I've heard that modern TVs have problems with some "classic" home computers like the Sinclair ZX81.
For exactly the same reasons.
The question is why this didn't cause a problem on older CRTs in the first place though
Simply because they were purely analogue, and could thus easily cope with (in fact not even notice) considerable variations outside their design specifications.
For example, with a VCR, the speed of it is continually adjusting to maintain the tracing etc. - on old TV's you had to alter the time constants in the line sync stages to compensate (which is also what the special VCR button did).
Modern TV's, as VCR is long obsolete, have no need to try and cope with it - so it's not included in the design specs.
A Panasonic and a JVC (both S-VHS), still going strong after many, many years of service. Not used anwhere near as much these days, just very occasionally (maybe twice a year) when my PVR is recording two channels but I want to record a third programme (the Panasonic has a Sony Freeview box attached for emergencies).
In my spare room there's also a Samsung VCR from the late 80s that still works fine, along with a Sony that was my parent's, and it still works fine too.
I also had an Akai VCR that one of my friends gave me, it worked fine for about a year but now gives an awful picture despite proper cleaning. Not worth any further investigation and repair, even if the repair only costs a tenner. Oh and the remote is missing too.
I'm not exactly confident with fitting plugs on things, as I am no expert with electronics!
You don't exactly need to be an expert! Its very simple. And iirc its something they taught everyone at school... And something everyone should know how to do!
Poor design of TV then. If I bought one like that it would go straight back.
Seeing as VCRs can still be bought new in the shops (usually with a DVD in the same box) they can't be described as obsolete so any modern TV should be expected to work with them.
Very easy fix for this though -- just push the signal through some sort of frame buffer.
Easiest solution for this would be an older DVD recorder, many of which digitise the image as they're going along. As they tend to be older, they're more tolerant.
Once they've taken the analogue signal, digitised and buffered it, and then reconverted it to analogue again, the resulting signal will be happily accepted by the newer TV.
Simply because they were purely analogue, and could thus easily cope with (in fact not even notice) considerable variations outside their design specifications.
I appreciate that when it comes to VCRs and the like (I touched upon it when I mentioned the signal being digitised).
Maybe I wasn't clear, but the comment was meant specifically about the ZX81 black level issue. My point being that if the white-picture-where-the-black-level-should-be-expected wasn't causing a problem, that implies older TVs didn't pay attention to any black level in the first place (since they wouldn't have "known" that a ZX81 rather than "normal" TV signal was connected), so why was it in the spec?!
The [1981-era] video detector detects the current of the video signal as it is supposed to be - none of this "expects" rubbish, it expects a video signal, including black level or any other kind of level.
Yes, but like I said if it doesn't use the black level, why did they bother with it at all?!
My pet hate with VCRs was tracking problems with HiFi sound. I know they were supposed to track automatically but often didn't. You bought a new film on VHS and the first time you played it hoped it would be OK. Sony VCRs were the worst for this problem.
Poor design of TV then. If I bought one like that it would go straight back.
Seeing as VCRs can still be bought new in the shops (usually with a DVD in the same box) they can't be described as obsolete so any modern TV should be expected to work with them.
My pet hate with VCRs was tracking problems with HiFi sound. I know they were supposed to track automatically but often didn't. You bought a new film on VHS and the first time you played it hoped it would be OK. Sony VCRs were the worst for this problem.
Never had any real problems specifically with HiFi VCR's - obviously head wear was the largest problem with HiFi, as the HiFi heads generally wore out a lot faster than the video heads - and specifically one channel (I can't remember which it was now?, but it was the higher frequency one).
Comments
For exactly the same reasons.
Simply because they were purely analogue, and could thus easily cope with (in fact not even notice) considerable variations outside their design specifications.
For example, with a VCR, the speed of it is continually adjusting to maintain the tracing etc. - on old TV's you had to alter the time constants in the line sync stages to compensate (which is also what the special VCR button did).
Modern TV's, as VCR is long obsolete, have no need to try and cope with it - so it's not included in the design specs.
In my spare room there's also a Samsung VCR from the late 80s that still works fine, along with a Sony that was my parent's, and it still works fine too.
I also had an Akai VCR that one of my friends gave me, it worked fine for about a year but now gives an awful picture despite proper cleaning. Not worth any further investigation and repair, even if the repair only costs a tenner. Oh and the remote is missing too.
You don't exactly need to be an expert! Its very simple. And iirc its something they taught everyone at school... And something everyone should know how to do!
http://www.pat-testing.info/wireaplug.htm
Very easy fix for this though -- just push the signal through some sort of frame buffer.
Easiest solution for this would be an older DVD recorder, many of which digitise the image as they're going along. As they tend to be older, they're more tolerant.
Once they've taken the analogue signal, digitised and buffered it, and then reconverted it to analogue again, the resulting signal will be happily accepted by the newer TV.
What do you mean by Multi-switch?
Presumably he means the system control switch, a rotary or slider multi-way switch that tells the electronics what position the mechanism is in.
I appreciate that when it comes to VCRs and the like (I touched upon it when I mentioned the signal being digitised).
Maybe I wasn't clear, but the comment was meant specifically about the ZX81 black level issue. My point being that if the white-picture-where-the-black-level-should-be-expected wasn't causing a problem, that implies older TVs didn't pay attention to any black level in the first place (since they wouldn't have "known" that a ZX81 rather than "normal" TV signal was connected), so why was it in the spec?!
Yes, but like I said if it doesn't use the black level, why did they bother with it at all?!
It was a free tv, so I'll not be taking it back
Never had any real problems specifically with HiFi VCR's - obviously head wear was the largest problem with HiFi, as the HiFi heads generally wore out a lot faster than the video heads - and specifically one channel (I can't remember which it was now?, but it was the higher frequency one).