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
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.
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
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?)
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
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
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
Robert Sumpton, W9RAS who worked at Heathkit, has a couple of videos on the HW-99 Addressing observed VFO instability
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!
