Adjust MFJ259b Freqency counter?
 

Is there an adjustment pot on the MFJ259b for the freqency counter and
if so, what number is it on the board? Mine seems consistently high, and
the guys in Starkville seem like blinded deer in the headlights when I
called on the subject.

Is there an adjustment pot on the MFJ259b for the freqency counter and
if so, what number is it on the board?

Gary-

It looks like the counter module is purchased as a unit, probably from
Optoelectronics. Therefore, MFJ may not know anything about it they don't need
to know.

I've looked for anything that might calibrate the frequency, but couldn't find
it. Perhaps further disassembly would have revealed a hidden trimmer
capacitor. I doubt it would be a pot, but you never know.

How far off is yours? Mine is close enough for its purpose of checking
antennas, but I wouldn't adjust a transmitter's frequency with it.

73, Fred, K4DII

Is there an adjustment pot on the MFJ259b for the freqency counter and
if so, what number is it on the board?

Gary-

It looks like the counter module is purchased as a unit, probably from
Optoelectronics. Therefore, MFJ may not know anything about it they don't need
to know.

I've looked for anything that might calibrate the frequency, but couldn't find
it. Perhaps further disassembly would have revealed a hidden trimmer
capacitor. I doubt it would be a pot, but you never know.

How far off is yours? Mine is close enough for its purpose of checking
antennas, but I wouldn't adjust a transmitter's frequency with it.

73, Fred, K4DII

It seems to read about 250 hz high. As you say, perhaps close enough for
government work, but I needed it the other day. A new ham came by with
one of the RS 10 meter rigs he bought last year on sale. From my
Kenwood, he was about 250 low and sounded just horrible, but the only
counter I had at home was the 259B and it showed it was real close, so
later I tried it on some 2 meter fm radios and it ran consistently high.
I used to have an original 259 that died and I recall the counter
circuit was on the back of the display and was adjustable. Even GOOD
counters can be adjusted, so there should be something here as well, but
I hate to take it all apart without a clue where to look.

Fred McKenzie wrote:
Is there an adjustment pot on the MFJ259b for the freqency counter and
if so, what number is it on the board?

Gary-

It looks like the counter module is purchased as a unit, probably from
Optoelectronics. Therefore, MFJ may not know anything about it they don't need
to know.

I've looked for anything that might calibrate the frequency, but couldn't find
it. Perhaps further disassembly would have revealed a hidden trimmer
capacitor. I doubt it would be a pot, but you never know.

How far off is yours? Mine is close enough for its purpose of checking
antennas, but I wouldn't adjust a transmitter's frequency with it.

73, Fred, K4DII

It seems to read about 250 hz high. As you say, perhaps close enough for
government work, but I needed it the other day. A new ham came by with
one of the RS 10 meter rigs he bought last year on sale. From my
Kenwood, he was about 250 low and sounded just horrible, but the only
counter I had at home was the 259B and it showed it was real close, so
later I tried it on some 2 meter fm radios and it ran consistently high.
I used to have an original 259 that died and I recall the counter
circuit was on the back of the display and was adjustable. Even GOOD
counters can be adjusted, so there should be something here as well, but
I hate to take it all apart without a clue where to look.

Fred McKenzie wrote:
Is there an adjustment pot on the MFJ259b for the freqency counter and
if so, what number is it on the board?

Gary-

It looks like the counter module is purchased as a unit, probably from
Optoelectronics. Therefore, MFJ may not know anything about it they don't need
to know.

I've looked for anything that might calibrate the frequency, but couldn't find
it. Perhaps further disassembly would have revealed a hidden trimmer
capacitor. I doubt it would be a pot, but you never know.

How far off is yours? Mine is close enough for its purpose of checking
antennas, but I wouldn't adjust a transmitter's frequency with it.

73, Fred, K4DII

Here is the complete calibration procedure for the 259B. A quick scan
through didn't show a way to change the oscillator, just check it.

http://www.w8ji.com/mfj-259b_calibration.htm

Dick - W6CCD

On Mon, 19 Jul 2004 02:04:12 GMT, Gary Danaher
wrote:

It seems to read about 250 hz high. As you say, perhaps close enough for
government work, but I needed it the other day. A new ham came by with
one of the RS 10 meter rigs he bought last year on sale. From my
Kenwood, he was about 250 low and sounded just horrible, but the only
counter I had at home was the 259B and it showed it was real close, so
later I tried it on some 2 meter fm radios and it ran consistently high.
I used to have an original 259 that died and I recall the counter
circuit was on the back of the display and was adjustable. Even GOOD
counters can be adjusted, so there should be something here as well, but
I hate to take it all apart without a clue where to look.

Fred McKenzie wrote:
Is there an adjustment pot on the MFJ259b for the freqency counter and
if so, what number is it on the board?

Gary-

It looks like the counter module is purchased as a unit, probably from
Optoelectronics. Therefore, MFJ may not know anything about it they don't need
to know.

I've looked for anything that might calibrate the frequency, but couldn't find
it. Perhaps further disassembly would have revealed a hidden trimmer
capacitor. I doubt it would be a pot, but you never know.

How far off is yours? Mine is close enough for its purpose of checking
antennas, but I wouldn't adjust a transmitter's frequency with it.

73, Fred, K4DII

Here is the complete calibration procedure for the 259B. A quick scan
through didn't show a way to change the oscillator, just check it.

http://www.w8ji.com/mfj-259b_calibration.htm

Dick - W6CCD

On Mon, 19 Jul 2004 02:04:12 GMT, Gary Danaher
wrote:

It seems to read about 250 hz high. As you say, perhaps close enough for
government work, but I needed it the other day. A new ham came by with
one of the RS 10 meter rigs he bought last year on sale. From my
Kenwood, he was about 250 low and sounded just horrible, but the only
counter I had at home was the 259B and it showed it was real close, so
later I tried it on some 2 meter fm radios and it ran consistently high.
I used to have an original 259 that died and I recall the counter
circuit was on the back of the display and was adjustable. Even GOOD
counters can be adjusted, so there should be something here as well, but
I hate to take it all apart without a clue where to look.

Fred McKenzie wrote:
Is there an adjustment pot on the MFJ259b for the freqency counter and
if so, what number is it on the board?

Gary-

It looks like the counter module is purchased as a unit, probably from
Optoelectronics. Therefore, MFJ may not know anything about it they don't need
to know.

I've looked for anything that might calibrate the frequency, but couldn't find
it. Perhaps further disassembly would have revealed a hidden trimmer
capacitor. I doubt it would be a pot, but you never know.

How far off is yours? Mine is close enough for its purpose of checking
antennas, but I wouldn't adjust a transmitter's frequency with it.

73, Fred, K4DII

Adjust MFJ259b Freqency counter?
 

On Tue, 27 Jul 2004 22:59:17 -0500, Bob Miller wrote:

On Sun, 18 Jul 2004 19:31:18 GMT, Gary wrote:

Is there an adjustment pot on the MFJ259b for the freqency counter and
if so, what number is it on the board? Mine seems consistently high, and
the guys in Starkville seem like blinded deer in the headlights when I
called on the subject.

this may or may not help, but at the site,
http://www.mfjenterprises.com/produc...rodid=MFJ-259B they have a
link to "calibration instructions"

bob
k5qwg

The original 259 has the counter on a daughterboard. There appears to be a
trimmer cap on it. Adjusting it is another matter, but it might be
possible to drill a hole in the main board to allow access to the trimmer.

Disassembling the 259 is non trivial, but easier than putting it back
together.




--
Chuck Forsberg www.omen.com 503-614-0430
Developer of Industrial ZMODEM(Tm) for Embedded Applications
Omen Technology Inc "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231 FAX 629-0665

Adjust MFJ259b Freqency counter?
 

Chuck Forsberg WA7KGX N2469R wrote:

Disassembling the 259 is non trivial, but easier than putting it back
together.

Mine came partially disassembled;-)

There's not a lot inside.