Rebuilding an SB-220 (for KJP)

Discussion in 'Amateur Radio Amplifiers' started by W1QJ, Jan 19, 2013.

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  1. AH6RR

    AH6RR Ham Member QRZ Page

    He is most likely sitting on his butt drinking a 807 or smoking a 420 or both, laughing his big Okole off thinking "Man did I get them all stressed out". Because he is a lonely person with nothing better to do than to stir the pot and unfortunely there are a lot of people just like him out there. Bob W4PG thanks for backing us all up with the way I saw how the Law is written, I have never been a Lawyer but I can read the law and after being a Boat Captain for 25 years with many endorsments for Hazmat, Radar and many more you learn how th read the CFR's and the one for amateur radio is very small compaired to the one for the boating industry so it only takes about less than 5 minutes to find what is needed. Any Hoo Lou does not manufactuer any amp he modifies them and for the most part if you want a amp for 6M you either mod an existing amp, have someone else do it for you or you buy a new one but the trick is there are just a very small few to pick from and they are either solid state or VERY expensive Tube type with Very EXPENSIVE tubes. I know I looked so I am not going to convert my SB-220 but I have no qualms about converting a Collins 30L-1 to run a pair of 4CX250B's because the 811 tube does not work well at 50Mhz so it is chop chop, hack hack I go. Sorry Collins fans but this amp was another poor condition amp (but not as bad as my 220 was) but I do feel like Dr. Frankenstien gleefully working in my lab. I cant wait until I get it completed so I can say "It's Alive Boris, It's Alive"
    :cool::cool:
     
  2. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    Actually, the term "calendar year" is well defined in legal terms. A "calendar year" is defined as the period, in the Gregorian calendar, starting on 1 January and ending on 31 December. This "calendar year" normally has 365-days, increasing to 366-days in a "leap year".

    Limiting something to "one time per calendar year" means any time within the 365-day (366-day in leap years) period starting on 1 January and ending on 31 December and that same thing is not permitted until the next period starting on 1 January and ending on 31 December. It is perfectly legal for this one time activity to be done on 31 December and then repeated the next day, 1 January. However, before the activity to be again repeated, a period of 365-days (366-days leap year) would have to pass.

    Glen, K9STH
     
  3. AF6LJ

    AF6LJ Ham Member QRZ Page

    Thank you for your honest answer, I know now.............
     
  4. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    RR:

    Although I do shudder at someone modifying a piece of Collins equipment, I definitely understand that there are times when either the condition of the unit is too bad to realistically restore the unit to original condition or that certain parts / assemblies are just not available. Personally, I have a Hallicrafters HT-33A, well, it is marked as an HT-33A but came from the factory with HT-33B circuitry, that someone tried to add 160-meters (did a real good job of tearing up the unit) as well as destroying the PL-172 tube. There are also some physical parts missing (like the bottom cover). That amplifier is going to be rebuilt using a Russian GS-31b tube. The GS-31b is the same diameter as the PL-172 so the original chimney will work fine. Going to the GS-31b allows some of the power supply components to be eliminated as well as other circuitry (i.e. screen regulator). When completed, the linear should be capable of a little more power output and yet retain the original physical "looks". Also, although it will still be pretty heavy, the weight will be reduced by 25-pounds to 30-pounds.

    Glen, K9STH
     
  5. AF6LJ

    AF6LJ Ham Member QRZ Page

    There is a fairly distinctive line between modified and butchered, it sounds like you are being as polite as possible in describing your HT-33B as modified, I would have said it was butchered.
     
  6. AF6CO

    AF6CO XML Subscriber QRZ Page

    Personally I don't see why you guys give KJP so much of your time. It's apparent how highly you think of him. Just in the short time that I've been on this forum I've been able determine what a great resource we have in Lou and others here like him. So if you just ignore the static maybe it will go somewhere else.

    As far as being spoon fed, doesn't it make more sense to ask a question rather spending hours or days finding an answer? There's no one being forced to give an answer, most people get pleasure helping others. You should try it sometime, you'll probably find it more enjoyable than trying to feel better about yourself by trying to belittle others.

    I'd much rather learn more about amplifiers than listen to you sling mud. If you think that the FCC will have a problem with the conversions make a phone call. Otherwise get over it. It makes me wonder if there are any moderators on this site. The other hobbies I have, this behavior wouldn't be tolerated on those forums.

    Thanks to all those that have helped and offered me help.
     
  7. AH6RR

    AH6RR Ham Member QRZ Page

    Like I said Stir the POT
     
  8. AH6RR

    AH6RR Ham Member QRZ Page

    Steve there are a number of very good people on this forum that are glad to help anytime. And now that you have the parts comming your way you too will have fun putting it back on the air. I personaly have repaired or modified close to 45 amps in the last 5 to 6 years. Starting with a Dentron MLA-2500 that I picked up for $75 because the owner did not want to try to repair it. It had 1 bad tube and finding a second one was dang impossible for under $350 so I sold the good tube for $275 and bought all the parts to convert it to use the GI-7BT tube. And Lou W1QJ, Tom W8JI and Karl K1MH and others helped me when I had questions freely. Same when I was given a Henry 2K-5 that had a power supply issue (I wish I had never sold that amp). I was asked to repair a Commander HF-2500 because the owner did not want to ship it to the mainland for $350 each way Lou pointed me the right direction to find the HV board and let me tell you you have to almost completey dissasemble the RF Deck to get to it 4 hours to get to the board 30 minutes to fix that and 4 hours to put it back together. I did end up cutting the bottom of the amp below the HV board and then placing a door over the hole so the next time it will only take 10 minutes to get the board out not 4 hours. Have fun with the restore.
     
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Sounds like that HF-2500 was a wacky design. No reason for what you describe, although I don't doubt you at all (never had one).

    As an engineer, one of my very first principles of design was "easy repair," because everything eventually needs it.

    If it couldn't be disassembled in a few minutes, the design was silly and likely to be rejected by the CE.

    One of the "easiest to repair" ham rigs is my old Drake TR-7, which is built like a computer, with motherboard/daughterboard construction. Almost anything that can break can be unplugged in 5 minutes or less, and then re-installed. Funny part is, what usually "breaks" is the card-edge connections which can get oxidized. A pink pencil eraser fixes most of those, and takes about a minute.:p

    Even my homebrewed stuff is designed to be repaired quickly. If I ever built anything that took four hours to disassemble, I'd fire myself.:eek:
     
  10. AH6RR

    AH6RR Ham Member QRZ Page

    Ask anyone who has worked on one of the HF-2500 the HV bord is under the tube with no access from the bottom you have to remove the tank, band switch the back of the amp and the center RF Shield jut to get to the tube box to remove that then you get to the HV board it was the biggest PITA I have ever seen at least that was on the older ones I have not seen a new one yet. All of that to change out 2 rectifier diodes and I changed out the metering resistors that had changed value. $350 labor to replace $4 worth of parts but the amp is still working fine after 2 years. I know I should have changed out all the diodes but you know job security :D but I did ask the owner if he wanted it done and he said just replace what needs it and the resistors is what he asked for because the HV was reading low.
     
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