question about 2SC2509 RF driver
 

Can someone please check something for me on a 2SC2509 transistor if
you've got one lying around? This is the RF driver used in the Kenwood
TS-120/130 and probably others. I'm repairing one of these PA assemblies
and trying to determine if the two transistors I've got are good or not.

Using the diode-check function of a digital multimeter, all the
junctions test OK except for one oddity: there's conduction with the +
probe on the emitter and the - probe on the collector (and base
open-circuit). Can someone tell me if a new, unused part exhibits this?

I would normally consider it a bad sign, except:
- All the other junctions show the normal expected operation.
- DC beta checks OK (around 65) with a Heathkit transistor tester.
- Both parts test exactly the same. (unlikely if they're damaged.)
- Seems I've heard somewhere that this type of transistor with the
emitter connected to the mounting tab (as oppposed to the collector)
required an extra metallization layer which might account for the
emitter to collector conduction described above.

Would appreciate any help with this. Reply either to the newsgroup or to
K9LY at arrl dot net

Tnx & 73,
Joe

"Joe LeKostaj" wrote in message
...
Can someone please check something for me on a 2SC2509 transistor if
you've got one lying around? This is the RF driver used in the Kenwood
TS-120/130 and probably others. I'm repairing one of these PA assemblies
and trying to determine if the two transistors I've got are good or not.

The 2SC2509 is popular bipolar RF transistor used as a driver transistor for
amatuer transceivers
(Kenwood TS-440) OR as the final transistor for low power (Yaesu FT70) and
CB transceiver usage.
http://www.cbsite.nl/modif/onderdelen/power.htm

13 watt output, 14 dB gain, freq to 30 MHz, 12 volts and
TO-220 package [B,E,C layout]

Helge Granberg's AN779 Application Notes shoudl be helpful (MRF475
referenced close X-Ref)
http://e-www.motorola.com/brdata/PDF...otes/AN779.pdf

w9gb
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Only reply through ARRL forwarding service to W9GB


Using the diode-check function of a digital multimeter, all the
junctions test OK except for one oddity: there's conduction with the +
probe on the emitter and the - probe on the collector (and base
open-circuit). Can someone tell me if a new, unused part exhibits this?

I would normally consider it a bad sign, except:
- All the other junctions show the normal expected operation.
- DC beta checks OK (around 65) with a Heathkit transistor tester.
- Both parts test exactly the same. (unlikely if they're damaged.)
- Seems I've heard somewhere that this type of transistor with the
emitter connected to the mounting tab (as oppposed to the collector)
required an extra metallization layer which might account for the
emitter to collector conduction described above.

--
Do not use Reply (spam logger & catcher).
Reply only through ARRL forwarding service to W9GB

"Joe LeKostaj" wrote in message
...
Can someone please check something for me on a 2SC2509 transistor if
you've got one lying around? This is the RF driver used in the Kenwood
TS-120/130 and probably others. I'm repairing one of these PA assemblies
and trying to determine if the two transistors I've got are good or not.

The 2SC2509 is popular bipolar RF transistor used as a driver transistor for
amatuer transceivers
(Kenwood TS-440) OR as the final transistor for low power (Yaesu FT70) and
CB transceiver usage.
http://www.cbsite.nl/modif/onderdelen/power.htm

13 watt output, 14 dB gain, freq to 30 MHz, 12 volts and
TO-220 package [B,E,C layout]

Helge Granberg's AN779 Application Notes shoudl be helpful (MRF475
referenced close X-Ref)
http://e-www.motorola.com/brdata/PDF...otes/AN779.pdf

w9gb
---
DO NOT use Reply.
Only reply through ARRL forwarding service to W9GB


Using the diode-check function of a digital multimeter, all the
junctions test OK except for one oddity: there's conduction with the +
probe on the emitter and the - probe on the collector (and base
open-circuit). Can someone tell me if a new, unused part exhibits this?

I would normally consider it a bad sign, except:
- All the other junctions show the normal expected operation.
- DC beta checks OK (around 65) with a Heathkit transistor tester.
- Both parts test exactly the same. (unlikely if they're damaged.)
- Seems I've heard somewhere that this type of transistor with the
emitter connected to the mounting tab (as oppposed to the collector)
required an extra metallization layer which might account for the
emitter to collector conduction described above.

--
Do not use Reply (spam logger & catcher).
Reply only through ARRL forwarding service to W9GB