a souvenir of my time there. Whilst I could probably find a 6M5/EL80 here in the UK, the double-diode/pentode within (6AR7GT) has no direct European equivalent and was apparently only made in Australia by AWV.

Would you like me to enquire about the ECC89s for you?

 
Posted : 16/01/2025 10:43 am
irob2345
(@irob2345)
Posts: 741
Honorable Member Registered
Topic starter
 

Oh a radio, not a TV!

Yes I know the one.

Is yours the desirable jade green one?

If you can't find a 6M5 a 6CK6 (TV video output) is exactly the same animal with G3 brought out separately.

The 6AR7 was indeed an AWV design, intended specifically for reflexed IF/audio operation. It has an unconventional pinout so you can't sub another bottle such as an EBF32 (without a socket rewire anyway). I could probably source one for you if needed.

Oh does your 6M5 have the crackles? The early Mullard ones had silver plated pins and suffer from silver migration between G2 and G1. You can scrape the silver away between the pins and fix it.

If Langrex ships OS I can go direct. The ECC89 in my Pye T18 is a little weak, although that doesn't make much difference using a modulator, it only takes a minute or so to hit its straps.

 
Posted : 17/01/2025 5:45 am
Cathovisor
(@cathovisor)
Posts: 6684
Famed Member Registered
 

@irob2345 Sadly, to my shame the radio remains unrestored to this day but as I now have a source of 1M switched pots with metal shafts for the volume control (the switch on mine has failed), I can do something with it. Mine is the more common cream model with the blue dial.

To my surprise, Langrex have a few 6M5s in stock but not their Pro-Electron counterpart (EL80); of course, the danger here is if there's another valve sharing that type number - here in the UK Mazda had a frequency-changer valve called the 6C9 that was nothing like the Sylvania 6C9!

Should I find I need a 6AR7GT, I'll be in touch - and I'm pretty sure Langrex do international shipping.

 
Posted : 17/01/2025 10:47 am
Share: