Had TX on all bands apart from 22 to 28 on a ICOM 735, turned out to be a relay which was replaced. Then removed the PA board to check for dry joints and then refitted and now have no TX on any bands. Receive is good throughout. What could have coursed this? Many thanks....
I have the Icom 7200. The power cord has dual blade fuses. Over time the fuse blades oxidise and the power drops off. Clean the blades on the fuses and power restored
Mr. Malik, I have a device with you, Icom 746 Pro. Youssef, I have a 746 Pro device. It has 100% reception and transmission, but it does not give a power reading in wattage. It is very low. Are there any patients? How can it be repaired? What is the faulty part? A picture so that I can complete it. Thank you very much.
Thanks Larry. That negative side fuse may be some extra protection in a mobile set up under some specific failures, but, you’re right, in this situation it is probably just adding some resistance to my supply lines. Oddly, I have a Kenwood mobile in my truck and it only has the positive lead fused. Hmmmm.
@@timtimeprojects3576 If that fuse blows the antenna jack ground foil opens, that causes many other issues. I've seen it happen many many times. I always cut them off in my installs, so I would not have to fix foil paths later. That fuse is only good in a positive ground situation. And then red lead fuse should be removed. Just a friendly tip from a 2 way radio repair guy. Good trouble shooting BTW.
2 things... 1) You need to tx longer..... This is how I found the power issue on my Ic706. The fuse holders were at fault on my power cord. 2) You never addressed the improper voltage reading on the Q2. I can understand that the voltage coming into the radio was dropping, but that shouldn't have produced the higher voltage on q2. I'm about to take on a radio with a similar issue, and thanks to your video.. the power cord will be the first item under test.
I meant to get back to the Q2 voltage but forgot to mention that the bias resistors did not match what was on the schematic so, I chalked it up to that. Maybe a factor fix for something. Looked to be original. As for the power cord, I plan on making a new one like the Kenwood design. Two sets of #14 wire that go in to each fuse. Also, don’t forget to look at your DC distribution center if you have a connection for multiple radios. Good luck and thanks for the input.
I keep scratching my head about the DC voltages for Q2,Q3 and Q4. I found a schematic online from Russia maybe, that shows the center tap transformer between those two stages feeds 8 volt to Q3 and Q4 not to Q2. That makes more sense. I haven’t had a chance to vet that yet tho. I’ll dig around some more.
