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#1
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ICOM IC-229H Schematic
Does anyone have a source for a PDF of the ICOM IC-229H transceiver
schematic? The ICOM site no longer has this on ther site and I can't find my maintenance manual (if I ever had one). What I need to know is if there is a bias resistor feeding some positive voltage to the mike audio pin (pin 1) of the microphone connector. WTIA -- 73 de K2ASP - Phil Kane |
#2
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ICOM IC-229H Schematic
In article . net,
Phil Kane wrote: Does anyone have a source for a PDF of the ICOM IC-229H transceiver schematic? The ICOM site no longer has this on ther site and I can't find my maintenance manual (if I ever had one). A quick Google on IC-229 turned up http://members.tripod.com/~Malzev/cb-funk/ic-229.htm and there's a PDF scan of the schematic. What I need to know is if there is a bias resistor feeding some positive voltage to the mike audio pin (pin 1) of the microphone connector. It looks so, based on the schematic cited above. From an 8-volt supply there is a 100-ohm decoupling resistor, followed by some electrolytic and other power-supply bypassing to ground. From this bypassed supply voltage, a 1k resistor R7 is connected to the MIC line. This same junction then goes through a DC-blocking cap C135 and thence to the source of a JFET Q2. So, I think you'll find roughly 8 volts DC sitting on pin 1, when measured with reference to the microphone ground-return MICE on pin 7. Short-circuit current to ground would be approx 8 mA. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#3
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ICOM IC-229H Schematic
On Wed, 15 Mar 2006 01:02:08 -0000, Dave Platt wrote:
A quick Google on IC-229 turned up http://members.tripod.com/~Malzev/cb-funk/ic-229.htm and there's a PDF scan of the schematic. So, I think you'll find roughly 8 volts DC sitting on pin 1, when measured with reference to the microphone ground-return MICE on pin 7. Short-circuit current to ground would be approx 8 mA. THat's what I needed, Dave. I will be using the IC-229H microhone with another radio (Elecraft K2) and I needed to make sure that a bias resistor was needed, Many thanks. -- 73 de K2ASP - Phil Kane From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon |
#4
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ICOM IC-229H Schematic
Don't forget to check the mods.dk site:
http://www.mods.dk/view.php?ListManuals=icom 73, Steve, K,9.D;C'I "Dave Platt" wrote in message ... In article . net, Phil Kane wrote: Does anyone have a source for a PDF of the ICOM IC-229H transceiver schematic? The ICOM site no longer has this on ther site and I can't find my maintenance manual (if I ever had one). A quick Google on IC-229 turned up http://members.tripod.com/~Malzev/cb-funk/ic-229.htm and there's a PDF scan of the schematic. What I need to know is if there is a bias resistor feeding some positive voltage to the mike audio pin (pin 1) of the microphone connector. It looks so, based on the schematic cited above. From an 8-volt supply there is a 100-ohm decoupling resistor, followed by some electrolytic and other power-supply bypassing to ground. From this bypassed supply voltage, a 1k resistor R7 is connected to the MIC line. This same junction then goes through a DC-blocking cap C135 and thence to the source of a JFET Q2. So, I think you'll find roughly 8 volts DC sitting on pin 1, when measured with reference to the microphone ground-return MICE on pin 7. Short-circuit current to ground would be approx 8 mA. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
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