08-24-2015, 06:19 PM
GRRRRR!!!!
After finishing up the HRO I thought it might fun to give the power supply from the RAS a try. Simple design with 4X 4mfd@600V. Two are wired together to equal 2X 8MFD on each side of the filter choke. They are paper caps.
The power plug is wired the same for both sets the RAS and HRO so it a plug n play affair. Plugged it all in and gave it a try. Everything looks good voltage is at 230vdc(dead on) but there is a strange tingle I get when I touch the p/s chassis. Hmmmm. Both filaments and B- on the p/s are not grounded to the p/s chassis, all is floating. As I was tuning around on the HRO there was a LOT of line noise. Connected the two chassis together and the noise cleared up. All this took abut 15mins. Then I noticed the smell of hot wax and I wasn't doing my legs!!! Shut her down felt the power transformer and bet you can't guess? Hotter than h**l. Filters seem OK,measured the current and It would jump up when they where charging and drop down to nothing as they should. Methinks the transformer is shorted.
For those keeping score that's 2 and 0. The output was open. I think I'm going to check the IF cans be fore I put a lot time in the thing. I'm hoping the SX11 doesn't have the same fate.
Terry N3GTE
After finishing up the HRO I thought it might fun to give the power supply from the RAS a try. Simple design with 4X 4mfd@600V. Two are wired together to equal 2X 8MFD on each side of the filter choke. They are paper caps.
The power plug is wired the same for both sets the RAS and HRO so it a plug n play affair. Plugged it all in and gave it a try. Everything looks good voltage is at 230vdc(dead on) but there is a strange tingle I get when I touch the p/s chassis. Hmmmm. Both filaments and B- on the p/s are not grounded to the p/s chassis, all is floating. As I was tuning around on the HRO there was a LOT of line noise. Connected the two chassis together and the noise cleared up. All this took abut 15mins. Then I noticed the smell of hot wax and I wasn't doing my legs!!! Shut her down felt the power transformer and bet you can't guess? Hotter than h**l. Filters seem OK,measured the current and It would jump up when they where charging and drop down to nothing as they should. Methinks the transformer is shorted.
For those keeping score that's 2 and 0. The output was open. I think I'm going to check the IF cans be fore I put a lot time in the thing. I'm hoping the SX11 doesn't have the same fate.
Terry N3GTE
