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Old October 29th 04, 01:45 AM
ULpilotSC
 
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Default trouble with dx-440/sangean 803a


I have a blown transistor in my sangean 803a (actually radio shack dx-440). It
is a small transistor (number Q307 on the board), on the small audio board that
connects to the batteries and the wall adapter socket. The only markings on the
transistor are 808 (across the top), and F E1 across the bottom. Tracing the
circuit paths I figured out the is a PNP transistor, and because it connects to
the NEC C1316C audio amp, I figure it is some type of AF transistor. The
problem is, I cant find a description of it anywhere, and I dont know what a
suitable substitution for it would be. If anyone has any information on what I
could use as a substitute, I would be much appreciative. I know this transistor
is the problem, because part of the back and top sectioin of it is missing (its
what happenes when you plug a dx-440 into a wall jack with the wrong polarity).
The radio clock runs, and I can change channels, etc. I just cant hear any
sound from it. Help! If you have an old blown up dx-440, I would love to have
q307.... hahahah.

-m.





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Old October 30th 04, 07:00 PM
Fred McKenzie
 
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I have a blown transistor in my sangean 803a (actually radio shack dx-440).
It
is a small transistor (number Q307 on the board), on the small audio board that
connects to the batteries and the wall adapter socket. The only markings on the
transistor are 808 (across the top), and F E1 across the bottom.

Mark-

Q307 is a 2SA695D/E, according to the Radio Shack DX-440 service manual. It is
PNP as you assumed.

Looking at the 2SA695 from the wire end with the flat (marking) side up, Base
is on the left, Collector is in the middle and Emitter is on the right.

From the manual's voltage chart for Q307:

Base 8.21 volts FM/AM/SSB+CW
Collector 8.92 volts FM/ 8.93 volts AM/ 8.92 volts SSB+CW
Emitter 8.94 volts FM/ 8.95 volts AM/ 8.94 volts SSB+CW

In case replacing just Q307 doesn't fix it, you may be ahead by replacing the
entire PCB. Such damage may have affected other parts as well. Good luck on
finding a junk unit.

73, Fred, K4DII

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Old October 30th 04, 07:00 PM
Fred McKenzie
 
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I have a blown transistor in my sangean 803a (actually radio shack dx-440).
It
is a small transistor (number Q307 on the board), on the small audio board that
connects to the batteries and the wall adapter socket. The only markings on the
transistor are 808 (across the top), and F E1 across the bottom.

Mark-

Q307 is a 2SA695D/E, according to the Radio Shack DX-440 service manual. It is
PNP as you assumed.

Looking at the 2SA695 from the wire end with the flat (marking) side up, Base
is on the left, Collector is in the middle and Emitter is on the right.

From the manual's voltage chart for Q307:

Base 8.21 volts FM/AM/SSB+CW
Collector 8.92 volts FM/ 8.93 volts AM/ 8.92 volts SSB+CW
Emitter 8.94 volts FM/ 8.95 volts AM/ 8.94 volts SSB+CW

In case replacing just Q307 doesn't fix it, you may be ahead by replacing the
entire PCB. Such damage may have affected other parts as well. Good luck on
finding a junk unit.

73, Fred, K4DII

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Old October 30th 04, 07:00 PM
Fred McKenzie
 
Posts: n/a
Default

I have a blown transistor in my sangean 803a (actually radio shack dx-440).
It
is a small transistor (number Q307 on the board), on the small audio board that
connects to the batteries and the wall adapter socket. The only markings on the
transistor are 808 (across the top), and F E1 across the bottom.

Mark-

Q307 is a 2SA695D/E, according to the Radio Shack DX-440 service manual. It is
PNP as you assumed.

Looking at the 2SA695 from the wire end with the flat (marking) side up, Base
is on the left, Collector is in the middle and Emitter is on the right.

From the manual's voltage chart for Q307:

Base 8.21 volts FM/AM/SSB+CW
Collector 8.92 volts FM/ 8.93 volts AM/ 8.92 volts SSB+CW
Emitter 8.94 volts FM/ 8.95 volts AM/ 8.94 volts SSB+CW

In case replacing just Q307 doesn't fix it, you may be ahead by replacing the
entire PCB. Such damage may have affected other parts as well. Good luck on
finding a junk unit.

73, Fred, K4DII

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Old October 31st 04, 01:29 AM
Robert Casey
 
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Default

Fred McKenzie wrote:

I have a blown transistor in my sangean 803a (actually radio shack dx-440).
It
is a small transistor (number Q307 on the board), on the small audio board that
connects to the batteries and the wall adapter socket. The only markings on the
transistor are 808 (across the top), and F E1 across the bottom.

Mark-

Q307 is a 2SA695D/E, according to the Radio Shack DX-440 service manual. It is
PNP as you assumed.

Looking at the 2SA695 from the wire end with the flat (marking) side up, Base
is on the left, Collector is in the middle and Emitter is on the right.

From the manual's voltage chart for Q307:

Base 8.21 volts FM/AM/SSB+CW
Collector 8.92 volts FM/ 8.93 volts AM/ 8.92 volts SSB+CW
Emitter 8.94 volts FM/ 8.95 volts AM/ 8.94 volts SSB+CW

In case replacing just Q307 doesn't fix it, you may be ahead by replacing the
entire PCB. Such damage may have affected other parts as well. Good luck on
finding a junk unit.

73, Fred, K4DII

Any general purpose PNP transistor should work.
Like a 2N2907.


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Old October 31st 04, 01:29 AM
Robert Casey
 
Posts: n/a
Default

Fred McKenzie wrote:

I have a blown transistor in my sangean 803a (actually radio shack dx-440).
It
is a small transistor (number Q307 on the board), on the small audio board that
connects to the batteries and the wall adapter socket. The only markings on the
transistor are 808 (across the top), and F E1 across the bottom.

Mark-

Q307 is a 2SA695D/E, according to the Radio Shack DX-440 service manual. It is
PNP as you assumed.

Looking at the 2SA695 from the wire end with the flat (marking) side up, Base
is on the left, Collector is in the middle and Emitter is on the right.

From the manual's voltage chart for Q307:

Base 8.21 volts FM/AM/SSB+CW
Collector 8.92 volts FM/ 8.93 volts AM/ 8.92 volts SSB+CW
Emitter 8.94 volts FM/ 8.95 volts AM/ 8.94 volts SSB+CW

In case replacing just Q307 doesn't fix it, you may be ahead by replacing the
entire PCB. Such damage may have affected other parts as well. Good luck on
finding a junk unit.

73, Fred, K4DII

Any general purpose PNP transistor should work.
Like a 2N2907.
  #7   Report Post  
Old October 31st 04, 01:29 AM
Robert Casey
 
Posts: n/a
Default

Fred McKenzie wrote:

I have a blown transistor in my sangean 803a (actually radio shack dx-440).
It
is a small transistor (number Q307 on the board), on the small audio board that
connects to the batteries and the wall adapter socket. The only markings on the
transistor are 808 (across the top), and F E1 across the bottom.

Mark-

Q307 is a 2SA695D/E, according to the Radio Shack DX-440 service manual. It is
PNP as you assumed.

Looking at the 2SA695 from the wire end with the flat (marking) side up, Base
is on the left, Collector is in the middle and Emitter is on the right.

From the manual's voltage chart for Q307:

Base 8.21 volts FM/AM/SSB+CW
Collector 8.92 volts FM/ 8.93 volts AM/ 8.92 volts SSB+CW
Emitter 8.94 volts FM/ 8.95 volts AM/ 8.94 volts SSB+CW

In case replacing just Q307 doesn't fix it, you may be ahead by replacing the
entire PCB. Such damage may have affected other parts as well. Good luck on
finding a junk unit.

73, Fred, K4DII

Any general purpose PNP transistor should work.
Like a 2N2907.
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