Sourcing Replacement Parts For Vintage HF Gear - Question ?

Discussion in 'Ham Radio Discussions' started by K5FRH, Jul 4, 2019.

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  1. K5FRH

    K5FRH Ham Member QRZ Page

    I have a stack of Heathkit, Drake and Yaesu HF radios I am getting ready to start going thru. Cosmetically all are in excellent condition.

    My question regards capacitor replacement. Is it better to purchase replacement capacitors individually thru, say, Mouser, or buy the kits thru Heathkit Store or Harbach. I also understand their is a thrid opinion that says "if it aint broke, dont fix it - in other words, you can create more problems than you can solve by replacing the electrolytics, paper capacitors, etc. by rote. However, I am dealing with radios approaching 50 years of life, so how much can you expect out of a lowly capacitor.

    I do have a great Variable AC Supply with current meter, so I can bring the units up slowly and monitor their current drain.

    Thanks for your help and suggestions.
     
  2. W4NNF

    W4NNF XML Subscriber QRZ Page

    The answer is "it depends" when asking about Mouser or Jameco compared to somebody like Hayseed hamfest. If the former has the cap you need, why not? Especially if it's cheaper to buy individually instead of a kit. But if you need something special, like caps in cans, look to the specialty guys...

    Your other question is easier to answer, "Don't even think about applying power, even with a Variac, to a piece of gear, say, 40 years old or older without replacing the electrolytics, paper/wax caps, and all that stuff. It HAS TO GO." As I'm sure you'll do, do a full inspection of the rig too looking for damage, the wear of years, wiring mistakes, etc. Then fire it up. :)

    ;)
     
    K5FRH likes this.
  3. KX4Z

    KX4Z Ham Member QRZ Page

    I think I’m going to make my own circuit board to fix Heathkit power supplies. I’ve probably done about five already by hand. I haven’t often seen shorted electrolytic’s, they’re basically just opened.

    Putting a modern capacitor in parallel has been pretty simple.

    I end up replacing about six electrolytic‘s on a Heathkit SB series plus power supply.

    Do the power supply first, turn it on while standing a good ways away.

    Once you verify a good voltage is there then you can fiddle with the transceiver
     
    K5FRH likes this.
  4. KC8VWM

    KC8VWM Ham Member QRZ Page

    Sometimes, rather than power the equipment from it's built in on/off switch, I will energize the circuit with a separate switch or even from a circuit breaker a distance away.
     
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  5. KD0CAC

    KD0CAC Ham Member QRZ Page

    With regards to your gear , you have some idea of what you have , and if its been used lately - old used gear that hasn't been used in some time - maybe the most likely to have dramatic cap failure - when turned on , after a long time .
    Then how much you value your gear , and how you want to value it in the future , 2 approaches to boat-anchors , museum pieces [ stuffing old cans etc. ] or not caring about seeing modern caps .
    It is cheaper to buy all parts at Mouser etc. , then to pay more for someone to make a kit for you - the issue there is what brands & sources the kit-builder uses .
    As I'm still learning electronics , to me at this point , capacitors are the most complicated passive components , so many types / uses and aspects of testing .
    As for types , electrolytic & wax caps are the first to just replace , do not bother to save .
    On a side note , when looking into an unknown rig , bringing up on a DIM-BULB-TESTER
    Will allow you to see if there are more things wrong than someone wants to bother with , power up for further testing , if the dim-bulb tester shows ok , or if the caps can be reformed for short use & further testing ,
    Then testing , again more more to that ,
     
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  6. KP4SX

    KP4SX Premium Subscriber QRZ Page

    Aack!
     
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    "Joe, you flip the switch."

    "No, Mike, you flip the switch."

    Charles: "I'll do it, using a 3 foot long stick."
     
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  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Re old capacitors and stuff, I usually test them before replacing anything as testing is faster and cheaper.

    My TR-7 (all SS, so no high voltage anywhere) is 41 years old and works exactly as it did when it was new, and I've never replaced anything other than the lamps in the meter and the dial. Zero capacitors replaced. But, nothing in there operates above 14Vdc. It's also never been "stored" for long...it's been "used" a whole lot. Whether that actually helps or not, I have no idea.

    My 62 year-old 75A-4 has some medium voltage stuff in it (tubes and what powers them) and has its original filter capacitors which are almost as old as I am. It's never been exposed to excessive heat or humidity and has also been used a whole lot and never really "stored." What surprises me about that one is it was designed for 115Vac line voltage and for several years now my line voltage is actually about 122-123Vac, so everything should be getting a bit hotter and running closer to the edge...still hasn't failed. Collins probably used good parts.:p

    I replace stuff when it fails.

    The filter caps in my Kenwood hybrids (TS-520S, TS-820S, TS-830S) that I've had over the years did fail but didn't cause any damage: First clue is the HV indicated by the panel meter is about half what it should be and the transmitter stops working properly. Replacements are cheap, but a bit of a PITA to install.
     
  9. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    Do NOT put a new electrolytic capacitor in parallel with an existing capacitor!

    Mouser is overnight to Irving, Texas. Look at the quantity price breaks and, if practical, purchase enough of the commonly used components at least the minimum for a particular price break. There are also a couple of stateside companies that have name brand components, from factory overruns, etc., that are very inexpensive. I do get certain components from those companies at times.

    The Collins 75A-4 was designed for AC input voltages of 105 VAC to 125 VAC. See page 1-2 of the instruction manual.

    Unless you are going to put the equipment in a restoration contest, in most units there is plenty of room under the chassis for individual electrolytic capacitors instead of purchasing a replacement can for a pretty fair amount of money. Some people do "re-stuff" electrolytic capacitor cans to "preserve" the original "look". Again, MUCH cheaper than purchasing cans from certain sources.

    Never reform an electrolytic capacitor. Old electrolytic capacitors are a time bomb waiting to go off and when they do fail, they often "take out" quite a few more parts and very often those parts are either expensive or unobtainable. Electrolytic capacitors and paper capacitors need to be replaced before applying power. Silver mica capacitors when used as coupling capacitors and bypass capacitors are now often having "sliver mica disease" and need to be replaced. Those silver mica capacitors with less than between 75 VDC and 100 VDC are generally still fine. New parts are inexpensive especially when compared with the cost of the damage that they can do when leaky or just plain bad.

    In some power supplies, especially the Heath HP-23- series / PS-23, you can mount new electrolytic capacitors on a piece of perf-board attached using some of the mounting holes that held the mounting bracket of the original capacitors. Slightly enlarge the holes that correspond with the terminals on the "snap-in" type of capacitors, bend the terminal over, and then solder to the bent over tab. MUCH cheaper than several other methods.

    There are all sorts of "tricks" that those persons, who work extensively on "boat anchor" equipment, have learned over the years that make repairing, restoring, etc., units much easier.

    If you need to repaint cabinets, I have, on my website, the Sherwin-Williams formulas for a number of different manufacturers:

    https://img1.wsimg.com/blobby/go/11...ds/Boat_Anchor_Paints-1.pdf?ver=1562269735742


    Glen, K9STH
     
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  10. K5FRH

    K5FRH Ham Member QRZ Page

    Thanks Glen.
     

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