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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. |
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 |
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 |
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 |
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. |
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. |
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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