My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at
Kenwood.net suggest that replacing a fist full of diodes with new diodes of
any of these types : 1S2588,1SS91S, BA282 will cure the problem.
Additionally, I have heard that 1S1587 diodes can be used. However, I have
been unable to find a source for these parts that will send or sell me just
a fist full. I haven't tracked down the manufactures of all the parts.
However, the BA282 seem to be made by Vishay.

Can any of you recommend a supplier for any of these parts? Thanks

Tom Tillander wrote:

My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at
Kenwood.net suggest that replacing a fist full of diodes with new diodes of
any of these types : 1S2588,1SS91S, BA282 will cure the problem.
Additionally, I have heard that 1S1587 diodes can be used. However, I have
been unable to find a source for these parts that will send or sell me just
a fist full. I haven't tracked down the manufactures of all the parts.
However, the BA282 seem to be made by Vishay.

Can any of you recommend a supplier for any of these parts? Thanks



Frequency drift is probably not the diodes. There have been problems
with one of the voltage controlled oscillators. The only problem I
know of with the diodes is when one band goes bad.

I sent my TS-440s in for repair and they replaced a few components
(not diodes) and it has been OK for a few years now.

Bill K7NOM

Tom Tillander wrote:

My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at
Kenwood.net suggest that replacing a fist full of diodes with new diodes of
any of these types : 1S2588,1SS91S, BA282 will cure the problem.
Additionally, I have heard that 1S1587 diodes can be used. However, I have
been unable to find a source for these parts that will send or sell me just
a fist full. I haven't tracked down the manufactures of all the parts.
However, the BA282 seem to be made by Vishay.

Can any of you recommend a supplier for any of these parts? Thanks



Frequency drift is probably not the diodes. There have been problems
with one of the voltage controlled oscillators. The only problem I
know of with the diodes is when one band goes bad.

I sent my TS-440s in for repair and they replaced a few components
(not diodes) and it has been OK for a few years now.

Bill K7NOM

"Tom Tillander" wrote in message
...
My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at
Kenwood.net suggest that replacing a fist full of diodes with new diodes of
any of these types : 1S2588,1SS91S, BA282 will cure the problem.
Additionally, I have heard that 1S1587 diodes can be used. However, I have
been unable to find a source for these parts that will send or sell me just
a fist full. I haven't tracked down the manufactures of all the parts.
However, the BA282 seem to be made by Vishay.

Can any of you recommend a supplier for any of these parts? Thanks







Hi Tom,

I have a TS-940 that had the same problem (freq.drift, blank display).
Was a problem on the PLL board. If I tapped/slapped the top of the transceiver or
tap the PLL board, it would also cause the rig to jump off freq., warble or make
the display go blank. It was caused by several broken solder joints on the bottom
side of the PLL board. Using a magnifying glass I found "rings" around the
component leads on the solder joints which were solder fractures. This has
happended twice on my rig, both on very hot days. Now I avoid operating the
rig when it gets hot in the shack (90-100 degrees) and have not had the problem
since. Have owned the 940 for 13yrs now.
You may want to inspect the solder joints on that board with a magnifying glass
before replacing parts.

Good luck on fixing your rig
Tom

"Tom Tillander" wrote in message
...
My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at
Kenwood.net suggest that replacing a fist full of diodes with new diodes of
any of these types : 1S2588,1SS91S, BA282 will cure the problem.
Additionally, I have heard that 1S1587 diodes can be used. However, I have
been unable to find a source for these parts that will send or sell me just
a fist full. I haven't tracked down the manufactures of all the parts.
However, the BA282 seem to be made by Vishay.

Can any of you recommend a supplier for any of these parts? Thanks







Hi Tom,

I have a TS-940 that had the same problem (freq.drift, blank display).
Was a problem on the PLL board. If I tapped/slapped the top of the transceiver or
tap the PLL board, it would also cause the rig to jump off freq., warble or make
the display go blank. It was caused by several broken solder joints on the bottom
side of the PLL board. Using a magnifying glass I found "rings" around the
component leads on the solder joints which were solder fractures. This has
happended twice on my rig, both on very hot days. Now I avoid operating the
rig when it gets hot in the shack (90-100 degrees) and have not had the problem
since. Have owned the 940 for 13yrs now.
You may want to inspect the solder joints on that board with a magnifying glass
before replacing parts.

Good luck on fixing your rig
Tom

Thanks, I'm aware of the "goop" issue as well.... I'm just trying to get
prepared for all contingencies. Are you saying Kenwood used to repair this
for free even if your warranty has expired?




Leigh W3NLB wrote in message
...
On 07 Sep 2003 14:41:00 GMT, "Tom Tillander"
wrote:

My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at
Kenwood.net suggest that replacing a fist full of diodes with new diodes
of
any of these types : 1S2588,1SS91S, BA282 will cure the problem.
Additionally, I have heard that 1S1587 diodes can be used. However, I
have
been unable to find a source for these parts that will send or sell me
just
a fist full. I haven't tracked down the manufactures of all the parts.
However, the BA282 seem to be made by Vishay.

Can any of you recommend a supplier for any of these parts? Thanks






There is a well-known problem with the VCO circuit. They applied a
coating during production which was supposed to protect the circuitry
from moisture. In fact, the coating was hygroscopic, and over time it
creates more problems than it cures.

The solution was to scrape all this gum out, replace the doides, then
apply a coating of hot-melt glue over the area to seal it. Kenwood
used to do this under warranty for all TS-440's, regardless of whether
the owner was the original purchaser or not. Don't know if they still
do.

73 de Leigh W3NLB

Thanks, I'm aware of the "goop" issue as well.... I'm just trying to get
prepared for all contingencies. Are you saying Kenwood used to repair this
for free even if your warranty has expired?




Leigh W3NLB wrote in message
...
On 07 Sep 2003 14:41:00 GMT, "Tom Tillander"
wrote:

My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at
Kenwood.net suggest that replacing a fist full of diodes with new diodes
of
any of these types : 1S2588,1SS91S, BA282 will cure the problem.
Additionally, I have heard that 1S1587 diodes can be used. However, I
have
been unable to find a source for these parts that will send or sell me
just
a fist full. I haven't tracked down the manufactures of all the parts.
However, the BA282 seem to be made by Vishay.

Can any of you recommend a supplier for any of these parts? Thanks






There is a well-known problem with the VCO circuit. They applied a
coating during production which was supposed to protect the circuitry
from moisture. In fact, the coating was hygroscopic, and over time it
creates more problems than it cures.

The solution was to scrape all this gum out, replace the doides, then
apply a coating of hot-melt glue over the area to seal it. Kenwood
used to do this under warranty for all TS-440's, regardless of whether
the owner was the original purchaser or not. Don't know if they still
do.

73 de Leigh W3NLB

as many posters have pointed.
2 problems - the goo & dry joints.
the goo can be removed carefully with tweezers etc, the dry joint can easily
be found by using freezer spray or lighter gas.
the joint will show the ring quite nicely & it makes it easier to see with a
bright light (goes dull)

not only the 440, some 430's & the 930's suffer the same.

i have known the VCO varicap diode to be trouble some aswell.

mike

"Tom Tillander" wrote in message
...
My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at
Kenwood.net suggest that replacing a fist full of diodes with new diodes
of
any of these types : 1S2588,1SS91S, BA282 will cure the problem.
Additionally, I have heard that 1S1587 diodes can be used. However, I
have
been unable to find a source for these parts that will send or sell me
just
a fist full. I haven't tracked down the manufactures of all the parts.
However, the BA282 seem to be made by Vishay.

Can any of you recommend a supplier for any of these parts? Thanks

as many posters have pointed.
2 problems - the goo & dry joints.
the goo can be removed carefully with tweezers etc, the dry joint can easily
be found by using freezer spray or lighter gas.
the joint will show the ring quite nicely & it makes it easier to see with a
bright light (goes dull)

not only the 440, some 430's & the 930's suffer the same.

i have known the VCO varicap diode to be trouble some aswell.

mike

"Tom Tillander" wrote in message
...
My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at
Kenwood.net suggest that replacing a fist full of diodes with new diodes
of
any of these types : 1S2588,1SS91S, BA282 will cure the problem.
Additionally, I have heard that 1S1587 diodes can be used. However, I
have
been unable to find a source for these parts that will send or sell me
just
a fist full. I haven't tracked down the manufactures of all the parts.
However, the BA282 seem to be made by Vishay.

Can any of you recommend a supplier for any of these parts? Thanks

On 07 Sep 2003 14:41:00 GMT, "Tom Tillander"
wrote:

My Kenwood TS440S is beginning to present symptoms (frequency drift and
intermittent dots in the display) of PLL unlock. Service Bulletins at

you WILL get a better answer on the ts440 email reflector that you are
subscribed to.


if i remember rightly...
if the dots is on only a few bands then try tuning vfo-1 a bit
if its dots on all bands then try vfo-5
and pick some of the ''glue'' away from the components as its supposed
to attract moisture.