Geist
12-22-2012, 11:11 AM
Hi All;
What is the difference between the Dumont 304-C and the Dumont 304-H ?? Where they like improvements -A, -B, -C etc.. Or did they stand for something such as -C, Commercial, -H, Heavy Duty, etc..
THANK YOU Marty
bob91343
12-22-2012, 12:12 PM
Scratching the head for old memories, I seem to recall that the entire series was pretty much identical. Mostly cosmetic differences, like the 401 vs the 401A, which simply had changed from inch calibrations to centimeter. I have owned several of these and don't recall any real differences. Maybe the H had higher sensitivity but I'm treading on thin ground here. Bandwidth on the entire series was about 100 kHz oops I mean 100 kc. I may still have some manuals.
bigbob
02-15-2014, 08:04 AM
Hi!
I realize this is an old thread but I wondered if I could tap your knowledge. I'm looking for a manual for a Dumont 401A. Would you still have one? Second, I saw info, online, where Fairchild took over Dumont. Would you happen to know if the Fairchild 401A is the same as the Dumont 401A?
Thanks for any info.
Bob
bob91343
02-15-2014, 05:01 PM
I think I still have Dumont 401/401A manuals. I used to own a 401R.
There were two versions, one with 'Sola' type power supply and the other with electronically regulated supply.
Einar72
02-15-2014, 10:10 PM
If anyone ever finds a manual for Dumont scope type 250-AH, I'd love to have a copy...
N2IXK
02-16-2014, 10:39 AM
I believe the "H" stood for "high brightness" or "high intensity", as it had an additional high voltage supply for the post-deflection accelerator.
The schematic here:
http://bama.edebris.com/manuals/dumont/304
shows the differences between the 304 and the 304H. The additional circuitry used in the 304H is shown in a dotted line area in the power supply. The note near the CRT intensifier connection describes the difference in the circuit.