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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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20th Jun 2019, 1:40 pm | #1 |
Tetrode
Join Date: Apr 2014
Location: Essex, UK.
Posts: 70
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NAD 4155 Tuner
The display on this tuner does not work until the unit has been switched on for some time. (5-10mins). Any idea what the fault is?
Thanks Kevin |
21st Jun 2019, 12:21 pm | #2 |
Heptode
Join Date: Nov 2009
Location: London, Ontario, Canada
Posts: 675
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Re: NAD 4155 Tuner
Hi Kevin,
The tuner has the service manual available on the hifiengine web-site: https://www.hifiengine.com/manual_li...nad/4155.shtml It looks like the tuner uses a vacuum-fluorescent display. Do check the filament voltage with a scope, as well as the other control signals to the display. Here are some articles on how to drive in general vacuum-fluorescent displays: http://www.kerrywong.com/2013/06/05/...ver-using-555/ http://www.kerrywong.com/2013/06/13/...isplay-driver/ https://www.instructables.com/id/A-S...-VFD-Displays/ The above should get you going. Regards, Peter |
21st Jun 2019, 6:31 pm | #3 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,394
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Re: NAD 4155 Tuner
Check the VFD's connections to the PCB- they often seem to be something like sparingly-tinned springy mild steel and love to go dry-jointed over time. Particularly the one or two at each end- these are very frequently the filament pins.
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21st Jun 2019, 10:38 pm | #4 |
Tetrode
Join Date: Apr 2014
Location: Essex, UK.
Posts: 70
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Re: NAD 4155 Tuner
Thanks for the responses chaps. I think it might be one or more dry joints too. One thing I noticed is that the display starts off blank before reading properly.
Kevin |
21st Jun 2019, 11:14 pm | #5 |
Tetrode
Join Date: Apr 2014
Location: Essex, UK.
Posts: 70
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Re: NAD 4155 Tuner
Just to clarify my last post, the display, on f.m, now reads 00.0 at first then 93.5 for example after it warms up. Used to be blank at first.
Kevin |
21st Jun 2019, 11:21 pm | #6 |
Rest in Peace
Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
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Re: NAD 4155 Tuner
Does the tuner still receive ok while the display is off/reading 00.0?
Alan. |
22nd Jun 2019, 3:33 am | #7 |
Tetrode
Join Date: Apr 2014
Location: Essex, UK.
Posts: 70
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Re: NAD 4155 Tuner
Yes
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22nd Jun 2019, 2:50 pm | #8 |
Heptode
Join Date: Apr 2008
Location: Eastbourne, East Sussex, UK.
Posts: 671
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Re: NAD 4155 Tuner
These are an excellent sounding FM tuner and well worth the effort of repairing.
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