Elecraft now has an Audio Protection Assembly circuit board, Part Number E850506 for $2.36 plus shipping.
The Audio Protection Assembly replaces the 470 uF output capacitors C2 and C3 on the RF board with a series combination of a 1 Ohm resistor and 470 uF capacitor. The same thing can be accomplished by replacing L13 and L16 (surface mounted "beads") on the KIO3 Audio IO Board with the appropriate size 1 Ohm surface mount resistor (or potentially even a leaded part). The advantage t modifying the KIO3 Audio IO Board is that it is not necessary to disassemble the K3 (and remove sub R and/or 2M transverter) to gain access. Note - the bead to resistor modification is my own adaptation and not recommended by Elecraft. 73, ... Joe, W4TV On 1/14/2014 12:21 PM, Dave Hachadorian wrote:
The speaker amp is U1 on the DSP Board. The IC is an LM4950TS. The pins are very closely spaced, too close for me. Elecraft now has an Audio Protection Assembly circuit board, Part Number E850506 for $2.36 plus shipping. Dave Hachadorian, K6LL Yuma, AZ -----Original Message----- From: Stewart Sent: Tuesday, January 14, 2014 9:36 AM To: Elecraft Reflector Subject: [Elecraft] K3 - No speaker output My K3's speaker audio seems to have gone West. Audio out of the phones, but nothing out of the internal speaker. It happened when I was installing a new external speaker, a DSP Desktop speaker from BHI. Having read some recent posts about the audio chip blowing up because of using a mono plug instead of a stereo one, I made sure that I used a the correct one. Following guidance in the K3 users manual I connected the speaker to the LH channel as I want to use my headset in stereo. I also took the covers off and checked for the modification involving 470ohm resistors. That mod was in place OK. I switched the K3 and the speaker on and got audio from the speaker. However, when I advanced the AF gain on the K3 to about 12 o'clock there was a pop and no more speaker audio from the K3. I have checked the BHI speaker with another rig and it works fine, so my K3 has developed a fault. I can't believe how sensitive it is to damage in the audio output, particularly with the care I took to try and avoid this sort of thing happening.... As I am quite OK with SMD's I would appreciate advice on what to change, where to get it and how... Not a happy bunny ! 73 Stewart G3RXQ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
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