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Old 19th Jul 2021, 11:57 am   #1
G8vsjDave
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Default Ferranti TC1004. Baptism of fire.

I have a small collection of sixties transistor radios which have been repaired and cleaned and are displayed round the house and Iíve been looking out for a 50ís or early 60ís television to complete my small collection. I doubt if my wife would let me have much more. I recently found a Ferranti TC1004 not far from me and at a price that I thought was acceptable. This is intended to be a long term project for the winter months with some minor cabinet repairs, but I wanted to see what the electronics was like. A visual inspection showed no sign of previous repairs. All the fuses were intact and looked original and both dropper resistors were fine. Initial cleaning was limited to a soft brush and the vacuum cleaner on blow out on the patio.
Once the chassis was out and on the bench I decided to check out the big smoothing capacitors (C115 andC116)
The reforming operation suggested one half of the smoother (C115 200uf) is leaky. Iím feeding mains via my variac, a diode and an 8.2k resistor. The leakage current is steady at 6mA but with only about 160 volts across the capacitor. The other half of the smoother (C116 100uf) charges to 230v with no detectable leakage. I guess ultimately, this a re-stuff job, but at this stage in the project, itíll be tack-on .
I snipped out the mains filter capacitor and replaced the boost capacitor then decided on a test. I reset the mains selection options so I could have full heater current but limited the HT to 160 volts (because of C115,) controlled by the variac. Powered up, the speaker clicked on channel change, and I could hear what I thought was a 50 Hz buzz, so Iím guessing the frame TB is doing something. The Line stage however was dead apart from a blue glow in the O/P valve. I havenít yet changed C105, (I believe it falls into the category of ĎThat Capacitorí). The test was limited to just a few minutes and after, I noticed the smoothing capacitor had a slight liquid leak Iíve ordered two electrolytes to replace the smoothing block and some capacitors to replace the wax capacitors. The biggest problem that I know about is that I have a duff tube (see wanted section). The very long term aim is to have some fifties television material on a hard drive feeding a standards converter . For now, I am using a processor based 405 line pattern generator and a VERY crude modulator. I have a digital multimeter, avo8 and a scope and although I have zero experience with valve equipment, I have worked with transistor televisions and repairing professional TV colour monitors.
ANY advice or suggestion is welcome.
Dave
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Old 19th Jul 2021, 9:22 pm   #2
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Default Re: Ferranti TC1004. Baptism of fire.

A nice chassis to start with and FM radio that works quite well. You may find service information easier to find under EKCO model T311 who produced all Ferranti models from 1956. There are also some Ekco threads in the search section. They are all very similar from 1954-61.

Is the top of the line output transformer in good condition? The 'plastic' case breaks down around the EHT rectifier terminals. Replacement cases are easy to fabricate from Perspex or Paxolin.

Regarding the CRM172. A CRM171 will work fine. It does not have an external coating but will be OK. You can also use the Mullard MW43-69 aluminised or MW43-64 non aluminised. The neck is slightly fatter but the scan coils should slide over OK. John.
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Old 20th Jul 2021, 4:30 pm   #3
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Default Re: Ferranti TC1004. Baptism of fire.

A quick up-date. I’ve fitted new capacitors to replace the smoothing block and can report that the LOP stage is working, but seems to be loaded somehow. I can draw an AC arc from the EHT rectifier but only about half an inch. The EHT rectifier heaters are not red, but I do have a blue glow from the 30P4, which I assume is unwanted. I’ll have a look around the output stage in a few days, because I have been told (in no uncertain terms,) by my wife, to get on with jobs outside. The top of the line output transformer is showing signs of starting to fall apart, but as long as I don’t touch it, it should be Ok for now. I have seen pictures of how they have been re-built and that will be a job for the future.
Dave
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Old 20th Jul 2021, 8:16 pm   #4
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Default Re: Ferranti TC1004. Baptism of fire.

The burnt conductive case of the LOPT is no doubt the cause of your lack of EHT. It's very common. It should not be damaged or discoloured. J.
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Old 4th Aug 2021, 10:26 am   #5
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Default Re: Ferranti TC1004. Baptism of fire.

The LOPT holder fell apart when I touched it so I've ordered a sheet of fiber board to re-build it, but it seems that order has been lost somewhere. I've cleaned the tuner and replaced the wax capacitor in there. The HT is low by about 50 volts, could this be due to the metal rectifier? The project is now on hold due to me being away for the next two months.
Dave
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Old 4th Aug 2021, 10:43 am   #6
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Default Re: Ferranti TC1004. Baptism of fire.

WOW! That is a really bad example of a broken down Ekco case second only to a similar one I've just rebuilt for an Ekco TMB272. Good news is the windings will be OK.
I doubt if the metal rectifier is faulty. I repaired countless numbers of Ekco receivers and never once replaced the rectifier. It is made by AUTOMAT, incredibly reliable. Ekco and other makers that had previously used he U801 valve needed something reliable to replace it.
I would suggest you make up a new case and give it a try. The line output stage is probably heavily loaded due to case breakdown as was the TMB272. Regards, John.
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Old 4th Aug 2021, 12:36 pm   #7
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Default Re: Ferranti TC1004. Baptism of fire.

I repaired many Ferranti/Ekco lopt like this. I made a former out of wood and built up the case with glass fibre mat and resin. The former was made 4 times as long as a standard lopt one and so when one was needed I just sawed one off. The difficult part was reusing the connection points so corona didn't ensue. Never had one fail. Peter.
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Old 6th Aug 2021, 9:23 am   #8
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Default Re: Ferranti TC1004. Baptism of fire.

An oddball fault we came across with this era of Ferranti/Ekco sets was for the pitch coating on the width coil,seen on lhs of second picture in post#5, to soften and the coil to slide down its former and touch the chassis.My then mentors cure was to slide the coil back and hold in place with a length of drive cord. This cured the problem so he duly notified 'Trader' in order to help others. The cure was published with the comment that the correct way was to replace the coil with a new one,completely ignoring the fact that the new one could do exactly the same. This fault did not occur on every set and left us with the opinion that the encapsulation was at fault. Peter.
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Old 6th Aug 2021, 7:26 pm   #9
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Default Re: Ferranti TC1004. Baptism of fire.

I repaired many of these line linearity coils that had slid down their former and shorted to chassis. With care you could slide the coil back up and place a grommet under the coil.
When it shorted to chassis a clue was the anode of the U191 boost diode would run red hot. John.
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Old 6th Aug 2021, 10:28 pm   #10
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Default Re: Ferranti TC1004. Baptism of fire.

Hi John,looking at the picture again I suppose the width coil was rather too substantial for this to happen so it must have been the lin coil. I later on thought of a wedge and your grommet sounds ideal. My career took a different turn so I lost contact with these sets....it was 60 years ago,doesn't time fly etc. Peter
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Old 10th Aug 2021, 10:12 am   #11
G8vsjDave
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Default Re: Ferranti TC1004. Baptism of fire.

I'm building a new LOPT holder, but need some advice about those brass 'connecting studs'. The wires from the transformer appear to crimped. Correct?
I assume these studs are unavailable. Is there an alternative?
What sort of solder is used on the chassis side? My soldering iron (Weller 45 watt) won't touch it. I will be away now for the next month so there will be no progress for a while.
Sorry to be a pain.
Dave
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Old 10th Aug 2021, 1:29 pm   #12
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Default Re: Ferranti TC1004. Baptism of fire.

Sounds a bit odd! The solder used by Ekco is standard Multicore 60/40 resin cored. It should be very easy to unsolder. Check your iron.

The leads from the transformer are coiled in the anti corona cups and just need unsoldering and gently pulling from the cups. You can make up anchoring tags for the new case by simply drilling holes in the right places and using 4BA solder tags, secured with likewise 4Ba nuts and screws.

You may be able to salvage the corona cups from the top of the transformer, [ wire ended U25 EHT rect] drill them out and refit to your new case with the same 4BA [or 6BA] nuts/ screws/solder tags.

If they are beyond salvage simply use solder tags and make round solder connections to prevent flash over. I've done quite a number in my time and never had a failure. John.
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Old 10th Aug 2021, 11:32 pm   #13
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Default Re: Ferranti TC1004. Baptism of fire.

Copper progressively diffuses into solder and thereby progressively raises its melting point, which is why old solder joints can be difficult to melt. The usual solution is to apply fresh solder to the old, which should then make the old stuff melt. If necessary, you can then remove the old and new solder mixture and apply fresh solder.

Last edited by emeritus; 10th Aug 2021 at 11:33 pm. Reason: typo
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Old 29th Sep 2021, 8:56 am   #14
G8vsjDave
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Default Re: Ferranti TC1004. Baptism of fire.

Hi folks, after some time away, Iíve had a chance to put some hours in on my TC1004. A new LOPT holder has been constructed (see picture,) based upon pictures I found on a 2007 thread, (EKCO T311 LOPT).
The line/EHT side of the chassis seem to be basically working, I have a good line whistle and I can draw a good spark from the AC side of the EHT rectifier. There appears to be a 24 Ohm resistor connected across the EHT rectifier heaters that is not shown on the circuit diagram. Is that correct?
Thanks to PYE 405 I now have a CRT which I believe to be good (Thank you Andrew). The original tube has suffered damage to the base socket, and some of the wires are missing. The new tube however, needs a base socket fitted. The base on my old tube is too badly damaged to be of use (see picture) so Iím placing an ad in the Ďwantedí section.
The plan now is to work on getting the cabinet woodwork cleaned and repaired, and then to fit the new tube and go for Ďfirst lightí
Thatís it for now. Iíll post an update in a few weeks.
Dave
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Old 30th Sep 2021, 7:11 am   #15
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Default Re: Ferranti TC1004. Baptism of fire.

Nice LOPT rebuild. J.
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