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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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19th May 2018, 2:53 pm | #1 |
Diode
Join Date: Feb 2007
Location: Canterbury, Kent, UK.
Posts: 3
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R1155 Hetrodyne box problem and distorted audio --- Help!
Anyone got any ideas on solving this?
My R1155 was working OK until recently, but now when I switch on the Heterodyne Oscillator, it kills the HT power supply. The resistance between the Heterodyne Oscillator unit HT+ and chassis is now only 800 Ohms (when it should be 27k+ if I'm reading the circuit correctly). There is definitely no fault in the HT+ wiring to the box - so I need to get inside the heterodyne oscillator box to find out what's going on. Anyone know how to get in to it? the external wiring to the box is pretty fragile. Also, I have another R1155 which works OK for an hour or so, then the audio gradually goes really horribly distorted. Any help appreciated. Allen |
19th May 2018, 3:02 pm | #2 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,289
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Re: R1155 Hetrodyne box problem and distorted audio --- Help!
Did you manage to sort out your Sailor Transmitter?
https://www.vintage-radio.net/forum/...d.php?t=137986 It's nice to get some acknowledgement of advice offered.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
19th May 2018, 3:48 pm | #3 |
Nonode
Join Date: Mar 2010
Location: Dukinfield, Cheshire, UK.
Posts: 2,038
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Re: R1155 Hetrodyne box problem and distorted audio --- Help!
Chances are it's an HT decoupling cap gone s/c. C44 looks a likely candidate - the 1.5 K in series could well be giving the 800 ohms reading if it has 'cooked' over the years. Diligent inspection and a logical fault-finding approach should sort it. Take photos or make diagrams first just in care wires come adrift etc.
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Andy G1HBE. Last edited by Andrew2; 19th May 2018 at 3:54 pm. |
19th Jun 2018, 6:27 pm | #4 |
Triode
Join Date: Jan 2018
Location: College Station, Texas, USA.
Posts: 11
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Re: R1155 Hetrodyne box problem and distorted audio --- Help!
Unless you are working from a different schematic with different component numbering, I think perhaps you didn't mean C44. In mine, C44 is one of the capacitors in the DF switching part of the receiver. Maybe you meant C12?
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20th Jun 2018, 9:27 am | #5 |
Octode
Join Date: Jul 2009
Location: Carmel, Llannerchymedd, Anglesey, UK.
Posts: 1,509
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Re: R1155 Hetrodyne box problem and distorted audio --- Help!
If I recall, the BFO is a bit awkward to work on. I expect that it would be necessary to disconnect the leads under the chassis and withdraw the BFO complete.
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20th Jun 2018, 9:38 am | #6 |
Nonode
Join Date: Jun 2010
Location: Spalding, Peterborough, Cambridgeshire, UK.
Posts: 2,859
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Re: R1155 Hetrodyne box problem and distorted audio --- Help!
I wonder if the OP fixed his fault?
I have 3 R1155's and such information is always handy. Rob
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20th Jun 2018, 10:17 am | #7 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,935
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Re: R1155 Hetrodyne box problem and distorted audio --- Help!
It would be good if like the old TV forum I belonged everyone post fault/cure were possible.
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