HW-12 A METER HARDLY MOVES IN TUNE POSITION - XCVR TRANSMITS THOUGH

Discussion in '"Boat Anchor" & Classic Equipment' started by W1FMX, Mar 29, 2021.

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  1. W1FMX

    W1FMX Ham Member QRZ Page

    While tuning an HW-12A that I have just restored, when the meter is in "Tune" position and the Final Tune Control is moved there is hardly any movement of the meter indicating relative power...a wattmeter indicates about 4-5 watts output when in tune. So, the meter moves slightly to reflect movement of the Final Tune Control, but just slightly. Otherwise, the meter works properly in Bias position and does accurately indicate a received signal's S units. The HW-12A transmits well despite the meter issue, and the output on voice peaks is about 75 watts on average. R61 is o.k. and CR60 seems o.k., too. Has anyone come across this problem?

    Thanks.

    73's,

    Bill
    N1LJQ
     
  2. W1FMX

    W1FMX Ham Member QRZ Page

    Follow-Up: After I wrote this note, I realized that I had not checked the Tune Level Pot to see if I could set the meter for S-3 level - that solved the problem.
     
    KE4OH likes this.
  3. AD4DQ

    AD4DQ Ham Member QRZ Page

    Thats great! I was reading the manual as I have a HW-12A to restore and it mentioned to tune to S6 level. I have had a HW-32A since 1990.
     
  4. W1FMX

    W1FMX Ham Member QRZ Page

    Hi,

    Thank you for your comment... that is great to hear that you have had an HW 32A since 1990 - talk about quality! Not only do they last a long time, but these rigs are really fun to use and I find the receiver works really well - good audio quality.

    As it happens, I just bought an old HW-32A that will need to be restored, so that is what I will do next. With the HW-12A that I restored, I had to replace about 25 resistors and the electrolytics, some micas, and a tube. The rig looked like it had been stored it an outdoor shed or damp basement. But, it cleaned up pretty well, though I had to re-paint the cabinet because of extensive rust (bought some "Heathkit" paint in dark turquoise online, but it did not look right when painted - a bit to blue, so I switched to Hunter Green and it looks really good, though obviously not original. On the other hand, the HW-32A looks pretty good for its age - almost mint.

    I had forgotten all about these "Single_banders" - in the late 1960's, I built a DX 60B and later and HW-100.

    Good luck with your new project!

    73's,

    Bill
    N1LJQ
     
  5. AD4DQ

    AD4DQ Ham Member QRZ Page

    I just picked up a HW-12A and it is in pretty good condition. Only one tube was bad. I replaced a couple
    capacitors the 20UF at 350. I checked it over good and aligned it up easily. The 6GE5's are 100% and the
    radio can put out 150 watts. I will have fun with it. Im looking for a HW-22A to add to my collection. I like
    the old tube radios. They are fun to work DX, work on and repair as well.

    169594607_4210164012350448_640505393657338882_n.jpg IMG_5969.JPG
     
  6. W3RU

    W3RU Ham Member QRZ Page

    If you are using the HP-23, be sure the B+ switch is set to 250 vdc for these rigs. 300 vdc is for the SB series 6146's, which MAY reach 110 watts if properly tuned, but even this is too high for longevity.

    Jack W3RU
     
  7. AD4DQ

    AD4DQ Ham Member QRZ Page

    Yes I have the HP-23A and make sure to use the switch to turn the bias down. I have another supply that does not have the switch so I’m lucky to have the 23A
     
  8. W3RU

    W3RU Ham Member QRZ Page

    The switch on the 23A selects the transformer B+ secondary winding combination to attain the 250 vdc B+. The bias pot may/may not be active in your rig - not sure how that works in the HW single bander series. The bias may be controllable using the bias pot in the HP-23A.

    In the HW-10x and SB series transceivers, the bias is controlled by a built-in pot for those rigs and a fixed, non-variable bias is supplied using via Pin 1 on the power plug, while the variable bias is still available using pin #11 . Both bias options are sourced for -130 vdc at the lower (250 vdc) B+ winding off the secondary and before the switch, and are not controlled by the 250/300 switch. Check to see which power plug pin is used in your rig - if it is via Pin #11, then you control the bias setting using the HP-23A pot.

    In the HP-23, the 250/300 vdc selection is hard-wired at the time of build based upon your chosen rig - no switch. The HP-23A PS is the most versatile and desirable model to have of the 5 variations. If your 23A had not yet been fitted with a 3-prong power cord, this would be a good modification. The original HP-23 was a real PITA with the fused power plug, it had no ground pin using the 2-pin design, and also the pilot light and power switch was "hidden" and not accessible on the rear chassis apron when mounted in the SB-600 speaker enclosure. The power indicator light in the HP-23 PS is ideal for mounting a fuse holder on the "hot" side of the 3-wire power cord - you can retain the pilot light by wrapping tape around the floating light (if you want to retain it for originality).

    Jack W3RU
     
    AD4DQ likes this.
  9. N4HZ

    N4HZ Ham Member QRZ Page

    Guys...what is the maximum power output from your HW12A when you are in "Tune" position and on dummy load? With the rear pot as high as it will go my HW12A only reaches 35 watts or so even after having gone thru alignment. In tune position should output power be capable of being adjusted to 100W output?
    Thanks
    Roger...N4HZ
     
  10. W1FMX

    W1FMX Ham Member QRZ Page

    Hi, Roger.

    I have my HW-12A tuned to a little bit higher than S3 in "tune position" (I found it can be between S3-S6 as indicated in the manual on Pg. 41/42), and the normal voice peaks are between S3-S6 as indicated on Pg. 50. Hooked to a dummy load, I get about about 10 watts output in tune position and about 80 watts at voice peaks while speaking. I have not replaced my finals, so they are o.k., but not the best. Still, the radio holds its own on the air and I generally get through using only a vertical on 80M. So, your getting 35 watts in tune sounds good to me.

    73's,

    Bill
    N1LJQ
     

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