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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 12th Jun 2022, 12:22 pm   #1
leonardsmith
Diode
 
Join Date: Jun 2022
Location: Stockholm, Sweden.
Posts: 1
Default Trio 9r-59 issues

Hi,

A couple of years ago I bought a Trio 9r-59 (the original, not D or DS or whatever) that I have used for receiving every once in a while. Last week i bought a GA-450 active loop antenna to use with the receiver. Yesterday I opened the Trio chassi for the first time. Now, to my issues

1.One of the caps connected to the transformator is blown to hell. It's a 0.01 μf cap with 600 WV according to the text on the cap, see picture. I know of course that there are a few 0.01 μf caps out there, but what type should I get? Ceramic? Electrolytic? I can't make out the type myself.

2.Since there is some hum from the power grid in the speaker/headphones I am considering also changing the power cap connected to the transformator. However the can reads "40-40 MF". What am I to make of this, it couldn't possibly be megafarad? Could it be milli? Or micro? Also any suggestions where I could find a replacement would be greatly appreciated. See picture for the appearance of the cap.

3.The loop antenna is not working quite as I had hoped. Maybe this is boecause of the blown cap - I don't know - or maybe some other reason? It was delivered with a bnc cable, however the Trio has banana plugs. I bought an adapter and plugged the feeder into Antenna terminal 1 (there are two on this model, A2 is shorted to ground per instructions from the manual when using random wire antenna) and antenna ground to receiver ground. However, when I use it I experience what I can only describe as "grounding error". If I touch the antenna ring, box or trim knob there is immediate response in the reception, which will suddenly get better, or sometimes there will be a lot of noise and distrubances in the output. The antenna seems to work best if it is aligned horizontally, parallel to the floor, rather than standing upright, which seems not quite right to me. Could this issue be related to the blown cap, or something else? Any suggestions would be greatly appreciated.

Many thanks in advance. As some of you probably notice from my writing, I am quite inexperienced in this area.
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Old 12th Jun 2022, 7:42 pm   #2
Silicon
Nonode
 
Join Date: Jun 2007
Location: Coulsdon, London, UK.
Posts: 2,152
Default Re: Trio 9r-59 issues

The 'silver' can has two 40 micro Farad Electrolytic capacitors inside.

The modern equivalent would be 47 + 47 uF 300V DC electrolytic capacitor.
A higher voltage (i.e. 400V ) would be OK and possibly easier to obtain.

The 0.01 uF capacitor with a 'Working Voltage' of 600V may have been a paper capacitor.

If it was across the mains, you should fit a Class X Safety Capacitor.
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Old 15th Jun 2022, 10:11 pm   #3
roadster541
Pentode
 
Join Date: Feb 2020
Location: Camborne, Cornwall, UK.
Posts: 124
Default Re: Trio 9r-59 issues

Leonard,
I had a look inside my 9R-59DS, your blown capacitor is in parallel with one of the rectifier diodes. I would replace it and the other, in parallel with the other diode, with polypropylene, something like these:
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Old 15th Jun 2022, 11:05 pm   #4
deswradio
Tetrode
 
Join Date: Sep 2020
Location: Lewes, East Sussex, UK.
Posts: 66
Default Re: Trio 9r-59 issues

That blown 0.01uF capacitor is a paper capacitor and is either C43 or C44 - I'd strongly suggest replacing all the paper capacitors in the radio (they are now quite old!). I've recently done a capacitor refurbishment on my 9r59de (all the electrolytics and paper) and it now feels a lot less fragile!

Best wishes

Des
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