UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Eddystone EC10, bands with no reception and added mystery component

Stuartsjg · 3rd Jan 2022, 12:44 pm

Hello,

First post but I have used this forum for info previously, including already helping with this radio.

History, this unit was given to a former colleague and it sat in a meeting room for years and years never used, nobody claimed it and it was put to the WEEE skip! Needless to say I spied it and rescued it.

Hooked it up and found all 5 bands were silent, this forum suggested to lift the screens on the transistors which gave me some sound on all bands and audio received on bands 3, 4 and 5.

I had no time for dealing with it further so sold it. Unfortunately the courier played football with it so the buyer found it cut out once the RF gain was over 30%ish.

So, I have it back, and changed out all the OC171's for AF178's - this restored full range of gain on the RF dial.

I've picked up signals on bands 3, 4 and 5 but nothing on band 1 and 2.

Still to do the voltage checks.

I have replaced the caps in the AC supply as they were dead, replaced the 500uF 30V for 2 x 470uF 25V and the 1000uF 12V for 2 x 1000uF 16V (as modern electrolytics are a fraction the size!).and this made massively reduced the mains noise. To check it further, I hooked up a 12V battery to the rectifier output so I had a perfectly clean supply and referenced to ground rod for the set.

Still nothing on band 1 and 2, the occasional band of noise so they are not dead, just not getting any reception.

I've been familiarising myself with the boards and schematics (I am an electrical engineer and day to day by profession work with PCBs and schematics, just not radio!) and found some parts have been added to the BFO section a 7803B 8-legged metal can component. Nothing conclusive coming up online.

Couple of questions out of my story so far which I'm hoping for help with...

1) any good pointers at what may be killing the two higher frequency bands?

2) in the UK / North East Scotland, are there any reliable strong stations I should be able to pick up in all bands, with and without CW and BFO?

3) what may be going on with the 7803B being added?

Any info or help will be appreciated, I'll update with the voltage analysis.

Thanks, Stuart G

3rd Jan 2022, 12:44 pm	#1
Stuartsjg Diode Join Date: Jan 2022 Location: Stonehaven, Scotland, UK. Posts: 7	Eddystone EC10, bands with no reception and added mystery component Hello, First post but I have used this forum for info previously, including already helping with this radio. History, this unit was given to a former colleague and it sat in a meeting room for years and years never used, nobody claimed it and it was put to the WEEE skip! Needless to say I spied it and rescued it. Hooked it up and found all 5 bands were silent, this forum suggested to lift the screens on the transistors which gave me some sound on all bands and audio received on bands 3, 4 and 5. I had no time for dealing with it further so sold it. Unfortunately the courier played football with it so the buyer found it cut out once the RF gain was over 30%ish. So, I have it back, and changed out all the OC171's for AF178's - this restored full range of gain on the RF dial. I've picked up signals on bands 3, 4 and 5 but nothing on band 1 and 2. Still to do the voltage checks. I have replaced the caps in the AC supply as they were dead, replaced the 500uF 30V for 2 x 470uF 25V and the 1000uF 12V for 2 x 1000uF 16V (as modern electrolytics are a fraction the size!).and this made massively reduced the mains noise. To check it further, I hooked up a 12V battery to the rectifier output so I had a perfectly clean supply and referenced to ground rod for the set. Still nothing on band 1 and 2, the occasional band of noise so they are not dead, just not getting any reception. I've been familiarising myself with the boards and schematics (I am an electrical engineer and day to day by profession work with PCBs and schematics, just not radio!) and found some parts have been added to the BFO section a 7803B 8-legged metal can component. Nothing conclusive coming up online. Couple of questions out of my story so far which I'm hoping for help with... 1) any good pointers at what may be killing the two higher frequency bands? 2) in the UK / North East Scotland, are there any reliable strong stations I should be able to pick up in all bands, with and without CW and BFO? 3) what may be going on with the 7803B being added? Any info or help will be appreciated, I'll update with the voltage analysis. Thanks, Stuart G Attached Thumbnails