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

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: My ts-830s xcvr has been working fine, till the other day, i turned it on and noticed i got a plate meter reading and i wasnt transmitting. I looked into the cage and the 6146 tubes were starting to glow as if i had been keyed down for a while. I shut it off,,,. is there something to look for initially or time to look for another one.. Louie
no...not in tune position
no...key not down
no...mic not keyed
it was in receive and receiving.

Hi Louie;

It doesn't sound like too big of a problem, the final stage is pretty simple, it should be easy to track down. During receive, all voltages are present on the finals, but the tubes are held off by a negative grid voltage. This prevents them from drawing any plate current. I'd guess something is wrong in the portion of the circuit that develops and controls final grid voltage. Perhaps the -95V supply is dead altogether.

Just remove the finals and troubleshoot without them in place. I hope this helps,
Best 73's,

I am having trouble adjusting the bias on my 830. I have followed your procedure below:
When I try to adjust to the bias pot to 50 ma I/P reading, needle will hold for a few seconds at 50,
then drop to zero or the needle will fluctuate up and down and then drop to zero. After this failed
adjustment process, when I flip the Send switch to Transmit (bias adjustment untouched) the I/P
reading is almost always zero but sometimes will read 50 or so and then fluctuate or drop. I am the
only owner of this rig and it has set idle for the last 15 years and all tubes are original. The rig
receives just fine.
Could by 6146s be bad or the send/receive switch be bad? Any thoughts you can share would be
appreciated. Mark

Hi Mark;

It sounds like it could be RL-1, the transmit/receive relay - That's how it can behave. Since your rig
sat for many years, I would think all the contacts in the radio should be gone over. I predict that a
can of contact cleaner/lube is in your future, and perhaps a new relay!

Since your rig sat for so long, turn it on, turn on the heaters, and leave it sit in receive mode for
about an hour - Give the getters in the tubes time to get rid of any accumulated gas over the years.
That gas will affect your plate current as well.

Hope this helps,
Best 73's,

Hi Ken,
Just a quick note -- I purchased another DG-5 that was in need of repair. I ran into two seperate problems. The power supply was fried.... I had to replace the 12 ohm 2-Watt resistors, and the 5 volt 3 terminal regulator. I was getting an 8 Mhz or so random counter on the counter display with NO counter input. I finally traced the problem to noise on the input side of the 5 volt regulator. I removed the input to the regulator from the PC board and cut the trace at the 2 Watt resistors and ran a wire directly from the 2 Watt resistors to the input leg of the regulator. I added a .1mfd bypass cap at the resistor side of the PC board. This solved the noise problem on the power line. I guess the noise was being coupled on the power buss by the close proximity of the PC trace to surrouding circuitry..... wierd at best. The second problem was the same as I mentioned before.... poor operation on the lower bands. Again, I changed R24 feedback resistor on the Schmidt Trigger (IC1) to 1.8K.... I used a pot to find the best compromise value between solid low band displays and
mutiple random digit displays on the frequency counter (with no input).  Hopefully, these fixes might aid you in the future. The DG-5 pc boards are the worst I have seen in any Kenwood equipment.
BTW, I will be at the Orlando Hamfest this Saturday. If you are going, I would like to meet you and say hello.
All the best,

Hi Jerry;

Thanks again for a helpful update - When it comes to DG-5's, any and all info is greatly appreciated!  I'll let you know about Orlando.
73, Ken

hi ken
i came across your web site and looked some of it over,very nice,in fact it`s great.  i realize this is your buisiness but i was wondering if you could tell me where you get your paint as i have a 220moniter scope that has a couple of bad spots on the case and would like to repaint it,any help you can give me would be apreciated.
thank you very much in advance
73` charlie

Hi Charlie;

I took a case top to my local Sherwyn Williams auto-paint supplier and they matched color and
gloss level spot on. I can no longer read the number on the paint cans they supplied, but it was
their industrial alkyd enamel. Hope this helps,
Best 73's,

Hi Ken,
I was just curious, Where can I purchase the Silver conductive ink for doing the Band Switch
repairs?  I just took in an 830 that has some loose rivets.
73,  Gordon

Hi Gordon;

Radio Shack has it - I think it's a Caig distributed product. Hope this helps,
Best 73's,

Ken will any other Kenwood vfo's work with the 830 besides the 230? I can get a nice vfo-520.

Hi Kevin;

The VFO-240, will work with the 830, and it is my personal favorite. The VFO-520 will not. The 240's
are less expensive than the 230, and they work even better in my opinion.

Best 73's,

Just a question - I have installed the couplers but when I go to set the bias I show no output on the
meter. Would this be an indication that the driver 12BY7A is bad or would one suspect I have made
an error? If you think in may be the driver I will get a check in the mail to you
The other radio in the room can detect an output from the 530.
Thanks ahead of time for the help.

Hi Bud;

Are you referring to setting the bias at 50-60ma in USB or LSB position? That has nothing to do with
the driver tube, it's just adjusting the grid voltage on the finals to obtain that amount of plate current
at idle conditions for SSB.

Turn the bias adjustment full CCW, turn down the MIC full CCW, place the mode switch in USB or
LSB, place the meter switch in Ip, key the rig, and adjust the bias for 50ma. Is this what you're

Best 73's,

Thank you - once you set me straight on the bias not having anyting to do with the driver I found this
problem. Able to set the 60mA.

Got an output but stayed to long in tune (high) and have smoked something that has a retifier burnt
smell to it. It just does not pay to rush something

Thanks again


Based on your prior advice, I was able to resolve my issue w/unstable tube bias setting. My Omron
RL-1 relay was sticky & with some compressed air it seems to be working quite nicely now. The
relay itself still looks brand new - see attached image.
As you suggested, I still need to treat the original relay with Caig cleaner/lube. Would you be kind
enough to be specific as to the exact Caig solvent you recommend, as Caig makes many different
cleaner/lube options?
73s Mark

Hi Mark;

Sorry for the delayed response, I've fallen behind on my email (again!). The cleaner Radio Shack
sells, a small kit of DeOxit and ProGold is good stuff. I use some contact cleaner/lube sold locally in
"bulk," but for one radio the Caig kit is plenty.
Best 73's,

Hello Ken
W e have here a kenwood ts520se we are having bad reciever problems . Cant hardly get it to
lock onto a sig. We get a garble sound . once we do get on freq it is stable.powers up and gets full
output with good reports.We have cleaned all switches with de ox id and the vfo .
This seemed to help little ,but still have the problem.I was wondering if you have had run across this
type problem ?
It was used by a bunch of heavy smokers for sure , we found smoke stain all over inside . We
were able to clean all this up.Thanks for any hint you might have for us
(a group of hams here in tennessee)

Hi Ken;

I've seen problems similar to what you describe, but they usually stop when I go through the
cleaning procedure as you did. There are several frequencies being used for mixing in the radio,
and one of them is obviously rather unstable! If you can get a frequency counter on each of them,
you could probably spot the offender. I have a counter plugged into the vertical output of my scope,
so I can measure frequency as I look around as well.

Does it occur on all bands and modes? If so, it is probably the VFO. I generally remove the VFO,
take off the case, and retighten and resolder everything. You can run the radio with the VFO
outside and exposed, and poke around various parts with an insulated plastic tool - This might
uncover the bad part/connection. I also clean the PCB in the VFO with lacquer thinner and then
blow it out with the compressor - Surprisingly, I've fixed some nasty instabilities that way. Don't ask
me how or why, it's like magic!

I hope this helps,
Best 73's,

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