Assembling a Heathkit HW-99

Discussion in 'Homebrew and Kit Projects' started by N5OLA, Jul 31, 2019.

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  1. N5OLA

    N5OLA Ham Member QRZ Page

    I recently acquired an unassembled HW-99 from around 1986 and plan on putting it together. As it's 33 yrs old, should I go ahead and replace all the caps when I assemble it, or would they still likely be okay?

    I know this rig has problems with the VFO (frequency drift, etc). Thankfully there are a number of good videos on this subject. Would love to hear from anyone who has put one of these babies together and who has any retrofit suggestions.

    N5OLA
     
  2. N5OLA

    N5OLA Ham Member QRZ Page

    I'm not sure if the HW-99 is a classic or a boat anchor, but as it's Heathkit I thought it might generate a response here.

    I recently acquired an unassembled HW-99 from around 1986 and plan on putting it together. As it's 33 yrs old, should I go ahead and replace all the caps when I assemble it, or would they still likely be okay?

    I know this rig has problems with the VFO (frequency drift, etc). Thankfully there are a number of good videos on this subject. Would love to hear from anyone who has put one of these babies together and who has any retrofit suggestions.
     
  3. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    HOLY COW!!!

    ABSOLUTELY replace ALL electrolytic caps with new, check all the resistors and replace any/all not within spec, just check all the parts... don't trust anything. Check EVERYTHING and replace anything out of spec with new. Check and double check your inventory of "known and confirmed good" parts before you lay a soldering iron to anything!

    What a great thread this will be to follow!

    Above all, take your time - rushing now will pay off with regret later

    Did I say "Wow" yet? :)


    Dave
    W7UUU
     
  4. N5OLA

    N5OLA Ham Member QRZ Page

    Dave, I share your excitement! So is there a way to test an electrolytic cap or should I just assume the oldies are unreliable? And do you recommend an online source (O RadioShack where art thou?)
     
  5. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    They are CHEAP. Just replace ALL the electrolytics.... www.digikey.com, www.mouser.com, and other such sites.

    You will find them ALL to cost pennies - and both sites have "no minimum" pricing.

    It's not like it's an old tube rig with expensive PS filter caps - all the caps you're dealing with will be small and cheap - absolutely no reason to trust the old ones.

    But TEST all of the resistors - carbon-comp resistors tend to go up in value - sometimes a LOT - even if "new old stock" - and again, resistors for a rig like this will be CHEAP.

    The one single "high cost" of this kit ... ist the fact it's an UNBUILT HEATHKIT.... so take your time, do it right, only install good components, and find success....

    Dave
    W7UUU
     
  6. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    I should mention... other similar posts/posters on this very site have "rushed through" the assembly of an ultra-rare "unbuilt Heathkit" and it was a DISASTER! They didn't take the time to do all of the above, and rushed the assembly - and the end result was junk.... at least as far as was ever posted.

    A certain very rare unbuilt Heathkit HW-9 QRP HF+WARC transceiver kit comes to mind.... ugh - that was tragic. Could have had a so-much-better outcome had planning UP FRONT been better thought through. That radio should have just been sold on eBay for $$$$ instead of ruined by a rushed and careless "assembly"

    Please don't repeat that experience - that is an OLD kit - worth a LOT of $$$ until the day you lay a soldering iron to it. Plan, plan, plan, and only then BUILD.

    Just my 2 cents....

    Dave
    W7UUU
     
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  7. N2EY

    N2EY Premium Subscriber QRZ Page

    What @W7UUU wrote is spot-on! I remember the HW-9 he describes - it could have been a contender, but the builder just dove in and started without checking anything. Last we heard, it was ten toes up.

    I'll add this:

    BEFORE starting the assembly, do the following:

    1) Copy the parts lists and do a complete inventory of ALL parts.

    2) Examine and test EVERY part.

    - Check condition of hardware - some things may have rusted or otherwise be in poor shape.
    - Inspect and test all resistors for proper value.
    - Check all switches for continuity when closed and open circuit when open.
    - Check all capacitors for value and leakage. Just replace the electrolytics; there aren't many and they're cheap.
    - Check all coils for continuity and condition.
    - Check all semiconductors that you can.
    - Check power transformer by checking resistance of windings, resistance of insulation (should be infinite) and then powering up, preferably with a Variac
    - Check all controls for value and smoothness.
    - Check variable capacitor for smoothness and clean/relubricate as needed.
    - Check crystals in a tester if available and you are sure the tester doesn't overstress the crystal.

    3) Make up a master list of parts to be replaced and get them before starting assembly.

    4) Enjoy!

    73 de Jim, N2EY
     
    N2SR likes this.
  8. W9GB

    W9GB Ham Member QRZ Page

    Robert Sumpton, W9RAS who worked at Heathkit, has a couple of videos on the HW-99


    Addressing observed VFO instability
     
    Last edited: Aug 1, 2019
    WN1MB and N5OLA like this.
  9. KE4OH

    KE4OH Ham Member QRZ Page

    New electrolytics all the way. Check resistors and replace any that are way out of spec (like 20% or more). Then build it! Don't let anybody talk you out of building it!! Then get on the air with it.

    Great find!
     
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  10. N5OLA

    N5OLA Ham Member QRZ Page

    Dave -- I happened to catch you today on Ham Nation 310 with your "fake Heathkits". Just WOW.
     
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