04-07-2014, 10:38 AM
OK, Mondial, thanks for the explanation. That makes sense to me now.
Now as to what to do about the malfunctioning MPX board. I was writing this post as you were posting, so thanks again - that is something I can check while I prepare a parts order (27 uF caps plus some caps for the next patient, which will be a Fisher 170 that I intend to sell once I fix it up).
I have three Fishers here (440-T, 700-T, 220-T) with malfunctioning/nonfunctioning MPX boards. I have some LM1310 ICs and could take the easy way out on the 440-T and 220-T and just build new MPX boards utilizing the LM1310 (No more coils! Only one adjustment, a trimmer pot), but since the board in the 700 serves to mute the receiver on non-stereo signals...??? I hope that 1 uF cap is the answer.
Oh, and guess what...my ECG 162 transistor order finally emerged from the black hole it had fallen into and is scheduled to be delivered today.
It left South Bend, IN on 03/31, then disappeared until it showed up yesterday in Louisville. Then it went through Evansville and was then sent here to Ferdinand. So...where were my transistors for five days? Probably went from South Bend to Louisville by way of San Francisco, Bangor, Maine and Austin, Texas. 
Now as to what to do about the malfunctioning MPX board. I was writing this post as you were posting, so thanks again - that is something I can check while I prepare a parts order (27 uF caps plus some caps for the next patient, which will be a Fisher 170 that I intend to sell once I fix it up).
I have three Fishers here (440-T, 700-T, 220-T) with malfunctioning/nonfunctioning MPX boards. I have some LM1310 ICs and could take the easy way out on the 440-T and 220-T and just build new MPX boards utilizing the LM1310 (No more coils! Only one adjustment, a trimmer pot), but since the board in the 700 serves to mute the receiver on non-stereo signals...??? I hope that 1 uF cap is the answer.
Oh, and guess what...my ECG 162 transistor order finally emerged from the black hole it had fallen into and is scheduled to be delivered today.
It left South Bend, IN on 03/31, then disappeared until it showed up yesterday in Louisville. Then it went through Evansville and was then sent here to Ferdinand. So...where were my transistors for five days? Probably went from South Bend to Louisville by way of San Francisco, Bangor, Maine and Austin, Texas.
--
Ron Ramirez
Ferdinand IN
