Rare Alba TC1717 CTV

The model number is actually TC1717 it was not very clear on the tag but closer inspection reveals the correct number.

Hi.

Nice set to have and certainly not common by any means. Alba re-badged many different makes and my father bought an Alba 24 inch mono single standard set late in 1969 that was a Philips 230 chassis, just had a slightly different speaker grille to the Philips. 

Good luck with the restoration.

Alba could have bought chassis and the other items they required to build the sets, I just wonder if in some/many cases the original manufacturers did all the work and Alba just became a merchandising company.

Seeing as I'm in the throes of some Thorny action, I just wondered how you're getting on with yours?

Posted by: Tazman1966

Seeing as I'm in the throes of some Thorny action, I just wondered how you're getting on with yours?

Making progress Tas. I now have a picture again after replacing lop TR. Sorting some decoder and signals panel faults. Full write up coming soon!

Look forward to it!

In the seventies I had loads of these 8000 series CTVs on rental including the Alba models TC1717 and TC1727. Also the Ferguson 3712 which was bought from Comet in Middlesbrough, that was in 1972.  I had no other choice but to pay the higher than trade price for the sets in order to keep up with the demand for sets to rent out.  

There was posh HMV version, now that's a set to look out for.  But the model I'm looking is the version with a vari-cap tuner.  

Till Eulenspiegel.

The 8000 was competitively priced so quite popular. What was the little Bush CTV with I think a 18 or 20 inch tube, it was in a one piece plastic cabinet, just can't remember the model?

Hi Trevor,

                    that'll be the Bush BC6100. It was introduced in 1976? as an 18" CRT model and followed by a range of  models which were available with 20, 22 and 26" Toshiba RIS CRTs.  

Till Eulenspiegel.

That's the boy David the 6100. We did a lot of rentals with them in Clydesdale but some of the engineers couldn't get their head round how the power supply worked. Often the line oscillator wouldn't start and the recommended service procedure was to start the oscillator with a PP3 battery and then fault find the problem,  unfortunately some of the field engineers would fit a PP3 as a permanent fix, the battery would last about 2 months then the set would be dead again, it wan't long before they got caught out when another engineer would lift the set to the workshop for proper diagnosis, it was a set I particularly liked, easy access and once familiar with it a simple set to fix.

Some of you will recall that I started renovating a rare early 1970s Alba CTV fitted with Thorn’s 8000A chassis a few months back.

At the time I managed to get some sort of picture out of it before the line O/P transistor went short. Well I was determined to get it finished in time for some Christmas viewing. After many delays due work and family commitments the little 17” Alba CT1717 from c1972 is at last finished and here is the tale of its renovation. its a bit of a long tail but hopefully worth a read read on how I coaxed this set in to showing pictures as good as the day it was new about 47 years ago!

This Alba CT1717 was rescued from a loft in north London where it had been stored since the 1980’s. New owners moved in to the house recently and discovered the set and luckily had the foresight to save it and offer it for sale on Ebay where I bought it.

Back on the bench when it first arrived home a quick evaluation showed a dusty but complete set which was not corroded so the loft must have been well ventilated.

Cosmetically the set was pretty tidy just needing a good clean.

Initial tests showed no obvious shorts or oozing smoothing cans so I powered it up to see what results were obtainable. Not a lot happened apart from the degauss coils making their customary short buzz and the CRT heaters were alight.

Quick checks around the mains dropper showed no obvious problems, no sections were open and the push fit connectors on the dropper seemed fine.

Removing the combined power unit and audio PCB which is buried down in the base of the chassis and a little inaccessible revealed a big dry joint on pin 1 of plug 9!, so maybe this was the cause of the set being laid up all those years ago?  This connection had clearly been arcing for a while as plug 9 was a little scorched around pin1. I Cleaned and re-solder the pin and tried again. This time there was a gentle crackle as the EHT climbed and the speaker was hissing. Connecting a signal source and trying to tune to a signal gave sound and a very narrow raster with a pretty dull and poor quality picture. Also the mechanical tuner buttons were jammed and would need looking at too.

Checking the main HT rail proved the narrow picture was due to a severe lack of volts as it measured about 120V instead of the required 180V. Adjusting the main EHT preset on the power board would increase and decrease the HT a little so clearly the PSU was capable of regulating and most likely there was a fault in the error amplifier. The cause was quickly traced to the pre-set EHT preset itself which had risen in value from 10k to over 30k! A replacement enabled the HT rail to be reset to its correct 180v and the raster once more fully filled the screen.

Connecting the set up to the DVD player for test card F showed the picture was lacking in contrast even when adjusted to max on the customer contrast control. The colour was also very poor with ‘Hanover blinds’ effect and the reds all looked very pinky. On the plus side there was plenty of brightness and the grey scale was excellent.

Congratulating myself on the swift progress made so far I removed the chassis and cleaned everything up, removing decades old dust and cobwebs. It cleaned up very well indeed.

After reassembly I decided to investigate the contrast fault first. I switched on and the EHT came up, then there was a crack and a wisp of smoke and the set was dead once more as the mechanical cut out had fired.

Initially I thought maybe I had disturbed or broken something during the clean up, so checked and double checked but could not find any errors.

Time for some faultfinding, the line transistor was disconnected and found to be short circuit. Was it killed or did it die?  Connecting the HT rail up to a lamp proved that it was still correct at 180v so the PSU was unlikely to be responsible. The green coloured tuning capacitor on the back of the line TR heat sink looked a little stressed. Testing it showed it was completely short circuit. A replacement 1500pf 2kv cap was sourced and with a BU208a fitted in place of the original a BU105. I reset the cut out and switched back on and was pleased to be rewarded by normal EHT and a raster again.

Great, that was a relief, so now back to the very weak contrast fault again. I checked around VT108 on the signals board which is the AGC driver transistor. The transistor was fine, its bias voltage is set by a potential divider of 2 fixed resistors, and a preset and the customer contrast control. Checks showed that the preset R143 was faulty making it impossible to correctly bias VT108. There seems to be a theme starting here with dud pre-sets!

So now we had a nice bright contrasted picture but poor weak chroma with heavy Hanover blinds effect ( a bit like the chroma was missing every other line) .

I gave the chroma delay line amp  pre-set a tweak and it immediately fell to bits! Another duff pre set! Thinking that would solve the chroma fault R198 was replaced and things did indeed improved a little, however it still did not look right. The reds looked magenta and the Hanover blind effect was still there, though to a lesser degree and predominantly on the red yellow and blue colour bars.

At this point I fell in to a trap of my own making. By adjusting the setting of the reference oscillator preset I discovered I could eliminated the Hanover blinds effect and the red colour bars looked about right colour too. After changing channel or removing the signal the reference oscillator however would not lock causing unlocked coloured bars. I reset the control to its original position which then brought the Hanover blinds back.  I concluded that maybe the reference oscillator was falsely locking causing phase errors in the decoder. Some time was spent checking the Oscillator and the phase loop to no avail. Tweaking the oscillator cured the fault and changing channel continued to make the oscillator loose lock.

After much time wasted getting nowhere and looking for inspiration I chatted to an experienced TV engineer about the problem recently.  He suggested that in actual fact the fault was more likely down to the chroma delay line its self being defective causing phases errors between the direct and indirect path of the chroma signal. My tweaking the reference oscillator was just masking the fault by cancelling some of the phase errors. I had not come across this before. In fact I have never experienced a faulty chroma delay line before so I was a little sceptical but thought it was a try.

I located a scrap late generation Philips G8 decoder panel in my spares and borrowed its blue coloured Mullard chroma delay line to see what would happen if I fitted it to the 8000a decoder board.

On switching back on the improvement on the colour bars was immediate and once I went through the alignment process for the chroma delay line and reference oscillator I was rewarded with lovely rich reds and blues and no more Hanover blinds and much more colour saturation too!

Probably quite an obvious fault in hind site but once you wander down a blind alley when fault finding it can be hard to find your way back!

The set was then put on soak test and after a short time the audio started to crackle and disappear. Sometimes switching the set off restored the sound sometimes not. No dry joints were found on the audio OP stage but when the sound disappeared the collector volts on the audio o/p transistor climbed up and no volts were on the emitter pin. Clearly the transistor its self was going OC internally intermittently.   A replacement MJE340 transistor was sourced and fitted and the sound problem was solved.

Further soak test did not show up any more serious problems. A few noisy convergence presets were treated to some DeoxIT spray and responded well with very good convergence being achievable on the crosshatch generator.

Attention was lastly directed at the jammed press button tuner unit. Dismantling it revealed that the nylon collars that retain the selector release springs had crumbled so the selectors could not return to their original position. Not having any replacement collars to hand I improvised with some small cable ties. I have included a photo to show what I did. It works perfectly and should some original parts be sourced I can easily replace them at a later date.

The Alba has now run for around 10 hours or so and is giving an excellent account of its self. Despite being a cheap entry level Colour set from late 1971 or early 1972 with no raster correction circuitry the picture is excellent, bright and pretty sharp too, especially considering it uses a low focus volts CRT.

The photos don’t really do it justice and the moiré pattern is a trick of the camera and does not show up on the set.

I have to say I am very pleased with the results with this relatively rare and pretty little set and can’t wait to watch some vintage 70’s Christmas specials on it over the festive season.

Hi Dave, 

Brilliant, interesting and an addictive read  ?

Many thanks for treating us to the tale of how the TC1717 was returned to good health. I can sympathise with the digression into the rabbit hole of fault finding, that's happened to me on more than one occasion.

By the way if you managed to find any NOS replacement washers I doubt that they would be of any use. I was offered some NOS replacements a while back, however when the person checked the packets the new washers had also disintegrated in the same fashion as we find in these aged tuners. Something to do with the plastic breaking down with age.

Not sure If you've followed any of my TV blogs but I've repaired in excess of 8 of these Thorn tuners for this fault now using M6 cup washers. They work perfectly and look correct once installed, you can see the 'Tuner article here' or just look up  some of the Thorn TV repair blogs here. To be honest though your solution works fine, is a simple neat repair and works well as you rightly demonstrate so no need really.

Once again congrats on a superb post and equally superb repair.

Did I imagine it that a similar looking DER set was made which had four light action channel selector buttons instead of the mechanic UHF tuner? We know a Baird 8000 series set was made which had the six button varicap tuner that was used in the large screen sets..

Till Eulenspiegel. 

Hi David,

Would the set you reference by any chance be the D|E|R 17"  'Compact' 5732 ?

This set was offered on rental in 1972 at approx £1.18 per week. You can see the actual TV, its the sixth set in the D|E|R brochure here

Hi Chris, except for the rearrangement of the controls the Alba TC1717 has same basic  cabinet design as the DER 5732.  Thorn was a very clever manufacturer and was capable of creating different models by mixing and matching cabinet presentation parts from the stores bins.

A lot of engineers didn't like the 8000 series models but I can say these sets gave me excellent service all though the seventies and into the early eighties.   Didn't like the look of the Ferguson 3712 though, I much preferred the Alba version and so did my customers.  Been on the lookout for the HMV 8000 model for years. One might turn up someday.  

Till Eulenspiegel. 

Hi Till. You seem to be one of very few that recall the Alba TC1717. I'm trying to establish if the slightly odd on off knob is original or not. It does not look like a thorn part but maybe Alba specified it?

That's right, the on-off knob doesn't look like a Thorn part but I'm absolutely certain it is the correct one for the Alba set.

Alba was the name used by A.J.Balcombe Limited and was derived from the name of the founder of the firm.   

Till Eulenspiegel.

Posted by: BRC 3000

I have to say I am very pleased with the results with this relatively rare and pretty little set and can’t wait to watch some vintage 70’s Christmas specials on it over the festive season.

What a fascinating story of repair/restoration and the joy of watching it is very well deserved indeed. ? 

Fantastic result. Just my era of set too as you know. Well done Dave.