K.b. 17" 'imperial' 1960/61

[Heatercathodeshort]

I had a return visit from Tas yesterday and yet again we rummaged through the junk pile and pulled out this 17" K.B. model RV30. I heaved it off the tip around 18 years ago and I have never touched it since!
It is a very smart receiver with tambour doors to cover the screen, twin speakers and bass and treble preset tone controls. I will post pictures of the completed restoration and cabinet soon.
The receiver chassis itself can only be described as a work of art. It is beautifully designed and assembled and a delight to work on. It is a 405 line receiver utilising the Brimar short neck 110 Degree CRT with it's rather odd 4v .3amp heater. It is equivalent to the Mullard AW43-89 or the Mazda CME1705. Providing the back panel will fit or can be easily modified the standard neck length C17AA, AW43-88 or CME1703 can be fitted without electrical modification. The tube is only 9" deep with a neck length of two and a half inches. [Poor thing..] This results in a very compact design and was fully taken advantage of in portables such as the Ekco TP373.
After withdrawing the chassis, it takes less than two minutes, it was noted that the receiver uses the old style, finned, selenium STC metal rectifier for H.T. rectification. This was checked and found to be very leaky. No mains fuse is fitted but a low value fuse is fitted in the supply to the rectifier and checking this revealed it to be O/C. The rectifier was replaced by a 56 ohm Radiospares power section and a REC53 silicon diode mounted on a small tag strip bolted to one of the old rectifier mounting bolts.The frame and line hold controls were broken off but the correct replacements were discovered in the 'pots' bin and duly fitted.
The chassis was then upturned and the mains filter capacitor snipped. Due to some strange resistance readings across the H.T. rail and the presence of my guest I decided to employ the use of a variac to power it up. The H.T. was slow to rise and appeared to reach a maximum of around 150v. The line timebase started up and a very poor semi frame collapse glimmered, showing 'first light'. It was then noticed that a pool of green capacitor 'wee' had appeared on the workbench so the receiver was switched off with the view to examination of the main smoothing block mounted underneath the tube.
The tube was soon removed, again very speedily and it had indeed leaked the filthy mess from it's corroded bowels. It was a rather short fat affair 100uf+400uf but a quick search soon unearthed a new electrolytic designed for the Thorn 3000 colour chassis, just the right size and suitably rated. This was fitted together with the CRT and power applied. This time 230v H.T. and a much better but dim raster but still badly out of shape. At this point it was getting late and had no wish to be called as a witness in a divorce case so Tas departed leaving me with the chassis full of Dubilier and Hunts capacitors. I promised I would not work on it till he returned some time in the future..So I lied..
This morning I decided to tackle the under chassis electronics and armed with a fist full of replacement capacitors set about the task of substitution.
This was a pleasant job as the original components could be unhooked from the tag boards with ease. There is a small printed panel mounted on the right chassis member containing the sound amp and output valve and strangely a single ECC83/12AX7 sync separator and frame sync amplifier. A few more waxies were discovered here and soon replaced. K.B. certainly disliked printed panels and a close look at this receiver shows how it paved the path towards the hugely successful and reliable VC series of monochrome chassis all of which were hand wired. With power once more applied and suitable adjustments carried out the raster was of good shape but still rather dim due to a worn CRT. It was noticed that the getter was very poor when the tube was removed and examined earlier. The chassis uses the reliable and unique 'Fireball' tuner and once the coil disc had been removed and the contacts and wipers cleaned, a good strong signal was displayed. The frame hold control was on its end with the occasional roll so a glance at the circuit put strong suspicion on the series resistor 180K. A check showed it as wearing the wrong colours at 270K so a new 180k was popped in place returning the hold control to it's central position. Warm up time was not much faster than a Bush TV12 so a new CZ3 thermistor was wired into the heater circuit to replace the rather tired original component. The set has been working all afternoon and still continues to be stable so should be O.K. The problem is going to be finding a replacement AW43-88/89 tube. The picture looks good but it is very weak, the enhanching properties of the digital camera not showing this but I will put 'Bertha' to work on it later this evening and see if she can work some life back into the old Brimar CRT. I have left out the howlers/mistakes that I committed while working on this receiver so guys with 'L' plates can sit back and feel satisfied with their efforts.. The magnetized plastic picture centering rings are locked solid and will require freeing off, hence the off centre picture. Regards, John.

[chipp1968]

Is it me or are sets from about 1960 rarer to find than alot of 50s models ? except the Gec BT302 types,which turn up regularly ,and why is that?
I rather like sets from about 1960 with slim tubes .My second fav period ,the first being 1936 up to the early 50s .I Look forward to seeing the cabinet.

[Tazman1966]

Originally Posted by Heatercathodeshort

...At this point it was getting late and had no wish to be called as a witness in a divorce case so Tas departed leaving me with the chassis full of Dubilier and Hunts capacitors. I promised I would not work on it till he returned some time in the future..So I lied...

Very convincingly too

To be honest, I fully expected that you couldn't wait to see such an attractive set working so no worries there. There's still plenty in your "to do" pile

Originally Posted by Heatercathodeshort

...The chassis uses the reliable and unique 'Fireball' tuner and once the coil disc had been removed and the contacts and wipers cleaned, a good strong signal was displayed...

Was this the cause of the no apparent signals when first tried?

Originally Posted by Heatercathodeshort

...I have left out the howlers/mistakes that I committed while working on this receiver so guys with 'L' plates can sit back and feel satisfied with their efforts...

One word...variac!

Nice write up John and a very entertaining afternoon was had. I look forward to seeing the finished result both in photographs and in the flesh too.

Cheers mate,

Tas

[audiomagpie]

Originally Posted by Heatercathodeshort

I decided to employ the use of a variac to power it up.

You're not loosing your bottle in your old age are you John?

An interesting and entertaining read, that's a shallow ol' chassis! Hope you find a suitable tube.

Greg

[Sideband]

Originally Posted by Heatercathodeshort

There is a small printed panel mounted on the right chassis member containing the sound amp and output valve and strangely a single ECC83/12AX7 sync separator and frame sync amplifier.

I wonder if it's the same printed panel used in the KB 'New Queen' that I had when I was a teenager? Had the same valves with the same function on it.

SB

[Heatercathodeshort]

I just popped out to the workshop and gave 'Bertha' a late night thrill. Connected her to the Brimar tube and gave it just a tickle to dislodge a stagnant layer of once emissive surface. The results are outstanding with 100% emission. It's an incredible bit of old kit and the tubes very rarely go down again! Just a box up and centre up and it's finished! J.

[Heatercathodeshort]

Originally Posted by audiomagpie

You're not loosing your bottle in your old age are you John?

No Greg. I was on best behaviour because I had another Forum member with me..
Mind you that does not usually stop me but it was those funny resistance readings that made me wobble and no slow heating rectifier to cushion the blow. J.

[GLENZ32]

Thats certainly an improvement picture wise! Nice looking chassis design too.

[murphyv310]

Hi John.
Your threads always put a big grin on my face and yet again you have done it.
I really wonder how many 405 line sets should have been dumped over the years? You, so many others and myself have a really good success rate in reviving these old sets and as I have said I am sure so many perfectly good sets must have been dumped. Strange though it is still happening so really nothing changes people today are in a way as bad as they have always been.
That is a cracking little KB and well worth fixing.
One thing for sure you WILL get a visit from me next year.
Keep up the good work.

[mark pirate]

That is one nice set, it's probably around thirty years since i played with a kb
They were so well built, glad the tube has come up well, glad to see you actually using a variac for a change

Mark

[Heatercathodeshort]

Originally Posted by mark pirate

Glad to see you actually using a variac for a change

When i'm good....Don't hold out much hope Mark. John.

[Heatercathodeshort]

These are the pictures of the RV30 assembled in it's rather nice cabinet. The protection screen is bowed and gives the set a very grand appearance. We have certainly lost the art of domestic design despite all the students getting degrees in arty crafty subjects. J.

[Heatercathodeshort]

These are the final off screen pictures of the RV30 with the digital camera switched to monochrome. The picture is very well focused, bright and with high contrast making it very difficult to catch in all it's glory with a digital camera.
I would certainly place this receiver and it's similar brothers and sisters from K.B. high up in the list of the finest 405 line receivers ever produced, certainly in a league with the Marconi VT161, and RGD 'Deep Seventeen' to name just two. I enjoyed this one. A lot less work than the Ultra W720 but thinking about it, that was fun too in a strange kind of way! Regards, John.

[oldticktock]

Hi John OMG! that's one gorgeous set and what a picture, I've only begun to appreciate sets of that period and do love the bow front design, hence getting a GEC BT322 recently. But your KB is to die for, to think it was dumped!! Fully agree about modern design, input some parameters into a design package on a 'puter' and out pops yet another nodescript box..shame

Chris

[JoshWard]

That looks like a nice bit of fun

Love the styling as well, as I was saying the other night to you I love a lot of late 50s early 60s stuff, no matter how cheap and nasty a lot of people may consider it!

The picture that's producing is surely evidence for the opposite, I've certainly never seen one of those 6-7 grand prewar sets producing such a nice picture

Josh.

[FERNSEH]

Before 1957 Kolster-Brandes (KB) did produce some rather odd TV sets.
From the introduction of the OV30 New Queen things got better and by 1960 the company were making some of the best TV sets available.
And not only reliable, KB were housing their sets in very attractive cabinets.
Looking at the chassis pictures of John's set one can see how the later models developed into the VV** range of dual standard receivers.
The TV10 series were the last 405 only TV receivers made by KB. It is known that some TV10/20/30 receivers were converted to 405/625 operation.

Many other 1960/61 405 only TV sets are well worth looking out for. Like the KB models many have interesting cabinet styles. There is a number 405 only receivers fitted with the "square corner" 19 and 23" CRTs. KB made such sets in the SV** and TV** range.
I believe that Brimar made CRTs with shortest neck, certainly the C17AF. They also made the C19AH which I understand was a 114 degree deflection angle type and had the short 50mm neck. Can anyone confirm this?

DFWB.

[murphyv310]

Some if not most 405 line only TV sets from the early 60's till the dual standard era produced stunning pictures. A lot of these sets survived into the 70's and you could say that was when the second set era started. Many people bought Dual Standard sets for BBC2 and when duplication arrived in 1969 people still used 405 for BBC1 & ITV as they never liked the results on UHF/625. I was digressing though, I remember servicing many Ekco T344, T368's, Murphy V310, V410's, Bush TV105, Tv115's KB's etc that were 405 line only in the early '70s. They were in bedrooms with a dual standard or colour set in the livingroom, the general consensus though was the old 405 line TV was the better picture and I feel it genuinely was.

[Heatercathodeshort]

Originally Posted by Sideband

I wonder if it's the same printed panel used in the KB 'New Queen' that I had when I was a teenager? Had the same valves with the same function on it.

Hello SB
Yes the printed panel that measures around 4" square contains the ECC83 double triode used as sync seperator and frame sync amplifier and the PCL82 sound pre amp and output. It has the full K.B. logo on the back of it and is very well constructed. It was used on the 'New Queen' 'Old Queen'
'Crown' and many other models. It was first used on the 'New Queen special' 'Kolstar' and 'Regina' models from 1958. Regards, John.

[slidertogrid]

What a fantastic set ! The first owner must have been very well off!
I can just imagine it being proudly demonstrated to friends!
As many have said the picture on 405 seemed much better than early 625.
Thanks for a great write up and pictures, very entertaining and inspiring, I must dig the old Bush TV24 out of the shed

Rich.

[GLENZ32]

That is one seriously cool looking set!