Hi all, I’ve been using my trusty Bush/Rank tv now for nearly 10 years every single day! With only one breakdown it’s been fabulous, which is surprising as it’s inherently very basic with respect to component count. I believe it uses the Toshiba T24 chassis, although there are some variations.
Anyhow, it’s been working fine for years using a VCR as an RF Modulator for my freeview box, recently I upgraded to Virgin Media and as with most things these days I require HDMI. I bought a HDMI to scart converter which works very well, it downscales to NTSC or PAL. However sadly this TV only produced a black and white picture with it!!
I’ve tried a different RF Mod, RF Channel, HDMI Source, SCART Lead etc and it still produces the same problem.
However, it works fine on my similarly aged 1981 Pye (Philips) KT3.
I noticed tuning the Bush out slightly produces the colour, so the problem must lie with the Bush TV! I’ve also tried AFC and it makes no difference.
Can anyone shed any light? Preferably RGB light lol, cheers.
Presume it still works with the free view box and VCR correctly.
If the old system works ok it suggests the HDMI converter is outputting a signal that is not true specification, the Philips handles it ok but the Bush must be more strict or the Bush is on the edge of working conditions and the two don’t mix.
If you have a scope it would be worth checking the chroma signal after the video detector to see if you can determine what is occurring.
The T24 will probably have a way of overriding the colour killer, see what the picture is like with that overridden.
Frank
Hard to say for certain if your RBM is actually faulty Jamie....
I have trouble with my Sony KV1320 (not strictly a true PAL set I know) being rather fussy about the video source, the hue being way out of adjustment with some sources, but it is perfect with a Sony DVD player on a cheap UHF modulator. A Philips PM5515 pattern generator is fine too, so I guess it could be a case of some set's although working ok to their spec, not liking the processing done within some converters.
To understand the black art of electronics is to understand witchcraft. Andrew.
Check the burst timing with respect to the burst gate timing.
When all else fails, read the instructions
Thanks for your help guys, after speaking to roger locally he advised me to adjust the chroma pot, which seems to have cured it indeed!
can anyway explain what the chroma pot actually adjusts? Am I right in thinking it adjusts the frequency deviation between the sound and video carrier?
Well it is a Toshiba, so I was right to talk a load of Tosh earlier. ?
Glad you got it working ?
To understand the black art of electronics is to understand witchcraft. Andrew.
Chroma pot, I would need to see the circuit to try and suggest an answer. Various possibilities come to mind.
Wouldn’t have thought it is the frequency deviation between sound and videos carrier, that is set at the transmitter.
Frank
A minor flying repair Saturday night! Jenny came through "TVs smoking!" I said "have you switched it off?" "no" she went.. Doh....
Anyway, TV still operating fine, nice rancid smoke plume behind it. I have my suspicions anyway...
Took the set into the dining room, dumped it on the floor and had a good look about, yep, mains filter. A RIFA of all things!
The stamp shows 1st February 1980... So nearly 43 years later, and still in continuous use.
Took the PCB upstairs, changed the cap, Job done. I also tweaked some of pots and yoke and produced a sterling picture compared to what it was showing. I guess over the years you don't notice how bad the image is getting. I've now got much sharper stronger colour, This tube is amazing though I have to say, It's now seen continuous use for nearly 13 years, the last time I was inside was 09/01/2013 and the "sub brightness" pot on the board is between 1/4 & 1/2 it's full travel so there's plenty of life yet!
Of course it would be even better if my phone showed the true extent of how good the image is but there we go.
Took the set into the dining room, dumped it on the floor and had a good look about, yep, mains filter. A RIFA of all things!
RIFA madness... (sorry). I replaced the smoking RIFA in my mother-in-law's sewing machine with another as she doesn't use it daily so it too will last another forty years I'm sure.
Is that an enormous mains transformer I see though?
The RRI T24 was developed from the 1978 Toshiba X53B chassis.
Till Eulenspiegel.
The RRI T24 was developed from the 1978 Toshiba X53B chassis.
Till Eulenspiegel.
It seems to be bulletproof. The CRT I believe is used in a lot of 80s Arcade Machines? Possibly akin to the longevity.
