OK bit of an update to my tinkering with the home made TV.
People may think I have some form of death wish, but honestly I do not, I just work in a hap-hazard way!
So I have the transformer PSU driving the make shift TV as it is, the small DG7-5 CRT is pulled from it's socket and wires soldered to the socket going to another socket on a 5 inch CRT.
The EHT generator is powered by a 12 Volt buck to HT and valve heater supply unit and that is powered by my small bench supply bottom left. The DVM is monitoring the EHT and the final should be 20 x reading.
I am trying a '5EP1'. This is a CRT with post acceleration, I thought I would try a situation where I am still using the voltages for the DG7-5 on the CRT but have approx 2000 Volts plus on the final anode.
As I am using grid modulation and varying the cathode for brightness then the brightness control can effect the focus etc.
I was surprised to find it did actually work OK with minimal tweaks to the Knobs. The final EHT voltage was at 2400 Volts.
I am over scanning the height by quite a bit so need to include a height control, looking with my eyes direct at the screen I can just make out the 2MHz grating, so not so bad after all.
It shows to me I can take the TV a bit further. I need to get hold of some better transformers, I need more heater current as I am very close to the limit for this one which is why the EHT is on a separate supply.
I also need to find a suitable adhesive that is thin enough to poor into the valve base that will re-stick it, I hate the prospect of un soldering the CRT base cleaning and then sticking it back on with araldite, I will ending breaking off wires yet.
Adrian
p.s. I do now have a focus and scan coil for the MW6-2
People may think I have some form of death wish, but honestly I do not, I just work in a hap-hazard way!
So I have the transformer PSU driving the make shift TV as it is, the small DG7-5 CRT is pulled from it's socket and wires soldered to the socket going to another socket on a 5 inch CRT.
The EHT generator is powered by a 12 Volt buck to HT and valve heater supply unit and that is powered by my small bench supply bottom left. The DVM is monitoring the EHT and the final should be 20 x reading.
I am trying a '5EP1'. This is a CRT with post acceleration, I thought I would try a situation where I am still using the voltages for the DG7-5 on the CRT but have approx 2000 Volts plus on the final anode.
As I am using grid modulation and varying the cathode for brightness then the brightness control can effect the focus etc.
I was surprised to find it did actually work OK with minimal tweaks to the Knobs. The final EHT voltage was at 2400 Volts.
I am over scanning the height by quite a bit so need to include a height control, looking with my eyes direct at the screen I can just make out the 2MHz grating, so not so bad after all.
It shows to me I can take the TV a bit further. I need to get hold of some better transformers, I need more heater current as I am very close to the limit for this one which is why the EHT is on a separate supply.
I also need to find a suitable adhesive that is thin enough to poor into the valve base that will re-stick it, I hate the prospect of un soldering the CRT base cleaning and then sticking it back on with araldite, I will ending breaking off wires yet.
Adrian
p.s. I do now have a focus and scan coil for the MW6-2
Learning as I go!
Youtube EF91 Valve
Youtube EF91 Valve
