|
Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
|
Thread Tools |
27th Jun 2020, 12:04 pm | #1 |
Hexode
Join Date: Aug 2014
Location: Dartford, Kent, UK.
Posts: 435
|
GEC 5639 Tone Correction Capacitors.
Does anyone know the working voltages of the tone correction capacitors C21 & C22?
Something in the back of my mind says they should be higher than 'normal' and I would like to get hold of them before fitting them! The ones in my set are very black and impossible to read - see picture. My set is missing the bottom cover and, if possible, I would also really appreciate a picture of what the original cover looks like. Kind regards John |
27th Jun 2020, 12:13 pm | #2 |
Banned
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
|
Re: GEC 5639 Tone Caps
Can you please explain "Tone caps" ?
I can see three new electrolytics rather poorly fitted. I don't know what "tone" caps you may be asking about. There is ONE sad looking paper waxy that I would remove on sight. That's about all I can see. Joe |
27th Jun 2020, 12:31 pm | #3 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
|
Re: GEC 5639 Tone Correction Capacitors.
The OP meant Tone Correction Capacitors.
Thread title updated.
__________________
Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
27th Jun 2020, 12:36 pm | #4 |
Hexode
Join Date: Mar 2012
Location: London, UK.
Posts: 347
|
Re: GEC 5639 Tone Correction Capacitors.
Just had a glance at the service sheet for the GEC BC5639. C21 is a 0.0015uf cap and C22 is 0.05uf cap. Theres no working voltage rating given on the trader sheet but as they're both waxies I'd just replace them them with 630v axial poly caps. You could possibly get away with 400v rated caps in those positions but would recommend going with 630v to be on the safe side.
Thanks, Peter
__________________
BVWS and BVWTM member |
27th Jun 2020, 12:38 pm | #5 | |
Banned
Join Date: Oct 2015
Location: Cornwall, UK.
Posts: 849
|
Re: GEC 5639 Tone Caps
Quote:
poppydog |
|
27th Jun 2020, 12:39 pm | #6 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,787
|
Re: GEC 5639 Tone Correction Capacitors.
The tone correction cap across the output transformer primary is normally rated at 1kV, though you can probably get away with a lower rating if using modern plastic film caps with self healing characteristics. Other tone caps just need to be rated at the HT voltage.
|
27th Jun 2020, 12:59 pm | #7 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
|
Re: GEC 5639 Tone Correction Capacitors.
Don't forget to disconnect the original HT filter capacitor if those new ones are to be left in circuit.
The HT filter resistor looks as though it's had a hard life at some point. Lawrence. Last edited by ms660; 27th Jun 2020 at 1:20 pm. Reason: correction |
27th Jun 2020, 1:09 pm | #8 | ||
Rest in Peace
Join Date: Mar 2011
Location: Basildon, Essex, UK.
Posts: 4,100
|
Re: GEC 5639 Tone Caps
Quote:
I would solder each capacitor direct to the solder tags, and strap the caps together to help stop them vibrating. I would also strap the single capacitor down as well to stop it vibrating and breaking the wires or cracking the solder.. Mike |
||
27th Jun 2020, 2:24 pm | #9 |
Nonode
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,364
|
Re: GEC 5639 Tone Correction Capacitors.
I'd also strongly recommend slipping on some red sleeving to cover the live wires to the replacement caps - otherwise, it's all too easy to get a belt when you are poking about with meter probes etc.
|
27th Jun 2020, 2:27 pm | #10 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
|
Re: GEC 5639 Tone Correction Capacitors.
Certainly a 1000V as stated or even 1500 V across the primary output transformer.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S |