One important issue when restoring any old set is to get a set which is a good restoration prospect. The first 2000 I obtained, about a year or so ago, had been stored in a moist environment and resisted my efforts to breathe life into the Line Output and EHT stages, so it was left pending further inspiration. This inspiration came in the form of another BRC2000 that had been stored in better conditions and had been used up until a few years ago. It came from a fellow collector who had found it inoperative and had need of space, so after I had recovered from an incident at work, the set went into the Transit Van, then back home into the Bush House kitchen to be worked on.
The kitchen workshop is derided in some quarters, but I have to say that it does me fine, all that space to use, quiet, warm, still in contact with the household and near to food and drink supplies!
The BRC2000 is of modular design, this means that all the panels can be easily removed and replaced, or in my case, removed from the set to be worked on separately.
The official BRC photograph shown here is of the set and its ten boards placed in their respective positions around it.
|This is my set at the start of its restoration. All the panels have been removed and placed on top of the set for this photograph. This makes the task of restoration look massive, but it is surprising how quicky the finished project takes shape. My set took just over 2 weeks.|
Initially, all the panels were removed and inspected. The 2000 used those horrible black cylindrical electrolytic capacitors that always dry out, so all these were replaced on sight. It is important to replace one in particular, on the video board, as it has about 200v across it and can go off like a little bomb!
All the boards were inspected for track damage and cracks. The convergence board had a beauty, right across, and so the tracks were bridged with copper wire and the board strengthened with a drop of araldite.
Another problem was with the tuner. The locking bar had come free at the back, and so this was attacked with the heavy duty soldering gun to restore tuning button operation.
APPLYING THE MAINS
It is very important to resist the temptation to just plug something in, and so the Power Supply was fitted, the tube base put back onto the CRT and the mains applied gently with a variac. This was done over several hours, in order to spare the main electrolytics on the Power Supply the traumatic shock of full mains. After a day’s in situ reforming, they seemed to be performing OK and there was no excessive ripple on the various PSU rails.
The Regulator board was fitted then, and I set it up as per the manual. Unfortunately, the 55v rail stayed sadly at about 48v, this was due to a high resistance skeleton pot. This was replaced and we tried again. The 55v now came on nicely, and so all the boards except for the EHT generator were refitted. I have to confess to fitting a 625 line only line timebase board, as this was the one that was in the best condition and I was of course spared the additional complications of a system switch. Hopefully the purists among our readership will not hate me too much!
There were no crashes or bangs when the set was powered again. Upon connecting an antenna, I was rewarded, after a few minutes twiddling, with good strong BBC1 sound. This at least proved that there was life in the tuner and the IF board. There was of course no raster. There was however no line whistle either when either of the line hold controls were operated. Checks on the regulator board showed that the 55v rail to the line board was high, which suggested that it was not being loaded down, i.e. the Line Timebase Board was sitting there drawing no current. There was a good healthy voltage at one side of the decoupling choke L6, but not on the other side. Close inspection revealed a fine crack in the track, just on the edge of the soldered connections to this coil. The coil was refitted and the tracks reinforced with another length of copper wire. We now had volts on the two parallel line transformers but not on the Horizontal Hold controls, or on VT1/2 Line oscillator stage as R15 was open circuit.
Replacing this rewarded me with a nice healthy line whistle and, joy upon joy!, the A1 voltage came up as well.
GETTING A PICTURE
I now refitted the EHT Generator and was rewarded with a healthy spark from its output, to which the Tripler was connected. The tripler itself, when fitted, sparked nicely and a blue spark was visible on the back opposite the CRT anode connection. The CRT was discharged and the tripler removed for inspection. The casing was crumbling, and a replacement one from Swindon - Thanks Dave! - was fitted. This gave me EHT and Focus Volts, but still no raster.
A look at the tube base revealed that the voltages on the Focus and A1 Anodes were present, as was the 30v supply to the grids. The heaters were all glowing away merrily. The cathode voltages seemed too high, however, and the 2.2K resistors checked OK, so I moved down to the video board. All three video amps were sitting there doing absolutely nothing as there was no Luminance Drive. This was put right fairly quickly, VT3 Luminance Emitter Follower BF115 was replaced.
We now had light on the CRT. Well, three lines, one of each primary colour. Frame Collapse was not down to the switching on the Convergence Board, I have made that mistake since!, but the Height Control series resistor, 4.7k, was open circuit and the two frame output transistors, BD124s in Push Pull, were in need of replacement. I now had frame scan, albeit impure raster, misconvergence and the Blue Raster was so far out that the picture looked like abstract art. It was, however, a picture!
RIGHT ON BLACK AND WHITE!
The old saying ‘Get it Right on Black and White’ holds very true, and so I set about the setting up procedure. I set up the grey scale by collapsing the frame with the switches on the Convergence Board and following the workshop procedures. Being something of a Coward when it comes to EHT, I used a method subsequently explained to me by Dave - Thanks Again! - this showed that we had a reasonable CRT.
The lack of degaussing was traced to a fault in the wiring loom. On the 2000 series, two sets of Degauss Thermistors are used, and so I wired this small board across the On/Off switch with an extra switch to enable in use degaussing by swapping Thermistors. and started the set up again. After a good degaussing session, I was rewarded with a raster that needed minimal adjustment to create a pure raster on all three primary colours and of course white. Viewing a Cross Hatch, I set up the static convergence with the magnets on the tube neck. This gave reasonable results, and so I set about the exact setting up procedure as described in the manual. Red and Green converged well, but Blue Vertical would not set up! The Blue Vertical Control is flanked by two 50uF Reversible Electrolytic Capacitors. As the other controls on this stage were OK, I replaced these two capacitors and the control itself. This made some improvement, but I found that this setting could be made to align very well when an extra reversible cap. was added in parallel with one of the two!
I then went through the whole procedure again to optimise the convergence. This now looked good. I then went through the grey scaling procedure again and was rewarded with a good Monochrome Picture. With it ‘Right on Black and White’, I advanced the colour control. No Colour at all.
GETTING THE COLOUR
The Decoder put up a fight! The first thing to do in this situation is to defeat the colour killer, this is done in the 2000 by applying a bias voltage to the base of the first chrominance amplifier stage. This rewarded me with floating pretty colours which tried to lock as the phase detector was rotated. The Burst Gate and its amplifier appeared to work, and the lack of bias was found to be down to the Killer Rectifier Diode, an OA91 and the two capacitors across the tuning coil on the 7.9 kHz amp stage.
This now gave me colour without the killer overridden, but colour and picture bore little relation to each other! To cut a long story short: Two Diodes and the Electrolytic in the Bistable, The two Diodes feeding the R-Y Demodulator, Track Faults on the 4.43 MHz oscillator’s Emitter follower, The Crystal Itself.- varied when touched! - were all replaced to give me stable colour. I then followed the setting up procedure as per the manual again, but the set still had a tendency to misrepresent colour on some picture content. It especially didn’t like Blue, however there are a couple of BRC mods for this, involving reducing the value of certain components in the Burst Gating circuit to eliminate Colour Information here affecting the phasing. When these were changed, we had a very good picture off the roof antenna.
The set responded well to a good clean and polish, a little meths was used to bring up the wooden finish of the cabinet and all the knobs were removed and cleaned with soap, water and a toothbrush. The brass handles responded well to a quick bath in - Coca Cola. This brings them up well, and to think how much of the stuff we drink!
The set was then promoted to the lounge, where the only problem I still have is Teletext Lines, has anyone got any ideas about how to remove them? In fact they aren’t THAT bad, but the more discerning members of my family, especially the less sympathetic to the cause, seemed to remark on them most.
| There has been one breakdown, this was traced, eventually!, to a high resistance track on the Line Timebase Board. This was reworked and, touch wood, the set behaves well. It gives a very good and clear picture, easily comparable with the nasty modern sets in the local showrooms. The wooden cabinet also makes the set a nice addition in the way of an item of furniture, and the stand, now strengthened by our local joiner, adds to the retro effect. People marvelled at colour in the 1960s and this set gives results that can give any set a run for its money! But, of course, some people say I’m a little biased!