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1977 Aphelion TV :Telefunken 712 Chassis

Pre War 240/405, Post War 405 Line, B&W Dual Standard, Colour Dual Standard, B&W S/S 625, Colour S/S 625 line, Hybrids. Standards converters & modulators, video recorders.
 
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Re: Telefunken Mystery : Model unknown : Chassis Telefunken

Post by CTV » Thu Jul 28, 2016 1:21 am

Thanks to a volunteer the question has now been posted on RM :thumb

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by CTV » Mon Aug 01, 2016 6:48 pm

Would anyone know where on this circuit the picture shift control pre-set is. The test card is slightly shifted to the left and I've yet to fathom how to shift it to the right.

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by jayceebee » Mon Aug 01, 2016 7:05 pm

If there is no line shift pot then there will be two pots on the line generator PCB. One will be the osc freq the other will be line phase, use this to centre the picture.

John.

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by Red to black » Mon Aug 01, 2016 7:19 pm

I only have the 714 diagram,
there is the line hold and line phase pots on the Synchronisier Baustein,
I don't know if the same adjustments are present on the 712, the width adjustment is on the Zeilen Baustein on that diagram.

You may be able to tweak these adjustments if the shift is not too far out.

Edit: cross posted with 'J' :qq1 (Jaycebee) :aak

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by CTV » Mon Aug 01, 2016 8:03 pm

OK I seem to have found the procedure your word clue 'Phase', setting me on track. The procedure does appear convoluted and there seems to be a screen print discrepancy on the E-W module. To adjust the picture shift, I 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. There does not appear to be SV562, there is an SV502 so I guess as is two pins that must be the one or maybe not.

Oh and I found the Remote enable disable on the deflection panel Google Translate helped "Mit Fernbed", "Ohne Fernbed"

Edit: Don't suppose anyone's got a Telefunken 712 remote approx 1976-1978, knocking about in their spares.

remote.jpg

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by CTV » Mon Aug 01, 2016 8:47 pm

Its pretty much there now, Its been centred and re-grey-scaled and I think its looking much better than the last time it showed TCF. All I want to do is run the scope over the decoder to ensure all is peaked as it should be. Problem there being information on setting it up is thin on the ground. Then it will be close up time, I may even do that now and quit whilst I'm ahead.

lastest.jpg

improve.jpg
Before and after picture centring and re-grey-scale

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by PYE625 » Mon Aug 01, 2016 8:51 pm

Very nice !! :aad

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by marc » Mon Aug 01, 2016 9:11 pm

It's looking well Chris :aad

Marc.

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by Doz » Mon Aug 01, 2016 9:18 pm

Very smart ...

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by The_Teleman » Tue Aug 02, 2016 8:10 am

That is excellent Chris , what a cracking set

Well done ! :aad

Chris

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by Cathovisor » Tue Aug 02, 2016 8:36 am

I was going to say, look for a pot labelled Zeilenphase but it seems you've done what needs to be done...!

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by sideband » Tue Aug 02, 2016 1:44 pm

That is an absolute cracker Chris! Well done and excellent work. :aad

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by malcscott » Tue Aug 02, 2016 4:17 pm

Well done Chris :thumb

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by yampy187 » Tue Aug 02, 2016 4:32 pm

Cracking set Chris! Well done mate!

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by CTV » Tue Aug 02, 2016 7:15 pm

One thing I completely forgot to address was the touch tuner user interface panel . It all works OK but only 3 of the indicator lights illuminate. I've not removed the unit yet but looking at it there appears to be little lamps all soldered onto the PCB. Has anyone come across these type before and would anyone know of an equivalent source. I'm still trying to find info on the Trader data, I could leave it as the set functions perfectly fine but it seems a shame to leave only three working. I vaguely recall mention British sets used something similar and the bulbs often blew.

chansel.jpg

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by Doz » Tue Aug 02, 2016 7:27 pm

What voltage are they chris? You maybe able to modify some of the little 12 capless blubs that fit car dashes, and rear central brake lights.

Peugeot 206 CC rings a bell.

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by jayceebee » Tue Aug 02, 2016 8:04 pm

The channel indicators used in touch tune sets of British manufacture were usually neon lamps. Using filament lamps would be unusual I would have thought due to their inherent unreliability but I may be wrong.

Looks very good now Chris.

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by Cathovisor » Tue Aug 02, 2016 8:19 pm

CrustyTV wrote:One thing I completely forgot to address was the touch tuner user interface panel . It all works OK but only 3 of the indicator lights illuminate. I've not removed the unit yet but looking at it there appears to be little lamps all soldered onto the PCB. Has anyone come across these type before and would anyone know of an equivalent source. I'm still trying to find info on the Trader data, I could leave it as the set functions perfectly fine but it seems a shame to leave only three working. I vaguely recall mention British sets used something similar and the bulbs often blew.

chansel.jpg

I'd say, "try Cricklewood".

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by CTV » Tue Aug 02, 2016 8:28 pm

Here they are, they do look like little neons, I have some similar that were recovered form a B&K tester but they are fatter and a fraction longer. They have component designations of LA10xx so I can try and see if the German manuals/ccts have any component details.

ch-1.jpg

ch-2.jpg

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by rob t » Tue Aug 02, 2016 8:31 pm


 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by jayceebee » Tue Aug 02, 2016 8:53 pm

From those pictures it difficult to tell but just look at the naked lamp with the set on. You can't mistake the orange glow of a neon.

As an aside I wonder why it seemed only German manufacturers adopted thyristor line timebases, did anyone else try them (Salora)?

We at Thorn had some imported 14" models as a stopgap until the TX9 was ready, the Ferguson 3787 and rental 8787 and 8180 fitted with the Nordmende F VI chassis (Nicknamed No Mendy) :bba

They sat unrepaired and unloved in the corner of most stock rooms until to shift them the company offered them to staff for for £5. To be honest they weren't too bad but not a patch on a PC1044 version TX9

Baird Model 8180 clone http://www.radiomuseum.org/r/nordmende_ ... _4201.html

John.

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by sideband » Tue Aug 02, 2016 9:49 pm

To be honest Chris, they look like ordinary bulbs....not neons. It should be possible to measure the voltage across the working bulbs. I have a few wire-ended bulbs knocking about. If they are neons, you can't mistake the orange glow and I would think that almost any small neon would work as a replacement.

Most small neon tubes that I've seen have two parallel bars inside without a supporting blob. That's what makes me think these are ordinary bulbs.

I wonder how long that fossilised spider has been there......!

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by Red to black » Tue Aug 02, 2016 10:07 pm

Agree with SB they look like ordinary lamps rather than Neons for pretty much the same reasons.

Hi Jaycee, I can only think of Grundig, Nordmende and Telefunken (German of course) and possibly Salora (Finland), not forgetting the Redifusion MK3 with Thyristor LOPT stages.

Was the Redifusion/Doric MK3 a German design ?

Edit: What about Sony with their GCS LOPT stage ?

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by jayceebee » Tue Aug 02, 2016 10:24 pm

Sony GCSs, now you shouldn't be mentioning those at this time of night, there might be ex engineers of a nervous disposition reading this. You'll give them nightmares. :ccf . Thankfully never had the pleasure.

Something in the back of my mind said Rediffusion MK3, again a set I have never encountered. I once repaired a MK4 but I think that was back to a BU208?

John.

 
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Re: Telefunken 712 Chassis: Early Aphelion?

Post by Red to black » Tue Aug 02, 2016 10:32 pm

jayceebee wrote:Sony GCSs, now you shouldn't be mentioning those at this time of night, there might be engineers of a nervous disposition reading this. You'll give them nightmares. :ccf . Thankfully never had the pleasure.

Something in the back of my mind said Rediffusion MK3, again a set I have never encountered. I once repaired a MK4 but I think that was back to a BU208?

John.


Yes, the MK4 used a transistor,
Salora I cannot recall if it was the F or G chassis that might have had a Thyristor LOP, I didn't see many as they were mostly old trade ins (scrap), I could be confusing one of these chassis that had a Thyristor PSU only, as I say I saw very few and serviced none.

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