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 Email Logs
PAGE 4
 

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.

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-
Need to pick your brain, but this should be easy.
You have helped me several times with my TS-830S; only drawback to this radio is the inability to
work split when the split is more than 2KC.
Here's the question>
I have the opportunity to buy a TS-570D, still in the box with a mic and DC power cord for $520
shipped to me with insurance. I was thinking about it but then I asked myself, WHAT IS A SIMPLER
Kenwood HF radio I could get that would allow me to work larger splits w/o having to buy a radio
with tons of bells and whistles I don't need or want? And that is the question I pose to you. What do
you recommend?

Take your time to answer.
Thanks,
Randy


Hi Randy;

I recommend a VFO-240 remote VFO for your 830S. That's exactly what they are made for!

Best 73's,
Ken

Once again, you have the answer I needed to hear...have you got one for sale or a recommended
source?
Thanks Ken,
Randy

Hi again Randy;

They appear pretty regularly on eBay - I don't presently have one available. There are 2 remote
VFO's for the 830S, the 240, which is my favorite, and the 230, which is digital with memories. The
230 usually goes for a very stiff premium. I do not recommend the digital model because it's more
prone to problems, being a very early digital design and rather complicated. The 240 is analog,
identical to the VFO in the 830S, and does what it's supposed to do very well with only 4 transistors!
The VFO in the picture on my home web page is a VFO-240 that works splits in style . . . 8^)

Best 73's,
Ken

Ken-
Once again, you have convinced me that what I thought was the right thing to do (VFO-230) may be
exactly opposite of what would satisfy my requirement. But never having used a VFO, I need some
assurances that it is as easy to use as you say. I guess there is a mechanism in the -240 that allows
you to monitor/use the transmit/receive without having to spin a dial everytime you transmit.? In
other words, if a DX is operating split, he may be listing on 14.225 (same freq that I would be
CALLING ON), and once I made a call, the vfo would somehow be listening on say, 14.220, which is
where I would be LISTENING to find out if he calls me...right? Can the TS-830S and VFO work that
way so I can SET the VFO and merely xmt and then auto switch back to the VFO for listening
purposes? Help me Ken...get me smart. Thanks,
Randy


Hi Ken,

I am using the TS-830S and was wondering if I use a SB-200 amplifier would I have to make any
changes to the keying line ? The SB-200 is 110 volts on the relay and did not want to damage the
TS-830S.

73,
Art


Hi Art;

The remote connector on the TS-830S has the amplifier control lines switched by RL-1-2 on the
antenna relay. Those are pretty substantial contacts rated for 240VAC at a few amps. You shouldn't
have any problem.

Hope this helps,
Best 73's,
Ken


Good morning Ken: I'm writing in hopes that you can help me locate what I feel is a problem in the
14VDC line in a 820 in helping a ham fix.

Given: Rectifier Board shows signs of trace overheating in the area of D-8- D11

Unsoldered the red wire to the 14V terminal so I can monitor what is going on when I feed 14V in
from an external source.

Replaced Relay Board with a working one from my personal 820S. The problem of low voltage on
the line is not C-1 and C-2 2200 mf 25VDC caps.

Measuring resistance on the disconnected red 14VDC line to ground I get about 45-50 ohms. My
working 820S shows zero ohms.

Current draw on the 14V line, in my good 820S, is about 125 or so ma in Receive. It is in excess of
500ma on the set that has problems. Something is dragging that 14 line down.

After a lot of unplugging boards and measuring voltage and current draw which is over 500 ma
when I feed 6-7 volts into the 14 volt line I have decided that the CH in the 14 volt line is a very likely
suspect.

CH must stand for choke which is being used as a capacitance input filter on the 14V line. The same
LV filter circuit is also in my 520S/SE.

There is no reference in the Service Manual what the value or the location of "CH" is. If I could find
it then I feel capable of eliminating it as a suspect but based upon what I've figured out the past day
or so I'd wager you a good cup of your favorite Starbucks that the CH is defective with an internal
short to ground.

Where is it?

Many thanks!
73 joe


Hi Joe;

You've done a nice job of tracking down the likely culprit - Now for the interesting part - I received
an 820 with a similar problem a few years ago and it behaved as you describe. It turned out to be
one of the leads of that choke was pinched under a screwed-down chassis partition and it had
chafed and shorted to ground. The choke is behind the IF board, under that aluminum colored
heat sink that is part of the DG-1 as I recall. It looks like a small filament transformer.

Hope this helps,
Best 73's,
Ken



Hi Ken,

It's been a while since I last emailed you. I'm the guy that has a sick 830 and also asked if you had
one for sale. I'm not looking to buy another 830 at the moment, but I do have a question related to
the sick 830 I have. If C6 (the 3pf capacitor inside the final cage) was "open" and not passing any
signal back to the driver tube, what would the radio do or not do?

Tnx Ken,
Mark


Hi Mark;

That cap provides negative feedback to the driver cathode. It would be the same thing as opening the negative feedback loop on an audio amp - Higher gain, more distortion.

Hope this helps,
Best 73's,
Ken


Hello Ken,

I'm using an old TS-830S. Last week I made some SSTV tests and
apparently I overloaded the final stage. All of a sudden smoke came out
of the transceiver and when I tried to transmit again after having
waited for some cooling time output power was pretty low. Having
exchanged and neutralized the final tubes, output is around 90W-100W on
10m, 15m and 20m but very low on 40m (about 20W) and80m (10W).

Before attempting further fixes I'd like to ask you some questions:

1. The varnish of L2, the plate choke is partly blackened. Could shorted
turns of this coil be the reason for low power output on the low bands?

2. Or could this also happen, if C7, C8 or L1, you offer in FR-100 kit,
are damaged?

3. Do you also ship spare parts and repair kits to Europe? Or do you
have local dealers here?

Thanks a lot for your help.
Vy 73 from Germany
Manfred


Hi Manfred;

Sorry to hear about the unfortunate incident with your TS-830S. When you run 100% duty cycle, you
have to really cut back on the plate current. After you have repaired it, try turning the LOAD control
CCW and dipping at lower output power. About 125ma max is about what you should aim for.

It could be the plate choke that is causing the reduced output on 40 and 80M. They are not easy to
find, and I presently don't have any. Rewinding is one possibility. You can check it out-of-circuit
with a grid dip meter - If it has a shorted turn it will affect the dipper when you get near it.

There's a possibility that the other choke could be damaged as well. It is part of the FR-100. A bad
cap would most likely look bad on all bands, not just the low bands - Although if the plate coupling
cap is now low in value, that could have that effect.

I ship to Europe all the time - I get as many orders outside of the U.S. as within our borders! Those
"boys down under" for instance are really into Hamming, I hear from them all the time.

I hope this helps,
Best 73's,
Ken


Hi Ken,
I bought a 520S a few years ago. It works fine and then I lose audio in the speaker, after a while it comes back on and after a while it fails again.  Do you have any suggestions on what the problem might be,
Thank you for your time
Joe


Hi Joe;

It's great to hear from the North Pole!

It's almost always contacts that are the culprit. There are several in line with your speaker. The
most common would be the headphone jack and the remote speaker jack. The easiest way to to
clean them up is to spray them with some contact cleaner/lube and run a plug in and out a few
times. Repeat this a few times. That may well fix it. If you don't use them very often, the contacts
may develop some corrosion and will open the line to the speaker. Give it a try and let me know
how it works out!

Best 73's,
Ken



Ken,

Thanks so much for your website, and info about supporting the Kenwood hybrids. It has certainly
helped this newby ham and TS-830 owner. I have a question about the Dummy Load kit I had
purchased from you (I hope these questions aren't too simplistic):

- You say use "brass" in your article. I have "copper"; any reason I can't use copper?
- When soldering the BAV21 between the red post in the lid and the center conductor plate, what is
the indicator that tells me which side of the BAV21 gets soldered to the red post?
- For the 1K 3W Resistors, the gold band should be on the ground, or 'lid' side, right?
- When I am using this just as a dummy load, should I remove the 0.01uf disk ceramic capacitor? Or
does it stay on the posts all the time? The schematic appears to say "no capaciter" as a dummy
load.
- I am interested in connecting wires from the posts of the dummy load, and connecting them to a
digital volt meter. This will allow me to measure my power whenever I want. I plan on having the
dummy load sit on the floor, so the wires would be 3-5' long to the DVM. Does this effect the
calcualtions? What guage wire/type do you recommend? (stranded, solid?)

I told you they would be simplistic! I appreciate the info, and look forward to returning to your site to
pick up a couple more items to ensure I can hang on to this great radio for a while.

Stephen


Hi Stephen;

Copper is fine! I said brass because it's probably easier to find.

The band on the end of the diode goes to the red post.

No difference - orient the resistors either way, they have no polarity.

You can leave the cap in place - when it charges it's out of the circuit anyway.

Wire size or length is not critical. It's DC, and your DVM has very high input impedance, so use
what's handy - it will work!

Hope this helps, good luck with your new dummy load,
Best 73's,
Ken


Ken,

On your rk-52 resistor package, I know where the (2) 10 ohm resistors and I know where the (2) 100
ohms go. But where does the (1) 470 ohm go, the only place I can find is R 9. Is this the correct
place.

Thanks
Mike


Hi Mike;

It's the screen resistor for the finals that's on the Rectifier board, the one in series with voltage pin
210A. On the 820 it is R6 on the rectifier unit.

Hope this helps,
Best 73's,
Ken


Ken,

On the HV-150B package, Is there any components in the kit that goes on the HV board itself. Sorry
about all the questions, I'm just used to working on the modern equipment. But thanks to you and
other hams I'm learning about these older radio's.

Thanks
Mike


Hi Mike;

The parts supplied all mount on the HV capacitors themselves. I've never seen those parts go bad,
but it would be a pain to try and remove and reuse the old ones! Also, I've never found bad
diodes on the HV board. The only troublesome parts are the HV electrolytics themselves - And
having to replace them after 30 years is not a bad track record at all. The caps Kenwood used in
general are holding up great.

73, Ken

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