Heathkit HW-101 woes

Discussion in '"Boat Anchor" & Classic Equipment' started by N5OLA, Jul 14, 2019.

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  1. N5OLA

    N5OLA Ham Member QRZ Page

    Hi -- I wish I had an elmer to help me troubleshoot my HW-101. It transmits fine, but the receiver sounds odd, over-modulated. And (separate issue) when I switch on the CW filter the volume drops out completely.

    I got back into ham radio after a 30 yr absence, and I don't have a shack equipped with more than a multimeter. I'd like to learn more, and am eager to open this baby up and start probing, but I don't really know where to begin. Maybe I'm the wrong person for this job.

    If there are any fans of this rig who have an insight into what might be wrong, I'd love to hear from you.

    73, N5OLA
     
  2. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    Is there a CW filter installed? The HW-101 did NOT come with the 400 Hz CW filter. It was an added cost accessory. The number of HW-101 units "out there" that do not have the filter is considerably more than those that do have the filter installed. Without the filter being installed, the unit will definitely be dead, on receive, when the filter switch is in the CW position.

    If there is a filter installed, try cleaning the 2-each slide switches that physically switch between the SSB and CW filter.

    Have you replaced the electrolytic capacitors in the transceiver? There is a very good chance that they have "dried out" and that can cause all sorts of problems.

    C-304, the bypass from Pin-3 of V-14, a 6GW8, the audio output tube, is definitely suspect. Replace this 20 mfd capacitor with a modern 22 mfd with a voltage rating of at least 350 VDC.

    Glen, K9STH
     
    N4EYZ, WD4IGX, KS4W and 3 others like this.
  3. K7TRF

    K7TRF Premium Subscriber QRZ Page

    The multimeter is a good place to start with a HW-101. Download the Heathkit assembly manual and perform the resistance checks from each tube socket pin to ground as described in the manual. Replace any carbon comp resistors that are more than 20% or so from marked value. Out of tolerance resistors, mostly reading much too high in value, account for an awful lot of the strange problems in Heath rigs of this vintage. Something like distorted audio could easily be a problem with out of spec resistors.

    As Glen posted above, if you do have the optional CW filter installed and get no audio with it switched in, then clean the slide switch. If cleaning the switch doesn't help, you could try measuring the resistance across the switch when the CW filter is selected. It should be basically zero ohms (or a very low value like just a few ohms depending on your meter accuracy). The switch itself may have failed which does happen in these rigs. Jumpering across the switch in CW mode should tell you if it's a switch problem.
     
    KX4OM, AI3V, N5OLA and 1 other person like this.
  4. K5MIL

    K5MIL Ham Member QRZ Page

    I always advise anyone working on any of the HW or SB series of Heathkits that haven't been used in some time to re-tighten all of the screws that hold the circuit boards to the chassis. Bad grounds of the boards to the chassis can cause any number of strange problems.

    Bill - K5MIL
     
    N4EYZ, WQ4G, KS4W and 3 others like this.
  5. W5RKL

    W5RKL Ham Member QRZ Page

    I agree with Glen, K9STH.

    Remove the power connection on the rear 11 in power connector, microphone from the MIC
    socket, speaker from the rear panel speaker socket, and CW key (if used) from the CW key socket..
    Remove the top and bottom covers.
    Turn the radio upside down with the front panel facing you.
    The crystal filters are in the middle close to the front panel.

    Click the link below then scroll down to view the picture showing how the filters are mounted to the
    filter "L" mounting bracket. The CW filter (404-284-1) is shown mounted in the correct position on
    the filter mounting bracket. The picture shows the transceiver upside down with the front panel
    facing "right" in the picture.

    https://forums.qrz.com/index.php?threads/surprised-by-the-heathkit-cw-filter.599118/

    The Larger size CW filter, part number 404-202, will not fit nor work in an HW-101.

    73
    Mike W5RKL
    https://www.w5rkl.com
     
  6. W7FOX

    W7FOX Ham Member QRZ Page

    As TRF said, get the manual, and follow the tune-up steps and trouble shooting guide. That alone is a good start, and may solve the problems. I've been working with this model for 50 years and I still go back to the manual at times. Good luck.
     
  7. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    OLA:

    If you need the manual for the HW-101, contact me, by E-Mail, at

    k9sth (at) sbcglobal (dot) net

    I have a PDF of the HW-101 manual that can be forwarded.

    Glen, K9STH
     
  8. W5RKL

    W5RKL Ham Member QRZ Page

    I have the HW-101 and SB-101 full assembly manuals on my website. Click the link below,
    scroll down the page to the Heathkit listing then click the HW-101 or SB-101 assembly
    manual pdf link(s).

    https://w5rkl.com/manuals/

    73
    Mike W5RKL
    https://www.w5rkl.com
     
  9. KJ6ZOL

    KJ6ZOL Ham Member QRZ Page

    I hate to butt in, but I bought a HW-101 at a swap a few months ago and it is in the closet awaiting the bench. Thanks to everyone for ideas as to what to look for when rehabbing.
     
  10. N5OLA

    N5OLA Ham Member QRZ Page

    Thanks to everyone for your advice. I'm going to take a deep breath and plunge into this rig shortly, and your timely wisdom will no doubt come in handy. 73!
     

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