UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Amateur and Military Radio

Notices

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

Closed Thread
 
Thread Tools
Old 6th Sep 2020, 11:40 am   #1
3CX1500A7
Diode
 
3CX1500A7's Avatar
 
Join Date: Sep 2020
Location: Bath, NE Somerset, UK
Posts: 4
Default Yaesu FRDX400 sensitivity

Hi,

Trying out an FRDX400 I bought at a rally a year ago. The sensitivity seems to be very low, but only on certain bands.

On 80m for example, when I connect a dummy load and switch on the xtal calibrator, once the signal is peaked with the preselector control the signal level is S9 indicated.

I was using the rx on 40 and it seemed quite deaf in comparsion to the other bands.

I did the same as on 80 with the calibrator signal and even when peaked it's much weaker, barely S1 shown on the meter.

I tried the alignment as mentioned on page 10 of the manual, i.e. adjusting L104 and L108 for maximum reading on 40m, but the signal doesn't ever get above S1 even at maximum.

All the other bands seem OK, the receiver is quite lively, but there is a definate "deafness" on 40.

Any comments or suggestions welcome

Thanks, Dave
3CX1500A7 is offline  
Old 6th Sep 2020, 5:04 pm   #2
dodgy-dxer
Heptode
 
dodgy-dxer's Avatar
 
Join Date: Mar 2008
Location: Newmarket, Suffolk, UK.
Posts: 611
Default Re: Yaesu FRDX400 sensitivity

The usual issue in kit that has stood idle is switch wafers (generally not specific to FRDX400)

Be aware of the switch wafer insulating material absorbing the "switch cleaner" and swelling up. Just rub the wafer using a cotton bud soaked in cleaner

Could be the band conversion crystal not oscillating?

With a signal generator you should be able to see where the signal is disappearing or where it jumps up

73 Fred
G4BWP
dodgy-dxer is offline  
Old 6th Sep 2020, 7:18 pm   #3
3CX1500A7
Diode
 
3CX1500A7's Avatar
 
Join Date: Sep 2020
Location: Bath, NE Somerset, UK
Posts: 4
Default Re: Yaesu FRDX400 sensitivity

Thanks for the info Fred, just did a clean with cotton buds soaked in switch cleaner round the contacts of the wafers, quick re-peaking of the two inductors and the S meter reading is now just over S9 when the preselector is peaked on the calibrator signal on 40m band


73, Dave
3CX1500A7 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 7:17 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.