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The PLL is locking on channel and receives signal from my generator on every channel. So far I have replaced TA7222P, MB3786, TR31, TR33, TR35, D60, Tr24. All Transistors are switching but not getting power thru the SO42P for the 8 volts it needs to kick into tx mode. Tr42 is switching also, I...

One thing I did find on the TA7222p on the voltage from the purple wire and the white wire to the chip is there is no voltage to it there at all. The purple leads out to the mic plug.

I also did notice on pins 7&8 are reading 0v on the ta7222p, on my other Cobra they are reading about 14v. I'm thinking the problem might be right in that general spot off the regulator...I hope. On the mb8735 ic 1 the 8v feed on the schematic coming out of the PLL comes from pin 6 at 8.09vdown...

I have no voltages to IC5 of 8.0 volts, no voltages to vr5 and to the clarifier, There are voltages missing all over the board, I can't understand what is going on here, makes no sence. pin 8 on the IC1 has 6.08 volt it is a bit low but the PLL must be good.

Also tone will come thru the Pa section.

I plug into the PA and it is giving me static now, but when I key mic nothing period but static. keying up has no effect on it what so ever. Tried another microphone same issue. Also regular speaker is putting out static. Put a tone thru generator and it will receive down to -50 dbm at 400HZ...

Ok I put the TA7222p in and the MB3756 into the board with new IC chips.. Voltages are as follows for MB3756, front of radio to back on pins 1. .47v 2. 0v 3. 8.38v 4. 13.53v 5. 0v 6. 8.37v 7. 13.53v 8. 8.34v TA7222P 1. 13.53v 2. 6.52v 3. 0v 4. 0v 5. 1.18v 6...

Will do. Dropped the TA7222P in this morning, didn't even plug it in, will wait for the MB3756 to show and get it in and see what she got. I had my hints that that chip was bad when I pulled it out of the other old parts radio I have here. I got to much of this junk laying around and got to get...

I pulled some voltages off of the IC4 MB3756 and the TA7222P IC6. IC4 MB3756 as follows front of radio to back. 1. .12v 2. 0v 3. 3.07v 4. 5.00v 5. .37v 6. 2.90v 7. 5.17v 8. 2.75v TA7222P as follows front of radio to back. 1. 5.20v 2. 2.04v 3...

Also the VR5 has not bearing what so ever on adjustment it is a definate voltage problem, just not sure of where. covers a lot of ground for sure.

Ok sounds good, I ordered new TA7222P for it and should be here tomorrow, I also Oreded the MB3756 but it wont be here till later this week. The original order they have not sent it or can't find it, I ordered another one tonight for it.

Another thing I did happen to notice is when receiving I turn the clarifier and it has no effect on the receive....

Yep the wiring is correct on the phone plug and mic plugs. The brown wire turned out to be black. I had to trace it. back. But it was a replacement wire.

I am missing the brown wire here some how. I might have to open up my other cobra 2000 gtl to locate this one. I don't know how I missed this...

Also I forgot to mention that TR24 was removed from the board, I replaced it with a new one already. I checked out TR26 and R131 they are fine. These are usually one of the first things I look for. I think this 93 board had some mods done but I can't put my finger on anything so far.

I picked that phone plug and all of the other switches from ebay at a reasonable price, They have come in handy here more than once already.

What is a real shame of all of this, the original radio board all it needed was a set of finals.

Replaced TR35 and still nothing.

Will do!

The original board had mods done to it and they took the phone plug out and put in a channel switch, which I see is a very common thing with these radios, I just about cry when I see this kind of thing done to these radios. I like to restore them back to original.