Ultra 6606 revival

[Colourstar]

'GET THEM WORKING!' roars the headline of the March 1972 Television magazine, over a teetering pile of 8 year old tellies pictured at the glamorous premises of Telecare Ltd, of Tottenham. The set in the middle of the pile is a Ultra Bermuda 850 series and as I have a similar model - and always do what I'm told - I thought I would indeed have a bash at getting it working.

This set came from welsh Wales, as evidenced by the dymo-tape labels applied to the VHF tuner. ITV contractor 'TWW' (Television West & Wales) disappeared in 1967, succeeded by Harlech Television (HTV). Quite why there is a 'BBC2' label on the VHF dial is a mystery, unless it was simply to indicate an alternative BBC1 service that could be picked up. I shall leave the labels in place as they are a part of the telly's history.

Although a dual standard set, the Ultra is simply '625 ready' as it has never had a UHF tuner fitted. That would indicate it wasn't used beyond the end of 1984 and was probably retired for a good few years before that.

There were two versions of the 850, one being a 'compact' with the dropper panel arranged at the bottom of the chassis frame, the other 'full size' with it at the left hand side. Mine is of the latter type. The upper (IF) deck is liberally sprinkled with a selection of crusty caps, a mix of brown Hunts all cracking merrily and those blue plastic TCC types that split along the seam. Festering in the murk of the lower deck (power supply and timebases) are a brace of black Hunts and crusty electrolytics. I suspect that for piece of mind all of these old timers will be facing eviction.

As found, the dropper was, frankly, a disgrace to the profession, crumbling to bits and festooned with RS polo mints. Luckily a NOS replacement was sourced and fitted in a trice. With mains gently and gradually applied, the valve heaters lit but there was soon the unmistakably hopeless hum of a can electrolytic with one or more dried up sections. A forum appeal yielded a replacement can (with many thanks to Greg!) and this was duly fitted.

The nasty noises were now no more and with full mains input there was something on screen. Yes, first light had dawned with the traditional squashed bottom/expanded top, but if you look closely you'll see it's a little more interesting than that....! With the exception of the dropper and main smoother can, all the original components are in place and it does show that even in their appalling state of decay they do still work, sort of.

Hopefully more to report this weekend.

Steve

[Colourstar]

And more pics...

[Colourstar]

...and the Ultra brochure circa 1963/4

[Nuvistor]

Is it possible that the set was used on a communial aerial system with BBC2 translated down to VHF, quite a common thing in the 60's.
Frank

[1955APREN]

Yes my thoughts as well possible Newtown or Welshpool communial aerial.
405/625 sw would have to be mod to work vhf on 625. I understand that
Aberystwyth also had a simler system , but I neaver worked that aera.
regards Derrick

[neil29]

Hi Steve, Nice to see some life in it and good luck with it . and I actually bought it from Bristol .


Cheers
Neil.

[Nuvistor]

The council flats and maisonettes in Wigan translated BBC2 to a VHF channel. The council communial aerial systems in this area were not that good, the 405 channels suffered from direct pickup of the signal on the cables, they were also unreliable.
They were converted to use UHF in the 70's, whether it was the standard of installation or just more modern equipment, or perhaps both but that system worked very well.
Frank

[Colourstar]

This set is proving an unhappy specimen of the 850 breed and producing quite a strange display.

Although the raster is more linear than in the earlier photo, following replacement of capacitors in the frame stage. there's still a major lack of height and that peculiar undulating distortion at the top- I wonder if there's some kind of insulation breakdown in the scan coils. The frame output transformer is also making a rather strained noise. Adjusting the frame hold varies the height of the raster from virtually a single line to what you can see on the photo. Adjusting the horizontal hold causes the raster to wrap around itself, again you can see a bit of this on the photo. Line whistle is strong and seems to be about the right pitch for 405.

V7 (ECC804) is part frame osc and line osc, whilst V13 (PCL85) completes frame oscillator duties (and frame output)

Voltages around these valves are generally a little low (between 5 to 20v down) but there's nothing that really sticks out as being very wrong.

There are no signals to look at yet, but that's no surprise as the IF deck is still awash with crusty Hunts caps...

Steve

[Focus Diode]

Could well be the scan coils at fault. I have a spare set of BRC coils if you get stuck.

If the set has the original red Jellypot LOPT the line whistle will indeed be very intense.

Cheers
Brian

[volte-face]

Have a close look at the frame coils temperature compensation thermistor on the yoke. If it looks or tests at all suspect, try running the set again with it shorted out. Not an uncommon failure.

[Colourstar]

Yes, very good point regarding that thermistor. It reminded me that in the past I've seen a similar undulating effect on a frame collapse on a BRC 950 set, which indeed turned out to be caused by that component. Unfortunately on this Ultra, the thermistor appears to be blameless; shorting it out makes no difference to the 'waves' in the display, so perhaps as Brian suggests it could be a problem with the coils.

Steve

[volte-face]

Oh well, to be fair it didn't look like "classic" thermistor failure, but it's good to rule it out as causing any increased resistance in that circuit.

Before going to the lengths of trying a different yoke, it may be worth just checking, if you haven't already, R124 (1 Ohm), which lurks in the vicinity of the top right of the chassis, under the signals board.

EDIT:
Actually, now having looked at the pictures of the chassis above, you have an dual standard 800 chassis, rather than an 850. (Which means that the R22 dropper that you have fitted is not quite correct for that chassis)

[Heatercathodeshort]

I have never seen such an effect on a television chassis before. At a guess I would say that there is heavy hum on the HT line. This may be due to a wiring fault or mains dropper connection. Very odd. I'd like to play with that one.
I remember the paxolin tag panel that supports the HT wire wound resistors used to become conductive but that usually blew the fuse.
If the scan coils have failed, it will probably be due to the lin sleeve having been pushed in too far and cooking them. Pull the sleeve out. It could be shorting. John.

[Colourstar]

Thank you V-F and John very much for your thoughts. It never crossed my mind that the set was anything other than an 850 series, although if it is an 800 then that would explain a few odd component discrepancies between the 850 manual and the set itself. Indeed there is no R124 listed for the 850! I have all the BRC service literature from 850 to 1500 but nothing for the 800. Are the dropper values very different I wonder?

It is quite possible that the replacement can electrolytic- a used Radiospares item- is not quite as healthy as might be hoped. Maybe I should hold out for another one.

There's no sign of the linearity sleeve so it could well be pushed right in. The knurled plastic knob on the yoke clamp assembly is going to take some persuasion to move as it appears to be stuck fast.

Steve

[Colourstar]

I think naming this thread the Ultra 6606 'Revival' has cursed it!

The line frequency started rising and falling then the sides of the raster began to rapidly close in.... Trying it subsequently just gives a rather strangled line whistle and no EHT.

I think I may have to shelve this one for the time being, sadly.

Steve

[Focus Diode]

Have you replaced the coupling capacitor between the line output valve and oscillator? What's the volts at the PL36 control grid?

I'll dig out some scan coils for you.

Does anyone know off hand if the dropper values differ between the 800 and 850 series?

One set I think we'll have to get going in May!

[Colourstar]

Hi Brian

Yes that cap has been changed, also associated resistors checked. PL36 control grid is at -29v which seems a bit feeble.

The line whistle has returned to something like full strength again (all on it's own) but the EY86 isn't glowing although it must be working to a small extent as that same old wonky raster is discernable but it blows out rapidly. The EY86 is new (old stock) by the way.

Incidentally the line oscillator valve is the lesser-spotted ECC804 and there are dire that 'an ECC82 is NOT a plug-in replacement'

Steve

[Colourstar]

Well this is all very odd. It's up and running again but without any obvious reason why. I'll have to check carefully to see if there's a dry joint somewhere.

I think we can definitely say that the scan coils are faulty as my eye was caught by a tiny but intense pinprick of blue/white light on the windings themselves, so there is some arcing/insulation breakdown in at least one spot and maybe more that can't be seen. I don't know anything of the set's history, so I'm not sure whether it spent years in a damp loft or cellar. Anyway, it looks like the coils are the heart of the raster problems.

It may live yet....

Steve

[Focus Diode]

Another thought could be the blocking osc transformer or surrounding circuitry, rather like what your Alba 1500 suffered from.

Anyway, it's back in action sort of! I'll sort out some coils for you.
Anything on the signals front?

We'll have the set displaying the TWW caption I'm sure.