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Kenwood TM-741A
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 |
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 $1.50. I don't know how that differs from the 2SD1902R. 73, Fred, K4DII |
I sent the radio back to kenwood...and they indicated that the Driver
Transistor Q23 2SD1902R on the two meter module was defective. This transistor is an inexpensive part...$ 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 |
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