Last G8 model

[Heatercathodeshort]

The Roberts RCT221 was a G8, the 261 was the G9. The only problem I ever encountered with the G9 was the 2200uf electrolytic mounted above that hot wirewound resistor.
Once remotely mounted on the chassis rail away from the heat I found this chassis incredibly reliable. It had a much better soft start power supply that never broke down and a very good picture. I think this chassis has an unfair reputation for failure. I sold quite a number of Roberts RCT221's and a lesser number of the G9 version mainly due to the smaller rooms that were common with many of my customers. Regards, John.

[Maarten]

Originally Posted by FERNSEH

The CRT: http://www.radiomuseum.org/tubes/tube_a66-410x.html Evidently according to the Radiomuseum the developer of the delta 110 degree CRT was Telefunken. I always believed it was Philips.

According to the radiomuseum, the datasheet in this entry was written by Telefunken Of course it is theoretically possible that this particular tube model was developed by them, but I think most licensing and cross-licensing went the other way so I would not dismiss your belief that the tube could have been a Philips development.

Standard Elektrik Lorenz, for example, apparently also had a license to use Philips technology but used other type numbers for their own modifications and developments (for example A66-501X while Philips and Telefunken did the A66-500X and A66-510X).

[bobbyball]

Originally Posted by FERNSEH

Hi Robert,
You pipped me to the post with your response and our answers to the question are very similar.

DFWB.

Hi David

Yes I saw the enquiry about the G8/G9 and as I have a G9 in the back kithen awaiting being put back together and tested I am quite familiar with the chassis!

I also have an example of the G8 chassis on the first post in this thread. Only difference with my example is that the teak veneer as fitted to the plastic tube surround was flaking off in places and looked awful so I took it all off, just has a black front now.

[FERNSEH]

Hi Robert, your G9 must the only one still in existence. G8s turn up often but I haven't seen a G9 since the early eighties.

DFWB.

[bobbyball]

Originally Posted by FERNSEH

Hi Robert, your G9 must the only one still in existence. G8s turn up often but I haven't seen a G9 since the early eighties.

DFWB.

Hi David

My G9 is the only one I have ever seen in the flesh so to speak. It's a nice example with fold back doors. I think I gave £2 for it at the household auction years ago. Weeping 2200 uF caps of course. Tube tests very good, just need to get it back together having, replaced loads of caps.

I did actually think it was a late model G8 at the time, it has a big enough cabinet, even depth wise but the shallower back panel gave it away in the end...

[hans]

Originally Posted by Maarten

Standard Elektrik Lorenz, for example, apparently also had a license to use Philips technology but used other type numbers for their own modifications and developments

In my experience only the Philips branded tubes lasted. I've even seen Mullards in the Tandberg CTV2 (A66-140X)and they were softer than the Philips ones of the same type.

Was there a difference in picture quality in the G8 and G9 sets? When I was in the trade there were virtually no 90 degree deltas about. The first inline (A66-500X) tubes gave better pictures than the 110 deltas, but they were old at the time. (G11 would be a inline set I suppose)

[MATTTT3222]

Typical,the G8 went wrong when I decided it was time to sell it !.
It is the later single signal pcb,and has lost chroma.
Does anyone have a schematic for it,my paper one went years ago,and I never really worked on many of these.(it has the TBA ics fitted)
Thanks,
Matt

[Welsh Anorak]

Hi
I was never impressed with the contast of the 110-degree tubes. The G9 was quite good, and certainly benefitted from the stability of the power supply compared with the marginal G8, but to my eyes the 'punch' was lacking.
The G9 wasn't too popular with dealers. I remember looking at a delivery of what we thought were G8s - or possibly the eagerly awaited G11s - with some dismay. This deepened when they arrived back within a year or two with nasty faults.
The biggest problem ISTR was a couple of large electrolytics (2200uF) on the line panel that failed prematurely and caused all manner of problems, though looking innocent. Frame and raster correction problems were the main bugbears, but unstabilised LT supplies could wreak havoc. At least Philips made up for it with the well-liked G11.
Glyn

[Maarten]

Originally Posted by hans

In my experience only the Philips branded tubes lasted. I've even seen Mullards in the Tandberg CTV2 (A66-140X)and they were softer than the Philips ones of the same type.

Mullard and Philips tubes could have come from the same factory theoretically (only way to tell for sure is to look at the white printing, the brand labels were sometimes applied according to demand). Assuming the tubes you have seen were mostly from their "home" factory this would indicate that Dutch production would have been better than British production. My limited experience with really soft tubes was mostly with the Standard Elektrik Lorenz ones. I'm not sure how they ever managed to get certified by Sony for a Trinitron licence...

About the picture quality: a 90 degree delta tube would have theoretically given a better picture, because of the smaller deflection currents and less need for correction.