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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

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Old 20th Mar 2012, 1:09 pm   #21
ppppenguin
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Default Re: Auroras at Crowthorne Tubes

The Domino was an excellent product in its time and the price was fair. It's just that the Aurora is both cheaper and better in every respect. Apart from a troubling tendency to get lost behind the sofa
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Old 20th Mar 2012, 4:31 pm   #22
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Default Re: Auroras at Crowthorne Tubes

Mine was the one with the intermittent "F" connector. It was one of the very first to be shipped in May 2006 (apart from Jeffrey's evaluation units). I connected it up to a dual-standard TV which hadn't seen a VHF signal since 1985, but I couldn't get a peep out of it! The fault cleared after a bit of fiddling with the cables, and didn't return for some years.

Being one of the early ones, the "sleep" feature kept catching me out, so Jeffrey very kindly updated the firmware, to make the feature optional. The unit survived the journey to and from North London without the fault putting in an appearance.

It was only a few months ago that the fault returned, and stayed just long enough for me to measure a dead short at the RF output. As soon as I had measured the short, it was gone. It continued to come and go, and the unit was becoming unusable, so something had to be done.

With Darryl's guidance, I removed the connector from the board (a difficult job involving two soldering irons and a lot of bad language) and dismantled it to find the swarf that had caused all the grief.

I should mention that Darryl had offered to replace the unit, despite it being over 5 years old, so I did have that option if my attempt at repair had failed.

I was pleased to find the fault at last, but that connector was a pig to remove, and I wouldn't want to have to do another. The chances of this happening to any other Aurora are slim indeed, so I don't think we need to worry.

The attached photo shows the connector, with the threaded barrel removed. The swarf can be seen as a thin dark line against the translucent insulation. It had been resting against the centre pin, making and breaking contact at random.

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Old 20th Mar 2012, 4:54 pm   #23
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Default Re: Auroras at Crowthorne Tubes

Thanks for posting Roy.

I am still amazed (and grateful) that you were not only able to get the connector off the board (a feat in itself!) but to disassemble the connector and find the fault. The picture is simply amazing. Roy and I corresponded about this for a while trying to determine what was going wrong, and taking a few measurements, but Roy's initial suspicions proved to be correct in the end. Myself and Tyco (the connector manufacturer) owe Roy a beer for this one!

Darryl
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Old 20th Mar 2012, 6:29 pm   #24
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Default Re: Auroras at Crowthorne Tubes

Or my Dinosaur.
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Old 20th Mar 2012, 10:07 pm   #25
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Default Re: Auroras at Crowthorne Tubes

Hi.
It would be interesting to see who were the original buyers of the multi-standard and SCRF converters in the UK.
The only other Multi-standard owner I know of is David Boynes!
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Old 21st Mar 2012, 5:00 pm   #26
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Default Re: Auroras at Crowthorne Tubes

I think my Domino was the very last one built; the web-site had announced it 'no longer available', but an e-mail enquiry resulted in my getting one after all. 400 turned an academic interest into a real hobby.

I still use it, and in comparison with the Aurora I think it's slightly 'raggy' on fast pans & the like. Perfectly good for everyday use.

Can anyone enlighten me about an odd phenomenon concerning American DVDs and British players. My aurora 'can't see' the picture from a US DVD, but a British 625-line TV can. I suspect that the video-out signal from the DVD player is some intermediate, non-broadcast TV standard, not listed in 'World TV Standards', and that this standard is close enough for a 625 set to cope, but not an Aurora.

Am I anywhere close, and if so, is an Aurora available for it?

Last edited by Brigham; 21st Mar 2012 at 5:02 pm. Reason: Dinosaur instead of Domino
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Old 21st Mar 2012, 5:11 pm   #27
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Default Re: Auroras at Crowthorne Tubes

I don't think either the Domino or the Aurora could cause ragging on pans. This is simply because neither does any interfield processing.

The problem with playing NTSC (strictly 525/60) material on a PAL (strictly 625/50) player is that the line and field rate will be 525/60. The colour subcarrier is coded as 4.43MHz PAL. This is the same as with most multistandard VCRs. Most TVs will be entirely happy with this but converters will not be.

There is no simple answer to converting 525/60 to 405. I think the expensive Aurora World Converter will do it. Alternatively some players may convert to 625/50 internally. The final approach is there may be software based converters that can convert the files on a DVD from 525/60 to 625/50. This need not be done in real time and the result can be burnt to a writeable DVD.

It would be theoretically possible to make an SCRF converter that takes 525/60 and outputs 405/60. Whether vintage TVs would like the non-standard field rate is another question. I don't think this is a sensible approach.
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Old 21st Mar 2012, 5:42 pm   #28
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Default Re: Auroras at Crowthorne Tubes

My guess is the DVD is outputting 525/60 with 4.43 chroma as Jeff suggests. In this case no rate conversion is being performed since most modern television will lock to just about any format.

One of the initial cost reducing measures I took on the SC converters is they cannot do any rate conversions. Since most people will be using their antique sets in the country of origin, or at least a country that uses the same mains frequency, this is usually not a problem. Adding rate conversion adds substantially to the cost and complexity of a converter.

I did create the SCRF-343A converter for just this occasion. Since the line frequency of 405/25 and 343/60 are nearly identical, one can operate a 405 set using a 60Hz source by only adjusting the frame rate of the set from 50 to 60.

Darryl
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Old 21st Mar 2012, 6:07 pm   #29
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Default Re: Auroras at Crowthorne Tubes

Presumably there's not enough space in the FPGA to make a switchable 405/50 and 343/60 converter, possibly with autosensing of input field rate.
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Old 21st Mar 2012, 6:25 pm   #30
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Default Re: Auroras at Crowthorne Tubes

Not with the one that is currently being used. I could go with a larger part, but that would raise the cost and I'm not sure if it would benefit very many users.

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Old 21st Mar 2012, 6:51 pm   #31
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Default Re: Auroras at Crowthorne Tubes

What's the likelihood of a domestic 405 set being able to manage 60 fields? Beyond the normal frame lock, I imagine. The mains frequency shouldn't be significant; we used to be on 40 cycles hereabouts, and we all watched TV.

Can the WC-01 do it? Perhaps it's time to bite the bullet: $1360 US is about 858 at the moment. Customs would probably bump it up, but it could still be under a grand.

I'll re-assess the ragging. I've not played the disc direct to 625, so it could be any one of a number of causes, or possibly my incorrect observation.
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Old 21st Mar 2012, 7:14 pm   #32
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Default Re: Auroras at Crowthorne Tubes

The WC-01 can do anything in to anything out. You just select the output standard and feed it with NTSC/PAL/SECAM. There would be no need to operate the set at 60Hz since it can convert 525/60 to 405/50.

The $1360 price is only if you require the optional driver board for mechanical televisions and even then this can be done externally by the user. The price for the unit is $985.

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Old 21st Mar 2012, 9:19 pm   #33
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Default Re: Auroras at Crowthorne Tubes

I have a Pioneer DVD player which will do NTSC>PAL. I just tried it with the SCRF-405A and I get sound only. Whereas my 1987 Ferguson will happily display a stable colour picture. I guess that means it (the Pioneer) is sorting the colour but leaving the lines/frames alone.

Regards,

Paul
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Old 22nd Mar 2012, 12:47 am   #34
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Default Re: Auroras at Crowthorne Tubes

Yes, that's exactly what I get, the DVD sound imposed on the built-in testcard. It seems that British 625-line sets can resolve US 525-line TV. Can you hear the drop in the line whistle?
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Old 22nd Mar 2012, 7:51 am   #35
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Default Re: Auroras at Crowthorne Tubes

PAL: 15625Hz; NTSC: 15734Hz (approx) About 0.7%, about a tenth of a semitone. Assuming you can hear those frequencies at all I think even a trained musician wouldn't notice that. You might just hear a beat note if there were PAL and NTSC sets operating in close proximity but I've never heard it myself.

If a set has an audible frame timebase the difference between 50Hz and 60Hz is very obvious.
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Old 24th Mar 2012, 10:16 pm   #36
Andy Green
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Default Re: Auroras at Crowthorne Tubes

Quote:
Originally Posted by murphyv310 View Post
Hi.
It would be interesting to see who were the original buyers of the multi-standard and SCRF converters in the UK.
The only other Multi-standard owner I know of is David Boynes!
I bought both the first multi standard type around 2004, and later a SCRF with the 405 NTSC option
(Although I am not in the UK, I am in the Republic of Ireland!)

Andy, EI3HG
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Old 24th Mar 2012, 10:53 pm   #37
murphyv310
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Default Re: Auroras at Crowthorne Tubes

Hi Andy.

I have two of the NTSC SCRF 405 line auroras, one of my off screen pictures from my modified Decca using Darryl's NTSC SCRF converter appears on Darryl's website.
Meanwhile the Multistandard converter carries on without a glitch, I find that it is one of the best pieces of equipment I have ever bought.
I would also say that the RT Russell Test Card Generator is another excellent piece of kit.
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