There is a nice rectifier on the external power input that should/might protect the rest of the meter.
Bob N5TX

This might help:

Bob N5TX

Hi Don,

many thanks.
I emailed to MFJ in parallel and I got short reply "schottky diodes surface mount 2820s"...
Which is surprising me a bit as I expected some damage around the power supply circuitry but these diodes are in RF detector part.
In worse case something like $75 + s/h would not be big issue for me just as I am in central EU so i am worrying if the cost will not be a bit high.

开云体育

MFJ Items For Sale

Dummy Load, Digital TNC switch,
Wall Wart, and more For Sale:

.

MFJ 264, 1500 Watt Dry Dummy Load For Sale:

The MFJ 264 is a dry dummy load. No need
for messy oil cans with this dummy load.

MFJ rates it as good for 1500 Watts -- for
a time. There is a graph of power rating vs.
time silk screened on to the case, as well as
in the included manual.

This one is completely NEW, still sealed,
in its original box. No scratches or defects.

Only $85.

.

Realistic 21-506 Dummy Load
50 ohms, DC-500 MHz, 15 Watts,
Large heat sink, similar to MFJ-261
$30

Realistic 21-506 Dummy Load
As above, except measures 64 ohms, $10


.

MFJ-1272 MX TNC / Microphone Switch For Sale:

This unit is made to go between your rig, your
PK-232 TNC (or equivalent), and your microphone.
It is a small unit with a mic jack on the front,
plus a switch to switch between your mic and
TNC. It saves a lot of wear and tear plugging
and unplugging cables.

The "MX" model has modular connectors for your
microphone, in and out.

This one works fine and looks like new.
With paper work for $25.

.

MFJ-1313 Wall Wart
12 V DC at 100 ma, $14

.


I also have many other accessories available such as many
different types of microphones, HTs, VHF and UHF rigs, HF
and VHF/UHF antennas, connectors, miscellaneous accessories,
etc.
Just too many to list here. Please e-mail your requests.

.
Prices do not include shipping from Florida.

Thanks.

73,

Ken, W8EK

Ken Simpson
E-mail to W8EK@... or W8EK@...
Voice Phone (352) 732-8400






.

Selling is allowed in this group for ham radio equipment only, and at least one of the items for sale must be related to the purpose of the group (this allows for a lot of variety of items!). We require that anything being sold here have a price with it. So "make offer" or anything like that will not be an acceptable post here. Please indicate if shipping is included, otherwise leave it out. Also, please indicate the general location of the equipment for sale, so others will know if it’s within driving distance for them, and if you're willing to meet someone X miles away from that location.

If you have any information about the item, please add it, as it will make it more likely that it will sell.

Just list similar to the following. This was a suggestion for the SWAN-AMATEUR-RADIO group. Just replace the Swan item with one that would fit the purpose of this group:

Swan 350D, great cosmetic condition, may need new final tubes since output drops somewhat on 15 and 10 meters. Model 117XC AC power supply included. Asking $325.00 OBO. Located near Charlotte, NC. Will drive up to 25 miles from Charlotte for pickup or delivery. Call 444-444-4444, or email hamoperator@....

MFJ Items For Sale

Dummy Load, Code Practice Oscillator, Digital
TNC switch, Wall Wart, and more For Sale:

.

MFJ 264, 1500 Watt Dry Dummy Load For Sale:

The MFJ 264 is a dry dummy load. No need
for messy oil cans with this dummy load.

MFJ rates it as good for 1500 Watts -- for
a time. There is a graph of power rating vs.
time silk screened on to the case, as well as
in the included manual.

This one is completely NEW, still sealed,
in its original box. No scratches or defects.

Only $85.

.

MFJ-557, Code Oscillator For Sale:

The MFJ-557 Deluxe Morse Code Practice
Oscillator features a Morse Code straight
key on a non-skid heavy steel base. It stays
put on your table and does not move around
while you are sending!

A volume control adjusts from barely audible
to blaring full sound. Tone control gives you a
wide adjustment from high "squeaky" to low
"booming" tones.

You even get an earphone jack for private
listening or you can plug in an external
speaker for super high volume in the classroom.

When you are done practicing, you can hook up
the straight key to your transmitter and go on
the air.

The MFJ-557 also has a built-in speaker and
adjustable contacts, and runs on a 9 volt
battery.

It measures 8 1/2 x 2 1/4 x 3 3/4 inches.

This one is NEW. I know for sure it is new,
since it is still sealed in its clear bubble
container.

Amazon sells these for $87. Buy this one for
only $50.

.

MFJ-1272 MX TNC / Microphone Switch For Sale:

This unit is made to go between your rig, your
PK-232 TNC (or equivalent), and your microphone.
It is a small unit with a mic jack on the front,
plus a switch to switch between your mic and
TNC. It saves a lot of wear and tear plugging
and unplugging cables.

The "MX" model has modular connectors for your
microphone, in and out.

This one works fine and looks like new.
With paper work for $25.

.

MFJ-1313
12 V DC at 100 ma, $14

.


I also have many other accessories available such as many
different types of microphones, HTs, VHF and UHF rigs, HF
and VHF/UHF antennas, connectors, miscellaneous accessories,
etc.
Just too many to list here. Please e-mail your requests.

.
Prices do not include shipping from Florida.

Thanks.

73,

Ken, W8EK

Ken Simpson
E-mail to W8EK@... or W8EK@...
Voice Phone (352) 732-8400






.

I had a similar problem a Yaesu Mark V Field. It worked ok with low power, but not above around 20 Watts. I found out that it was stray RF. I ran my 600 ladder line differently from the tuner so that the RF was at a 90 degree angle and it works fine at 100 Watts now. I also grounded the rig to the tuner.

73 Richard W4MCD?

Hi Allan,
I have used the 939y and cable with FT 891 with good results. I have not had to retune after going to full power. Once you get it tuned at the higher power does it stay tuned? ?I wonder if there is some component heating up? What kind of antenna? I would try using a dummy load and see what happens. ?

Mike AD0L?

I have a 993B with a Kenwood that had similar problems. I found inside a resistor network on a vertical board at the center rear had a bad solder joint. it was really loose and wobbly.?
It is a real pain to get to it to resolder as I had to disconnect everything at the rear panel including removing the four banana jacks to get clearance to swing the main board up. I left all the front ribbon cables alone.
I resoldered all the blobs on that resistor board while I had it out and that seemed to fix it.
You may want to test it by putting pressure on the resistor board while transmitting to see if it is a bad contact before you tear it down. Use a plastic tuning tool or similar as that area is hot with RF.

Good luck

Dennis N4KPI

Anyone using an MFJ-993B with an MFJ-5124Y interface cable to a Yaesu tranceiver? I have been attempting to get the unit to work correctly. At low power it autotunes correctly; when I increase power the SWR increases so that I have go through the retune process several times. MFJ tech info service is useless and is no help, as expected. Is it just this unit or is it common behavior.

K3YZ

When I formed the group, my intent was to cover all the MFJ related brands, but a group name would be too long to cover them all. This is a question about matching 811As without a tube tester with the intent of using them as spares in an Ameritron 811H amplifier.

I do not have a tube tester but I am hoping to find someone in south central Ohio who does have one.

I would like to find a way to test 811As without buying a tube tester if I can't find one nearby. And some tube testers don't do thorough tests anyway.

Can you use an 811A in an amplifier circuit at low drive after neutralization to check tube parameters in order to match a set of 811As for use at higher power?

I have an Ameritron 811H. Eventually I will replace these 811s with matched 572Bs. In the meantime, I have 9 spare 811As, Six were purchased together and appear to be from the same lot, from the same shipping box. Three others were given me when I bought the amplifier. I was told it's not all that important to match these, but I would think otherwise. I was hoping setting up a few in the amp, maybe just one, using low drive level, might give me what I need to know from either voltage or current measurements on the Ameritron's meters.

Maybe there's a special rig I can build just for testing these and 572B tubes for this purpose?

Thoughts?

Donald KX8K

MFJ Items For Sale:

TNC/Microphone Switch, Stereo
Synthesizer, Original Boxes,
and more

.

MFJ-1272 MX TNC / Microphone Switch

This unit is made to go between your rig, your
PK-232 TNC (or equivalent), and your microphone.
It is a small unit with a mic jack on the front,
plus a switch to switch between your mic and
TNC. It saves a lot of wear and tear plugging
and unplugging cables.

The "MX" model has modular connectors for your
microphone, in and out.

This one works fine and looks like new.
With paper work for $25.

.

MFJ-1501 Stereo Synthesizer

This is a sort of odd unit. You can plug it
in to the mono headphone or speaker jack
on your rig. It will produce a stereo output
that can be used to drive stereo speakers.
It is quite useful to use with powered
computer speakers.

One can select one of two inputs. Separation
is adjustable, as is volume.

12 Volt DC required.

This one works fine, and looks like new.
With manual for only $40.

.

Original Empty Boxes For Sale:

All are original boxes that also include the
inserts that came with them when new.
Some may even have plastic bags.

MFJ 200 BX Xtal Cal $3
MFJ 407 C Keyer $10
MFJ 564 Paddles $8
MFJ 870/872/873/874 Grandmaster SWR/Wattmeter
MFJ 986 Large Ant Tuner $18
MFJ 1270 B TNC $10
MFJ 1284 M TNC Pgm $3

These are original boxes only.

.

MFJ-1313 Wall wart power cube

Provides 12 Volts DC at 100 ma.
It has
an 1/8 inch plug on it.

This one works fine and looks fine. $12

.

I also have many other accessories available such
as many different types of microphones, HTs, VHF
and UHF rigs, HF and VHF/UHF antennas,
connectors, miscellaneous accessories, etc.
Just too many to list here.
Please e-mail your requests.

.

Prices do not include shipping from Florida.

Thanks.

73,

Ken, W8EK

Ken Simpson
E-mail to W8EK@... or W8EK@...
Voice Phone (352) 732-8400



.





.

MFJ Items For Sale:

Power Supply, TNC/Microphone Switch,
Stereo Synthesizer, Original Boxes,
and more

.

MFJ-4230 MVP Power Supply:

The MFJ-4230 MVP is 25 Amps continuous
and 30 Amps surge at 13.8 VDC. Voltage is
variable from 4 to 16 volts. It is a compact
switching power supply.

The front panel features 5-way binding posts
that allow easy access connections for your
rig and station accessories. The back has
two sets of Anderson Power Pole connectors.

Cosmetically, I do not find a scratch on this
one. Electrically, it works as it should.

With paper work for only $100.

.

MFJ-1272 MX TNC / Microphone Switch

This unit is made to go between your rig, your
PK-232 TNC (or equivalent), and your microphone.
It is a small unit with a mic jack on the front,
plus a switch to switch between your mic and
TNC. It saves a lot of wear and tear plugging
and unplugging cables.

The "MX" model has modular connectors for your
microphone, in and out.

This one works fine and looks like new.
With paper work for $25.

.

MFJ-1501 Stereo Synthesizer

This is a sort of odd unit. You can plug it
in to the mono headphone or speaker jack
on your rig. It will produce a stereo output
that can be used to drive stereo speakers.
It is quite useful to use with powered
computer speakers.

One can select one of two inputs. Separation
is adjustable, as is volume.

12 Volt DC required.

This one works fine, and looks like new.
With manual for only $40.

.

Original Empty Boxes For Sale:

All are original boxes that also include the
inserts that came with them when new.
Some may even have plastic bags.

MFJ 200 BX Xtal Cal $3
MFJ 407 C Keyer $10
MFJ 564 Paddles $8
MFJ 870/872/873/874 Grandmaster SWR/Wattmeter
MFJ 986 Large Ant Tuner $18
MFJ 1270 B TNC $10
MFJ 1284 M TNC Pgm $3

These are original boxes only.

.

MFJ-1313 Wall wart power cube

Provides 12 Volts DC at 100 ma.
It has
an 1/8 inch plug on it.

This one works fine and looks fine. $12

.

I also have many other accessories available such
as many different types of microphones, HTs, VHF
and UHF rigs, HF and VHF/UHF antennas,
connectors, miscellaneous accessories, etc.
Just too many to list here.
Please e-mail your requests.

.

Prices do not include shipping from Florida.

Thanks.

73,

Ken, W8EK

Ken Simpson
E-mail to W8EK@... or W8EK@...
Voice Phone (352) 732-8400



.





.

MFJ Items For Sale:

TNC/Microphone Switch, Stereo Synthesizer, Original Boxes,
and more

.

MFJ-1272 MX TNC / Microphone Switch

This unit is made to go between your rig, your
PK-232 TNC (or equivalent), and your microphone.
It is a small unit with a mic jack on the front,
plus a switch to switch between your mic and
TNC. It saves a lot of wear and tear plugging
and unplugging cables.

The "MX" model has modular connectors for your
microphone, in and out.

This one works fine and looks like new.
With paper work for $25.

.

MFJ-1501 Stereo Synthesizer

This is a sort of odd unit. You can plug it
in to the mono headphone or speaker jack
on your rig. It will produce a stereo output
that can be used to drive stereo speakers.
It is quite useful to use with powered
computer speakers.

One can select one of two inputs. Separation
is adjustable, as is volume.

12 Volt DC required.

This one works fine, and looks like new.
With manual for only $40.

.

Original Empty Boxes For Sale:

All are original boxes that also include the
inserts that came with them when new.
Some may even have plastic bags.

MFJ 200 BX Xtal Cal $3
MFJ 407 C Keyer $10
MFJ 564 Paddles $8
MFJ 870/872/873/874 Grandmaster SWR/Wattmeter
MFJ 986 Large Ant Tuner $18
MFJ 1270 B TNC $10
MFJ 1284 M TNC Pgm $3

These are original boxes only.

.

MFJ-1313 Wall wart power cube

Provides 12 Volts DC at 100 ma.
It has
an 1/8 inch plug on it.

This one works fine and looks fine. $12

.

I also have many other accessories available such
as many different types of microphones, HTs, VHF
and UHF rigs, HF and VHF/UHF antennas,
connectors, miscellaneous accessories, etc.
Just too many to list here.
Please e-mail your requests.

.

Prices do not include shipping from Florida.

Thanks.

73,

Ken, W8EK

Ken Simpson
E-mail to W8EK@... or W8EK@...
Voice Phone (352) 732-8400



.





.

MFJ Items For Sale:

TNC/Microphone Switch, Stereo Synthesizer, and more

.

MFJ 422 B electronic keyer

This keyer is made to go on the back of a
Bencher Paddle. It includes sidetone, and
has adjustments for volume, tone frequency,
and weighting, as well as speed.

It will key either positive or negative
voltages, and is powered by an internal
9 V battery, or external 5 to 9 volt supply.

This one works 100%, and looks great also.
With paper work for $45.

.

MFJ-1272 MX TNC / Microphone Switch

This unit is made to go between your rig, your
PK-232 TNC (or equivalent), and your microphone.
It is a small unit with a mic jack on the front,
plus a switch to switch between your mic and
TNC. It saves a lot of wear and tear plugging
and unplugging cables.

The "MX" model has modular connectors for your
microphone, in and out.

This one works fine and looks like new.
With paper work for $25.

.

MFJ-1501 Stereo Synthesizer

This is a sort of odd unit. You can plug it
in to the mono headphone or speaker jack
on your rig. It will produce a stereo output
that can be used to drive stereo speakers.
It is quite useful to use with powered
computer speakers.

One can select one of two inputs. Separation
is adjustable, as is volume.

12 Volt DC required.

This one works fine, and looks like new.
With manual for only $40.

.


MFJ-1313 Wall wart power cube

Provides 12 Volts DC at 100 ma.
It has
an 1/8 inch plug on it.

This one works fine and looks fine. $12

.

I also have many other accessories available such
as many different types of microphones, HTs, VHF
and UHF rigs, HF and VHF/UHF antennas,
connectors, miscellaneous accessories, etc.
Just too many to list here.
Please e-mail your requests.

.

Prices do not include shipping from Florida.

Thanks.

73,

Ken, W8EK

Ken Simpson
E-mail to W8EK@... or W8EK@...
Voice Phone (352) 732-8400



.





.

First, the new pricing structure for NEWLY formed groups on groups.io
beginning January 18, 2021.

Basic (free) groups formed on or after that date stay free *up to 100
members*. After that, it will need to be upgraded to a premium group.
Premium groups ($220/year) are good up to 400 members, after which a
per-member fee ($.05 per month or $0.55 per year) is added to the $220
per year premium group fee. That will bring a burden on some new
groups, so I created some more ham groups that may grow, or flounder,
but I wanted to beat the deadline so those groups will not be charged
extra fees, or any fees, for that matter. If they take off and are
useful, that will be great. If they flounder, I might just delete the
group if members agree, or if there are no co-owners by the time I
review whether the group is worth keeping.

If you were thinking of creating a group for one of your interests,
THIS IS THE TIME TO DO SO before the new pricing structure goes into
effect. If you need help with that, email me *privately* and if I'm
not overwhelmed with requests, I will try to help. You must be willing
to assume group ownership as I will leave the group after creating it
and you've been made a group owner. If you need help getting started
with the group, I can hang around for a short while and direct you to
documentation on how to run a group.

As for the new groups I created last evening, I will list their web
addresses below.

Please contact me *privately* ONLY IF you are interested in joining
one of these groups AND ARE UNABLE to use the join button on the web
site or find the join process confusing. I would like to avoid what
happened when Yahoo closed their groups and I offered to help people
if they were unable to join themselves. I was overwhelmed with
requests to help, and I'm sure not all of those were from people who
had difficulty joining, so please give it a try yourself first. Go to
the site and press the join button on the group(s) you are interested
in. Follow the simple instructions and you will be approved. All new
members will be moderated for a short time so don't expect to post
immediately. There's only one moderator right now (me), and I work for
a living, sleep at night, and take naps because of my health condition
in late afternoons sometimes. I donate some of my time for community
work, am a minister, and have to wisely use my time.

But I don't want anyone to not join one of these groups because they
find it difficult to join.

YOU CAN JOIN ANY OF THESE GROUPS BY EMAIL by sending a message to the
subscribe address. Take the web address name at the end of the URL and
change it by adding [email protected] to it.

For the FT-757 group (as an example):
/g/FT-757GX
Send an email to this address:
[email protected]
no body text is required in the message, just the address, but to make
your email program happy, you can put the word subscribe in the
subject and message fields.

These new lists are email reflectors only with no storage (a change
that was made almost a year ago by GIO's owner). If I had created them
before February 2020, they would have storage. We will work something
out for storage if the groups get large enough and have a need for
that.

I will need moderators for these new groups, and soon after they get
on their feet, a co-owner who has some real interest and hopefully
experience with these different brands of radios.

Contact me off-list if you are interested in volunteering with any of
these groups. I will help you out with anything you need to know about
how to manage a group as a moderator or co-owner.

I will list the NEW groups first, then list the other amateur radio
groups I created.

Note that most of these are not model-specific and are
"general-purpose" groups for a BRAND of radio or a general-purpose
group for a type of equipment. I did not create any group for which
there already was a general-purpose discussion group for that brand of
radio, like Drake and some others. I am not interested in amassing a
lot of groups to manage. My purpose is just to see that interests in
major amateur radio brands are covered by some group for our amateur
radio community.

Let me know *privately* if I missed a MAJOR brand of vintage or
current brand of amateur radio and I will decide if I want to create a
group for that, but I'm not interested in managing lots and lots of
ham groups. My purpose is to get these groups created so they will be
grandfathered under the old pricing structure and won't cost the group
owner (me) money based on how many members there are.

Antennas will be covered by our ham-antennas group, so I didn't think
creating a new group for the major makers of antennas would be useful
and might just splinter the community across more groups. The antenna
tuners group is not approved yet but should be by later today so you
should be able to join in a few hours if you're interested.

The NEW groups are:

Alinco /g/Alinco-Amateur-Radio
Antenna Tuners /g/Antenna-Tuners
Anytone /g/Anytone-Amateur-Radio
Collins /g/Collins-Amateur-Radio
EF Johnson /g/EFJohnson-Amateur-Radio
Kenwood /g/Kenwood-Amateur-Radio
MFJ ham equipment /g/MFJ-Amateur-Radio
National /g/National-Amateur-Radio
Swan /g/Swan-Amateur-Radio

Existing groups created previously:

Baofeng /g/Baofeng
CHIRP radio programming tool /g/CHIRP
Yaesu FT-757 /g/FT-757GX
Yaesu FT-767GX /g/FT-767GX (only 1 member, me)
Ham radio antennas
Ham Radio Help group
Icom /g/ICOM
Icom 746 /g/Icom-746
Icom 746 Pro /g/Icom-746Pro
RF Amplifiers



Donald -- AD8DY
Formerly KJ3I



----------------------------------------------------
Some ham radio groups you may be interested in:
/g/ICOM /g/Ham-Antennas
/g/HamRadioHelp /g/Baofeng
/g/CHIRP

The next message is about some new groups I created to have a
general-purpose discussion group for some brands of amateur radio
equipment and radios before groups.io's new pricing structure goes
into effect Jan 81, 2021.

It is a long message, so I just wanted to give you a heads-up. I
cross-posted it to all the groups I manage.

I will be looking for moderators for the new groups and even some of
the established groups, so if you're interested in helping, please
email me privately about this.

For the rest, please read my next post. It's a long and detailed one.

Donald -- AD8DY
Formerly KJ3I


----------------------------------------------------
Some ham radio groups you may be interested in:
/g/ICOM /g/Ham-Antennas
/g/HamRadioHelp /g/Baofeng
/g/CHIRP