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W0BST
03-02-2008, 10:45 PM
I recently got a Kenwood TS-530SP. I'm probably heaping abuse on my finals as I learn how to tune the rig correctly. I am getting faster, and trying to give the rig some cool down time if I feel I am taking too long to get it tuned.

To make matters worse, earlier this weekend I got excited when I heard a Dominican station on 15 meters and transmitted without consideration of what band I was tuned for. Feel free to give me the old "Everybody has done it" so I don't feel quite so stupid. ;) I realized my mistake fairly quickly and the station even came back with my correct call the first time :confused: even though the wattmeter barely budged !!! but now I can't seem to get 100w on all the bands.
I only transmitted a couple of seconds on SSB.

Anyway, now I still get about 100w out (while tuning into a dummy load) on 40m, and about 50w on 20, 17, and 15. Haven't tried any others. It IS possible that I'm just doing something wrong and that 100w is attainable but this new guy is screwing it up; but I'm tuning up by the book, as per the manual, step by step in the recommended order.
I can get the needle to hit 100w on peaks but not within the 265ma plate rating, except on 40 meters.
So I'm assuming I damaged the finals. Already. :mad:
Is it likely that I damaged anything else in addition to the finals? Is it going to hurt anything to continue to use these (damaged?) tubes? I'd like to continue to use these until I feel comfortable that I'm not going to damage a new set... I'd hate to pop a couple new ones in and waste them too.


***************

Ok now I'm pretty sure I've just been doing something wrong cause I got 100+ out of 20m and about 95 on 17, with plenty of resting time in between, into a 50ohm dummy load. So who knows what the heck I'm doing wrong?

WB2WIK
03-02-2008, 11:20 PM
Everybody's done it and normally that shouldn't hurt the 6146s at all. They're pretty rugged tubes, although of course nothing lasts forever.

"Tuning up" a TS-530S takes about five seconds total if you take time to yawn in the process. It's really very simple and unfortunately the "instructions" make it sound more difficult than it is.

If you use the TUNE function, that will allow you to peak the driver stage without generating much power at all -- and you can stay in TUNE for hours without damaging anything because the rig's set to low power in TUNE. Run the drive level up to the point where you get an ALC indication and peak the driver stage (which also peaks the receiver preselector at the same time -- it's the same control) for maximum ALC indicated. If that runs offscale, reduce drive level and re-peak. Once you've done that, the driver shouldn't require re-peaking at all.

Switch to CW, plug in a key and close the key to generate a signal, and peak the plate TUNE and LOAD controls in sequence for maximum registered output power. Check ALC again to make sure the reading is within the scale limits so marked. Check plate current, but don't be terribly concerned about it. 250mA is pretty typical, can run a bit higher or lower. The rig should produce about 100W output power on each band. The tuning process does not take long, and once you've done it a few hundred times, you'll find it's possible to do it pretty well in just a few seconds.

The 6146s are force air cooled (fan) in the TS-530S and even if the plates get red, that usually won't hurt the tubes unless you just keep tuning and tuning and tuning...for no reason, because there is never any reason to do that.

The unfortunate thing is that 6146s "aren't what they used to be." Brand new Chinese 6146s are not as good as the old RCA (and other) American made ones from the 50s, 60s and 70s. But nobody in America makes them any more. I still have some "new" (never used, but very old, manufactured in 1972-73) RCA 6146Bs that, when installed in an old rig such as the TS-530S, almost always work better than "brand new" tubes made last week.

The sacrifices we make for a hobby.

WB2WIK/6

AG3Y
03-02-2008, 11:34 PM
"I can get the needle to hit 100w on peaks but not within the 265ma plate rating, except on 40 meters.
So I'm assuming I damaged the finals. Already. "

I see a red flag here. How are you measuring that 100 watts on "peaks" ? ? ?

The RF power readings should be taken on a steady state RF output, such as key down CW, or RTTY with a 100% duty cycle.

As has been said so many times on this site , you will NOT see 100 watts on a meter if you are in the SSB mode. Most meters only respond to AVERAGE power, and the AVERAGE power of the human voice is only 30% of the peaks.

Seeing 30 watts on the meter would be what I would expect. In fact, I have to wonder why you are seeing such a high value on the one band you mention. THAT would seem to be the unusual situation.

Good luck! 73, Jim

W0BST
03-02-2008, 11:58 PM
"I can get the needle to hit 100w on peaks but not within the 265ma plate rating, except on 40 meters.
So I'm assuming I damaged the finals. Already. "

I see a red flag here. How are you measuring that 100 watts on "peaks" ? ? ?

The RF power readings should be taken on a steady state RF output, such as key down CW, or RTTY with a 100% duty cycle.

As has been said so many times on this site , you will NOT see 100 watts on a meter if you are in the SSB mode. Most meters only respond to AVERAGE power, and the AVERAGE power of the human voice is only 30% of the peaks.

Seeing 30 watts on the meter would be what I would expect. In fact, I have to wonder why you are seeing such a high value on the one band you mention. THAT would seem to be the unusual situation.

Good luck! 73, Jim

Yeah I don't know why I wrote that. I am tuning first in 'tune' mode, then in CW, as per the instructions. I've gone back through and made 100+ on 80, 40, 30, and 20, and got almost 100w on 17, then a few minutes later I came back and couldn't get it above 50 on 17m. The rig is turned off for a while now, my 2 year old wants her daddy :-) I'll fiddle with it a bit more tonight, see what I can figure out.

BT

W0BST
03-03-2008, 12:17 AM
Everybody's done it and normally that shouldn't hurt the 6146s at all. They're pretty rugged tubes, although of course nothing lasts forever.

"Tuning up" a TS-530S takes about five seconds total if you take time to yawn in the process. It's really very simple and unfortunately the "instructions" make it sound more difficult than it is.


Hell, the FIRST STEP (by the book) takes me that long.

W0BST
03-03-2008, 12:21 AM
Yeah I don't know why I wrote that. I am tuning first in 'tune' mode, then in CW, as per the instructions. I've gone back through and made 100+ on 80, 40, 30, and 20, and got almost 100w on 17, then a few minutes later I came back and couldn't get it above 50 on 17m. The rig is turned off for a while now, my 2 year old wants her daddy :-) I'll fiddle with it a bit more tonight, see what I can figure out.

BT

Actually now that I'm doing it again I do recall why I wrote it that way; I wanted to make it clear I had my wattmeter set to Peak, as opposed to Average. But yeah, I see your point, I guess that setting makes no difference when using CW.

KA4DPO
03-03-2008, 12:34 AM
Straight answer to a direct question. You damaged the finals. You didn't kill them but they are weak. If you were getting 100 watts on 40, 90 to 95 on 20 and 15, and 80 watts on ten that could be considered normal but soft tubse drop off quickly with frequency. Find a pair of new 6146Bs, install and neutralize them and don't worry, we've all done it....:D

W0BST
03-03-2008, 12:48 AM
Straight answer to a direct question. You damaged the finals. You didn't kill them but they are weak. If you were getting 100 watts on 40, 90 to 95 on 20 and 15, and 80 watts on ten that could be considered normal but soft tubse drop off quickly with frequency. Find a pair of new 6146Bs, install and neutralize them and don't worry, we've all done it....:D

That would explain why I got to about 100w on 17 then couldn't get much over 50... but I'm down to the last half of 10m, and I've gotten 100w on everything else. I guess what you're saying is that they'll put out plenty of power for awhile, after a rest, then drop off like a rock?

KA4DPO
03-03-2008, 01:03 AM
That would explain why I got to about 100w on 17 then couldn't get much over 50... but I'm down to the last half of 10m, and I've gotten 100w on everything else. I guess what you're saying is that they'll put out plenty of power for awhile, after a rest, then drop off like a rock?

Exactly, they will tune up full power then quickly start to fall off when they are soft. They might have already been soft when you got the rig so it might not be anything you did. Remember to only use 6146B, not 6146 or 6146A.

The 6146W are ok but only after a certain date and I don't recall what the specific date is. Glen, K9STH knows a good bit about 6146s so you may wan't to PM him. If you need any help getting the finals neutralized let me know and I'll try to talk you through it.

John..

KB3ILN
03-03-2008, 01:26 AM
Would that be the same finals to use in a TS 520?

W0BST
03-03-2008, 02:01 AM
Would that be the same finals to use in a TS 520?

Yep, according to google they are the same, although I've never operated a TS520

KA4DPO
03-03-2008, 02:29 AM
Would that be the same finals to use in a TS 520?

Yes, the original Japanese S2001A was a direct copy of the 6146B. and was used in all of the Kenwood tube final tranceivers starting with the TS-520 and was also used in the 599 through 599D twins.

K8JD
03-03-2008, 04:46 AM
I have the old TS520 (no S)I changed my S2001 tubes for 6146B tubes after about 10 years of constant use. I never could get any ALC reading on 10M, but was ok on all the other bands...just tuned up for best output with the driver tuning. I never went for more than 200 mA of plate current on the dip. That gave me 100 W out on cw on all bands except 10 M. There I got about 65-75 Watts out on CW.
I still use this rig just about every day and the first set of replacement tubes are still in it working fine..
Lately I just use it on 80 M because the band switch is nearly worn out and I use my newer rig on the other bands.

K4AX
03-03-2008, 06:09 AM
If you tune up on a band and get 100 watts with no problem, then at a later time your only getting 50watts... check the band switch. Jiggle it for maximum volume on receive, if it does change when doing so. That is a problem with the 520, 530, 820 and 830.

I have the 830, and other than that one problem the radio runs and looks like it was made last week. You can pop it open and clean the contacts. There is a lot of information on the net on these rigs, have you joined the yahoo kenwood group for them yet? They have a group just for the hybreds.

http://groups.yahoo.com/group/TS-520_820_530_830/

KC2QXE
03-03-2008, 03:04 PM
You are going to love this radio by the way, I have a TS-530S and love it. Once setup properly and with a decent mic you will get great audio reports. Do your self a favor and pick up the SP-230 for it too, you should spend about $40-$50 for it.

Anyway, don't discount those tubes yet. Chances are you only have a few bad resistors that went bad. There are four on the finals board and two on the rectifier board that will sacrifice themselves to protect the transformer and tubes. This is a very easy thing to test for.

The other handy thing to do at this point is to go to radio shack and pick up a can of caig's deoxit and blast the band switches while turning the band switch (with the radio off).

Go to k4eaa.com and read all about these radio's also join the TS-520_820_530_830 yahoo group. There are a lot of knowledgeable people on that list that could tear any one of the Kenwood hybrids apart and put them back together with blindfolds on.

If you do try and replace the tubes don't forget to neutralize the tubes.

K9STH
03-03-2008, 05:36 PM
Several things on the 6146 family of tubes:

First of all, for the article on the 6146 that was published in Electric Radio a while back (and has been reprinted in several other publications with my permission) go to

http://k9sth.com/Page_2.html

and the link is the first under the heading "Articles".


Next, you can always replace the 6146B/8298A tubes with 6146 or 6146A/8298 tubes. However, when you do this you cannot run more than 75 percent of the power that you can run with the 6146B/8298A. The Japanese 2001A is the same tube as the 6146B/8298A.

But, you cannot usually go the "other way around". That is replace the 6146 or 6146A/8298 with the 6146B/8298A. In most transmitters the 6146B/8298A will not neutralize properly. There are exceptions but generally trying to replace the earlier versions with the later version results in all sorts of problems. Even within certain models of transmitters one example may work fine with the later tube and other examples will not. I have worked on like 3 identical models of transmitters with serial numbers within 10 of each other and the 6146B/8298A worked fine in one and yet would not work in the other 2. Frankly, it just seems that the component tolerances were "just right" in the transmitter in which the later tubes worked.

When RCA first introduced the 6146B/8298A in early 1964 they stated that the later tube was completely compatible with the earlier versions. Unfortunately, this did not "pan out". However, due to the fact that RCA stated that the later versions were compatible the military changed the manufacturing specifications on the 6146W from the 6146A/8298 to the 6146B/8298A and did not change the nomenclature. This caused all sorts of problems. Frankly, the only way to tell if a 6146W is the older type or the newer type is from the manufacturing code date. Unfortunately, the contracts with various manufacturers were changed at different times so even that is not exact. Basically, any 6146W with a code date in the first half of 1964 is going to be the equivalent of the 6146A/8298 and any 6146W with a code date beginning in 1965 is going to be the equivalent of the 6146B/8298A. As for code dates in the second half of 1964 the tube may be either version.

The 6146 is completely interchangeable with the 6146A/8298. The only difference between these tubes is the fact that the 6146A/8298 has the "dark heater" ("filament"). The "dark heater" allows the tube to function over a larger "filament" voltage (it was designed for use in mobile two-way radios where the voltage can range over a wide variation). The 6146B/8298A is a completely different tube that has a 33 percent higher power rating than the earlier versions.

There are several things about the 6146 family that are outlined in the article.


Now, the 6146 series is very robust EXCEPT for the grids. You have to be VERY careful not to overdrive them. Although RCA eventually specified a maximum grid current of 3 mA per tube (down from the original 3.75 mA, then 3.5 mA, then 3.25 mA) you will get the best tube life if you do not run more than 2.5 mA per tube. This means a total of 5 mA when 2 of them are in parallel. Frankly, you can run as little as 3.5 mA for the pair and you will get just as much power output as when you run 6 mA grid drive.

The problem that you are seeing is often caused in the TS- series by a weak driver tube (a 12BY7 if I remember correctly). Many amateur radio operators have replaced the finals and still have the same problem with power output. You definitely need to verify that the driver is functioning correctly. By the way, a tube tester is not the best way to check tubes. I have seen many tubes that test fine yet would not work well in the unit. Conversely, I have seen many tubes that test bad yet work fine. The best tube tester in the world is the unit itself.

Glen, K9STH

KL7AJ
03-03-2008, 05:45 PM
Several things on the 6146 family of tubes:

First of all, for the article on the 6146 that was published in Electric Radio a while back (and has been reprinted in several other publications with my permission) go to

http://k9sth.com/Page_2.html

and the link is the first under the heading "Articles".


Next, you can always replace the 6146B/8298A tubes with 6146 or 6146A/8298 tubes. However, when you do this you cannot run more than 75 percent of the power that you can run with the 6146B/8298A. The Japanese 2001A is the same tube as the 6146B/8298A.

But, you cannot usually go the "other way around". That is replace the 6146 or 6146A/8298 with the 6146B/8298A. In most transmitters the 6146B/8298A will not neutralize properly. There are exceptions but generally trying to replace the earlier versions with the later version results in all sorts of problems. Even within certain models of transmitters one example may work fine with the later tube and other examples will not. I have worked on like 3 identical models of transmitters with serial numbers within 10 of each other and the 6146B/8298A worked fine in one and yet would not work in the other 2. Frankly, it just seems that the component tolerances were "just right" in the transmitter in which the later tubes worked.

When RCA first introduced the 6146B/8298A in early 1964 they stated that the later tube was completely compatible with the earlier versions. Unfortunately, this did not "pan out". However, due to the fact that RCA stated that the later versions were compatible the military changed the manufacturing specifications on the 6146W from the 6146A/8298 to the 6146B/8298A and did not change the nomenclature. This caused all sorts of problems. Frankly, the only way to tell if a 6146W is the older type or the newer type is from the manufacturing code date. Unfortunately, the contracts with various manufacturers were changed at different times so even that is not exact. Basically, any 6146W with a code date in the first half of 1964 is going to be the equivalent of the 6146A/8298 and any 6146W with a code date beginning in 1965 is going to be the equivalent of the 6146B/8298A. As for code dates in the second half of 1964 the tube may be either version.

The 6146 is completely interchangeable with the 6146A/8298. The only difference between these tubes is the fact that the 6146A/8298 has the "dark heater" ("filament"). The "dark heater" allows the tube to function over a larger "filament" voltage (it was designed for use in mobile two-way radios where the voltage can range over a wide variation). The 6146B/8298A is a completely different tube that has a 33 percent higher power rating than the earlier versions.

There are several things about the 6146 family that are outlined in the article.


Now, the 6146 series is very robust EXCEPT for the grids. You have to be VERY careful not to overdrive them. Although RCA eventually specified a maximum grid current of 3 mA per tube (down from the original 3.75 mA, then 3.5 mA, then 3.25 mA) you will get the best tube life if you do not run more than 2.5 mA per tube. This means a total of 5 mA when 2 of them are in parallel. Frankly, you can run as little as 3.5 mA for the pair and you will get just as much power output as when you run 6 mA grid drive.

The problem that you are seeing is often caused in the TS- series by a weak driver tube (a 12BY7 if I remember correctly). Many amateur radio operators have replaced the finals and still have the same problem with power output. You definitely need to verify that the driver is functioning correctly. By the way, a tube tester is not the best way to check tubes. I have seen many tubes that test fine yet would not work well in the unit. Conversely, I have seen many tubes that test bad yet work fine. The best tube tester in the world is the unit itself.

Glen, K9STH


Best test of your driver stage is the GRID current on the finals.

W0LPQ
03-03-2008, 06:09 PM
duplicate ... for some reason...

W0LPQ
03-03-2008, 06:12 PM
Well said Eric. I have in the past tried to get guys to understand that point, they either refuse to understand ... or it does not agree with "their" thoughts.

As always, Glen has good advice also. Must have that dialogue saved in memory..!

KL7AJ
03-03-2008, 06:16 PM
Must have that dialogue saved in memory..!

We could probably do this with just about EVERY question on here!


For redundant questions about dipoles, press 1

For redundant questions about SWR, press 2

For redundant questions about tube finals, Press 3

For great puns from KL7AJ, press 4

:)

eric

K0CMH
03-03-2008, 08:09 PM
Regarding 10 meter output:

I do not know if this applies to the Kenwood in question, but many of the old tube rigs, particularly many of the Heath line, have a statement in the manual that 10 meter power is reduced. A number of the tube rigs only put out about 60 -70 watts on 10 meters.

Those of you familiar with this model Kenwood can comment on this.

Also, the comment about measuring the grid current on the finals: Do you mean to measure the miliamps by touching the pin on the final tube that goes to the grid with one probe of the meter and grounding the other lead?

W0LPQ
03-03-2008, 08:38 PM
0CMH that will allow you to measure VOLTAGE ... not current. I know my S Line measured grid current directly... (which as I remember was actually a voltage across a resistor).

WB2WIK
03-03-2008, 09:31 PM
Meters all read current. Ones calibrated for voltage have a resistor in series with them. Ones calibrated for higher currents have a resistor in parallel with them. But what they are responding to is current.

To measure grid current with the Kenwood, it's easy and requires no external metering: Just switch the meter switch to Ig.

WB2WIK/6

W0BST
03-03-2008, 10:16 PM
Meters all read current. Ones calibrated for voltage have a resistor in series with them. Ones calibrated for higher currents have a resistor in parallel with them. But what they are responding to is current.

To measure grid current with the Kenwood, it's easy and requires no external metering: Just switch the meter switch to Ig.

WB2WIK/6

I assume that is the same as Ip, plate current? My meter does not have an Ig setting.

K9STH
03-03-2008, 10:59 PM
YPV:

No!

Actually "plate current" readings on the vast majority of amateur radio equipment is actually the current drawn through the cathode. This includes, among other things, the current drawn by the screen grid(s) in the tubes. However, most of the current shown on the meter will be the actual plate current. The reason for measuring cathode current instead of plate current is that the wiring for the meter switch is considerably simpler and it is much safer (in terms of voltage potential).

The "grid current" is the amount of current drawn only by the control grid(s). Unfortunately, your transceiver does NOT have a grid current position on the meter (I looked up the manual on BAMA).

As such, there is no way to tell the condition of the driver tube and the only way to check it is going to be by substitution. The driver tube is a 12BY7A.

Glen, K9STH

WB2WIK
03-03-2008, 11:15 PM
The TS-530S doesn't have an Ig meter scale?

Oops, thought it did.

My old TS-520 did...if the 530 does not, that's one thing they left out.

The ALC meter scale can be used for peaking the driver stage, though...it's just not "calibrated" to read grid current.

If you can get sufficient drive to make the ALC meter read at least mid-scale, you almost undoubtedly have enough drive.

Normally with these rigs when the driver tube starts to fail, you can't get enough drive to make ALC work and that's the first obvious clue.

WB2WIK/6

WA7KKP
03-04-2008, 10:35 PM
If you're making solid contacts, I wouldn't worry a bit.

If your tubes are soft or flat, you can easily check them by briefly de-tuning the finals -- you should easily get 400 ma. If not, the 6146's are in need of replacement. Do this quick and pay attention, this can be hard on tubes if you dawdle around.

Gary WA7KKP

KL7AJ
03-04-2008, 10:39 PM
If you're making solid contacts, I wouldn't worry a bit.

If your tubes are soft or flat, you can easily check them by briefly de-tuning the finals -- you should easily get 400 ma. If not, the 6146's are in need of replacement. Do this quick and pay attention, this can be hard on tubes if you dawdle around.

Gary WA7KKP

KKP

If you're attempting to get full output with insufficient drive, you could be running the tubes in a very inefficient manner, and you will shorten their life. Even if the Ip is within limits, you can still overdissipate them.

eric

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