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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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11th May 2021, 12:47 pm | #1 |
Diode
Join Date: Oct 2020
Location: Guildford, Surrey, UK.
Posts: 6
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Trio 9R-59DS
Hi,
Guys, I need some help here! I have just acquired a Trio 9R-59DS. On testing I found that MW AM was loud and clear. With a little teaking I got some volume from the shortwave bands on AM. However, on the amateur bands (USB or LSB) there is hardly any volume at all. I have tweaked the IF coils on the top of the chassis for max signal strength. That's where I've got to. Is there anyone out there that knows this rig that can suggest the next steps I should try? Best regards, Malcolm G4TJK Last edited by paulsherwin; 11th May 2021 at 1:03 pm. Reason: To comply with forum rules |
11th May 2021, 5:06 pm | #2 |
Heptode
Join Date: Jan 2011
Location: Croydon, London, UK.
Posts: 773
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Re: Trio 9R-59DS
Hello Malcolm,
Assuming this is a fault and not just down to band conditions/aerial, a good place to start would be to check the voltages around the product detector valve (V6). The circuit diagram has them marked as: Cathode (pin 2) 2.7V Anode (pin 5) 150V Screen (pin 6) 64V. Any that are a long way off would suggest a component fault in that area. Paula |
12th May 2021, 9:19 pm | #3 |
Heptode
Join Date: Jan 2008
Location: Ashhurst, Manawatu, New Zealand
Posts: 570
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Re: Trio 9R-59DS
https://www.manualslib.com/manual/12...o-9r-59de.html
Click on "Download" at the top of the page and pass the "I'm not a robot" test! Hope it was only the IF transformer cores that you tweaked.
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22nd May 2021, 4:43 am | #4 |
Diode
Join Date: Oct 2020
Location: Guildford, Surrey, UK.
Posts: 6
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Re: Trio 9R-59DS
OK. An update.
I have completed the alignment process as per the Service Manual. Here is the situation now (starting with the IF): - AM Reception is good, generally, although I notice that I lose signals on low frequencies of the bands - Band C, in particular. (Using my FT-991A to detect the LO I can see that the output level drops to zero as frequency is decreased. In the case of Band C, I suspect capacitor C103, 4000pF. Will investigate further. - After working on the BFO I can receive and resolve sideband signals, but the audio volume level is VERY low. Has anyone else seen these problems? Best regards, Malcolm G4TJK |
22nd May 2021, 10:03 am | #5 |
Nonode
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 2,015
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Re: Trio 9R-59DS
Isn't this set a known one where degradation of the wax on the coils is responsible for lower Q and Osc stopping problems? Search this forum for "Q Killer wax" and several threads come up.
I would investigate that before suspecting capacitors which were generally well made parts in those sets as far as I recall. |
22nd May 2021, 10:23 am | #6 |
Dekatron
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,761
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Re: Trio 9R-59DS
This earlier forum thread might be of interest and help:
https://www.vintage-radio.net/forum/...d.php?t=114061 A bit clearer copy of the manual here: https://www.pa3esy.nl/ontvangers/9R5...0Schematic.pdf
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22nd May 2021, 12:50 pm | #7 |
Tetrode
Join Date: Jan 2008
Location: Shetland, UK.
Posts: 79
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Re: Trio 9R-59DS
A few years ago I was given a Trio 9R59DS and the same problem with copying ssb stations. Fortunately I had in the radio room at the time an unused Codar PR30 RF Preselector, with this unit connected to the Trio the problem was instantly resolved with ssb signals with plenty of gain. I suppose that was the easy option and I am still using the rx with the preselector.
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23rd May 2021, 9:07 pm | #8 |
Heptode
Join Date: Dec 2003
Location: South Yorkshire, UK.
Posts: 900
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Re: Trio 9R-59DS
I think the wax going bad is probably overstated. The mica capacitors in these sets are very troubling but often start working when heated. I think that’s why people talk about melting the wax makes a repair it’s actually the heat. These sets are stunning performance by today’s standards. The main thing they had in there favour was the price new
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24th May 2021, 4:45 pm | #9 |
Diode
Join Date: Oct 2020
Location: Guildford, Surrey, UK.
Posts: 6
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Re: Trio 9R-59DS
Chris,
Thanks for ypour videos on the 9R-59DS, very entertaining AND instructive. I've watched them all carefully and tried to copy your approach. Heating the tuning circuitry associated with Band C fixed the problem of zero reception at the low-frequency end of the band. AM recption is fine, but I am still trying to fix the issue of very low audio (volume) with SSB signals. I've ordered a couple of replacement valves associated with the BFO/SSB side. Fingers crossed they make a difference. I have not changed any caps. Any thoughts? Best regards, Malcolm G4TJK |
25th May 2021, 8:49 am | #10 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,288
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Re: Trio 9R-59DS
I certainly found electrically leaky electrolytic capacitors in my set and I'm not talking about the smoothers. Cathode bypass IIRC.
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25th May 2021, 9:43 am | #11 |
Heptode
Join Date: Dec 2003
Location: South Yorkshire, UK.
Posts: 900
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Re: Trio 9R-59DS
Again a lot of the capacitors in the metal cans are paper and all the ones I changed on my 9R were found to be very leaky although the capacitor value remains good. Good luck
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28th May 2021, 10:44 am | #12 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,288
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Re: Trio 9R-59DS
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