Ferguson 1500 series Television

[steve1010uk]

Also good advice from Paula, it's worth having a good look at the wiring of the line scan coils, it could just be something simple like a corroded or broken connection to one side of the line coils

[Silvered_Mica]

I wouldn't suspect the scan coils yet, check C92 it might be momentarily dragging down the boost rail. Also check the correction cap C90, it probably won't cause the symptoms you have but I think it's a Hunts moldseal type if memory serves.

[Red to black]

With a keystone raster like that it will always be a scan coil fault

[Welsh Anorak]

Agreed. I'd remove the yoke and have a close look at the coil terminations - you may see a green bit of corrosion, especially if the set's been in damp conditions.

Luckily any contemporary scan coil assembly will do, but best if you can find a 1500 one - shouldn't be too difficult.

[Hybrid tellies]

If the scan coils are ok it may be the linearity sleeve.

If these are ok check the voltages around the line output stage and line oscillator valve.
I have had a few faults like this in the past where by checking voltages around the line oscillator valve has cleared or partially cleared the fault whilst I touched one of the valve base pins with the meter probe helping to localise a fault to a capacitor or resistor.

[thermionic]

Hi everyone.

I offered to repair this set for Newgirl2013 after she had posted a request for a TV repairer in Cornwall in the Services Wanted section.

I collected the set on Friday, and had a chance to put it on the bench today to see what could be done.

First impressions revealed a 20” 1500 chassis in a Ferguson coat, with a 4 button mechanical tuner. The tuner buttons were sluggish and not latching. A round white mains cable is fitted which is not original, - this would have been a flat twin cable with a grey or black sheath originally.

The back cover was removed after removing the 5 original screws & washers from the back. That’s a good sign! This revealed a PCB with a green solder resist suggesting that this is a late model.

The CRT installed is a ‘SOLUS’ brand, which I understood was a replacement market brand rather than one that would be supplied direct to a manufacturer, but the valves fitted are a mix of SOLUS, T.C.E and Mazda, so maybe its original.

Examining the soldering on the main PCB, it appears to have had no work done on it, - even the solder on the dropper tags looks original!

That’s it for now, next is power up to confirm the fault condition as described by Sharon, above.

Cheers. SimonT.

[Newgirl2013]

Hi Simon
The mains lead came as a surprise
I would never thought it would be a three core
When I used to see the 1500s the mains leads were always twin grey mains leads
Hope you can sort the tv
Many thanks
Sharon

[thermionic]

Last night It was back to the set, and power up time!

Up came the strange raster that Sharon (Newgirl2013) had witnessed. There was a louder than normal background hum from the speaker, and the main HT line (HT1) was much lower than it should be.

Out with the multi section electrolytic then - and what a mess was discovered! All 3 sections of this can were practically high value resistances, and only a mere suggestion of any capacity.

A rummage through my box of multi section electrolytics did not yield an exact replacement, ( 150uF + 150uF + 100uF ), but I did find a can that I hoped would, at least, get the chassis up & running whilst I try and source an exact replacement.

My substitute can ( 100uF + 68uF + 220uF )was carefully adapted to fit the PCB footprint, whilst being careful not damage the PCB. I was rewarded with an almost normal raster, which, thankfully, has lifted any suspicion from the scan coils…. Yay!!

[thermionic]

………Incidentally, The date codes on the electrolytic and this valve seem to date this set from very late 1977, so it really must be near the final run of these great chassis!


So, the next job is to repair the push button mechanism on the tuner, so that a signal can be tuned in to evaluate what needs attention next.

( The frame timebase is an obvious patient)!

Cheers.

SimonT.

[Welsh Anorak]

Well, you live and learn!
The green chassis lacquer does point to the very last production run. You seem to have a pretty decent CRT as well which will only get better with time.

We used to look after well over a hundred of these TVs for a local holiday camp until it was deemed that the happy campers deserved colour. Radio Rentals offered an excellent deal to the owners, so soon the camp was full of TX9s and the skips were full of the poor 1500s.

[Colourstar]

You know I could be wrong but I wonder if that set has had a later chassis put in. I'm sure when I had one of those some years ago it had the red pcb. I don't have the relevant Ferguson brochure to hand but I'd put that cabinet design with the basic mechanical tuner to about 1973. I think by the time of the very late 1500s in 1977 they were using varicap tuners.

I'll have a rummage through my Ferguson brochures to see if I can prove (or disprove) my theory!

Steve

[thermionic]

Originally Posted by Colourstar

You know I could be wrong but I wonder if that set has had a later chassis put in. I'm sure when I had one of those some years ago it had the red pcb. I don't have the relevant Ferguson brochure to hand but I'd put that cabinet design with the basic mechanical tuner to about 1973. I think by the time of the very late 1500s in 1977 they were using varicap tuners.

I'll have a rummage through my Ferguson brochures to see if I can prove (or disprove) my theory!

Steve

That would be interesting, Steve. A replacement chassis is a possibility.

The model number on the back cover is 3821, if that helps you in your quest!

Cheers……SimonT.

[thermionic]

Today, I’ve repaired the tuner.

It was suffering from the usual Thorn mechanical tuner problem! The plastic spring retainers on each of the selector shafts had disintegrated, the remains rattling around the bottom of the sets cabinet.

The usual remedy for this is to fit appropriately sized steel washers onto each of the 4 shafts, and this is exactly what I did.

The surface rust was removed with fine grade sandpaper and GT85 spray. Finally, the shafts and square section rear actuator bars had a very small smear of petroleum jelly applied.

The other failure mode on these particular tuners is that the tuner unit actuating bar can become detached from the pivot ends. The bar, which is attached by solder onto the pivot ends usually becomes loose due to the solder fracturing. On this particular tuner, the soldering appears original, and is still in good condition with no signs of distress.

Tomorrow, we’ll have a picture!

Cheers……. SimonT.

[thermionic]

Originally Posted by Welsh Anorak

Well, you live and learn!
The green chassis lacquer does point to the very last production run. You seem to have a pretty decent CRT as well which will only get better with time…….

Thanks Glyn.

Yes, the CRT looks promising, I must admit that I was surprised to see one branded SOLUS, I’m not sure who would have originally manufactured these, a European manufacturer maybe?

At least it’s not one of those Unitra tubes with the phosphor that looks like the surface of the moon!!!

SimonT.

[Bobdger]

Most of the 6823s that I had new in 1976 had green colour pcbs. I used hi melting point solder for the tuner bars. Inside the tuner are 4 silver springs that earth the bar with the movable tuning gangs. I use to remove them, the solder was always cracked and clean with carbon tet. Bob.

[HamishBoxer]

Solus tubes were pretty good, as were there valves, not sure if made in UK or not.

Get your Weller gun out for that tuner bar.

[Newgirl2013]

Hi Simon
Are you going to replace the chassis?
Sharon

[Hybrid tellies]

During my spell at Radio Rentals, and if memory serves me correctly we used Thorn New Life tubes for colour and Solus Tubes for black and white.

That Green chassis along with the use of a mechanical tuner indicates to me that this is an earlier version 1500. By 1977 they were using electronic varicap tuning and the more common red PCB. Maybe the smoothing can was a replacement fitted in 1977.

One final point the early 1500, like the 1400, may need the width chain resistors checking/changing as they could burn up and catch fire.

[thermionic]

Today the tuner was refitted, and the set powered up. No great surprises....... a picture was soon tuned in!

My only issues were an intermittent frame height variation, which was due to R123. ( 330K), and Width variations due to R131 (1M8).

The ubiquitous R44 ( 47K) was factory fitted with a 1 Watt resistor. Its value was checked anyway, and was fine. As this set is being returned to a forum member, then I replaced a few capacitors as a precaution. These were, - C84 - mains filter capacitor. C77 - heater bypass capacitor, - C82 Boost Rail de coupler and C98, - PL504 Screen grid de coupler. The capacitors in these positions were of a type that I don’t have faith in.....simple as that!

The remaining electrolytics are mostly Rubycon and are in good condition.

This chassis is definitely late 1977 so I guess it’s possible that this has been fitted into an earlier cabinet with the mechanical tuner and replacement CRT?

The set will be soak tested now to see if any other issues present themselves. I’ve been offered a replacement main electrolytic, so will wait now for this to arrive.

Cheers. SimonT.

[thermionic]

Originally Posted by Newgirl2013

Hi Simon
Are you going to replace the chassis?
Sharon

Hi Sharon. No, we were wondering if this chassis is newer than the cabinet! So, it may have been swapped over at some point in its history.

SimonT.