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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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20th Jul 2018, 8:34 pm | #21 |
Tetrode
Join Date: Sep 2017
Location: Waalre, Netherlands
Posts: 67
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Re: Tuners in Philips G6-G11 CTV chassis
Hi Synchrodyne (post #19),
to be honest I have no clue (yet). In a sense it is very surprising to have Philips sets with rotary tuners as late as 1975 (K9 chassis). By then the standard sets were already at the third generation varicap tuners! Assuming you're right, however, and that indeed by then still rotary tuners were used, I can only link this to the non-availability of a matching varicap tuner. Which could or could not have had to do with the IF changes in Australia. In the end it was a business decision to develop a specific derivative or not. Again, some more detailed info about the actual tuner used in the Philips sets in Australia could help to narrow down the discussion. Cheers, Pieter |
20th Jul 2018, 8:38 pm | #22 | |
Nonode
Join Date: Sep 2017
Location: Stockport, Cheshire, UK.
Posts: 2,002
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Re: Tuners in Philips G6-G11 CTV chassis
Quote:
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20th Jul 2018, 10:36 pm | #23 |
Hexode
Join Date: Mar 2014
Location: Dublin, Ireland
Posts: 398
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Re: Tuners in Philips G6-G11 CTV chassis
Just to elaborate slightly - specs for Philips VHF tuners of the era explicitly included system 'I' in the list of systems covered (systems B, C, D & I)
J Last edited by kan_turk; 20th Jul 2018 at 10:44 pm. Reason: Word omitted |
20th Jul 2018, 11:34 pm | #24 | |
Nonode
Join Date: Jan 2009
Location: Papamoa Beach, Bay of Plenty, New Zealand
Posts: 2,944
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Re: Tuners in Philips G6-G11 CTV chassis
Quote:
The picture includes the front page of a servcie manual that is labelled "K9A", in which the "A" suffix might mean the Australian variant. On that page one may just make out that the VIF was 36.875 MHz, the later standard Australian value. Cheers, |
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20th Jul 2018, 11:46 pm | #25 | |
Nonode
Join Date: Jan 2009
Location: Papamoa Beach, Bay of Plenty, New Zealand
Posts: 2,944
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Re: Tuners in Philips G6-G11 CTV chassis
Quote:
The SAWF makers catered for a variety of IFs from the start. I have an early Plessey datasheet, undated - but the fact that it refers to the SL1430 IF preamplifier rather than the SL1431/2 is the “tell” - that includes the SW453 for South African system I with a 38.9 MHz VIF. Cheers, |
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21st Jul 2018, 2:45 am | #26 |
Nonode
Join Date: Jan 2009
Location: Papamoa Beach, Bay of Plenty, New Zealand
Posts: 2,944
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Re: Tuners in Philips G6-G11 CTV chassis
More on the Australian K9A at:
http://www.videokarma.org/archive/in...t-237987.html; and: https://www.radiomuseum.org/r/philips_02kd254_k9a.html The first suggests that the rotary VHF tuner was a locally-made unit. Cheers, |
21st Jul 2018, 8:20 pm | #27 |
Tetrode
Join Date: Sep 2017
Location: Waalre, Netherlands
Posts: 67
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Re: Tuners in Philips G6-G11 CTV chassis
Interesting findings on the Australian Philips chassis!
The fact that the rotary tuner in the Australian K9A chassis had to use the new 36,875MHz IF meant that a "new" tuner had to be designed (Australian channels and IF). Given the date (10 years after the last known internal Philips rotary tuner design) makes it less likely this was a Philips tuner. At the same time it was customary to shift older models ownership to the more remote design and production centres, and as we know technologies have the tendency to live much longer than one expects. So it might equally well have been possible that some team somewhere designed the required new model. Only more detailed service info will tell us. Cheers, Pieter |
22nd Jul 2018, 1:04 am | #28 |
Nonode
Join Date: Jan 2009
Location: Papamoa Beach, Bay of Plenty, New Zealand
Posts: 2,944
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Re: Tuners in Philips G6-G11 CTV chassis
One possibility is that the tuner was simply carried over from preceding monochrome models. Philips Australia VHF tuners would have been “different” from that start, with the Australian channelling (inclusive of Band II and sub-Band III allocations) and the original 36.0 MHz IF. Adjustment to the 36.875 MHz IF was probably not a major operation – a slight change of local oscillator tuning relative to the RF tuning and a slight shifting of the tuning of the output coil, perhaps.
The Australian channelling might have been a bit of a challenge in the early varicap era, which in turn may have resulted in retention of rotary tuners for longer than was done elsewhere. Judging by the K9A pictures found so far, it had an actual rotary tuner and not simply rotary switching of a varicap type. This is deduced by the apparent absence of the pop-out present drawer at the bottom of the control panel. The following K9A-2 model had the regular K9 six pushbutton set for station selection. Presumably by the time it was released (1976-77?), varicap tuning covering all of the Australian VHF channels had been worked out. Here is a picture of another K9A version, showing the rotary tuner: https://www.radiomuseum.org/r/philip...?language_id=2. Cheers, |