GEC2110 G8 A823, which is top?

[Philips210]

Hi.

I would say that the first generation Philips G8 (520 series) is the best of the three sets though it was let down by the unreliable LOPT. The G8 had a well layed out chassis with good access and generally very predictable fault patterns. The picture quality was very good and the service information was comprehensive as usual for older Philips sets.

The GEC 2110 comes a close second in my view. They were great to work on (apart from the double-sided foil print, although not too bad really) and also gave a great picture. The LOPT was more reliable than the G8. The single line output transistor was better than the other two sets in that there was no balancing necessary. I also remember the saga of the touch tune versions, and something about the touch pad surrounding plastic becoming conductive causing intermittent channel changing. I once had an ITT CVC7 with similar problems.

Sadly, the RBM A823 comes last in my view. Although I quite liked these sets, I always thought that the colour decoder was not up to the standard of the G8 and 2110. I think though the later 2-chip decoder did give a better performance.
I never knew of anyone having to replace the LOPT and even the tripler was more reliable than the other two sets, just as well since access to the LOPT and tripler is a little awkward. The EHT cap was odd in that the lead comes in axially to the connector as opposed to the normal side entry.
The PSU board was poor though, what with hot resistors and thermistors causing blackening of the PCB. The convergence board was good and the procedure was easy to follow and achieve good results. Access was not as good as the G8 and 2110 especially for taking measurements on a working set.
I wondered about the variable performance on the A823 being down to those horrible PCB carbon composition resistors. Virtually every single one that I have tested are out of tolerance.

Regards
Symon

[hans]

Maybe a bot OT, but how were these sets in comparison to Continental and Scandinavian sets?

[Peter.N.]

Regarding Symon's point about the GEC double sided print, as at one time I was working almost exclusively on these sets I found that if you apply the iron to the print itself it holds it onto the board, you must however make sure that the solder has melted all the way through before you try and lift the component.

Peter

[Heatercathodeshort]

Yes Peter,
I managed to get the hang of the double sided print, having worked on the first receiver to use it, the Sobell TPS180 series. It was not a problem and as you say, if you worked from the top, everything would unsolder easily.
Hello Hanns,
I think some of the Continental receivers were as bad but not so down costed as our brands. Overall we did a pretty good job considering the stop/go policies of governments that created big problems for volume manufacturers. The Radio industry was always used as a tax income knowing that the public loved it's telly. Add to this the British trait of never wanting to pay a fair price for anything and you can see the problems the poor makers were up against.
Hello Symon,
I too had a love/hate relationship with the A823. Some operated OK for long periods but others were frequent visitors to my service dept. It could have been a great chassis if a little more care had been exercised during development. Looks like the poor A823 has failed it's exam. The G8 was everyone's favourite and well deserved. [I still like GEC receivers] Regards, John.

[neil29]

The CTV184 that i bought from keith a while back has an ic in the power supply . were these panels availible as direct replacements? and are they better than the originals. cheers neil.

[gec2110]

If you had to remove the chassis for eg tube replacement the A823 was the most compact compared to the other two, yes i do think that the G8 520 was the best G8 esp the convergence board which was good and reliable and stable
The G8 550 had a lovely looking cabinet for the time and we did sell a lot of these and had may on rental in the shop i worked in. we sold a lot of Murphy model 2215 in white as wll with the trumpet stand it is a shame the pic did not do the cabinet justice

[jayceebee]

IC PSU never saw one of those, any chance of a picture? Did they modify the degausing circuit? There was always loud laughter in our workshop when anyone left the degaus coils unplugged and then switched on as the 680 ohm went up in smoke

[Hybrid tellies]

Originally Posted by Hybrid tellies

Both the G8 and the 2110 are great sets producing good results and are nice to work on. They both suffer from tuner selector problems which are easily sorted and the early G8 with that decoder is not the best. If you are going for the GEC 2110 be very aware of the double sided pcb's.

We saw a lot of the RBM A823, I think we were a main agent for RBM in Bath. Reliability wise the A823 compared favourably with the G8, GEC 2110 and the BRC3000. But as many have said the pictures on the A823 were always a bit on the soft side. Having said this our customers liked them because of the soft pictures and the good audio quality that these sets produced.
Its interesting to note that even the more modern Ranks sets such as the T20,T22 and T26 all had this soft looking picture, there never seemed to be enough range on the contrast control.

[line sync]

Just reading what Neil said about the A823 power supply PCB that used an IC.
I've seen inside lots & lots of A823s and never seen a power supply like that.
I'd love to see a picture, Neil.

[Studio263]

Originally Posted by Hybrid tellies

Its interesting to note that even the more modern Ranks sets such as the T20,T22 and T26 all had this soft looking picture, there never seemed to be enough range on the contrast control.

Not the 18" Z718 though, with it's Toshiba RIS tube. They were always pin sharp with contrast to spare, I never encountered one with a flat tube either.

Does anyone have one of RBM's 110 degree delta chassis sets? Looking at the circuit it seems to have been designed for performance rather than economy, better than the G9?

As far as the Continentals go, the G8 was good but it's not a patch on a well set-up K70! The K12 was also sold as being somewhat better than the locally produced G11 alternative. GEC made some beautiful sets for export only, they had very clean looking white cabinets with black fronts and carefully styled controls. They coundn't have been more different to the cheesy-looking models that they offered in the UK!

[MALC SCOTT]

I have seen a few of the modified psu panels. They may have been made by the same company which produced the modified I/F panel for the Pye 725 chassis which used a sawf filter. Were they called Ledco??
We used the modified psu panels in field trials at Rediffusion, but the performance was poor. HT was unstable and pictures would bounce all over.
The VA1104 degause thermistor was replaced with a soft start circuit.

[MALC SCOTT]

Sorry, i should have stated the VA1104 mains surge thermistor

[neil29]

Ok then here are a couple of pics (not the best quality and my second attempt). cheers neil.

[Welsh Anorak]

Hi
Never seen one of those before - but I think you're right with Ledco as the manufacturer as it looks similar in quality to the CDA panel they offered to replace the Pye hybrid's.
Back to the question - I suppose we all liked the G8 although the HT stability left a bit to be desired, as did the later "toast" convergence panel and the flappy buttons - and of course the LOPT. Oh yes - the 'not the TDA530' panel with the varying greyscale - help! The earlier ones were better with the square buttons and G6-esque convergence panel, although the frame board was certainly improved later. The A823 was always poor in terms of performance and the 2-chip decoder made things worse. I quite liked the GEC, though decoder faults could be puzzling (though not on a par with the 823) and that 47v zener and the power supply resistor could annoy you. Mind you, as production went on things did improve.
As an aside, I would argue the T20-26 gave excellent pictures provided the tube was good as did the Z718, and the oddball Z179 did prove the SL901/918 decoder could work well when the circuit was designed properly.
I think all three had good and bad points - best picture GEC and best design G8. Worst cabinet - 2110! Worst controls (customer ans convergence) - G8, unless someone had used Servisol on the GEC.
Glyn

[Heatercathodeshort]

I think you have just about summed it up there Glyn. J.

[MALC SCOTT]

The oddball Z179 produced first class pictures, but it must have had a huge component count on the very large decoder board.

[Clydeuk]

As a child of the 70's, I missed out on this Golden Age, apart from acquiring (and wrecking) some of these chassis in the 80's. I fell in love with the G8 after we rented 2 sets from Visionhire in the 80's, the latter being the G22K550, which I still love to this day.

Where I lived at the time was a holiday resort and bedsit land. A small shop dealt almost exclusively with GEC 2110 sets, always Granada badged, selling them at the time for about £50 with 3 month's warranty. Walking past the shop there were never 2 sets showing with the same grey-scale, not even anywhere close to the same. Anyway the poorer end of town was flooded with these sets.

One day in the pub and old man asked if I would have a look at his TV, i was only a dabbler at the time with a very limited knowledge. When I called at his flat there was a lovely looking GEC set in a white cabinet. He told me it had simply "gone off". On first inspection the fusible resistor attached to one of the droppers had sprung open. I was going to resolder it back up again (I didnt know that something may have caused it to open at that time). I then spotted that the CRT was broken, not a small pin hole but the entire bowl had a huge crack around it and had separated from the face. I told him about this, I suspected he had dropped the set, though there was no evidence of any cabinet damage. He still maintained the set had just gone off while viewing. Anyway a week later he gave me the set.

Back in my old shed I had another one of these, with an intact but untested tube, and since I liked the white cabinet I proceded to replace the broken tube, believing i would have a nice set afterwards. I switched on (from a distance) and was greeted with an intense sparking noise, loads of ozone smell and before I could switch off the sound of glass cracking. My replacement CRT on inspection now had a visible fracture line running from the EHT connector to the scan coils.

After reading through this thread I wonder if i had the 3rd harmonic capacitor fault, evidently the EHT was way too high, I've never seen a CRT fail this badly!

[gec2110]

Never seen a white 2110 before .
That fault you describe would have been the cap and the 47 volt zener as well as the BU. The good thing about the Gec at time it only had one line output transistor
and did not need balancing.

[ukcol]

Originally Posted by neil29

Hi all. one thing that ive wondered about for a while with the A823 chassis. is why did they turn the A803 scan drive panel around so that the height controls etc were facing inside the set? cheers neil.

Early production of the A823 had a problem with line synchronization and turning the scan drive panel upside down was an early attempt to get round it.

In this chassis the line sync pulses were used to make the tuned primary of a transformer (called the discriminator phase transformer) ring. This gave a single crude sine wave at the secondary, that coincided with each line sync and lasted for approximately the line fly-back time. The secondary of this transformer fed the line flywheel discriminator. In service by adjusting the core of this transformer (and hence it’s tuning) the picture information could be centred on the raster; the raster being centred by a separate adjustment.

The diodes in the flywheel discriminator were fed with pulses from the LOP TX in the usual way for phase comparison purposes.

Unfortunately this same transformer was mounted inside the influence of the magnetic fields generated by the scanning output circuitry and these fields induced a voltage waveform into the discriminator transformer in such a way as to cause the line to lock out of phase, with the line fly-back portion of the picture information down the middle of the raster.

If you changed channel it was 50-50 whether you got a normal picture or this false line lock.

The first silly suggestion was that you adjusted the line speed slightly low. Not a very elegant solution and you still had the problem but less often. The next solution was to turn the scan panel upside down, which was a better solution but still not 100%.

Finally the problem was solved by a new discriminator transformer which had both the primary and secondary windings reversed. As far as the circuit was concerned the phase relationship between the primary and secondary of the TX remained the same, but the induced voltage waveform from the stray fields was reversed and the problem solved.



Once this and other early problems (mentioned by others) had been addressed, by the standards of the time the A823 was a very reliable chassis.

Colin M