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Thread: The TS-530/830 mod and upgrade thread

  1. #11
    "Island Bartender" KG4CGC's Avatar
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    WOW!
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  2. #12
    Administrator N8YX's Avatar
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    Tip #6: Product Detector upgrades

    Also present on AG6K's "Circuit Improvements" page. Several modifications are made in this area. One involves swapping the OEM 1N60 diodes used in the product detector for low noise-figure Schottkys. The LO side of the bridge is unterminated; a resistor to ground fixes this. Next, a few components in the IF bypass RC network are changed - opening up the received bandwidth a bit, and as Rich noted "...you'll get the full effect of sky noise". The modification makes for a more robust sound from the speaker - and if less bandwidth is desired, the Narrow filters can be activated...or an accompanying SP-230 with its built-in audio filters can be used...or both.

    Component changes on the '530's IF Board are as follows. These are applicable to the TS-830 as well, though depending on production run, not all parts may need to be swapped. The '830's component designators are different and will be covered in another post.

    - R41 is changed from 6.8K to 2.7K
    - C35 is changed from .033uF to .01uF. This is a polystyrene unit
    - R42 is changed from 47K to 3.9-4.7K (I used 4.3K)
    - D16-D19 are changed from 1N60 to 1N6263 or similar Schottky parts. I got a bunch of these from K4EAA and matched them to .001v forward drop before installation

    Prod-Det-1.jpg

    A 100 ohm, 1/4w resistor is added from the junction of R39 and R40 to ground:

    Prod-Det-2.jpg

    (Insert obligatory Linda Hamilton "...terminated..." quote here.)

    Follow the service manual procedure and adjust the product detector via TC2. I used a scope and got the null down to the point that the LO energy was unobservable at the test point, the drain of Q4. I've tried using 1N5711s in my FT-90x projects and found the weak-signal performance to be a slight - but not a great - improvement. The 1N6263s seem to work better, at least in this application.

    FWIW, I checked sensitivity with a signal generator at 14 and 28MHz. I cannot turn it down to the point that the signal isn't detectable (.01uV or thereabouts), and the recovered spectrum is very low in noise.
    Last edited by N8YX; 06-14-2018 at 09:55 AM. Reason: Grammar
    "Everyone wants to be an AM Gangsta until it's time to start doing AM Gangsta shit."

  3. #13
    Administrator N8YX's Avatar
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    Tip #7: Balanced Modulator update

    Another one borrowed from AG6K. The modification cleans up the transmitted signal a bit at the balanced modulator. In the 530, diodes D27-D30 (1N60) are changed to the same type as used in the previous modification. Follow the service manual procedure and null the carrier after the IF Board is reinstalled in the radio. The mod is applicable to the '830 too, albeit with different component identifiers.

    I found it easier to do all IF Board mods at once, and in addition I replaced the large filter capacitors at the rear of the board with 450v, 105c-spec units while I had things apart.

    Bal-Mod-Diodes.jpg
    Last edited by N8YX; 06-14-2018 at 01:24 PM. Reason: Grammar
    "Everyone wants to be an AM Gangsta until it's time to start doing AM Gangsta shit."

  4. #14
    Administrator N8YX's Avatar
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    Tip #7: Fix TS-530 "S meter slam"

    According to users, assorted 530 series rigs will slam their S meter's needle to the right on power-up. The meter in the rig on my bench was hitting its pin hard enough to be audible. Engaging the RF Attenuator, turning the AGC to Fast (or Off) and disconnecting the antenna can either reduce or eliminate the condition - if one remembers to do so.

    User group comments reflect that the condition is 'normal' - although neither of my 830s do it. This prompted me to study the '830's AGC and S meter circuitry, and to attempt to identify a root cause.

    A couple things become evident: The TS-530 series really IS a cost-reduced version of its big brother, as many key circuits are implemented in the same way but are lacking in a few areas. In the case of the '530's IF Board, a meter snubber circuit present in the '830 is missing. Then there's the matter of the AGC timing capacitor being installed backwards relative to that of the '830.

    The fix involves pulling the IF Board, removing and re-installing C84, then adding a few components to the foil side. Easiest to do while you have the board out for other modifications:

    AGC-Fix-1.jpg

    This is the "after" pic, with the capacitor installed as per the '830 ('+' terminal to the RF Gain control).

    Next, add a 33uF 16-25WVDC capacitor and a series 1.5k 1/4w resistor from the 'M(eter)' line (pin 2 of connector 10) to ground. Circled is C84 - foil side - for reference.

    AGC-Fix-2.jpg

    The orange tantalum capacitor next to the yellow circle is an addition. It's across R106 (10k) and connects to the (new) negative side of C84. Again, present in the '830. I used a 0.39uF 35WVDC part - though I may swap it for a 0.1-0.22uF some day (the latter value being used in the '830).

    The S meter still pins on power-up, but with much less force - and somewhat less duration. AGC and ALC functions were checked and are not affected by the mod...only the action of the meter itself, and only from a cold start.

    Further work may be done, at which time I'll edit the post as needed.
    "Everyone wants to be an AM Gangsta until it's time to start doing AM Gangsta shit."

  5. #15
    Administrator N8YX's Avatar
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    Adding a band to your 530/830 AUX position

    As shipped, both series of rigs had provisions for adding an auxiliary band...according to Kenwood, for receive only. This band spot can also be made to transmit, and does not involve butchering the radio in any way.

    What it does involve is a decent amount of resourcefulness, patience and a careful touch with the soldering iron. A well stocked junk box and test bench helps too - as does a well stocked beer cooler, for use with your friends whose junk boxes have all the required parts.

    This isn't a so-called 'screwdriver' mod. Some component fabrication is required, as is removal of the RF Board and tinkering around the final amplifier assembly.

    WARNING: VOLTAGES INSIDE WILL KILL YOUR ASS DEAD IF NOT CAREFUL. Bear in mind this ain't your grandfather's transistorized PA set.

    I've chosen to add 27.0-27.5, as later on we'll look into how to make the '+0.5' switch work with it too. This will net us complete coverage from 27-30MHz, and will be useful in driving transverters whose IFs are at 27 or 28MHz. I'd refrain from adding 60M to the rigs - their VFOs run at 5.5-6MHz and there will possibly be an issue with reciprocal mixing products. Counter and PLL programming theory will be covered and is useful in adding other band ranges.

    WARNING: USING THE COMPLETED RIG IN A SERVICE WHICH REQUIRES CERTIFICATED EQUIPMENT CAN PUT YOUR LICENSE IN JEOPARDY. EMERGENCY, RX OR TRANSVERTER USE ONLY, PLEASE.

    There are several steps which are required to add a new band, and each will get its own section:

    -Program the Counter Board
    -Remove the RF Board and gain access to the PA compartment
    -Wind coils
    -Install coils (and on the '530's RF Board, add Transverter connection components)
    -Configure the PA band switch
    -Update PA compartment components as required
    -Replace removed components and assemblies
    -Align RF Board and test
    Last edited by N8YX; Yesterday at 09:13 AM. Reason: Grammar
    "Everyone wants to be an AM Gangsta until it's time to start doing AM Gangsta shit."

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