23-10-2017, 02:24 PM
(This post was last modified: 23-10-2017, 02:42 PM by Murphyv310.)
Thanks Jeffrey.
I'm all red with embarrassment.
Being fair I am more than surprised this has worked so well, I really think using the Jellypot in starvation mode is the secret.
I have another TV22 that I fitted a 900 Jellypot LOPT and I did this leaving in the PZ30 and using a 30P4 line output valve, the Line stage runs at 110 volts with no stabilisation, it has a Plessey Blocking oscillator transformer but a different circuit to the latest modded set. My earlier TV22 is brilliant, the picture is extremely bright and works very well indeed.
On this set I have two very simple shunt regulators, one for HT as it changes dependent on line frequency as does the EHT even with stabilised HT to the line stage, the EHT is stabilised at 5400v (says 5500 on my EHT meter) which is 1400v above the minimum of the tube, this is done with 9, 600v avalanche diodes.
Results are impressively good on 240 & 180 at 120 lines it is noticeably poor, very difficult to read smaller writing and making out a face that is any smaller than a third of the area of the screen difficult. On the scope the lower standards are even worse, not a bit of entertainment value at all.
I've actually recorded a test card onto minidisc on 90 lines onto one channel and sync onto the opposite channel and this works too rather blurry though. Oh what fun!!!!d
I'm all red with embarrassment.
Being fair I am more than surprised this has worked so well, I really think using the Jellypot in starvation mode is the secret.
I have another TV22 that I fitted a 900 Jellypot LOPT and I did this leaving in the PZ30 and using a 30P4 line output valve, the Line stage runs at 110 volts with no stabilisation, it has a Plessey Blocking oscillator transformer but a different circuit to the latest modded set. My earlier TV22 is brilliant, the picture is extremely bright and works very well indeed.
On this set I have two very simple shunt regulators, one for HT as it changes dependent on line frequency as does the EHT even with stabilised HT to the line stage, the EHT is stabilised at 5400v (says 5500 on my EHT meter) which is 1400v above the minimum of the tube, this is done with 9, 600v avalanche diodes.
Results are impressively good on 240 & 180 at 120 lines it is noticeably poor, very difficult to read smaller writing and making out a face that is any smaller than a third of the area of the screen difficult. On the scope the lower standards are even worse, not a bit of entertainment value at all.
I've actually recorded a test card onto minidisc on 90 lines onto one channel and sync onto the opposite channel and this works too rather blurry though. Oh what fun!!!!d
