Designed by: Steve Foster
Chassis: Telefunken 712
Notes: This set has the Chroma IIA with TDA 2140 & TDA2160, Chroma IA with a TDA 2150. Also fitted with the early Infra Red remote option.
This is evidenced by the 197 stickers on every module, this I have found out means it was produced in the 19th week of 1977.
Original List Price : £000.00 ( to be ascertained but was very expensive)
Integrated Circuits: Yes
CRT: Telefunken A66 500X
This is an iconic British designed set using the German Telefunken 712 chassis. I had been looking for a 70’s iconic set such as the Keracolor or the the Murphy “Accoustic-Deluxe”. The Keracolor was basically a Decca Bradford in Glam-frock, the Murphy you just don’t see coming available. The Aphelions crop up occasionally and when an opportunity arose that was the one I opted for.
The condition of the set is quite amazing with no damage. The electronics appear to be original with some surface rust in places suggesting it has been garage or shed stored for a number of years. The set is big and I mean BIG. my jaw dropped when the specialist courier arrived this morning to off-load on my drive. It somehow looked so much smaller in the photo before I purchased and the ones I’ve taken below don’t really give the right impression of its sheer size. Due to the shape this is a two man lift absolutely no way to move on your own. Its a 26″ CRT and the whole the thing is a weighty behemoth.
Background to the Aphelion and Steve Foster
This set was designed and initially released in the 1970’s by Steve Foster ( whom I have been in contact with, thanks for the info Steve) and is a high-quality receiver. Steve designed and made these for a company called ‘Rayleigh service centre’ based in Rochford Essex. It seemed that whatever colour he made when placed in the outlets window, (Colour Centre at Marble Arch) was the colour that sold. Many celebrities bought the Aphelion and it was featured many times on top of the pops, the Jo Brand show and showcased at the ideal home exhibition. It is also featured in a design icon book.
Telefunken was the chassis of choice but they did use two others, they were completed in a ratio roughly 80% Telefunken, 15% Grundig and 5% Philips. None of the cabinets were numbered. The estimate was they made approx 200 units and they came in white, fawn, black, pink and some specials. That was split roughly as follows :- 70% white, 15% fawn, 8% black, 7% pink, a red one, one yellow one and a purple one.
Steve relaunched the TV in the early 1990’s using the more modern 28″ Thomson Nicam TV chassis with SCART connectivity. In this second Thomson run they probably made only around 120. This means its fairly safe to say less than 400 Steve Foster Aphelion TV’s were ever made. From that number probably very few survive and especially the earlier 70’s production run like this one and I would imagine even less working.
You can follow this sets progress here or on the here
My 1977 Aphelion
Before We Start
The CRT needs to be tested, I’m sure most who follow these repairs know but for those who may have just dropped in here first, we test the CRT at the outset because the heaters may be o/c, there could be internal shorts or the cathodes very low emission. If any of these scenarios prove to be true then we will have saved much time, effort and components, no point wasting time if the set is a non starter. Of course if the CRT is low emission there is always the option of rejuvenating but the results are dependant on if its has been bopped before, this option is a last resort and should never be done until the TV has produced a raster.
The A66 500X is a 26″ In-Line tube with quick heating cathodes ( 5 seconds). The deflection angle is 110 degree and the tube is a 20AX. The “20AX” system is the first in the world to achieve a self-converging system for large screen sizes up to and including 26in in the 110° format. The 110° tube system achieves a more compact picture tube by deflecting the beam through a wider angle, allowing a usefully shorter neck and considerably reduced cone bulk.
In the case of this Telefunken A66 500X, I can confirm its a good one so the repair job is viable. Filaments are intact, no internal shorts, emission is good, tracking spot on and life tests show it to be a cracker. Remember the tube has likely been asleep for nigh on 30+ years, the emission will improve with use and this was further evidenced with the tube left running on the B&K, the meters showing a steady increase on all guns.
Finally with some help from a neighbour the Telefunken has made it into the workshop. Now an assessment of the electronics will be undertaken before applying power. You can begin to see now just how big this set is. Its sitting atop a 25″ Ferguson 3700, a BRC 2000 chassis based console colour TV. Anyone who knows the BRC 2000 console sets will know they are huge themselves, the Telefunken dwarfs it.
Without the aid of a manufacturers servicing manual I managed to figure out how the TFKN 712 chassis withdraws from the cabinet and folds. Underneath the main chassis I could see left and right were two substantial plastic side rails. Also underneath were two grooved bars, theses bars are pivoted on one end. These are swung left and right which unlocks the two plastic side rails. You then gently lift from the front and the side rails slip into the rails allowing the whole chassis to be extended out from the set by about a 1½ feet, this now gives plenty of clearance front, back and sides.
The two upright side panels have a locking hinge bar, when this is unlatched each panel can be swung down to a horizontal service position. Finally the Line stage cage can be hinged up giving access to the the components within. All in all superb access is afforded to the service engineer, I’m sure many who were called out to this type of chassis would have been grateful for the access give by the designers.
Now I can start to visually assess each panel and look for anything untoward, dry joints etc before applying first power
The TFKN 712 chassis like most sets of this period including British ones, employed a modular chassis design. As mentioned above the chassis is modular design, the modules being grouped in three main assemblies.
1) The signals board which has Video, I/F, sound, Tuner Chroma I, Chroma II and RGB
2) The deflection board which has the vertical output, vertical oscillator, E/W pincushion, Sync and power supply module
3) The Line output board
I can now use the bench microscope to inspect all the daughter boards fro problems.
Some of the boards removed for inspection.
Found and replaced one of those notorious WIMA’s (C401) in Power supply module I, which was blown. Tested the main smoother (C403) which is looking good. Next onto Power supply module II
Power Supply II, the Thyristor regulator module. An in circuit test revealed C427 10uF @ 100V was o/c. Removed and confirmed. I’ve fitted a 10uF 400V. Also The large can C441 2200uF @ 40V read as leaky everything else checks out OK. Perhaps these 3 cap failures in the power supply modules are the reason the set was retired. Checked C441 on the bridge at rated voltage yep its totally o/c.
Inspected, tested and cleaned the deflection modules today, Sync,E-W correction, Vertical Osc and Vertical output. The only cap to fail as leaky was C492 2200uF 35V on the Vertical output module. If anyone is keeping tally on the purple perils, on this suite of modules six purples tested with one failure. Total tested thus far including the PSU modules, 10 with 2 failures. There’s still a load more on the I/F, sound, RGB and line timebase.
Removed the RGB module from the signals board, tested the three electrolytics, all passed.Upon inspection under the bench scope a dry joint was found on one leg of C345 in the blue drive. Hard to see in the photo but when waggled, the leg moves in the pad. Other than that all appears OK.
Power Supply Module I
Power Supply Module II
Next up for testing : Line timebase
Unlike the rest of the set the Line timebase panel is fixed to the right hand frame. From the vertical position its frame can be swung to latch at 45 degrees or 90, thereby affording good access. I’m beginning to really like the thought that has gone into the design of this chassis. Telefunken went even as far as to include expected waveform diagrams at the test points on the print side, in the form of additional screen print.Anyway back to the status, C584 1000uF 50V was the only electrolytic found to be faulty, it was leaky and replaced.
Its difficult to get across just how well thought out this chassis is, the modular approach is taken to a new level with virtually every element of the set broken down like a circuit block diagram but represented as daughter boards. You can remove every element, RGB, Sound, I/F, Chroma I and Chroma II. Simple interconnect edge pins, a few locating screws and out they all pop. Makes testing and isolating a complete breeze. Then over to the two PSU modules which again are simply removed via a couple of screws and interconnects. The Deflection board is the same story, with the sync, e/w correction, vert osc and vertical output. finally the line timebase is the singular largest module.
Not forgetting that the modules can be mounted in the reverse side of the signals ground plane board which eases the ability to do in-circuit testing on the chosen board. This is a great idea and one I have encountered before on the thorn 9000 series chassis but not to the degree available on this set, all very impressive.
All the modules were re-installed and the set powered up, presented with a rather Red but full screen raster.
The fire up the Test Card generator, fed in test card F.Well the decoders working but the colours are not great due to the dominance of Red. I Need to do some checks maybe its been twiddled or perhaps some voltages/waveforms are astray, we shall see.Well the decoders working but the colours are not great due to the dominance of Red. I Need to do some checks maybe its been twiddled or perhaps some voltages/waveforms are astray, we shall see.
There is a problem with Red drive, this is confirmed with the scope.
There has been much confusion with service data and my Chroma IA and Chroma IIA boards with regards to component variances especially the IC’s. The only service data I have is the Trader sheets and Radio & Television Servicing, both show different IC’s and number of. A fellow member found me data from another model which appears to be a match for my set up.
The boards varied mine being populated by Telefunken TDA 2140, TDA 2150 and TDA 2160 and are more akin to the 714, the rest of the set matches the 712. Below the Chroma IIA from the 714
From the waveforms above it would suggest IC302 – TDA2160 the Synchronous demodulator and RGB matrix is faulty.
After much in-depth testing on the IC it was found to be innocent. The fault turned out to be far simpler but odd, a track in the Red circuit had been deliberately cut, quite why will remain a mystery. Track repairs were performed resulting in the red drive being restored.
Red drive virtually non existent
Bread board piggy backed onto Chroma IIA IC output for red transposed to green circuit, if the IC is faulty then Red will work. It didn’t this test confirmed the IC was not faulty and the error condition must exist on the RGB board and the red circuit.
Cut track found, why was it cut?
Close up under bench microscope
Now for the repair. Old tracks each side of the breach prepared and ready for new copper.
Red drive restored
Bread board and hard-wires removed, IC socket reinstalled along with the IC, low and behold we are in business.
Update: Almost time to put the back on
Picture centred, to adjust the picture shift, you need to short-circuit two pins ( SV562) on the E-W module. You then adjust R452(Vertical Freq) on the oscillator board for centre. Then adjust R517 ( for full width), R561 ( to correct trapezium distortion) and finally readjust width via R518 for slight over-scan. SV562 on the module fitted to this set was labelled SV502.
Then it was re-grey-scaled, result below.