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-   -   Dansette Electrolytic Capacitors (https://www.vintage-radio.net/forum/showthread.php?t=44162)

john600601 14th Aug 2009 11:26 pm

Dansette Electrolytic Capacitors
 
Hello all. I am working on a Dansette Major Record Player (EL84 valve amp) which needs the smoothing caps replacing as it makes a terrible loud buzz. I have been told the original "3 in 1" silver can is obsolete but you can fit 3 separate caps in its place. The original values were I believe 16, 32 and 25uf from memory. I feel capable of putting them in once I have them but am not sure exactly what I need to buy (someone told me the original values are no longer available so I have to get the nearest value to the originals). I have been looking at http://www.cricklewoodelectronics.co...me.php?cat=162 but there are so many different types I am stumped:( Could anyone advise what I need? Thankyou.

Darren-UK 15th Aug 2009 12:25 am

Re: Dansette Electrolytic Capacitors
 
You'd be better going to RS. Have a look at this page.

Suitable components would be Part Numbers 226-7277 (15uF @ 450v), 267-7321 (22uF @ 450v) and 324-5436A (33uF @ 450v).

Note that voltage, which is the DC rating and these examples are 85deg axial efforts.

You've been told correctly that you need to get the nearest value to the old capacitors. Cricklewood don't seem to stock anything suitable to replace the original 33uF job with, or the 16uF for that matter (nearest appear to be 47uF and 22uF respectively) although I've looked only at the page you've given the link to. You don't really want to start messing about wiring capacitors in series or parallel to get near to the value you want.

Michael Maurice 15th Aug 2009 9:48 am

Re: Dansette Electrolytic Capacitors
 
You might find that you need an account to purchase parts from RS, they have a trade counter the phone number is 0121 359 8844 They are only open on Monday - Fridays from 8.00 - 4.30.

If they cant or wont help, try Farnell which stocks a similar range. http://uk.farnell.com

I hope this helps you

Darren-UK 15th Aug 2009 9:58 am

Re: Dansette Electrolytic Capacitors
 
Ah yes, my apologies for that. I think you do need an account to use RS. Thanks for pointing that out, Michael.

john600601 15th Aug 2009 7:05 pm

Re: Dansette Electrolytic Capacitors
 
Thanks Darren and Michael. I may set up an account with RS as I do buy a few components & cable etc from time to time and I will buy the caps and see how I get on! Thanks again. John

'LIVEWIRE?' 15th Aug 2009 7:45 pm

Re: Dansette Electrolytic Capacitors
 
If you register with rswww.comyou can buy from RS without having 'an account' as such. I occasionally buy things on-line from them on a 'payment with order' basis.

john600601 15th Aug 2009 8:26 pm

Re: Dansette Electrolytic Capacitors
 
Thanks for the tip. John.

audiomm 15th Aug 2009 10:31 pm

Re: Dansette Electrolytic Capacitors
 
Quote:

Originally Posted by john600601 (Post 265221)
Hello all. I am working on a Dansette Major Record Player (EL84 valve amp) which needs the smoothing caps replacing as it makes a terrible loud buzz. I have been told the original "3 in 1" silver can is obsolete but you can fit 3 separate caps in its place. The original values were I believe 16, 32 and 25uf from memory. I feel capable of putting them in once I have them but am not sure exactly what I need to buy (someone told me the original values are no longer available so I have to get the nearest value to the originals). I have been looking at http://www.cricklewoodelectronics.co...me.php?cat=162 but there are so many different types I am stumped:( Could anyone advise what I need? Thankyou.

I would hesitate to stuff the can with 3 separate caps unless I could guarantee the replacements could handle the ripple current. Most replacement axial lead electros will not have the ripple handling capacity of the original can.
Unfortunately I have seen the results of under-rated caps used in this situation ( but not by me) - a fire tends to focus the mind :).

On the bright side, you can still get multi-section can types - 2 in 1, 3 in 1 and even 4 in 1. Antique Electronic Supply in USA carry a good selection but be warned - they are not cheap. See http://www.tubesandmore.com/. Search on C-EC as this is the part number prefix for all their multi-section caps.

Also try http://www.askjanfirst.com/eindex.htm
They have a good selection of multi-section caps but maybe not 3 in 1.

Cheers

Mike

Steve_Bell 15th Aug 2009 11:53 pm

Re: Dansette Electrolytic Capacitors
 
The 25uF is the cathode bypass cap and only needs to be rated at 25v. This might save some space.

ALANS ANITAS 16th Aug 2009 12:13 am

Re: Dansette Electrolytic Capacitors
 
.May I also suggest you try www.justradios.com in Canada. They are very helpful, and will reply to any enquires almost by return. You can also phone. They stock a much larger range than is available in this country, and are members of the BVWS. Delivery is by airmail and is often quicker than British companies.

Regards

ALAN

Jimmyhaflinger 18th Aug 2009 2:03 pm

Re: Dansette Electrolytic Capacitors
 
Quote:

Originally Posted by audiomm (Post 265413)

I would hesitate to stuff the can with 3 separate caps unless I could guarantee the replacements could handle the ripple current. Most replacement axial lead electros will not have the ripple handling capacity of the original can.
Unfortunately I have seen the results of under-rated caps used in this situation ( but not by me) - a fire tends to focus the mind :).


Mike

That's scary

I have just replaced the leaky 50+50mfd 300vdc smoothing can in a valve record player with two 47mfd 350vdc axial blue jacket Philips capacitors from the late 70s, as used in the deflection/convergence section of Philips K12 CTVs, hopefully they won't explode!

Station X 18th Aug 2009 2:43 pm

Re: Dansette Electrolytic Capacitors
 
Modern electrolytics have a vent hole to stop them exploding. I always choose reservoir capacitors wil a ripple current rating of at least twice the HT current.

John_BS 18th Aug 2009 5:36 pm

Re: Dansette Electrolytic Capacitors
 
Just a general observation re. electrolytic capacitor replacement in old sets: of those which I've measured recently* (admittedly not a huge number so statistically small sample), the old ones tend to have capacities above the nominal value, whereas modern caps are usually pretty close. So when choosing "nearest nominal value" it may be better to opt "up" unless the match is very close (c.f. 47/50uF).

John

*after reforming

john600601 18th Aug 2009 10:41 pm

Re: Dansette Electrolytic Capacitors
 
Thanks for all the replies everyone! I have bought the caps from farnell; 15uf 450v, 22uf 450v, 33uf 450v, (all 105 degrees-C) so fingers crossed it will be successful. Will let you know how I get on. John

john600601 20th Aug 2009 1:08 pm

Re: Dansette Electrolytic Capacitors
 
Hi again. I have had the capacitors arrive; the 22uf 450v was quite large in size so I ordered some 22uf 25v as there was not going to be adequate space to mount the three. There are 6 holes on the circuit board where the old can has been removed and I have worked out which caps go to which hole (as the original can was marked triangle/square/dash to represent the values) but my question is do these capacitors have a positive and negative or can they be fitted either way round? If they have to be fitted the correct way am I right in assuming the outside pins of the original can are negative (as original can is marked "can negative"). With the new caps one 'end' is longer than the other but there are no apparent + or - symbols. Can anyone help? Thanks. John

Darren-UK 20th Aug 2009 1:15 pm

Re: Dansette Electrolytic Capacitors
 
These caps have a row of arrows down the side which point to the negative lead. Make sure you wire them correctly or they'll go "POP".

Regarding the 22uF job, why not wire it in temporarily (add temporary longer leads or something) to check everything else is working ok - then you can change it when the 25v effort arrives.

john600601 20th Aug 2009 4:09 pm

Re: Dansette Electrolytic Capacitors
 
Thanks Darren, I can see that now. So if it was printed on the original can "can negative" would I be correct in saying the three "legs" on the outside of the can are the negative? John

geofy 20th Aug 2009 5:34 pm

Re: Dansette Electrolytic Capacitors
 
Could you take some pictures of these? The original should have the different shaped tags you mention, these are all the positive sides of the capacitors, the can being the common negative side.

But with the new capacitors the convention tends to be arrows pointing to the negative end while the longer lead is the positive end.

They MUST be connected the correct way round, otherwise it will end in tears :o You must be certain of this before switching on.

It might be an idea to replace the metal rectifier with a silicon diode rectifier. You can ask for more info on how to do this.

Geof

john600601 20th Aug 2009 6:05 pm

Re: Dansette Electrolytic Capacitors
 
1 Attachment(s)
Thanks for replies. The photo shows the connections of the old can (with corresponding shapes) 32uf (replacing with 33uf) is square, 16uf (replacing with 15uf) is triangle and 25uf (replacing with 22uf) is dash. Basically as far as I can see the three "positives" are in the centre of the can and the three "negatives" around the edge. I have typed in which connection I believe is which if it makes sense. Thankyou.

Simon Gittins 20th Aug 2009 7:33 pm

Re: Dansette Electrolytic Capacitors
 
John,
The 3 legs are indeed the common negative connection.

You need to look at the print where these 3 legs connect; if all 3 are linked then it will work as per the labels on your photo. Sometimes one leg goes to an isolated part of print just to anchor the can. The negative connections of the replacement capacitors need to be connected together and to the negative connection point of the original can.
Post a picture of the print side of the board if you're not sure.


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