|
Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
|
Thread Tools |
22nd Dec 2019, 3:30 am | #1 |
Hexode
Join Date: Mar 2018
Location: Bishop Auckland, County Durham, UK.
Posts: 373
|
Ferguson 385RG radiogram repair
This AM/FM radiogram dates from around 1956 and uses E series B9A valves. The previous owner liked 50s retro furniture and had bought the Ferguson to listen to records in his "man cave". The cabinet had been extremely rough so he had carefully brush painted it in satin black paint and fitted four metal "hairpin" legs. However he knew nothing about electronics and told me that the radio wasn't working and the sound was a little quiet when playing records.
Once home I put the chassis on my bench (the kitchen work top) to have a proper look. The audio amplifier circuit uses an EL84 output valve and the triode section of an EABC80. Voltage checks revealed that a 100K resistor feeding HT to pin 9 of this valve (anode) had risen in value to over 500K. With the audio section now working, attention was turned to the radio. A few more voltage checks led to the discovery of two open circuit 47K resistors that supply the screen grid connections of the ECH81 and EF89 valves respectively. Lastly I replaced the old auto changer record deck with a 1970s Garrard SP25 fitted with a stereo cartridge (wired for mono). I hope that this hasn't upset the purists but I now have a nice looking period radiogram which sounds amazing on FM and can play both 78rpm and modern vinyl records.
__________________
Regards Martin Last edited by martin.m; 22nd Dec 2019 at 3:47 am. Reason: grammar |
22nd Dec 2019, 9:36 am | #2 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,431
|
Re: Ferguson 385RG radiogram repair
Shouldn’t upset anyone, you have something you like and saved something from the tip. Nice Christmas present.
__________________
Frank |
22nd Dec 2019, 10:45 am | #3 |
Rest in Peace
Join Date: Mar 2011
Location: Basildon, Essex, UK.
Posts: 4,100
|
Re: Ferguson 385RG radiogram repair
Also probably lengthened the life of many treasured records.
Mike |
22nd Dec 2019, 10:48 am | #4 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,288
|
Re: Ferguson 385RG radiogram repair
Well done. Proper fault finding. Beats changing all the caps and then wondering what to do when it still doesn't work.
__________________
Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
22nd Dec 2019, 1:05 pm | #5 |
Hexode
Join Date: Mar 2018
Location: Bishop Auckland, County Durham, UK.
Posts: 373
|
Re: Ferguson 385RG radiogram repair
Thank you Graham. I find that valve circuitry is usually straightforward and logical, unlike modern electronics featuring ICs and surface mount components.
__________________
Regards Martin |
22nd Dec 2019, 1:17 pm | #6 |
Nonode
Join Date: Nov 2016
Location: Aberaeron, Ceredigion, Wales, UK.
Posts: 2,884
|
Re: Ferguson 385RG radiogram repair
I completely agree Martin, modern electronics leaves me cold, you have done a nice job.
John |
22nd Dec 2019, 1:27 pm | #7 |
Heptode
Join Date: Jul 2008
Location: Hereford, UK.
Posts: 719
|
Re: Ferguson 385RG radiogram repair
I had one of these years ago. IIRC it has a nice curvilinear speaker.
Last edited by electrogram; 22nd Dec 2019 at 1:32 pm. |
22nd Dec 2019, 7:14 pm | #8 |
Hexode
Join Date: Mar 2018
Location: Bishop Auckland, County Durham, UK.
Posts: 373
|
Re: Ferguson 385RG radiogram repair
Thank you John. Electrogram, I'm not sure what you mean by a curvilinear speaker. The Ferguson has an old fashioned 8 inch round speaker (Rola I think).
__________________
Regards Martin |
22nd Dec 2019, 7:37 pm | #9 |
Heptode
Join Date: Jul 2008
Location: Hereford, UK.
Posts: 719
|
Re: Ferguson 385RG radiogram repair
What I meant to say was that the speaker has a curvilinear - I believe that is the term often used - cone, one where the angle varies from the centre to the edge, it is supposed to give the unit wider frequency response than a standard type. Fairly unusual to find one on such a relatively humble radiogram
|
22nd Dec 2019, 9:28 pm | #10 |
Heptode
Join Date: Mar 2017
Location: Romsey, Hampshire, UK.
Posts: 521
|
Re: Ferguson 385RG radiogram repair
Hi Martin.m
I have one of these radiograms as the main source of entertainment in my shack. Still use the Collaro autochanger for playing stacks of 78's. My Ferguson was bought new by my Grandparents when they retired from keeping a sweet shop in Burgess Road, Southampton. So still in the same family and in shiny original condition ! I love the damped lid which slowly closes and cuts out the "needle chatter" as it comes to rest. Cheers, John (Mr 1936). |
22nd Dec 2019, 10:52 pm | #11 | |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,843
|
Re: Ferguson 385RG radiogram repair
Quote:
Bush referred to one of the 8" Celestion speakers on their VHF64 as having a "exponential" cone. |
|
4th Jun 2020, 9:36 am | #12 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,288
|
Re: Ferguson 385RG radiogram repair
__________________
Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |