Yep, my SB-221 has an aluminium box near the input tuners that has "do not break seal" sticker! The back has a FCC data and statement of compliance sticker signed by the ham that built it in 1981.
In order or most likely: Power supply HV diodes shorted. Power supply HV caps shorted Transformer itself shorted Tube shorted. Never over fuse it. Take out tubes, try it, if it still shorts, open the capacitor bank, if it still shorts, open the power supply diodes, if it still shorts after that, its the transformer. If it stops shorting when you take something out, then that is 'usually' the problem.
Nice amp! I’m very interested in knowing more about the input tuning circuit. I’m working on an old beat up sb 220 myself right now and I’d like to make it more efficient overall. The input swr is too high for me
from the net, but I agree: Power Supply: 4) Power supply improvements include removing the 30K resistors across the filter capacitors and replacing with 68K 5 watt wire wound resistors to reduce heat near the capacitors. I replaced the original HV diodes with 1N5408 3A diodes. I removed the original Zener diode and replaced it with a series of seven 1N5408s.
This one was too long to cut n paste, but it is what I went by for the Input on this one. I ended up taking one turn out of the 10 meter input coil, but it was still a little too much inductance so I ended up removing the adjustment slug out of the coil too. Then the Input cap was changed to a variable 100-300 pf and the output cap was upped to 100pf fixed. Drake L4B has an input tuner with better Q than the Heathkit and you can also go by the Drakes to get figures. www.qsl.net/wa5bxo/ag6k/sb220ci.html
Yep, both. Has a terminal strip underneath that you connect jumpers to change it to either 110 or 220. Also, as Spaceflight said, it is highly recommended to run it on 220 as with any amp doing 2kw or more.
Yep, my SB-221 has an aluminium box near the input tuners that has "do not break seal" sticker! The back has a FCC data and statement of compliance sticker signed by the ham that built it in 1981.
Those were the days.
I really enjoy your videos and learn a lot, please keep them coming
Thanks, will do!
Do you repair these amplifiers
Sorry, no. I retired from it and only roll my own.
Good video! Thanks Doc.
Welcome!
Uncle Charlie, and Roll My Own! :)
That's how I roll LOL.
Can you tell me where I can get the manual for the Tram Automatic SWR meter or would you sell me a copy?
I have a Chris sideband 600 when I turn it on it vibrates for a minute and blows a fuse can you tell me what to look for I know you're busy
In order or most likely:
Power supply HV diodes shorted.
Power supply HV caps shorted
Transformer itself shorted
Tube shorted.
Never over fuse it. Take out tubes, try it, if it still shorts, open the capacitor bank, if it still shorts, open the power supply diodes, if it still shorts after that, its the transformer. If it stops shorting when you take something out, then that is 'usually' the problem.
Nice amp! I’m very interested in knowing more about the input tuning circuit. I’m working on an old beat up sb 220 myself right now and I’d like to make it more efficient overall. The input swr is too high for me
from the net, but I agree:
Power Supply: 4) Power supply improvements include removing the 30K resistors across the filter capacitors and replacing with 68K 5 watt wire wound resistors to reduce heat near the capacitors. I replaced the original HV diodes with 1N5408 3A diodes. I removed the original Zener diode and replaced it with a series of seven 1N5408s.
5) I removed the RF network at the grids and grounded each grid together and to the chassis.
7) I put back to back 1N5408 diodes across both meters to protect them.
This one was too long to cut n paste, but it is what I went by for the Input on this one. I ended up taking one turn out of the 10 meter input coil, but it was still a little too much inductance so I ended up removing the adjustment slug out of the coil too. Then the Input cap was changed to a variable 100-300 pf and the output cap was upped to 100pf fixed. Drake L4B has an input tuner with better Q than the Heathkit and you can also go by the Drakes to get figures. www.qsl.net/wa5bxo/ag6k/sb220ci.html
@@tramdr ok thanks!
I see you have worked on the "Palomar 300A" black face, I'm in Ohio, an have a hand down that's been used hard. How would someone contact you.
Tramdr at Yahoo.com but I don't work on others. I have a few though, might sell one.
Does it run on 110 or 220 ?
Both, but they highly recommend using it on 240 volts.
Yep, both. Has a terminal strip underneath that you connect jumpers to change it to either 110 or 220. Also, as Spaceflight said, it is highly recommended to run it on 220 as with any amp doing 2kw or more.
Is that 60 pep or 60 ave going into it for 2000 pep out?
avg
@@tramdr ok thanks. How much pep do you think u put in
Around 150
@@tramdr thanks for the info
Nice amp
Thanks!