Giving Big Bertha a spin

Bread and butter chassis for me, fond memories, the next version with the EF184 last Video I.F amp and separate 405/625 contrast controls were even better.

All good on 625 apart from a slight caption buzz. Probably a small adjustment of L28 quadrature tuning coil is needed, but I did this two years ago and was happy it was ok back then. 

The core did need a tweak in some sets, one problem with the 11U chassis was the single preset contrast, it was sometimes difficult to get a good balance between the two standards, this could affect the buzz.

I think the winding itself could move and it's a critical setting, it was so much better though than some makes, the buzz on captions was a feature with some of those.

Still it was an excellent chassis.

One version of the 11 chassis series of receivers I particularly liked wasn't a Pye but was  the majestic looking Ekco console which had push button tuning for UHF and VHF.  The TC435, would that be right?  As Frank states the all later production models were very good indeed.  Very early sets made in late 1962 were not so good because they didn't have stabilised timebases.

Till Eulenspiegel.

We had the Ekco T433 (19inch) for our first TV, 1970 so long ago. Second hand but easy job to get like new performance. Used on 625 only has we have Winter Hill about 8 miles line of sight. Even with its low performance Lowestoft valve tuner we had plenty signal into the front end.

The T433 had the push button tuners like the T435, probably identical apart from the cabinet and CRT size.

A tweak of a quarter turn of L28 has silenced the caption buzz and slightly increased the audio content too.

A peak over the chassis.....

Till Eulenspiegel said
One version of the 11 chassis series of receivers I particularly liked wasn't a Pye but was  the majestic looking Ekco console which had push button tuning for UHF and VHF.  The TC435, would that be right?  As Frank states the all later production models were very good indeed.  Very early sets made in late 1962 were not so good because they didn't have stabilised timebases.

Till Eulenspiegel.  

Speaking of Ekco....

Is your set the fringe version with flywheel sync?

The green covered service manuals, that brings back memory's.

nuvistor said
Is your set the fringe version with flywheel sync?

Hi Frank, yes there is a piggy-back board with an ECC82 in a screening can. You can see it at the top left of the chassis picture above.

 Here is your Ekco T433 Frank 

Till Eulenspiegel said
One version of the 11 chassis series of receivers I particularly liked wasn't a Pye but was  the majestic looking Ekco console which had push button tuning for UHF and VHF.  The TC435, would that be right?  

Till Eulenspiegel.  

It was the TC437.

Till Eulenspiegel.

Here is Big Bertha residing at Chris's house....

Chris has p-l-e-n-t-y of space for her to stretch her legs, would you like her back home Chris? 

 Here is your Ekco T433 Frank   

And I still like the cabinet style and control layout.

PYE625 said
Chris has p-l-e-n-t-y of space for her to stretch her legs, would you like her back home Chris? 

  

Ermm that was two years ago since then that room has seen 34 early colour TV's arrive and about half of them 25"-26" consoles. This year in an attempt to free some space I'm going to be trimming down the collection, this is not going to be an easy task but one that has to be done.

Excellent chassis...also fond memories. There is a story of my 11U on the old forum. Mine has been in the family since new and was bought by my mother in 1964 for the start of BBC2. It was the first brand new TV we had and felt proper posh when we had a new aerial fitted on the roof....one of the first UHF aerials in the road. The set was in use right up until 1985, maintained by my brother in it's early years and me in its later years. When my mother and brother moved into a flat in 1982, the TV went with them but was relegated to her bedroom, the main set being a Thorn colour set (my brother worked for Radio Rentals). Some sort of fault developed and my brother considered it 'not worth messing about with'.....My mother hated throwing things out so just kept it. She died in 1991 and the set remained unloved and more-or-less forgotten until my brother moved out in 2005. I offered to help shift some of his stuff and called one morning to find the 11U standing the hall. He said he'd ordered a skip and 'that old thing is destined for it'......oh no it's not! Five minutes later it was in the back of my car. 

Needless to say it now has excellent pictures although the speaker is not so good and is rattling so I need to sort that out. Mine has the EF184 in the IF stage and the stabilised line stage. One of the most reliable sets of its time I think and I must have repaired hundreds of them in the early 70's when I started in the Trade...not because they were unreliable but simply because there were so many of them about. 

Story here

PYE625 said
A tweak of a quarter turn of L28 has silenced the caption buzz and slightly increased the audio content too.

It was very common for L28 to become unwound. This was discovered by an engineer I worked with who was intrigued as to why some sets had a buzz that wouldn't tune out or would tune with difficulty. He ordered a new coil (you could do that in 1970) and opened it to compare with an original faulty one. The new coil had the turns neatly close-wound around the former. In the faulty one, the turns had spiralled up the former due to the black pitch used to secure the winding having cracked allowing the turns to become loose. Pushing the turns down neatly and securing with wax cured the problem and we did that on any set that had a buzz. A slight adjustment was required to the core but we never fitted another new L28. 

That's a great story Sideband, and you were very fortunate to save it from being thrown into the skip.

sideband said

PYE625 said
A tweak of a quarter turn of L28 has silenced the caption buzz and slightly increased the audio content too.

It was very common for L28 to become unwound. This was discovered by an engineer I worked with who was intrigued as to why some sets had a buzz that wouldn't tune out or would tune with difficulty. He ordered a new coil (you could do that in 1970) and opened it to compare with an original faulty one. The new coil had the turns neatly close-wound around the former. In the faulty one, the turns had spiralled up the former due to the black pitch used to secure the winding having cracked allowing the turns to become loose. Pushing the turns down neatly and securing with wax cured the problem and we did that on any set that had a buzz. A slight adjustment was required to the core but we never fitted another new L28.   

 Indeed L28 had become unwound in my set. I hope it is still secure, don't really want to disturb it again.

Chris said

  

Ermm that was two years ago since then that room has seen 34 early colour TV's arrive and about half of them 25"-26" consoles. This year in an attempt to free some space I'm going to be trimming down the collection, this is not going to be an easy task but one that has to be done.  

34?  Crikey that is a lot. 

No, Bertha has made her home in Chatteris and will not go despite me trying to move her on. After all, it was me that gave her a new lease of life and she is settled now. 

No only Pye, Ekco and Ferranti, but PAM too. I've been given the opportunity to rescue a rare Pam version of the 11U chassis which is currently living on borrowed time.

If I can engineer a way of bringing it up from London to ATV land,  then it will be saved for posterity. I really don't have the room, but if it saves a lovely dual standard set from the skip....

Steve