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Kenwood YK-88C-1 & TS-940S Question

Discussion in 'Radio Circuits, Repair & Performance' started by KK4WX, Apr 25, 2015.

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  1. G3YRO

    G3YRO Ham Member QRZ Page

    Did you not realise you can have that with the original Digital Board?

    Having only paid £300 for my TS-930S, I must admit I was reluctant to spend more money on it with expensive aftermarket modifications.

    I feel I have overcome the original PSU design flaw . . . and my various mods have cost me almost nothing.

    But I know I was very lucky that my two 250Hz CW Filters cost me nothing !

    Roger G3YRO
  2. GM8PKL

    GM8PKL Ham Member QRZ Page


    My friend attempted the trick to 'illuminate' the additional digit, but for some strange reason it didn't work with my board. That said, I bought the Piexx to provide the enhanced tuning features (and also to get some more modern silicon; that original board was looking a tad dated) and it has made it an absolute delight to 'drive', so though it was quite pricey, I reckon that it was worth every penny (and the additional digit was just the 'cherry on the top', as they say).

    Curiously, my friend recently forwarded this article from a 1987 Ham Radio magazine and it notes that R400 was under-specified (and there was a factory change note to instruct its replacement). My radio is a very, very early model (different power arrangements to the later ones) but the original owner had had it regularly serviced, so when I looked at R 400, I extremely happy (but not entirely surprised) to find that it was of the higher dissipation variant as recommended in the change note (and that it had even been correctly soldered onto the signals board, not just a crunch the old one and solder the new one to the remains of the old legs) so that was a very pleasant find. Given that was done, I'd suspect that the IMD mod was done too, but I've yet to check that out.

    All good fun and I intend keeping it going for a very long time.


    PS Given its great age, I do hope that it's cool to upload that PDF from the very old magazine, but if not, my sincere apologies to the moderators.

    Attached Files:

    Last edited: Aug 11, 2020
  3. G3YRO

    G3YRO Ham Member QRZ Page

    I agree with many points in that article Briain . . . I have done lots of adjustments to my '930 (and repairs too) with hardly any test equipment . . . it's really not Rocket Science !

    I certainly love my TS-930S . . . I rate it against any of the modern flagship rigs . . . but the very reason I chose a '930 is because it is actually repairable yourself, unlike most of the rigs even a few years later.

    It's very easy to see if the Standing Current has been turned up on the PA . . . but I disagree what the guy in that article says about the ALC Time Constant . . . it is WELL worth reducing the delay so you get much increased Talkpower . . . with no apparent increase in transmit distortion products. (these rigs are much cleaner than most with Transistor PAs anyway, as they don't run on 13V)

    Roger G3YRO
  4. AJ4SN

    AJ4SN Ham Member QRZ Page

    When I added the narrow filter to my FT897, there was considerable signal attenuation. I thought that something was wrong, and I contacted the manufacturer, but it turns out that's just the additional loss caused by the filter. Of course, it's possible that you have a bad filter. I'm just sharing my own experience.

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