Introduction

The CTV22

I've had a shuffle about in the display room so as to make access easier for the repair. There's no chance of getting the whole TV into the workshop as the 26" Aphelion is still taking up space in there along with the Ferguson 3700 that is waiting for me to find the motivation to install its new 25" CRT and then Ferguson 3703 which is having its PSU repaired on the PCB bench.

What I will likely do is remove the Decca's chassis to the work bench for close visual inspection, any remedial repairs can be performed there prior to refitting to the cabinet for power application.

The Decca in position, easy access to front and rear, space on top for the scope when needed.

Background

The chassis was designated the “Battersea” the CTV22 is a Dual Standard, Hybrid Colour, however although the chassis is almost identical to my Decca CTV25, The CTV22C does away with valve EHT Generation by using a much safer solid state tripler for EHT. Decca also released this version of the chassis for the CTV25 as can be seen below.

Why Rare?

Well hardly any 22" dual standard hybrid CTV's were made, even fewer are known to have survived and some are just plain extinct! Sets released in time for the launch of colour in 67 were either 19" or 25". 22" duals came the following year and only made for a very short run, I think one year. Once all the channels went colour around 69, manufacturers eagerly switched to the simpler single standard, you'll find lots of S/S 22".

Only 5 manufacturers bothered with 22" duals, this 22″ Decca is one of those super rare examples of what was probably one of the last Dual standard colour hybrids. It filled the short gap between the Decca CTV25 and the much loved Decca Bradford. As I mentioned at the start, you will be hard pressed to find any 22" CTV duals as there were not many manufactured in this period, in fact  there were only five others.

The only other 22″ colour dual standards were made by :-

• Bush CTV174D
• Murphy CV2210D
• Philips G22K503
• Stella ST2211

The Sets Current Condition

The original I.F. panel had been robbed long ago to fix another set.  The original tuner suffering the same fate, the good news being the set came with a bag that contained another tuner and IF panel. Also in the intervening two years since I acquired this set, I've managed to gather some spares to maintain the CTV25 and CTV22.

Other observations

There’s loose and cut wires all over the set and one or two just laying on the chassis who knows where they come from, a lot to contend with just with them. There's a split Mullard VA8650, a wire disconnected from the scan coils and what looks to be the degauss plug floating. There’s no single switch to change standards, it operates on channel change/micro switches, there’s a Bowden cable and a solenoid which again is all disconnected. One of the fuses is missing on the power pack. Other than that everything seems to be OK with no apparent missing components or cracked PCB’s. All the control knobs were missing but thankfully I have quite a stock of CTV knobs and the correct ones were found.

At this stage I’ve no idea how it all goes back together, thankfully I have the full Decca workshop maintenance manual that covers the CTV25 & CTV19.

There is a section covering the version of the CTV25 (shown at the top of this page) that had the tripler chassis, the same one as used in this CTV22 except it used a slightly different convergence panel. I also have my CTV25 for some of the similar references.

The cabinet was scrapped down and re-oiled which can be seen below now looks in top condition.

Further Photos

The cabinet after some elbow grease and refinishing came up a treat

Replacement knobs were found from stock

Wide Chassis view of the CTV22 &CTV25

• 
  For Comparison, above is the CTV22 chassis, the CTV25 (below) with full thermionic EHT generation. Note: the IF panel on the CTV sits on the chassis behind the luminance, whereas on the CTV22 its sits on a runner to the left hand side

All those loose and cut wires................... 

Next Steps

Scan the maintenance manual for the library so those that wish to follow along can do so.

But first things first, get the B&K out and test the tube, if its a dud then its a non starter as I don't have a spare 22" in stock.

More to follow.............. Including the panel transistor, valve and diode line-up/functions