1969 Bush CT187CS
1969 Bush CT187CS
A823 Chassis
Model: BUSH CT187CS
Year:1969
System: 625 Line
Original List Price : £000.00 ( to be ascertained)
Valves: None, all transistor and single IC decoder
General Info:
Yet another donation, this one from Stan. This by all accounts is a very early A823 from 1969, this CT187CS having the single chip decoder. It has a veneered cabinet in light tone semi matt tropical olive and is fitted on a plinth with tapered legs constructed of Afomosia finished to match the cabinet. The cabinet is provided with doors to match. The picture tube mask is finished in dark olive and black bordered by a silver plastic trim.
The vertical control panel carries the following controls from the top: Volume with On/Off switch, the four push-buttons of the u.h.f. tuner, Colour, Brightness and Contrast control.
Circuit Features
Wide range automatic chroma control. Integrated circuit decoder and intercarrier amplifier.Full d.c. component is restored by clamps in the luminance and chrominance circuits. Line and frame flyback suppression. Stabilised time-bases and E.H.T. Supply.
Intermediate Frequencies
Vision 30.5 MHz
Sound 33.5 MHz
Intercarrier 6 MHz
I think there were a few mods to the PSU to make it more reliable, faulty tantulum capacitors and video output transistors on the decoder board. The rest of the set was pretty reliable from the experience I had with them. I found the picture not quite as good as the CDA driven Pye!/Ekco sets but they had there own troubles. Was the vision IF 39.5 not 30.5?
Good memories of installing and fixing these sets. you have it working very well, congratulations.
Frank
Can I see a picture of the IC. I find it very interesting that in 69 ICs were working their way into our homes.
Hi Andrew,
I will endeavour to take a photo of the decoder panel, the set is currently in an awkward place and requires a two man lift so bear with me and keep checking back for the updated photo’s.
In the meantime I’ve added as requested a photo of the I.C. which is an SL901. I’ve added a plan view of the decoder board showing the location of the single decoder chip.
During the 1970s and early 1980s, the various editions of the Rank A823 series accounted for the majority of our CTV rental stock. They were no more and no less reliable than most other contemporary sets. However, a high percentage of service call-outs with the single chip version of the chassis were due to a) poor reset on the mechanical tuners, which often needed a tiny tweak on changing channels; b) Intercarrier buzz on sound, which also made the tuning critical. Indeed, it was sometimes very difficult to find a setting that got rid of the buzz without getting colour drop-out. The later A823AV and A823B sets featuring the double chip decoder were more satisfactory all round.
The chassis looks very small inside that large cabinet, plenty of air around it for good ventilation !
A great example of a classic design.
I have the same set with a cabinet date October 1969. I picked it up in 2006 for £60 fully working from a cracking guy in Bradford.
I know Mikey405 and Steve aka “colourstar” (whom I first met in 2006) Steve recently picked up a CT187CS and yours Chris makes 3. A few collectors I know who do not use the internet own 5 of these old single standard “monsters” but I guess It’s anyone’s guess to how many now survive! Old colour sets turn up all the time.
Hi Chris, Are you going to keep the later sound/i.f panel and if so do you have one?. if not I’ve got a few of the earlier boards and you’re welcome to one if you want it.
Cheers
Neil.