Kenwood TS-830S Deafened Receive Repair!

Discussion in 'Radio Circuits, Repair & Performance' started by N9PCT, Mar 20, 2019.

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  1. N4CVX

    N4CVX Ham Member QRZ Page

    Thanks for all the helpful responses. I found a Final Choke complete with the tube HV metal caps on eBay. Also ordered final amplifier rebuild parts such as capacitors and resistors, etc., from K4EAA. I've ordered a lot of stuff from him and his XYL over the years including that poster-sized TS-830 Schematic which I Framed for the ham shack. I'll keep you all posted on how the repairs are going. My concern now is why, when I plug the rig into 110 vac, it still crackled and emitted smoke, even though no key down or other actions which might put it into transmit.
     
  2. N8YX

    N8YX Ham Member QRZ Page

    Which components did this?
     
  3. N4CVX

    N4CVX Ham Member QRZ Page

    That I will find out tomorrow. What ever it was crackled and smoked but the fan sucked the smoke out so I didn't see what it was last time. I didn't want to leave power on until I had time to do a closer inspection. The rig is uncovered and on my workbench now. Once I find out what burned I'll post pictures. That'll be tomorrow after I get my usual chores finished.
     
  4. N4CVX

    N4CVX Ham Member QRZ Page

    I'm back with a report on my TS-830S smoking. I took the covers off and got the capacitors discharged. As I posted earlier, the Final Choke was toasted. I found a new choke with the tube caps on eBay and it looks almost new. I discovered that I had a "grid to cathode short" on one of the 6146W finals. The 1W 10 ohm cathode resistor burned and the tube's center plug on the bottom was melted (plastic cover melted and disconnected when I pulled the tube). I have the "TS-830 Survival Guide" edited by Olaf, DL9AI and the various TS-830S manuals and repair manuals. My plan now is to replace the components on the final board. I have plenty of parts from K4EAA, BTW. Then order new 6146B tubes and a new 12BY7.

    I figured out where the smoke started and after pulling the tubes applied 120vac power again. No smoke and fan was running without moaning.

    My second TS-830 which I use daily on 30M is now suffering from no ALC which I understand is a problem with the 12BY7. I check the bias on it and made sure it was 60ma, but still no ALC on key-down or tune. It puts out about 25 watts on CW. That's the next project, HI HI

    Hope this clarifies the situation. I'll be interested in reading your responses,, comments and advice. Happy New Year !

    Dave
     
  5. KD4QFT

    KD4QFT Ham Member QRZ Page

    One main fault with alc is the rf board
    The wafer switches are copper with brass rivets, on the third bank of the band switch the copper to brass corrodes and poor connection occurs.
    Remove wafers from board and make a fine scratch and solder connection on each wafer, I personally do all three banks of the switch no cost but a lot of time
    I purchased 10 830s recently two like new rest as parts
    Colin
     
    N4CVX likes this.
  6. N4CVX

    N4CVX Ham Member QRZ Page

    OK, thanks for info. This weekend I'll pull the covers off my "good" TS-830 and check the RF Board. I'm pretty sure you are correct in your diagnosis. I replaced the 12BY7 with a new one from Ken K4EAA and after I checked the grid current, buttoned the rig back up. I tuned up and noticed when I ran the procedure, I saw 60ma (OK), and got 25 watts out into a dummy load in the "tune" position. I finished tuning, then plugged in my straight key and tried the CW key down for a few seconds test. The ALC indication fluttered back and forth and the power out on the in-line swr meter showed fluctuations very quickly from 100 down to about 50 and in between. I let the rig cool off for a few minutes, then tried again and same thing. So, I'm thinking you are correct. Now to tear the rig down again and clean up the RF board. I'll give all the switches and rotating stuff another shot of de-oxit (last time was a couple of years ago when I last rebuilt the rig). Oh yeah, and I ordered two new 6146B tubes -- Chinese and I hated to send the business, but found no other source of guaranteed brand new 6146B's for under $100 each. These were $38.00 each. We'll see what happens with them and if OK, I have to get two more for the other TS-830 after I finish cleaning it up.
     
  7. KD4QFT

    KD4QFT Ham Member QRZ Page

    HI
    DEXOIT WILL SOME TIMES WORK BUT SOLDER IS BETTER
    USUALLY LAST TWO ROTARY SWITCHES ON RF BOARD ARE THE CULPRITS
    SWITCH NEAREST PA AS MANY CONTACTS TO SOLDER SECOND FROM PA ONLY AS I THINK FOUR
    A SMALL SCRATCH FROM COPPER TO BRASS RIVET IS BETTER THAM CLEANING AS IT IS NOT THE MOVING PART IT IS THE BRASS TO COPPER RIVET CONNECTIONS
    MAKE SURE YOU KEEP SHAFT IN POSITION WHEN TAKEN FROM RADIO EASY YO MOVE ONE WAFER AND GET IN WRONG POSITION
    I HAVE MANY SPARES INCLUDING TUBES IF YOU NEED PARTS
    ONLY HAVE ONE SET OF GOOD OUTPUT GE 6146B THOUGH
    GOOD LUCK
     
  8. N4CVX

    N4CVX Ham Member QRZ Page

    I posted my results on FaceBook's TS-830 page and will re-post it here, the advice I received here and on the FB group was very valuable. Even though I have the "TS-830 Survival manual" and all other repair manuals, I sure appreciate your help. I've been working on radios since I built my first Heathkit back in the early 1960's so I'm not to worried about messing something up but the sophistication of the TS-830S makes me go slowly and carefully!

    From the FaceBook TS-830 page:

    "... the band switches and general crud on the actual contacts. Just as someone here on this forum suggested to me. After I pulled the top and bottom off, I used de-oxit spray on everything that moved or contacted inside then used a piece of 0000 sandpaper (non-metallic) to slide in between the contacts. On the band switch, the ball-bearing detent was fouled but de-oxit cleaned that up. I sprayed the various pots and other switches as well. Let the rig sit for about 3 hours then used my air compressor to gently blow air through it. Found a dead bug in there too, one of those stink bugs we get down here in the South. It evidently Rode the Lightning. TS-830S #2 is going to be the real chore what with a complete rebuild of the Final Cage including all components."

    "... (several days later ...)

    Update on my TS-830S Tune-up Work. This rig has fairly new 6146B's and a new 12BY7 (replaced the old one during this repair job). I didn't "push" the power even though I probably could have and gotten close to 125~130 watts.
    Readings: Dummy load with Bird Wattmeter:
    28.500 110W all OK Carrier at Level 4
    24.900 110W all OK Carrier at Level 4
    21.225 120W all OK Carrier at Level 4
    18.110 100W all OK Carrier at Level 4
    14.200 100W all OK Carrier at Level 4
    10.100 110W all OK Carrier at Level 5
    7.225 110W all OK Carrier at Level 5
    3.725 115W all OK Carrier at Level 5
    1.925 110W all OK Carrier at Level 5
    Worked a couple of guys on 20 meters with good audio reports; appreciated the filters this rig has, particularly the narrow SSB and CW ones. Then worked another guy on 30 meters with good CW report and used the CW narrow filter -- no ringing but really had to fine-tune his signal which was about 544.
    Now on to the next TS-830S with the blown (melted 6146W's base). Lots of work there.
     

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