Technical Questions & Answers
For Kenwood Amateur Transceivers TS-520, TS-520S, TS-820, TS-820S, TS-530S, TS-830S, and more!
From the K4EAA Ham Radio Mailbag
PAGE 1
 

Over the years I have received and answered many thousands of technical questions from Ham Radio Operators.  At this juncture, I suspect I have answered every Kenwood question that is possible to ask at least once - And several, many, many times.   While it takes a fair amount of time to add to the FAQ, with pictures and diagrams and the like, the email questions can be copied and pasted reasonably quickly.  That is what I have done here - Although This is becoming a large task as I get into it as well . . .

I will be adding to these as time permits, as I have over four years worth, after all!   You can either read through the emails page-by-page (like a novel!), or search the site for keywords which will lead you directly to your area of interest.   ENJOY!   Ken, K4EAA


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Ken:
 
I am originally from Deland.  When I was in my early 20's, neighbor Walt taught me something about tuning tank circuits.
 
First, verify proper neutralization, if applicable.  Now, switch meter to relative power and apply full drive, that is to say sufficient drive for peak output. Alternatively, use outboard power meter.
 
Rock the plate tune control back and forth with respect to the approximate optimum with one hand (We are talking small displacements here.) while advancing the loading with the other hand.  Advance loading until highest power peak is seen on plate control swings.  Remove hand from load, and tweek plate tune for max power.  You are done!  These settings should (must!!) coincide with plate dip.  If not, rig is improperly neutralized.
 
When done, back off drive for desired output.  I like about 75 watts PEP with 6146 type tubes........prolongs life.
 
Procedure takes 10 seconds at most, and usually about 5.
 
73  Matt


Hi Matt;

Thanks for writing and sharing your thoughts.  I don't agree with that tune up procedure and wouldn't recommend it for two important reasons:

1)  Tuning for maximum power output is dangerous, as one should be watching plate current, not a power meter or relative power meter.  Especially if it's like a Bird wattmeter that has a very slow time constant.  It puts final components at risk during the tune-up, and worse if the operator leaves the rig in a high plate current condition.  I've seen too many blackened plate chokes and cooked resistors in rigs where someone wasn't watching their plate current carefully.

2)  Reducing the drive to reduce power output negates the functionality of the ALC.  Without ALC the output power is highly dependent on the operator's speech loudness and position relative to the microphone.  Plus, the processor if used will not function properly either.   The proper method of reducing output power is to load up at reduced plate current.  The LOAD control is your power output control, not your DRIVE control.   With modes like PSK, I agree that you can used the DRIVE control to reduce power output, but that is because it is a fixed amplitude signal, unlike speech.  Reducing the output by reducing the position of the LOAD control has another benefit - It reduces harmonics and RFI because of the increased output C on the tank.  And again, running with positive ALC indication will assure that you have maximum "talk power," that your voice level will be constant, and your speech processor functions properly.  The way Kenwood intended!

Hope this helps, best 73's,
Ken


Hello again!

I mailed you about a year ago when I bought a derelict TS-830 (I live in Sweden). The initial problem was a fried audio chip, i fixed and many other small problems (PSU caps, band switch etc.) but I suspect that the previous owner went amok with the screwdriver. Receive worked semi OK, but transmit was weak on one band and next to non-existent on the others. I suspect it is completely de-tuned.

A year ago I didn't have the gear, but I have now kitted up with Signal generator, Frequency counter, spectrum analyzer, etc. and got the 830 out of the closet and said "right, let's tune this anchor up". I didn't get very far though.

I get stuck on step 3 “carrier adjustment (1)”  I get 1VRMS instead of 0.3V as specified at TP3 and adjusting the T16 slug makes no difference!  I am measuring TP3 on the RF unit as I can only find a TP1 and TP2 and there seems to be no TP3 on the PLL board. Is there a typo in the service manual? Is there another place where I should be measuring on the PLL board? TP3 just does not seems to exist on the PLL board!

On step 9 "VCO adjustment and check" it says check levels at TP3 on the RF board and there it says 1V. This is what I am getting there.

I feel I am missing something obvious here! Any pointers would be much appreciated!
Peter


Hi Peter;

My service manual says to adjust T16 on the PLL board while measuring TP3 on the IF board and set to 0.3V on the CCW side of peak.

Try that!

Best 73's,
Ken


TS-830S not “gold” label SN 1040766, no WARC Mod

Can get good ALC swing
Peaks & Dips good
100W into dummy load (I built it from your plans!)
So I think the driver & finals are good
MC-50 mic set for HIGH impedance (thanks for your instructions)
Receive is great

Making contacts on 20, 40, and 80 but getting audio reports of “too much treble”, “no bass”, “does not sound like a Kenwood Hybrid”

Also tried a Cobra Hand mic (wired it up per your pinout instructions), same reports

Also tried an old Turner +2 SSB CB Desk mic, even worse (probably impedance mismatch)

I bought this rig locally used so I don’t know where she’s been, or how she’s been treated

Visually the rig looks good. Cal Fischer NF5P at hamrepair.com repaired a variable cap last summer, said the rig looks good, very clean.

Ken, you are the Kenwood Hybrid Elmer & Guru… so, any ideas why my TS-830S has thin transmit audio?

73, David


Hi Dave;

Not only does it have thin transmit audio, it probably has thin receive audio as well!

It is probably the USB and LSB trimmer caps accessible through the bottom of the case that need adjustment.  Those adjustments will center the audio in the filter passbands as you wish.  Turn on the calibrator, and while tuning through the calibrator signal, adjust the USB and LSB trimmers in their respective modes until the lower end of the passband extends to about 100Hz, without going through zero beat and hearing the "other side" of the carrier.  Whatever you do on the receive side will be the same on the transmit side.  Since the passband is only 2400 Hz wide (through the filters), you want to center it so it extends from perhaps 100 through 2500 Hz.  Kenwood sets it to 300 to 2700, but a little more bass can sound better.   Over the years it may have drifted way higher.

Hope this helps, 73's,
Ken




ken, i've had contact with you before...and i read your web site often to get hints on kw hybrids. I have one question that may sound stupid: can i use a regular vtvm instead of an rf vtvm to neutralize finals? just not too skookum on such things.

                                      tnx and 73's JT

Hi J.T.;

You'll be able to use a VTVM or DVM if you build a simple diode detector using a 1N34 or Schottky type diode.  http://www.io.com/~n5fc/rfprobe1.htm
has a schematic for an RF probe, and you won't need the resistor divider - You want as much signal as you can get!   It will enable you to see the null pretty clearly.  Make sure you terminate the antenna connector with a small 47 or 51 Ohm resistor as well.

Hope this helps, 73's,
Ken


Hi Ken! Great site. I may have a patient for you...

My 820 appears to be working fine on 40M. When I switch bands to 20, 15, or 10, It appears to be almost deaf on receive. I've worked around with the tuner (an MFJ-949D) and can get the audio to sound louder but when I tune up and down the band I just hear the occasional squeal. It will transmit on these bands just fine. I can get to 1:1 SWR with full 100W output.

My antenna isn't good at 80 or 160 so I haven't tried them.  Also I can't receive WWV on the JJY/WWV switch.

Can you give me any pointers or should I start boxing it up?

Thanks!  Mike


Hi Mike;

You might start with a simple alignment of the RF board coil pack, as described in the service manual.  That will either cure the problems or show you where other issues exist.  Try that and let me know how it works out.  I'd be happy to get it right for you, but you might give this a try first.

Hope this helps, best 73's,
Ken


Hi Ken,
 
Thanks for your great web site.  I appreciate the information you have there, as I am new to the Kenwood hybrid thing.
 
The power output on my TS-530s is a bit weak (around 80W) when my Ip is set at 265mA, and based on info on your web site I thought it might be my cathode resistors.  I measured them last night and got 7.5 ohms, so that seems the probable cause.  I have access to a sizable selection of resistors.  Is there a particular type of resistor that I need to get or avoid so long as they are the right resistance, wattage, and tolerance?  Might I have hurt anything else by running the rig this way for a while?  In the event we don't have any of the right resistors in our stock, would you please forward your contact/paypal info so I can buy some from you?
 
Thank you, Mark

Hi Mark;

The resistors should be non-inductive, such as carbon composition, metal oxide or metal film.  Stick with 1/2W resistors, do NOT increase the wattage rating.  Thanks for the nice compliment, good luck and best 73's,
Ken


Hi Ken,
Hope you had a great holiday.
I was curious, Do you have a source for the 3SK73 FET or do you sell them?  Discontinued stuff is getting harder and harder to find.

Thanks,
73, Gordon

Hi Gordon;

I use the NTE222. It is a good substitute for many of the dual gate MOSFETs Kenwood used.

Hope this helps, 73's,
Ken


I hate to bother you, but I have a issue I am not sure about. Operating cw my readout reads about 800hz low from the actual freq, the display shifts to the correct freq on xmt with my vfo 230, but does not on the internal vfo. A good friend tells me I am on freq on the VFO 230 but 800 hz low on the internal vfo on xmt on cw. Plus I cannot work stations on the internal vfo that I can with the vfo 230. In tune position the readout is correct.
 
Now a mod was done to the 830 to cut the xmt offset to 80 hz internally ( a small circuit board and pot  is under the chassis marked tx offset) IS there a way to align the readout to show the tx freq at all times.
 
This is what was done by a previous owner: And the receive is by far better with this rig, just the tx freq issue.
 
 
The first and second IF filters were replaced with 500 Hz units, the TX offset was cut to 80 cycles, and the product detector diodes were changed to drop the noise floor. Also, modified RIT to increase swing to 14KC, clipped RF to allow T/R on WARC bands 10, 18, 24.5, re-adjusted notch in IF board for deeper notch, disabled digital hold, using switch for filter skirts and enabling a preamp, installed shielding around IF filter to prevent blowby.
 
 
I believe I want to bring the tx off set back to original. My other 830s shows the shift from rx to tx on both vfo's and reads out the exact freq as the first 830s on receive. I will likely try disabling the tx offset mod and hope I don't screw up anything else. I don't have a schematic of the mod, but I think I can match up the original wiring.
 
 Any Suggestions?  Larry


Hi Larry;

There are Kenwood CW filters that are centered 700 Hz from where the 830's would normally be - These were used in later units like the TS-930.  People have mistakenly installed these filters and then performed mods to the radio to get the passband centered again.  With the incorrect filter the audio would peak 700 Hz high, at about 1500 Hz.  Could this be the case with your radio?

Rule of thumb is to remove the mods, especially if they're causing problems as yours is, and put it back to normal.   The offset caused by the improper filter can be taken up by the IF Shift without affecting transmit frequency.  The CW offset is produced by a voltage applied to a varactor diode in the carrier oscillator,  so it is adjustable.

Hope this helps, 73's,
Ken


I like contest and I usually work cw with a TS940s along CT software (by K1EA).   I do own a TS830s plus VFO-830 also.  On top band (160-80) my old TS830s exceeds the TS940s, TS830s receiving performave is excellent.  Because the TS830 has a negative VDC grid block transmitter, interfacing PC and TS830 is quite difficult for me.  I tried a optoisolator interface without result. Usual trade interfaces don't work with TS830 I wasn't able to find interface information neither on Internet nor on CT user group I found your outstanding web page so I hope you might have some information on the matter or you might give some address to whom I should apply
Thanks Ken.
My best 73, Ed

Hi Ed;

You can either add a small relay or build a simple interface with a PNP transistor.  I've done it both ways and either way is suitable.  Try this link for a schematic of a simple gid block keying interface:
http://home.att.net/~jacksonharbor/gridbsch.pdf
They no longer offer the kit for sale, apparently.

Good luck with your 830S and thanks for writing!
Best 73's,  Ken

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