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 2
 

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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I am the proud owner of a TS-830S.  When I got my transceiver, I checked to see what filters were installed. It has only a YK-88S1 installed and I know that the transceiver has space for four filters. Would you please tell what other filters I need for my transceiver? I also have the SP-230, VFO-230 and AT-230. I am still looking for a SM-220 at a price I can afford.  Lastly, I want to find the optional knob for the VFO-230 and I would like a matching knob for my TS-830S, even though my transceiver is not the gold edition.  Can you help with the optional knobs ?  Thank You. God Bless.
73 de Jim


Hi Jim;

You probably have 2 SSB filters installed in your Kenwood - One is the small Murata ceramic filter nearby.   The others are CW filters at 8.83 MHz and 455.7 KHz.  They are available here:
http://www.inrad.net/
Click on "Products by Radio"  then "Kenwood" " and then "TS-830" and you'll be there.  Get them as wide as they offer, as the VBT can make them narrower, but not wider . . .

I am tooling up to make the heavy Kenwood knobs with ball bearing finger spinners.  I'm presently building a CNC mill for that purpose, as well as a few other needs I have.  Keep an eye on my web site, hopefully someday soon I'll have some spiffy knobs for sale!

Good luck with you radio and 73's,
Ken



Hi Ken,
 
Quick question,  I am going to tune my TS-520S front end.  I know the coils are very fragile and easily broken.  I thought about spraying each coil with Radio Shack Contact Cleaner/lubricate to free up any stuck slugs.  What do you think?   Or is there a better way?
 
Thanks and 73's,  Jerry


Hi Jerry;

Spraying is a good idea.  I've even shot a little WD-40 onto the stubborn slugs.   Anything you can do to keep from breaking hard-to-find slugs and forms.

Best 73's,
Ken



Ken:

I recently decided to keep the TS-830S which I purchased as a project several years ago ( all it really needed was the filter caps).  Well after giving it a nice home in the operating table, I was happy and it worked well until today when it lost receive sensitivity.  It can just detect a 1.0 uV signal with 3.0 uV sounding good but not moving the meter.

If my signal tracing with the RF millivoltmeter is correct, Q1 the Rf amplifier has failed.  Thanks to your posted instructions for repairing the Band switch wafers, I feel fairly confident that even with my6 aging eyes, I can remove the RF board and replace the FET.

Problem one is to obtain one, thus the question  Do you sell them and if not can you suggest a source or a replacement.  Also while I have it apart do you recommend replacing anything else such as your shaft couplings etc.

Thank you for any help you may wish to provide.
73 Allen


Hi Allen;

Do you get good signal up to and including the gate of the RF amp?   I usually find that the signal falters before the gate, because of any of a number of causes, notably the input transformer (L41 as I recall) or the diode that protects the gate of Q1.  I've even found bad coax and problems with the ATT switch.   If it is indeed the FET, I'd use an NTE222 from NTE.  You can get them online from a number of sources, or maybe even locally if you have an electronics store.  Different package, but you can easily mount it as it has 4 leads also.

Replacing the bandswitch coupler on 530's and 830's is always a good idea.  The originals will fail at some point.   A thorough cleaning of ALL contacts, switches, pots, cap wipers, relay contacts etc. is almost always needed in these rigs.  A lot of anomalies and problems will suddenly disappear.  Other than the couplers, I don't replace any parts that have not failed - Most will be still working fine over the next 25 years.

Hope this helps, 73's,
Ken




Ken,
 
I know you are extremely busy so thank you for taking the time to review this inquiry. I have been an amateur radio operator for almost 20 years and the only four rigs I have owned are the IC-720, IC-751A, TS-440S (I shouldn't have sold that rig) and now an FT-897D. After reviewing your web-site I have decided to look for a Kenwood Hybrid. I am interested in a 530, 820 or 830. I really think I want to find a clean 830 but I may have an opportunity to purchase an 820 with a bad power transformer. Two questions: Should I wait and for an 830; or if I purchase the 820 what would it cost for you to replace the power transformer in addition to your alignment and clean-up charge?
Finally, I have been watching QTH,com and Ebay, are there any other sources fro Kenwood Hybrids that you could share with me? Thank you again.
 
73,   Paul


Hi Paul;

Welcome to the world of Kenwood hybrids!   Just about any model that you choose will be a pleasure to operate.   The TS-820S with bad power transformer would not be a good deal - The transformers are expensive, and there's a few hours to get it installed.    The 830S has the best receiver, especially when all 4 filters are present.  That VBT, Notch and IF Shift are hard to beat.   That said, the 820S single conversion is one of the quietest and best performers out there as well.  I get letters from Hams all the time that tell me they can hear signals with their (i.e.) 520S that are unreadable on their expensive, new digital whatever . . .  8^)    I gave my grandson a 520S and a 530S when he got his General and then Extra, and he thinks the 520 has a little edge over the 530 under some conditions.

I have gotten almost all my rigs from eBay - You have to be prepared for the shock of what some sellers think of and advertise as "Mint," but the best selection has been there.  Absolute best is when you can find a Ham locally who bought it new and hardly ever used it!   It's worth a stretch to get one in original condition with no visible signs of corrosion - There are lots still out there.

Hope this helps, 73's,
Ken



Hello there Ken.

Nice Web page you have there.  I am working on my General and purchaced a TS-520s that is in need of a little work.  Nothing big I hope.   I need to replace the lamps in the meter and VFO dial, removing the cover I think I saw the red wires that power the lamps but could not figure out how to remove the bulbs.  If you have any hints for this operation please let me know.   Other than that a fresh coat of paint will make my rig look great.  thanks
Roger


Hi Roger;

To get at the lamps you have to remove the front panel.  Some of the VFO dial has to come apart as well.  That is well worth the effort, because you can soak and clean everything up at the same time.   These rigs look better than new when you clean and polish all the front panel parts!

Remove all the knobs, take off the nut on the meter switch, and after you remove the 4 panel screws top & bottom, it will come right off.   Hope this helps, 73's,
Ken



Hi Ken,
 
I was playing with one of my Kenwood 520's today.  The oldest one a straight 520 has a phono jack on the
rear right side for the output to a transvertor.  It delivers about  .570 of a volt of RF at the operating freq.
It's too bad that a freq. counter couldn't be hooked on here to readout your freq.  It just supplies RF when
transmitting.
 
Also,  I found out the telephone patch jack on the Kenwood 520SE is a great place to takeoff audio signal
for slow scan TV.  It's output level is great for driving my dell laptop on slow scan!   I am thlinking about a way to add a counter to the old 520.  I have a DG-5 on the 520SE
 
73"s   Dale


Hi Dale;

During receive, the 3 signals (VFO CAR and HET) have to be combined to get a frequency readout, just as in the DG-5.   The transmitter chain does that to supply the carrier when transmitting as you've discovered.   The 520 used an optional DK-520 to provide signals to the DG-5 - This was then built in to the 520S.   I have a schematic of the DK-520 on my web site, on the schematics page.

Hope this helps, 73's,
Ken




Hi Ken,

I hope you might be able to help me out with a TX problem.  I just received my TS-520 a few hours ago from an ebay purchase.  Let me preface this by saying that I have been away from hamming for some years now so I have much to catch up on.  Other than a qrp rig I built this TS-520 is the only rig I now have.

Using the 520 manual I followed the instructions step by step.  First I checked out the RX and all works fine so far.  Good calibration, lots of signals coming in, etc.  Then I went through the transmitter set up and everything was fine for awhile.  My power meter showed about 110W out on CW on 40M.  Then I went through the same procedures on 20M and once again all seemed fine.

PROBLEM:  Then I went back to 40M but now I am getting a ZERO ALC meter reading in Tune mode and ZERO RF meter readings in CW mode.  Plate current is set at 60ma (note: when I first fired the TX up I read the meter incorrectly and realized after the first 40M success that it was set at 120ma but after setting to 60 it still worked fine on 20M).  HV meter reading shows a bit over 800v.  I went back to 20M and it is the same problem there as well.

I have checked every switch and control multiple times including the SG switch.  The filaments on all tubes are lit.  Does this sound like a rough one to try and diagnose and fix on my end?  If I end up having to send it to you for repair is your waiting list still over a month?
Any help would be greatly appreciated.
Thanks, Ron


Hi Ron;

It is probably not the finals, but could be the 12BY7A.   Power up the rig, turn your SG switch OFF, place your meter to monitor ALC, and tune up for max ALC using just the CAR control while peaking with the DRIVE control.

If your driver tube is failing you will see the ALC indication falling steadily with time.   You can keep the rig keyed for a few minutes because you've turned off the finals with the SG switch.    Alternatively, wiggle your bandswitch and see if that affects ALC - If so, your bandswitch needs cleaning.

Hope this helps, 73's,
Ken



One question:  Is there a trick to getting at the bandswitch shaft coupler on the TS-820S?  I've loosened the screws, broke the coupler apart with a screwdriver and removed the "flex" pieces.  I've also removed the driver board, removed the screws from the RF board and loosened the front coupler.  There isn't enough clearance to remove the remaining pieces of the plastic coupler (by sliding them off the shaft) between the long shaft that runs through the switch wafers on the RF board and the bandswitch inside the RF cage.  I certainly don't want to have to remove the front panel to take out the short jackshaft between the "gear" (I don't know what else to call it) and it's bracket on the panel.  If I can get the two screws out that hold the rear bandswitch (inside the RF cage) , I might be able to slide that back far enough to get enough clearance, but I don't want to risk mangling the screw heads if that's not going to buy me anything.
 
Regards,   Al


Hi Al;

You are correct.  When the front panel comes off, the shaft can then be slid forward through the hole in thew sub-panel.  As you've probably already found out, access to the coupler is best achieved through the bottom of the chassis, through that rectangular opening that looks to have been made for the purpose.  This is the only way to replace the coupler.

My standard brass couplers will not fit the short opening in an 820, they are too long.  I supply the original Kenwood coupler for that one application in an 820.  The supply is getting low, so I might one day tool up for the shorter shaft.   In an 820, the detent is at the front of the radio, so the torque exerted on that coupler is not great - It only has to spin the rear bandswitch, and not drive the stiff detent.   On the 530's and 830's the detent is in the rear, and eats up those couplers more quickly.

I hope this helps, please write with any other questions.
Best 73's,
Ken



Hi Ken

Thanks for quick the reply.  This is what I have found:  The receive seems to be back to normal. Just about every circuit board mounting screw was loose. I tightened those and pulled and re-seated the connectors on the boards. Good audio and receive now.

There are a couple of mods. The final heater circuit has a .5 ohm res. in series with the heater switch and terminal H on the final board. I guess they are trying to lower the heater voltage. Any merit to this ?

Also a 2.2k between terminal SG and PD2 on rect. board. Again, remove ?

Who ever did these mods must have used a jack knife and soldering copper and a camp fire for heat. What a mess.  There was a phono jack added on the back panel that went to the keying line I believe. I removed this.

I don’t have a very clear schematic, but have a original manual coming.  I am going to replace the ext speaker jack also. Seems kind of worn out. I am thinking of changing to ”. I don’t think I have the smaller one.

I also plan on changing the line cord. There was split core on the outside and a ton of very loose beads on the line cord inside. I will remove those also. Some other owner must have had RFI problems in his shack.

All in all, it’s a pretty nice radio. Front panel is excellent. Cabinet is very good also.  I purchased it from a ham in Texas for $285.00 shipped w/speaker. He said it was sent to Avvid 4  months ago to get checked out. Either he is pulling my leg, or the guy at Avvid never took it out of the box. I have not heard of Avvid.

Thanks for the tips on paint. I have the speaker cab. all ready to paint. I found a place that will match any type of paint. They will make a small bottle or 55 gallon drum. So we shall see.   Thanks again
Phil


Hi Phil;

Many of the original tubes have lasted for 30+ years, so I don't really believe the filament mod is necessary.  There is already a 150uh choke from PD2 to SG1, maybe it was open and the guy subbed whatever he could find.  Remove the resistor, check the coil for continuity, and replace if necessary.

I have full beautiful 830S schematics on my web site here:
http://www.k4eaa.com/schematics.htm

Hope this helps,
Best 73's,
Ken


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