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CTV Ferguson 59P7 Saved From The Grave

 
Jayceebee
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It’s nearly two years ago since I collected this Ferguson 59P7 fitted with the infamous Thomson ICC5 chassis, it was saved by Rich, Slidertogrid from a skip alongside other stuff bound for the great showroom in the sky. Lots of things have happened since, Covid of course and I now have a new workshop to spend lots of time when I retire which could be this November when I reach 66. I probably wouldn’t have driven from the North East to save it if I hadn’t been due to collect a new car in Derby, it was just another hour or so further down the road to Peterborough.

The set has sat waiting to be looked at since then and with the new workshop almost fully operational I decided it was time to haul it onto the bench. Rich had given it a look over previously, had found a s/c ceramic cap on the mains filter board and had what looked like a very dim raster. Exactly the same symptoms were seen when I tried it here, but the dim display on the screen was not a raster, the set in actual fact had field collapse but due to DC flowing in the scan coils. No characteristic horizontal line could be seen as the electron beam was aimed way above the top of the phosphors, the illumination was due to random electrons being reflected back in a diffuse manner after hitting the CRT bowl.

On seeing this I was fairly certain that this would be a relatively simple repair, dry joints or an o/c RF01 immediately sprang to mind but although examining the PCB there indeed were numerous dry joints but attending to these and an ohms check on the resistor was fruitless. I don’t quite understand why but dry joints are a major cause of problems with the ICC5 and many components have had their leads trimmed incredibly short which seems to exacerbate the problems, it can be rather difficult to get solder to flow on to the legs and make a sound joint. The ICC5 also introduced us to MELF components, essentially standard axial resistors and capacitors without leads, just metal end caps soldered directly on to the PCB.

Looking at the circuit shows the ICC5 to be very unusual in employing a thyristor in series with the scan coils and a winding on the LOPT operating in class D. The majority of the frame processing is buried in IL14 a TEA2029C IC, checks showed a healthy sawtooth at pin 5 but nothing at pin 4. I removed the thyristor DL22, but tests proved it to be blameless, Chris kindly supplied a replacement IL14, but it still refused to generate any output. The problem with these later field circuits is that you have a kind of chicken and egg situation as I mentioned earlier in the G6 posts when talking about field generators ICs where the driver won’t give any output unless there’s some feedback. A little trick I learned was to generate some artificial feedback and see if it would open the driver. A wet finger on the feedback pin 2 immediately produce a rather ragged 50Hz buzz from the LOPT and a rather contorted field scan on the CRT. I soon found the height pot in the feedback path to be o/c, a first for me on an ICC5.

On fitting a replacement and switching on the results took my breath away, the picture was absolutely superb, it’s probably as a good as the day as the set was unboxed. I knew the CRT being a Philips 45AX would be decent, but not this good.

Sorry for this rather long post, but I think this much maligned set deserved it, and thanks for saving it Rich, it was well worth it. It helps that without the complications of NICAM and N/S correction, the latter needed with Super Planar CRTs the chassis is easier to handle, as the two large extra PCBs made it a bit unwieldy.

One last thing, while I had the set plugged it but not turned on the RIFA cap or WIMA in my case let go while my back was turned, filling the place with white smoke and leaving a smell for many days. The filter network unfortunately in on the unswitched side of the mains.

1
2
3
cct

John.

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Topic starter Posted : 08/07/2021 8:41 pm
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Red_to_Black
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Nice one JC 
I have had that fault a handful of times, but as you say it is not one of the more usual fault/s that causes this symptom.
I have had to replace quite a few of the other pots along "the back wall" on this chassis before as well, but not for this fault but because they have gone extremely noisy/scratchy and you couldn't set up the geometry properly.

The TEA2029C (IL14) chip is very reliable on this chassis and only very, very rarely to blame for faults, I have replaced it myself many times as well (as I had spare ICs to hand) as it is easier to rule it out early doors when you have some of the more obscure faults.

If you want to reset the child lock Pin number on these go into reset Pin menu then when it requests the 'old pin number' press the usual RGB and Y for five seconds that is commonly used for just clearing the child lock, this then allows you to change to a new Pin no.
Incidentally if the Pin has never been changed from new then the factory default code was 0000 

 RE: the Point of Sale message, this only still worked though if certain channel positions hadn't been renamed/over written, something like channel positions from beyond 10 to 30 IIRC, which reminds me, you also had to check all of the channel positions before re-sale in case someone had renamed them with naughty four lettered words 
Ps. I probably have the details for calling up the PoS message, it was something along the lines of pressing and holding Vol up and CH down on the sets local buttons while switching the set on at the main switch, or vice versa, I could probably look it up if wanted.

this is a slight copy of two posts added by myself on UKVRR forum but clarified a bit better  😊  re: child lock mainly for technical information to be added on this forum too 👍

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 08/07/2021 8:49 pm
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Lloyd
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Well saved! Picture looks excellent on it, tube looks like it's got loads of life left in it yet. Closest thing I've got to that is an ICC3 in a B&O frock, the MX2000, it doesn't look anywhere near as good as your Fergy though, I think my tubes a bit clapped out, coupled with a dodgy screen pot on the LOPT making the brightness fluctuate annoyingly at random times!

Regards,

Lloyd

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Posted : 08/07/2021 8:54 pm
Red_to_Black
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Another point on this chassis(mainly for people not familiar with it) is that the heatsinks, both line and chopper are also part of the chassis return paths and should be also stripped of old solder cleaned and re-soldered just like some Sony late crt sets, they are part of the circuit. 👍

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 08/07/2021 9:04 pm
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crustytv
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I'm absolutely stunned by the quality of that picture, it's outstanding! This is the first time I've ever seen an ICC5 chassis set, all I've heard is people saying how awful they were, rarely singing their praise. A good save and I think a very clever addition to your emerging collection, John. 👍

I have a feeling the much maligned later sets might start to get a following, I wonder how many have survived? I suspect very few compared to the abundance of 70's sets.

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Posted : 08/07/2021 9:24 pm
Red_to_Black
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Yet another strange feature of this version of the chassis (not that it applies now of course!) is that with the set in text mode you could adjust the text contrast by using the contrast buttons on the remote(note this did not affect the sets normal contrast status whilst in this mode) this can be stored using the red fastext key as 'normal/preferred preference' so long as the osg was still on screen as the red key was  pressed, this also applied for any other setting of the analogue controls for preferred preference ie. by pressing the red key whilst whatever OSG was still on screen, you could also adjust the colour (saturation) of the text display by using the colour control in this mode, B&W text anyone? 😊 This due to the way the colour decoder chipset is arranged  on this set.

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 08/07/2021 9:33 pm
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Red_to_Black
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@crustytv

I knew you would come round to my way of thinking 😉 , it is just that they were a very compact chassis, complex and quite unusual for the day coupled with early SM components (MELF resistors, [metal endless leadless frames]) led them to to be much maligned somewhat unfairly imo, poor soldering at production/assembly didn't help of course.

Although Thomson had used the novel thyristor field output stage prior (ICC4 at least) it was not common in the UK at that time.

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 08/07/2021 9:43 pm
Jayceebee
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Thanks for the kind comments, as soon as I saw the picture of it in the skip straight away I thought I could do something with it, plus for a 24" it has quite a small footprint. As I say it's probably the simplest version of the ICC5 series and because of the 45AX CRT probably the coolest running. Change to a Videocolor CRT with it's toroidal coils and things changed, as others have said they lost their first flush of youth quickly. The line output and E-W stages could suffer very badly from overheating components and the MELFs together with the print could suffer badly. Stick a Super Planar CRT in it and there had better not be any radiator or other ferrous metal object within ten feet or the purity could suffer badly. Once you got to know it's foibles they weren't so bad unless ran 24/7. Unfortunately what followed was not great, ICC9 and beyond some were just a sick joke on us. I think it was the ICC19 that would trip a few seconds after switch on because a slightly soft CRT couldn't reach a set beam current in time after just a year or two old

Baz, the heatsinks were the very first thing I checked when I took the back off and also that the reservoir cap had bleeder resistors fitted 👍

John.

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Topic starter Posted : 08/07/2021 9:52 pm
Red_to_Black
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One last quirk of this version of the chassis (are there any more? 🤣 ) is that when in AV (scart mode) pressing the text button put them into RGB mode on the vast majority, on some later versions this put the set into S-Video mode, mainly the 'Q' versions but I could be wrong here 😎

Thanks JC, I thought you would have known about heatsinks 👍 , it has caught out many an otherwise competent engineer though that was unfamiliar with the 'quirkiness' of this chassis, mind so did Sony 🙂

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 08/07/2021 10:03 pm
Till Eulenspiegel
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As I have mentioned elsewhere a number of 21" ICC5 sets were made with a 90 degree CRT. These proved to be very reliable. Receiver was housed in the strange looking "Interiors" cabinet. Symmetrical styled cabinets for the stereo models. But the really odd looking set was the mono version. Nevertheless, the sets were well liked by owners or renters.

Till Eulenspiegel.

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Posted : 08/07/2021 10:06 pm
crustytv
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Posted by: @red_to_black

early SM components (MELF resistors, [metal endless leadless frames])

I guess that must be what this extract from a 1985 Ferguson Feedback was introducing https://www.radios-tv.co.uk/vintage-electronics-blog-forum/thorn-advice-on-the-emergence-of-chip-components-smd/

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Posted : 08/07/2021 10:30 pm
Red_to_Black
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It wasn't just MELF resistors, there are low-ish value MELF capacitors too, these have a lime green body which you may be able to see from Johns picture of the bottom of the pcb, although it must be said I can count on one hand (ok maybe two!) the amount of faulty MELF components I ever needed to replace in a few hundred of these sets that passed through my hands! Mostly the usual high value resistors with high-ish voltage across them, so pretty much the same as any other set

The main problems down to dry joints were due mainly to 'high mass' items such transformers, heatsinks, inductors etc...etc. all usually carrying high currents at line frequency so pretty much again the same as other sets really.

The ICC5 didn't use any SM semiconductors, neither did the IKC2, nor the ICC7/8, no, oh no that special place in TV engineers hell was reserved from the ICC9 and IDC2 onwards 😉 .

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 09/07/2021 5:39 pm
Till Eulenspiegel
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Picture of my Ferguson 51K5.

Ferguson 51K5 (2)
Ferguson 51K5 RCU (2)

 Till Eulenspiegel.

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Posted : 09/07/2021 6:59 pm