Hello Everyone i am working on a hippo currently and am a little stumped . I recently did a recap and am having some difficulty's, It starts to warm up and then blow`s the light bulb . I have rechecked and double checked my work and can`t seem to find why this is happening . The 35y4 test`s good but i swapped it out with another good one , still dint change anything and i also swapped out the 50b5 as well I have been going through resistor`s and they seem to be within reasonable spec . The only thing that i can think of next is could the socket be causing this problem . ? Any tips would be much appreciated!
Check the polarity of the filter caps. If you have any in backwards it will cause excessive current thru the hv. This in turn will blow the lamp out. If this is the case the offending cap is toast and must be replaced with a new one. Also a half open heater in the rectifier tube will blow the lamp too.
About that 50B5? I do not have a sch for the code 125 but the info I have shows 50L6 or 50A5. The 50B5 is a seven pin tube was only used a few years before being replaced by the 50C5. Something about mixing the 35W4 and the 50B5 in AA5 sets being a fire hazard.
https://frank.pocnet.net/sheets5.html
Thanks for the tips i will take a look again at my caps again , Think i should swap the 50b5 with a 50l6
The deal on the 50B5 is that plate and heater pins are next to each other which there could be a possibility of arcing. It was superseded by the 50C5. 50C5 same tube specs but different pinout to limit the arcing possibility. 50A5 and 50L6 along with the a fore mention tubes have same specs but bases and or pinout are different so none of them are directly interchangeable.
okey gotcha ! The next time i work on it i will recheck all of my cap`s
Hello again everyone ! the hippo has been resolved it came out to be the audio output transformer ! installed a different one and it is back to life ! thanks again