Collins R-648/ARR-41

 

June 8, 2025 - Ordered a  5749 tube - one of the RF-AMPs showed questionable.

June 1, 2025 - Yesterday I finished testing the tubes - found two that were weak and one that needed replacing (it had a short).  I ordered those on eBay,

Today I took the cabinet out and painted it with the wrinkle coat - it looks good and the next step is to put it in the oven at 200 degrees for one hour.

May 29, 2025 - I hear voices!!!  Late yesterday I hooked up an antenna and was able to hear some conversations on 80M and today heard some more on 40M.

May 28, 2025 - SUCCESS TODAY - Yesterday I was having issues with the radio blowing fuses - I finally took all the modules out and on power up every other time with all the modules out the fuse would blow.  I was sure the issue was in the switch which had been replaced by a previous owner - turned the switch on with the power supply off and it worked fine - turned power supply off/on and tested again - blew fuse.  

The radio calls for a 5-amp fuse and I was using a 4-amp fuse as that was all I had except a 8-amp fuse.  Tried the 8-amp fuse and tested on/off multiple times and no issues - yesterday did order the correct 5-amp fuses and a new switch - I'll try tho new 5-amp fuses when they arrive.  I put all the modules back in and powered her up with headphones connected - lot's of normal normal radio static - tomorrow I will hook my signal generator up and see how it performs.

May 26, 2025 - Finished rebuilding the power supply - only a few components remained from the original (two resistors, the tube socket and the frame with plug) when I started and I luckily found a original dynamotor.  All voltages look good - now to look at the R-648. and be sure no wiring under the chassis was modified around the power supply plug.

Below is what I started with.

May 25, 2025 - Working on rebuilding the power supply.

March 31, 2025 - Fixed the power wiring on the front panel - now getting 27.5v over to the power supply module's plug.

March 30, 2025 - Test fitted the power supply module and looked at power connections and built up the power cable.  On the front panel I found several of the power lines disconnected.

March 29, 2025 - Here's the connector on the bottom of the power supply module.

March 28, 2025 - Started building up the dynamotor power supply - i had to purchase the 1H choke and the dynamotor - got them mounted.  Still missing some other parts.

March 26, 2025 - More cleaning and put a black rubber plug in the hole on right side near headphone jack - she's cleaned up real nice.  Also checked out the dynamotor - Red is 250v positive and black is 250v negative and white is 28V positive and blue is 28v negative.

March 22, 2025 - More cleaning - this time with Simple Green - looking better but still needs some more work.  Ordered a dynamotor for it off of eBay and a 1H choke from Mouser, but will need to acquire a few more parts to get the power supply working.

March 21, 2025 - It arrived and looks great inside but unfortunately the dynamotor is missing.  I picked up the power connecter last weekend at the Sevierville Hamfest.

March 18, 2025 - Picked this Collins R-648/ARR-41 up on eBay over the weekend - it should arrive on Thursday.  Hopefully I can bring it back to life - it's basically an airborne R-390.