Need Help with my Kenwood TM-741A Triband FM Mobile Radio.....I purchased
the radio new some 12 years ago, with the 220MHz. Module Installed....The
Radio Has 144 Mhz / 220Mhz / 440 Mhz.....For years the radio worked
excellent....Then about 5 years ago I had lost the out put on 144 (two
meters)... However , the other two bands functioned fine...220/440mhz... I
sent the radio back to kenwood...and they indicated that the Driver
Transistor Q23 2SD1902R on the two meter module was defective. This
transistor is an inexpensive part...$ 3.05 ea. Anyway...It seems like the
same problem occured the other day...all the symptoms seem the same...Can
anyone shed some light on why this seems to happen often?? Also is it
possible to replace this 2SD1902R transister with something capable of
handling some what more power dissapation?? What ever happened to those
motorola hep sustatutes?? Any and all info supplied here will be greatly
appreciated....

Thanks
Carl
N2MFW

Carl Domanico wrote:

Need Help with my Kenwood TM-741A Triband FM Mobile Radio.....I purchased
the radio new some 12 years ago, with the 220MHz. Module Installed....The
Radio Has 144 Mhz / 220Mhz / 440 Mhz.....For years the radio worked
excellent....Then about 5 years ago I had lost the out put on 144 (two
meters)... However , the other two bands functioned fine...220/440mhz... I
sent the radio back to kenwood...and they indicated that the Driver
Transistor Q23 2SD1902R on the two meter module was defective. This
transistor is an inexpensive part...$ 3.05 ea. Anyway...It seems like the
same problem occured the other day...all the symptoms seem the same...Can
anyone shed some light on why this seems to happen often?? Also is it
possible to replace this 2SD1902R transister with something capable of
handling some what more power dissapation?? What ever happened to those
motorola hep sustitutes?? Any and all info supplied here will be greatly
appreciated....

Thanks
Carl
N2MFW

Motorola dropped the HEP line at least 15 years ago. So did GE,
Workman, and several other replacement lines. ECG was recently bought by
NTE, the sole survivor of the universal semi replacement business.
http://www.nteinc.com/ has a downloadable database for finding
replacement parts. There is no cross reference for this part, but you
can check their on line parts search to see if it has recently been
added.
--
9 days!


Michael A. Terrell
Central Florida

I sent the radio back to kenwood...and they indicated that the Driver
Transistor Q23 2SD1902R on the two meter module was defective. This
transistor is an inexpensive part...$ 3.05 ea. Anyway...It seems like the
same problem occured the other day...all the symptoms seem the same...Can
anyone shed some light on why this seems to happen often??

Carl-

As far as I know, the Band Units are the same in the TM-742A. I recently had
my Two Meter Unit to fail, but it wasn't a single transistor - it was the SAV17
Power Amplifier Module. It cost $54.95 from RFParts Company, the Kenwood parts
supplier.

It may be possible to remove the cover of the PA Module, and replace individual
components, but that was more than I wanted to tackle. I suspect that Kenwood
wouldn't do that either, since labor costs could exceed the price of a
replacement.

The 2003 RFParts catalog lists a 2SD1902 for $1.50. I don't know how that
differs from the 2SD1902R.

73, Fred, K4DII

Carl Domanico wrote:

Need Help with my Kenwood TM-741A Triband FM Mobile Radio.....I purchased
the radio new some 12 years ago, with the 220MHz. Module Installed....The
Radio Has 144 Mhz / 220Mhz / 440 Mhz.....For years the radio worked
excellent....Then about 5 years ago I had lost the out put on 144 (two
meters)... However , the other two bands functioned fine...220/440mhz... I
sent the radio back to kenwood...and they indicated that the Driver
Transistor Q23 2SD1902R on the two meter module was defective. This
transistor is an inexpensive part...$ 3.05 ea. Anyway...It seems like the
same problem occured the other day...all the symptoms seem the same...Can
anyone shed some light on why this seems to happen often?? Also is it
possible to replace this 2SD1902R transister with something capable of
handling some what more power dissapation?? What ever happened to those
motorola hep sustitutes?? Any and all info supplied here will be greatly
appreciated....

Thanks
Carl
N2MFW

Motorola dropped the HEP line at least 15 years ago. So did GE,
Workman, and several other replacement lines. ECG was recently bought by
NTE, the sole survivor of the universal semi replacement business.
http://www.nteinc.com/ has a downloadable database for finding
replacement parts. There is no cross reference for this part, but you
can check their on line parts search to see if it has recently been
added.
--
9 days!


Michael A. Terrell
Central Florida

I sent the radio back to kenwood...and they indicated that the Driver
Transistor Q23 2SD1902R on the two meter module was defective. This
transistor is an inexpensive part...$ 3.05 ea. Anyway...It seems like the
same problem occured the other day...all the symptoms seem the same...Can
anyone shed some light on why this seems to happen often??

Carl-

As far as I know, the Band Units are the same in the TM-742A. I recently had
my Two Meter Unit to fail, but it wasn't a single transistor - it was the SAV17
Power Amplifier Module. It cost $54.95 from RFParts Company, the Kenwood parts
supplier.

It may be possible to remove the cover of the PA Module, and replace individual
components, but that was more than I wanted to tackle. I suspect that Kenwood
wouldn't do that either, since labor costs could exceed the price of a
replacement.

The 2003 RFParts catalog lists a 2SD1902 for $1.50. I don't know how that
differs from the 2SD1902R.

73, Fred, K4DII