One of my blog readers informed me regarding the Astron linear power supply that the outer case on the pass transistors at the rear of the supply are live with about 24 volts. These pass transistors are isolated from the case and the heat sink so the potential is there to inadvertently via a PL259 connector, USB cable or any other conducting item at the rear of your setup to short the pass transistor and destroy them. This morning I once again was searching the internet to see if anyone had devised a solution for this very issue. I came across a web page . This individual has the RS-35A power supply and came up with a great solution using a 3D printer. Now I am not at all up on the whole 3D printer thing but click on the link above (web page) and have a look at the pictures they posted. The covers look great and are very professional looking. It would look to me the plans are available to those who have access to a 3D printer to produce the guards them self. I would really like a set of these for my RS-25 but just short on the 3D printer part of things.
To my fellow bloggers have a look at the above link and do post any 3D printer info you may have as well.
As a side note below are some links to great information regarding Astron power supplies.
|Repaired and working|
|Negative to case ground|
I found this great site online regarding Astron power supply trouble shooting and repairs. This document really helped me with the trouble shooting and eventual repair of the power supply. There was another online article I came across regarding how Astron now and then has the negative terminal grounded to the case of the supply.
|New bridge rectifier|
With the new bridge rectifier installed and wires re-soldered, the pass transistors back in place and finally I did remove one connection of the Varistor to test it (tested ok) I had to also re-solder that back on as well. It was now time for the smoke test.......and I was pleased that no smoke was found and the power supply is now working without issue. I did connect it to the Icom 7610, adjusted the power to 50 watts and the power supply successfully passed the load test as well. This power supply is under sized for the Icom 7610, I now have a new Astron power supply that is sized correctly. I am now wondering if I should keep this supply or sell it?
|Passed load test|
|No lack of action|
Band QSOs Pts ZN Cty
7 6 18 3 5 3.0
14 10 29 6 10 2.9
21 2 5 2 2 2.5
Total 18 52 11 17 2.9
I found Sunday to be a tough one my signal was just not being heard and I am guessing it was just the propagation? The few times I was on the radio on Saturday I had no issues making contacts. Some of the bonus things here at VE9KK were:
- The new Astron power supply worked just fine.
- I was able to work Europe on 40m which never happened at the old QTH with the MFJ 1788 antenna.
- Speaking of antennas it was a joy to use the End fed antenna, I was able to change bands without returning. The
magloopI used for so long had to be re-tuned on the same band and for sure on band changes.
- On Saturday (when I was on) I was able to get into Europe, Central America and South America without issue.
During my time on Sunday during the contest I was greeted with an on screen message that N1MM+ stopped working as it was not able to communicate with com3. Com3 is my CAT control for the Icom 7610 and in a nutshell, this meant I was having RFI issues with one or more of my USB cables. I thought I had solved this issue already with snap on chokes?? I had a fast glance at the snap on chokes an noticed some had "un-snapped". I shut things down and spent well over an hour to fix the situation once and for all!! More on that later this week in another post. I restarted the rig and software and did a few tests and I was good to go, but the bands did not seem to want to co-operate. Having said that the bands sure were alive with opportunity. I heard nothing from the south pacific or Asia. Overall, I had a great time while in the chair at the radio and am looking forward to other CW contests.
1. I am recently retired and I was told you would slowly forget what day of the week it was, well that has not happened as of yet. I can say that with regards to ham radio contesting this retiree has mixed up what contest was on what weekend! In my last post, I had the idea of the CQWW CW contest was on this past weekend and in fact, thanks to my fellow bloggers I was informed it is next weekend. When I went back to the ham radio contest calendar site it sure was plain as day that in fact, it is next weekend. This is a good thing because my new Astron power supply will be here and I will be good to go
2. In my last post, I indicated the
|Pass transistor testing|
Now the power supply troubleshooting is done and I have to thankfully replace only one component and again the failure of the power supply is my own fault. The power supply is an Astron RS 20M and it is rated at 16 amps continuous, this has been just fine when I was operating QRP at my previous QTH. As my readers know I am now retired and have moved to New Brunswick and my new antenna is an
Back to the final power supply troubleshooting, I checked the 2 pass transistors and they both passed. I then checked the balancing resistors connected to the emitter of each pass transistor and they were both good. There were some capacitors that I also checked and they too passed. It seems that the only component I need is a bridge rectifier along with a tube of dielectric paste for the pass transistors and a new bridge rectifier. I am very happy the repairs are minor to the power supply.
|Positive test results|
|Dusty but looks ok|
and turned on the power supply hoping for the best and the best did not happen, the power supply did not turn on and I found this new fuse had blown as well. One thing was for sure and that is the CW Worldwide CW contest was over. My thoughts were on the power supply and getting the cover off to see if anything was obvious as to what the issue was that I forgot about my Icom 7610. It was about an hour later it occurred to me......"did my 7610 suffer any damage?" Since my power supply was out of service I had to come up with another way to power up the 7610. I decided to use the battery that is used with my Elecraft KX3 for outdoor op's. I connected it up and pressed the 7610 power button and NOTHING happened!! I just felt sick at this time, my brand new Icom 7610 also took the hit as well? I was thinking about checking the Icom 7610 inline fuses to see if they saved my rig by taking the fault? I decided to take a break and do some thinking and I was glad I did. On my return to the radio room, I decided to check the battery voltage and low and behold it was at 10 volts and the Icom needs 12.7 volts DC to power on. I charged the battery ( that was the longest hour ever!!) and tried again and thank goodness the Icom powered on. It was now time to get back and troubleshoot the Astron power supply. It was now time to see if there was any visible damage to the internals of the power supply?
I was not able to see anything in the power supply with a visual check. Checking the schematic diagram I checked out the power on switch and it was good, next