Had a chuckle over the paradox of Peter saying the original selenium photo-cells were made of unobtainium :-) . Often when one actually finds something 'made of' Unobtainium, it's usually at least 30% alloyed with Unaffordium. Coming up 5 years ago, I had the immense privilege and joy of visiting Bletchley Park and TNMOC. This was no easy feat given I live in New Zealand! To stand in that hallowed place to behold the testament to Tom's original ingenuity and Tony's (and many others') tenacity in resurrecting 'ground-zero' of the modern computing age, was something of a spiritual experience for me. While Alan Turing laid the theoretical foundations, it was the likes of Tommy Flowers who put practical flesh and muscle on the bones and made Colossus come alive. On this very parts supply topic I similarly recall asking one of rostered volunteers how they got on for replacement valves and he replied that (at the time) the very sort needed by this rebuild, were still being made in Russia. I found this quite an ironic giggle because I knew that 2 Colossi ended up at GCHQ and were likely used to decrypt Lorentz-based Soviet SIGINT post VE Day and into the 50s as the Cold War got frostier. I'm willing to bet they helped play a strategic part in the West's airlift response to the Soviets' blockade attempt on Berlin. But at 8.5kW power consumption in an enclosed room, it's no wonder the WRENs stripped down to their lacy lingerie while they took Colossus for (Lorentz rotors start) runs through the summer months of '44 and '45, and used it as a clothes dryer in the depths of winter!!
There are people on TH-cam who actually make valves as a hobby, they would probably love to contribute handmade replacement valves for such an important exhibit. I've seen several on youtube but the only name I can remember is glasslinger. Although one needs quite a lot of skill it seems that only rather basic equipment is needed and raw materials are easily obtainable. It is mostly about glassblowing and something a bit like making jewelry. Someone who has already made several valves would probably find it easy to make an almost exact replica of any valve you give them.
Had a chuckle over the paradox of Peter saying the original selenium photo-cells were made of unobtainium :-) . Often when one actually finds something 'made of' Unobtainium, it's usually at least 30% alloyed with Unaffordium.
Coming up 5 years ago, I had the immense privilege and joy of visiting Bletchley Park and TNMOC. This was no easy feat given I live in New Zealand! To stand in that hallowed place to behold the testament to Tom's original ingenuity and Tony's (and many others') tenacity in resurrecting 'ground-zero' of the modern computing age, was something of a spiritual experience for me.
While Alan Turing laid the theoretical foundations, it was the likes of Tommy Flowers who put practical flesh and muscle on the bones and made Colossus come alive.
On this very parts supply topic I similarly recall asking one of rostered volunteers how they got on for replacement valves and he replied that (at the time) the very sort needed by this rebuild, were still being made in Russia. I found this quite an ironic giggle because I knew that 2 Colossi ended up at GCHQ and were likely used to decrypt Lorentz-based Soviet SIGINT post VE Day and into the 50s as the Cold War got frostier. I'm willing to bet they helped play a strategic part in the West's airlift response to the Soviets' blockade attempt on Berlin.
But at 8.5kW power consumption in an enclosed room, it's no wonder the WRENs stripped down to their lacy lingerie while they took Colossus for (Lorentz rotors start) runs through the summer months of '44 and '45, and used it as a clothes dryer in the depths of winter!!
There are people on TH-cam who actually make valves as a hobby, they would probably love to contribute handmade replacement valves for such an important exhibit. I've seen several on youtube but the only name I can remember is glasslinger. Although one needs quite a lot of skill it seems that only rather basic equipment is needed and raw materials are easily obtainable. It is mostly about glassblowing and something a bit like making jewelry. Someone who has already made several valves would probably find it easy to make an almost exact replica of any valve you give them.
You could probably fit a replacement solid-state circuit into the base of an old valve, and incorporate an LED to make the tube glow.
The best replacement for a 1943 pentode valve is an 8 billion MOSFET FPGA.