Icom: Icom ic-751a

[ch62]

Just picked one up. Don’t have an antenna up yet so all I can confirm is it powers up. I opened it and it still has the original memory board. I purchased the upgrade from Piexx and it should be here by the weekend. Instructions to make the replacement look pretty straightforward....remove screw, pull old board out, press new board in, put in the screw and should be goo to go. Is there anything special that I’m missing or anything I need to be careful of so I don’t brick the radio?

Thanks.

Carl

 

[k6cpo]

Just picked one up. Don’t have an antenna up yet so all I can confirm is it powers up. I opened it and it still has the original memory board. I purchased the upgrade from Piexx and it should be here by the weekend. Instructions to make the replacement look pretty straightforward....remove screw, pull old board out, press new board in, put in the screw and should be goo to go. Is there anything special that I’m missing or anything I need to be careful of so I don’t brick the radio?

Thanks.

Carl

I borrowed an IC-751A from a friend (I later bought it from him) and replaced the memory board right after he loaned it to me. The replacement was just as you said above and went perfectly. As long as you carefully follow the instructions, you should be fine.

 

[ch62]

I borrowed an IC-751A from a friend (I later bought it from him) and replaced the memory board right after he loaned it to me. The replacement was just as you said above and went perfectly. As long as you carefully follow the instructions, you should be fine.

Thanks for the reply. It powered up, so I’m asumming the battery in it now is still good. I’m interested to see what it’s reading when I put a meter to it. The SN is 10003. Not sure if this can tell me when it was built.

I was able to find a 2KL w/power supply and AT500. It’s on the way in a big brown truck it should be here next week. The radio came with an uninstalled PS35 that appears it has never been used. I’ve been looking for an external supply and found a PS15, but not a PS30. At this point I’m thinking of giving the PS35 a try, after I get the memory installed. I don’t see me doing any CW work. Is the anything else I should be thinking about?

 

[k6cpo]

If I had the PS35, I'd probably use it, but the radio can be powered from any decent power supply that supplies 13.8V. I use an Alinco DM-330MV through a RigRunner 4008 to power my entire station (two mobiles, the 751A, autotuner and a timewave ANC-4 noise reducer.) My Heathkit SB-102 is powered separately. The manual warns about exceeding 15V on the power supply, so be careful.

I'm getting my 751A set up for CW, but I have a major hurdle to overcome. I have to learn the code first...

One problem I encountered was a broken solder joint on a circuit board on the lead from the antenna connector to the board. It was causing problems with receive and transmit. Once I found the broken joint and resoldered it, the radio is working like new.

 

[ch62]

Icom IC 751a

Hi. I recently purchased a 751a. The radio powered up and received signal. I did not attempt to transmit. The SN is 10001. The original memory was still functional. Based on other pictures, it appears to be an original board. There was no data stored that I need.

I decided to pull the board and replace it with the Piexx board with replaceable battery. When I pulled the old board I noticed that one of the pins on the 8pin section is missing. I believe it is the third pin. Is this pin intentional removed or has this been damaged by a previous owner? I replaced the board with the Piexx and it powers up and receives signal.

Thank for th help in advance.

 

[FKimble]

Don't know about that radio, but it's not uncommon to see connectors that don't use all the pins. Look for a pin pushed out the back or for a wire nearby with a pin or broken pin attached. If nothing is found then most likely the radio didn't need all the available pins/slots in the connector.

Frank KK4YTM

 

[ch62]

Thanks for the reply Frank. I checked the old connector, and no pins were stuck in it. Also found a picture of a logic board that is for sale on EBay and it is missing pin 3 so I feel good. Interestingly, when I put a meter to the battery that is soldered on the old memory board I still get 3.01v. Pretty amazing for a battery that is probably offer 20 years old. Guessing they don’t make them lik that anymore......

Carl

 

[ipfd320]

I Also have the 751a--great old radio---here is the service manual on pdf--------

http://www.qsl.net/ash_ares/IC-751A ser.pdf

 

[ch62]

Thanks for this. Great reference material.

 

[902]

My primary ham HF radio is still an IC-751A. It was the second one I got - the first one had a problem and the dealer exchanged it for me. I did the Piexx mod and it went fine. I was afraid to lose the memory, but in 33 years and 3 QTHs, this radio never really failed. I've used it for ham and MARS, both, even took it out to the field and to several contests.

The nice thing about this radio is that you can use the jacks in the back of it to connect to a Down East Microwave transverter and have a 6 or 2 meter, or 222 or 432 MHz SSB/CW radio. You can even do higher bands and get into serious weak signal work. I have one 6 and one 2 meter transverter and I've made all sorts of VHF DX contacts with them. You set the 751A on 10 meters, make some minor configuration changes and you're good to go. I built a minibox with relays to do all of the switching back in the mid-90s, but that was a major move ago and it's probably in a box in the garage.

One of the problems I ran into was some grounding problem on the PA module in the back of the radio. It prevented my Bencher paddles from working. It's not too hard to trace down. Mine was due to corrosion that I subsequently repaired.

Good luck with it - I think you'll love it!

 

[k6cpo]

Just picked one up. Don’t have an antenna up yet so all I can confirm is it powers up. I opened it and it still has the original memory board. I purchased the upgrade from Piexx and it should be here by the weekend. Instructions to make the replacement look pretty straightforward....remove screw, pull old board out, press new board in, put in the screw and should be goo to go. Is there anything special that I’m missing or anything I need to be careful of so I don’t brick the radio?

Thanks.

Carl

My primary ham HF radio is still an IC-751A. It was the second one I got - the first one had a problem and the dealer exchanged it for me. I did the Piexx mod and it went fine. I was afraid to lose the memory, but in 33 years and 3 QTHs, this radio never really failed. I've used it for ham and MARS, both, even took it out to the field and to several contests.

The nice thing about this radio is that you can use the jacks in the back of it to connect to a Down East Microwave transverter and have a 6 or 2 meter, or 222 or 432 MHz SSB/CW radio. You can even do higher bands and get into serious weak signal work. I have one 6 and one 2 meter transverter and I've made all sorts of VHF DX contacts with them. You set the 751A on 10 meters, make some minor configuration changes and you're good to go. I built a minibox with relays to do all of the switching back in the mid-90s, but that was a major move ago and it's probably in a box in the garage.

One of the problems I ran into was some grounding problem on the PA module in the back of the radio. It prevented my Bencher paddles from working. It's not too hard to trace down. Mine was due to corrosion that I subsequently repaired.

Good luck with it - I think you'll love it!

I've got a Bencher paddle and a straight key hooked up to mine through a little switch box I made. Now all I have to do is learn the code...