Kenwood Ts 850s Serial Numbers

Got a new rig: Kenwood TS-850S I got a nice opportunity to upgrade my ham shack with a Kenwood TS-850. Mods and options: Inrad roofing filter on the first 73M IF. Kenwood IF-232C interface; The serial number of the rig is over 5 million, built. I've already had a few CW QSOs with this old Mercedes of radios:) Wow! Something totally. Kenwood software serial numbers.

Guy:I have always thought that it was fairly easy to tell how old a Kenwoodradio was by it's serial number and for the most part, I think I am right.Let's say you have a TS-850 or TS-870 and the serial number is in the 8million range, that is 800134. This would indicate that hte radio was madein 1997. The first number minus 1 seems to equal the last digit of the yearin which the radio was made. In the case of other radios you must be fairlyaware of the years during which the radio was made. In other words an 8million serial number on a TS-940 means that it was made in 1987 becuasethey weren't made after 91 or so.Now the dillemma. The TS-940 has a serial range of 10 million (1989) duringwhich some very significant changes were made to the design of the radio,such as soldering in the eprom to eliminate erratic problems. You naturallywant to get that latest serials that exist for a certain radio to get themost recent updates to its design.

I recently acquired one with a serialnumber of 20 million.???Does anybody have a clue as to when this radio might have been made? Am Ito assume 1991?Is this method of determining age accurate for Kenwood?Larry AD0G. Quote: Guy: I have always thought that it was fairly easy to tell how old a Kenwood radio was by it's serial number and for the most part, I think I am right. Let's say you have a TS-850 or TS-870 and the serial number is in the 8 million range, that is 800134. Congregation afghan whigs raritan. This would indicate that hte radio was made in 1997.

The first number minus 1 seems to equal the last digit of theyear in which the radio was made. In the case of other radios you must befairly aware of the years during which the radio was made. In other words an 8 million serial number on a TS-940 means that it was made in 1987 becuase they weren't made after 91 or so. Now the dillemma. The TS-940 has a serial range of 10 million (1989)during which some very significant changes were made to the design of the radio, such as soldering in the eprom to eliminate erratic problems.

Younaturally want to get that latest serials that exist for a certain radio to get the most recent updates to its design. I recently acquired one with a serial number of 20 million.??? Does anybody have a clue as to when this radio might have been made? Am I to assume 1991? Is this method of determining age accurate for Kenwood? Larry AD0G. Thank you John.

The first thing I did was call Kenwood and they say thatthere is NO way to tell a radios age by the serial number unless you havethe manufacturing list (that only they have). However, I have received emailreplies that pretty much back up the rule of thumb that I mentioned. Somaybe it is a fairly accurate way to tell a Kenwood radio's age.As to the 8,000,000 or 8 million. Aren't you the guy who spells 'DUAL' as'DUEL' in his posts? You are correct, it does have 7 digits.Larry AD0G. why don't you call Kenwood and ask them how the serial numbers work? And 8 million is 8,000,000 not 800000.

John Guy: I have always thought that it was fairly easy to tell how old a Kenwood radio was by it's serial number and for the most part, I think I amright. Let's say you have a TS-850 or TS-870 and the serial number is in the 8 million range, that is 800134. This would indicate that hte radio wasmade in 1997. The first number minus 1 seems to equal the last digit of the year in which the radio was made. In the case of other radios you must be fairly aware of the years during which the radio was made.

In other words an 8 million serial number on a TS-940 means that it was made in 1987 becuase they weren't made after 91 or so. Now the dillemma. The TS-940 has a serial range of 10 million (1989) during which some very significant changes were made to the design of theradiosuch as soldering in the eprom to eliminate erratic problems. You naturally want to get that latest serials that exist for a certain radio to getthe most recent updates to its design. I recently acquired one with a serial number of 20 million.??? Does anybody have a clue as to when this radio might have been made? AmI to assume 1991?

Is this method of determining age accurate for Kenwood? Larry AD0G.

Thank you John. The first thing I did was call Kenwood and they say that there is NO way to tell a radios age by the serial number unless you have the manufacturing list (that only they have). However, I have receivedemail replies that pretty much back up the rule of thumb that I mentioned. So maybe it is a fairly accurate way to tell a Kenwood radio's age. As to the 8,000,000 or 8 million.

Aren't you the guy who spells 'DUAL'as 'DUEL' in his posts? You are correct, it does have 7 digits.

Larry AD0G why don't you call Kenwood and ask them how the serial numbers work? And8 million is 8,000,000 not 800000. John Guy: I have always thought that it was fairly easy to tell how old aKenwood radio was by it's serial number and for the most part, I think I am right. Let's say you have a TS-850 or TS-870 and the serial number is in the8 million range, that is 800134. This would indicate that hte radio was made in 1997. The first number minus 1 seems to equal the last digit of the year in which the radio was made.

In the case of other radios you must be fairly aware of the years during which the radio was made. In other words an8 million serial number on a TS-940 means that it was made in 1987becuase they weren't made after 91 or so. Now the dillemma.

The TS-940 has a serial range of 10 million (1989) during which some very significant changes were made to the design of the radiosuch as soldering in the eprom to eliminate erratic problems. You naturally want to get that latest serials that exist for a certain radio to get the most recent updates to its design. I recently acquired one with aserial number of 20 million.??? Does anybody have a clue as to when this radio might have been made?Am I to assume 1991?

Is this method of determining age accurate for Kenwood? Larry AD0G. The basic idea you have is correct but there is a slight variance on the'serial number'stuffs.The first digit normally shows the year they produced the specific itembut it is not always'the first digit - 1 = the year of production' equation.

This equationworks with TS-850 butnotwith other models. If you have a TS-940 with 20million serial number,it must be the latestproduction from Kenwood.

They stop making them when they first releasedTS-950, andthey remade them by public demand and they put serial number from 20mil.Before this, Ibelieve 8million is the latest production. I don't know why it jumpedfrom 8mil to 20mil(onlythose Kenwood guys know). I have a 940 with 7 million serial number andit is believed tobe made in 1988. By the way, spelling mistake is a common thing in anynewsgroup anditshouldn't be a problem as long as it does not cause any trouble todeliver the author'sopinion.Christopher VA3UT. Quote: Guy: I have always thought that it was fairly easy to tell how old aKenwood radio was by it's serial number and for the most part, I think I amright.

Let's say you have a TS-850 or TS-870 and the serial number is in the8 million range, that is 800134. This would indicate that hte radio wasmade in 1997. The first number minus 1 seems to equal the last digit of theyear in which the radio was made. In the case of other radios you must befairly aware of the years during which the radio was made. In other words an8 million serial number on a TS-940 means that it was made in 1987becuase they weren't made after 91 or so.

Now the dillemma. Convert plt to pdf kiplinger. The TS-940 has a serial range of 10 million (1989)during which some very significant changes were made to the design of theradio, such as soldering in the eprom to eliminate erratic problems.

Younaturally want to get that latest serials that exist for a certain radio to getthe most recent updates to its design. I recently acquired one with aserial number of 20 million.??? Does anybody have a clue as to when this radio might have been made?Am I to assume 1991? Is this method of determining age accurate for Kenwood? Larry AD0GSent via Deja.com you buy.

.The TS-850S Repair PageThe Kenwood TS850S Amateur Radio Transceiver is avery popular radio. It was in production from 1989 until around 1996 when theTS870 replaced it. This page is dedicated to helping 850 owners keep theirradios on the air. This is starting to become a bigger and biggerchallenge as time goes on.I would like to thank all of those who have providedinformation used on this page. If you have other information that would be ofinterest, please pass it along to me and I will add it to the page. Mye-mail address is.One of my personal frustrations has been thereliability of some of the DDS chips (you can find them on the CAR board,underneath the metal cover behind where the speaker rests).

These are expensivelittle buggers to purchase ($28 each) and I have had all of them fail on threedifferent radios!! I have also received enough mail from other people to believethat there is a component reliability problem with them (perhaps limited to theparts made '90 and '91). Kenwood hasn't owned up to there being any kind ofreliability issue. Recently, I replaced a YM6331 on a board that Kenwoodhad worked on before. They had replaced the other 3 of them. I don't like itwhen a manufacturer obviously knows there is a reliability problem and theydon't own up to it.It appears that the early chips with the part number6631 on them have the problem and the newer chips, with 66312 on them are fixed.I would suggest if you have an 850 with the 6631 chips in them, that youconsider swapping them all out with new ones at the first sign of trouble.I am not aware of any failures with the 66312 parts yet.If you need to have one of these reworked but don'thave the equipment, send me a note and maybe we can work something out. I amwilling to replace the parts for $25 each, or $75 for a board plus shipping.

Ifyou send me your board, leave it mounted on the metal plate.Also - if you know of any junker 850s that could beused for parts - please let me know.Here are some links that you might finduseful:. A good collection of 850mods. Step bystep instructions on how to make your MONI control adjust the CW sidetonelevel. before it leaks andruins your radio! This was contributed by Bill Smith, KO4NR. You can purchase parts for your radioon-line.

Please be prepared to pay top dollar for partshowever. Look here for service bulletins andelectronic copies of the manuals. (it appears this might be a dead linknow). Lots of goodinformation here. Learn who I am. By requestfor those who can't get a copy of the service manual.Enjoy!73 Tree N6TRCommon Problems with the 850 and PossibleCuresReduced receiver sensitivity and transmitter output asyou increase frequency.

This is the typical symptom from the mostcommon component failure I have heard of in the 850. The cause is that some ofthe band pass filters on the RF board are always enabled by the 74LS145 decoderchip. You can verify this by using a voltmeter and seeing if one of the outputsfrom the chip is always 'low' (near zero volts).I would suggest putting a socket down on the board for this IC -so if it ever fails again, you can replace the part quickly. This will requireremoving the RF board (which is the one underneath the radio with the shinyshield on it).

The IC is under this shield.I have received a comment that Kenwood often replaces a MI303diode when replacing this chip (thanks K5TSQ). There is mention of amodification on the Kenwood ftp site that might also help eliminate thisfailure.

Check out and of the service bulletin (thanks VE3PNfor updated URLs).I believe this failure might be a result of a high voltage beingpresented on the receiver input. I do think one or two of the failures I haveseen might have been caused by transmitting with full power with a differentradio with antennas that were close.

It has also been suggested the 47K ohm DCinput resistance of the receiver could easily allow nearby lightening hits toproduce a high voltage. Perhaps putting an inductor on the RX antenna input toground would help as explained as follows (thanks K0ZL):cure by removing the surge absorber tube on the small pcboard connected to the antenna connector, (remove top cover of filter unit,top of rig, rear-center, to get to it). Obtain a 1-2 milli-henry pi-woundchoke (one of the big oldies-but-goodies), and tack solder the surge absorberacross it. Reinstall the assemble where the surge absorber was.

Younow have 2 ohms to ground dc, and much harder to develop high staticvoltage.Frequency display is all dots - and the radio sends 'UL'in morse code over the speaker (indicating an unlocked condition with thefrequency synthesizer): This failure might be temperature related- and possibly show up more often when tuning the VFO in specific places (around1800 - 1850 kHz is one place I have seen it fail). This is probably the DDS chipon the carrier board that produces the VFO frequency. The CAR board is under thebracket that would hold the voice memory board if you had it (under that door onthe top of your radio). Remove the four screws that hold the bracket and findthe CAR board with the four big chips on it. You can put a scope on thePLL-1-DL01 output and watch the output voltage as you tune around.

On afunctioning board, the output level should be pretty constant as you tune theVFO through a 500 kHz segment. If the output changes a lot when the VFO jumpsfrom one frequency extreme to the other, then the failure is probably the IC1DDS chip. They cost $28 and will require you to have the right equipment to workwith surface mount VLSI ICs.One step you should take first is to make sure all of theconnections to the CAR board are good.

Remove all of the cables, andreseat them.Raspy signals on some bands - maybe no display or alldots: I had this problem with one of my radios after taking it toLouisiana for the Sweepstakes. The signals on 20 meters all sounded raspy- and broad.

At first, I thought it was something wrong with thetransmitter of the other station, but when all of the signals on the band hadthe same problem, I knew it was my receiver. I believe my transmittedsignal sounded as bad.

It seemed to be temperature related and in extremecases, the LO1 output from the PLL board was going away. And then Dave,NR1DX, hit the nail on the head with this:I just finished fixing the second TS-850 in my career withthis problem.particularly symptomatic is the raspy sound which gets worse asthe unit heats up. In both cases TC1 on the PLL board needed only to be adjustedso that TP2 reads 5.0v. (See the service manual page 98, step 8).

Thelittle trimmer cap TC1 inside the VCO-2 can has been documented as getting flakywith time. On the first radio the problem occurred at about year 7 resetting thecap cured the problem and the radio ran fine for another year without incidentbefore I sold it and upgraded to a TS-950SDX.I recently came on abargain ($550) TS-850SAT (10 years old) which was too good to pass up (includingthe a 500HZ and 270 Hz CW filters and a DRU ). It had this same problemonly worse in that after setting the cap the unit would play fine. For awhile, then drift back into the same old problem.

I then replaced thecheap Kenwood trimmer cap with a glass piston trimmer cap which so far afterfour hours is stable as a rock. Ill send you a picture of the mod ( if you wantit) as I had to drill a hole in the side of the VCO-2 can to mount the newtrimmer cap.So check your problem radio's PLL - TP2 when it gets raspy,I'll bet it is no where near 5Volts, the setting is quitecritical.When I checked the voltage on TP2 (located near the front of theboard right next to the smaller shiny box), it was around 4 volts. Iadjusted it up to 5V, and things sounded worse.

That was until I removedthe lead to the DVM (it was acting like an antenna and picking up all sorts ofjunk). After that, the radio sounded like new. When I thanked Dave,I got this in response:Don't thank me. Thank Cliff at AVVID he is the one thatclued me in the first time three years ago. The guy isamazingandYou will see the little piston cap on the left of the VCO2can. The little melt from the soldering iron on the edge of the little blueplastic thingy was an 'aw- $#!^', in trying to clear the holes in the board.Didn't hurt it electrically.To do this you have to remove the wholeVCO2 enclosure there are about 5 places where the can is soldered to PLL boardplus three wires.

If you have never used solder wick now is a good time tolearn. Removing the can is almost as difficult as brain surgery but still not asbad as changing one of the DDS chips.Passband tuning is erratic while on SSB, but seems okayon CW. People also tell me I am off frequency. This happened to one ofmy two TS850Ss. The culprit was IC4 on the CAR UNIT (DDS chip) that generatesthe CAR signal (on the bottom of the CAR UNIT schematic page).

They cost $28 andwill require you to have the right equipment to work with surface mount VLSIICs.The SSB and/or CW monitor functions do not work - or isvery distorted on SSB. Another DDS chip on the CAR unit (IC3) producesboth the RF frequency used to demodulate the SSB for the monitor function (MCAR)and also the audio tone used for the sidetone (STON). If this chip isn't workingcorrectly, it would explain these failures.

They cost $28 and will require youto have the right equipment to work with surface mount VLSI ICs.Receiver overloaded by AM BC stations. Thiscould be the 74LS145 failure mentioned above. It could also be the diodementioned in the Service Bulletins (thanks KS4XG). I also had this problem inspades on one of my radios - but it turned out to be a pair of back-to-backdiodes I had installed when adding the external RX antenna modification.Removing this cured the problem.ALC voltage problem (from NB1B): The problemmanifested itself as varying power output; if you close the key and watch thepower meter, it will go from zero to full output and then back to zero output onabout a 5 second cycle.

What is happening is easy to see by using an externalwattmeter and putting the 850 meter on ALC; the ALC goes from zero to max as thepower goes from max to zero. This was explained to me by the guy that diagnosedand fixed the problem.

The circuit that is bad is one that has resistors,transistors, and capacitors all on a multi-legged component. It is amultivibrator that develops a voltage that is then rectified and amplified andis used as the ALC voltage.Something goes bad and it causes a very slow oscillation, andthe ALC voltage swings from zero to max and back again, causing the power tooscillate in step. I don't know how much the part cost, but the guy spent 8hours on the radio (not a Kenwood Factory Rep) before he could figure out whatwas going on. Since then, I have seen probably a dozen postings from hams thathave had the identical problem that have sought an explanation forit.Also, K0BX reports the same problem: The DC-DC boardX59-1100-00 fails and causes the power output to go up and down.

First time Ihad Kenwood replace it for a total cost of $150.00. This past December Ireplaced it my self for a cost of about $14.00 with shipping. I have a detaileddescription on how to do this repair on my and then go to TS850S ALC/TX PROBLEM.And this from K2UT: One of my 850s had theDC-DC board replaced about 18 months ago after experiencing the usual problem:output power oscillating back and forth. Had it repaired and the rig wasworking great.

Then, about 4 months ago, a newproblem appeared. I hada couple DC-DC boards on-hand for repairs, but this didn't seem to fit the usualpattern.When the rig was on for a while but not transmitting, the firstSSB transmission would peg the ALC meter for a couple seconds with no output. Itwould then drift back down to a normal level, and output power would rise.Transmittingagain within 10 seconds would work fine; no ALC problem. Afterabout 15 seconds, the cycle would repeat.I called Kenwood and suggestedthe DC-DC board, but the repair tech didn't think it could be the problem. Rigwent back to Kenwood for repair.

The f.ing DC-DC board! $135 andsix weeks spent when I couldhave repaired it myself.Low Receiver Sensitivity (from K7FR):The only failure that I had on either of my 850's was that one ofthe switching transistors that muted the receiver during xmit went sour andwouldn't go all the way to cut-off in receive. This had the effect of puttingabout 20dB of pad into the receiver. This happened on both. The first one wentout to be fixed the second one I did myself.Low receiver sensitivity could also be related to the first itemon this list. Also, I noticed an interesting problem while at W5WMU last time.One of the 850s that lives there was down in sensitivity from the one I tookwith me.

I am not sure what the problem is, yet. It could be this switchingtransistor problem.No receive except on FM (from W9PL/7):My 850 was purchased new in 1993. It was repaired twice underwarranty for the same symptoms. The symptoms (to make a long story short)involved an inoperative receiver in all modes other than FM. The initial failureoccurred after a few months of use, in 1993. The second failure occurred afteronly 5 hours of operation following the first repair action.

However, since thesecond repair action, it has worked just fine and I am very happy with theradio. The first time they repaired it, Kenwood replaced a VMI308 diode and a3SK131(M) FET (Q15) on the IF Unit.

Q15 is the last of stage of IF AMPpreceeding the SSB Demod. The second time they repaired it, they replaced thesame FET (Q15) on the IF Unit. I suppose they had a 'bad' run of Q15 FET devicesat that time.Poor solder connections. It is possible thatone of my DDS chip failures was really due to a poor solder connection.

Inoticed when replacing the chip that there wasn't a lot of solder on the ICpins. I was able to reuse this chip on another board and it came up and workedfine.

The following comments are from an ex Kenwood service person: The historywe were given regarding the solder quality is that amateur gear is a very lowpriority, low quantity production run at Kenwood. The PCB blanks are all made ata plant at one time for the estimated life production run of the rig. Then theyare shipped to a plant where maybe 6 months or even years later the PCBs areused for a small run of the units. This plant is on a coastline and the boardssuffer from salt air corrosion problems, so the solder does not wet properly.

Ican believe that story, but they still suffer from very poor QC with regard toinsufficients, cold solder, and lack of eyelet properly done before soldering onthe older PCBs. Kenwood has service bulletins out on some boards, where theypoint out 30 to 60 feed through for shotgun resoldering of eyelets with a barewire fed through the eyelet hole when resoldering and then clipped off.CT2HMX sent me the following - radio fails in the FMtransmit mode - FM microphone amplifier not working: I saw the BoardX59-3000-03, FM mic amp and all components were okay.

I put a 1 kHz tone, 5 mv,into the the mic input on the front of the radio and saw the signal on C630 onthe RF board (X44-3120-00). I did not see the signal on the collector of Q609however. The hfe (beta) of this transistor was very low and I replaced Q609(2SC2912A) on RF board and the problem was solved. The old transistor wasn't bad- but the hfe gain was very low and caused the failure.DJ3TZ offers the following story about repairing the rotaryencode: I recently had a problem with my 850 which I could fixmyself and would like to share this information. It concerns the rotary encoderthat transforms any movement of the main frequency dial into digital pulses. Thepart in question is a COPAL RMS20 encoder.For a long time, my KenwoodTS-850 had the problem that while turning the main frequency dial, the frequencywould stop changing with the last digit jittering. For several years, theproblem occurred so rarely that it did not really hinder operation, and I saw nochance to locate the problem.

Recently, however, the problem became moreserious, making the radio almost useless. Using the 850's service manual, I wasable to locate the encoder and its connection to the radio's main databus.The encoder has two data outputs, A and B. Both carry digitalsignals at 5V level. Its frequency depends on the rotation speed and the signalsdiffer in phase to allow for clockwise/counterclockwise detection. Together withmy friend Theo, DJ9PK, I observed these signals with an oscilloscope. One ofthem vanished whenever the the frequency stopped changing.Taking a lookinto the encoder, we tried to locate any kind of mechanical problem, perhaps alittle bit of dust, but there was none. The encoder consists of amagnetized wheel and an magneto resistive Hall sensor, in addition with someelectronics.

Checking the signals from the sensor revealed that is analogous. Itconsists of a voltage of approximately 2.5 V DC plus approximately 80 mV AC whenturning the shaft.We found that the amplitude of the AC voltage stronglydiffers while turning the shaft. The reason is perhaps that the magnetic fieldproduced by the wheel is not constant, but seems to depend on its positiontowards the Hall sensor. The amplitude seems also to depend on other, unknownfactors.The PCB inside the encoder has an IC that obviously works as acomparator and digitizes that input. Checking its 8 pins revealed that two carrythe input coming from the sensor, two carry the digital output, and two pins areconnected to reference voltages. These reference voltages can be adjusted withtwo variable resistors on the left and the right of the IC.Turning oneof the resistors fully into one direction causes the digital output to becomeconstantly low or high, respectively, because the reference voltage then isalways higher or lower then the sensor signal.

Within a range of 10 or 20degrees, the comparator works as intended.