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 > General Vintage Technology > Components and Circuits

Notices

Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

Closed Thread
 
Thread Tools
Old 6th Aug 2022, 10:16 pm   #1
Federica66
Diode
 
Join Date: Aug 2022
Location: Rome, Italy.
Posts: 5
Default Mysterious capacitors.

Hi, the capacitors in the pics are mounted on the tone boards of an old electric organ, brand Farfisa. 1uF-40V.
They look like ordinary electrolytic capacitors but they are mounted on a yellow plastic cup....?...and they look to me a bit different from a common electrolitic.
...and they are mounted with the positive down on the pcb and the negative up...?...
I suspect they are wet tantalum capacitors.
What do you think about them?
Is it possible to detect a capacitor with these info?
Thank you in advance.

Federica
Attached Thumbnails
Click image for larger version

Name:	web.jpg
Views:	283
Size:	66.6 KB
ID:	262320   Click image for larger version

Name:	tantalum-web.jpg
Views:	241
Size:	74.0 KB
ID:	262321   Click image for larger version

Name:	web01.jpg
Views:	216
Size:	78.6 KB
ID:	262322  
Federica66 is offline  
Old 6th Aug 2022, 10:25 pm   #2
joebog1
Banned
 
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
Default Re: Mysterious capacitors.

I think they are standard electrolytics. The yellow insulation cup is to give them some support on the PCB, if that wasnt there they would vibrate and eventually fall off the PCB. I would replace them with PCB mount low leakage caps of 1uF and 63 volts working.

Joe
joebog1 is offline  
Old 6th Aug 2022, 10:28 pm   #3
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,800
Default Re: Mysterious capacitors.

I've not seen wet tants that look like that. Is there any DC bias voltage? If so, then Al would be fine.

By the look of that resistor, somebody has been really expressing themselves...

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is offline  
Old 6th Aug 2022, 10:37 pm   #4
joebog1
Banned
 
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
Default Re: Mysterious capacitors.

I think thats a germanium diode David. It made me look twice too!!.

Joe
joebog1 is offline  
Old 6th Aug 2022, 10:41 pm   #5
Sideband
Dekatron
 
Sideband's Avatar
 
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,549
Default Re: Mysterious capacitors.

Yes they are standard aluminium types probably Philips. Just fit ordinary types. As Joe said, the yellow cap is to provide support. Lots of Philips circuits like that in the 70's.
__________________
There are lots of brilliant keyboard players and then there is Rick Wakeman.....
Sideband is offline  
Old 7th Aug 2022, 7:52 am   #6
Diabolical Artificer
Dekatron
 
Diabolical Artificer's Avatar
 
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,637
Default Re: Mysterious capacitors.

Wet tantalums are heavy, you can feel the difference in weight same as between steel and aliminium.

Andy.
__________________
Curiosity hasn't killed this cat...so far.
Diabolical Artificer is offline  
Old 7th Aug 2022, 9:01 am   #7
Jac
Heptode
 
Jac's Avatar
 
Join Date: Jun 2006
Location: Eindhoven, Netherlands.
Posts: 640
Default Re: Mysterious capacitors.

Yes, the capacitors are Philips.
Standard aluminium electrolytic ones.

Jac
Jac is offline  
Old 7th Aug 2022, 12:58 pm   #8
Maarten
Dekatron
 
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,185
Default Re: Mysterious capacitors.

They're standard aluminium electrolytics by Philips. They can be replaced by standard radial types.

Edit: What Jac says.
Maarten is offline  
Old 7th Aug 2022, 1:15 pm   #9
paulsherwin
Moderator
 
paulsherwin's Avatar
 
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,787
Default Re: Mysterious capacitors.

Another vote from me. As said, those plastic mounts were quite widely used in the 60s and 70s.
paulsherwin is offline  
Old 7th Aug 2022, 1:38 pm   #10
sortedradio
Heptode
 
sortedradio's Avatar
 
Join Date: Jan 2008
Location: Sheffield, South Yorkshire, UK.
Posts: 653
Default Re: Mysterious capacitors.

I have restored 2 Farfisa organs, replacing these caps, and can also confirm that they are standard electrolytic types.
__________________
Martin
BVWS member
GQRP Club
sortedradio is offline  
Old 7th Aug 2022, 6:48 pm   #11
Federica66
Diode
 
Join Date: Aug 2022
Location: Rome, Italy.
Posts: 5
Default Re: Mysterious capacitors.

Thank you very much for the support and the expert answers....but there are some questions still open...I'll try to cut one of these capacitors and I'll show the result...it is strange the yellow little plastic cup...there is a lot of space and this organ is like a wardrobe....I saw sometimes these wet tantalum caps come with a strong plastic casing...?....for protection? a failure can be explosive?.....the voltage in this circuit is around 5 and 9 Volts DC so I think too low to make a cap vibrate....the Philips caps from 60's often are blue...I try to investigate more....I'll let you know....and thank you a lot.
Attached Thumbnails
Click image for larger version

Name:	Tantalio.jpg
Views:	67
Size:	30.3 KB
ID:	262384   Click image for larger version

Name:	GTCAP-CA53D-Series-200C-Axial-Wet-Tantalum-Electrolytic-Capacitor-6-125V.jpg
Views:	65
Size:	28.0 KB
ID:	262385   Click image for larger version

Name:	images.jpg
Views:	65
Size:	3.5 KB
ID:	262386  
Federica66 is offline  
Old 7th Aug 2022, 6:51 pm   #12
Federica66
Diode
 
Join Date: Aug 2022
Location: Rome, Italy.
Posts: 5
Default Re: Mysterious capacitors.

Thank you...the plastic mounts were widely used? great!
Federica66 is offline  
Old 7th Aug 2022, 8:11 pm   #13
Federica66
Diode
 
Join Date: Aug 2022
Location: Rome, Italy.
Posts: 5
Default Re: Mysterious capacitors.

As promised this is the inside of the capacitor and the last pic is about a common electrolytic cap...to cut the casing I wore gloves, a mask and glasses for protection....just forgot the earplugs....!....that's just for curiosity but I don't know if it says something interesting or relevant...after all I don't know nothing about the capacitors construction.
Attached Thumbnails
Click image for larger version

Name:	open-01.jpg
Views:	75
Size:	104.6 KB
ID:	262389   Click image for larger version

Name:	open-02.jpg
Views:	69
Size:	47.7 KB
ID:	262390   Click image for larger version

Name:	open-03.jpg
Views:	71
Size:	57.5 KB
ID:	262391   Click image for larger version

Name:	open-04.jpg
Views:	68
Size:	89.4 KB
ID:	262392   Click image for larger version

Name:	open-05.jpg
Views:	61
Size:	71.7 KB
ID:	262393  

Federica66 is offline  
Old 7th Aug 2022, 9:02 pm   #14
factory
Octode
 
Join Date: Jul 2009
Location: Cheshire, UK.
Posts: 1,706
Default Re: Mysterious capacitors.

Axial wet tants are very heavy compared with ordinary aluminium capacitors, as has already been mentioned. Wet tants are also very expensive, due to the casing being made from tantalum or silver, these are the only materials that resist corrosion from the acid based electrolyte used, do not cut open wet tants.
Example of a failed wet tant from a Tek oscilloscope below, note the corrosion.
Click image for larger version

Name:	DSC_7943b.jpg
Views:	104
Size:	123.7 KB
ID:	262397

However those are just cheap ordinary aluminium electrolytic capacitors from Philips, here are a whole bunch of them in a Philips car radio.
Click image for larger version

Name:	SAM_3245a.jpg
Views:	93
Size:	98.1 KB
ID:	262396

David
factory is online now  
Old 8th Aug 2022, 7:00 am   #15
Federica66
Diode
 
Join Date: Aug 2022
Location: Rome, Italy.
Posts: 5
Default Re: Mysterious capacitors.

Thank you David and thank to you all, guys....it was important for me because it is 30 years we plays this old Ballata Farfisa but recently the notes are going a bit down of tune....yes, there is a screw for adjusting the tones back in tune but it is a sign that after 50 years the electrolytic caps are failing and need to be replaced with the right ones.
I'm definitively convinced that Mr. Philips's wife was trying to sell out little yellow plastic caps unsuccessfully....that's the only explanation why they are there...
Federica66 is offline  
Old 8th Aug 2022, 7:31 am   #16
joebog1
Banned
 
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
Default Re: Mysterious capacitors.

The vibration problem occurs from the speaker!! It is an organ after all. You don't mention if it has built in power amplifier, but many organs of this age did have built in speakers and power amplifiers.

Joe
joebog1 is offline  
Old 8th Aug 2022, 12:13 pm   #17
Refugee
Dekatron
 
Refugee's Avatar
 
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,549
Default Re: Mysterious capacitors.

I am pretty sure that Phillips made axial mount capacitors with a longer negative lead and added the plastic caps for the remaining life of the tooling to make them.
After that they will have followed Japan and started making radial ones.
I have seen those yellow mounts in TVs in the past.
You might have to crank the leads a little bit in one or two crowded positions with modern radial parts.
Refugee is offline  
Old 9th Aug 2022, 12:52 pm   #18
Maarten
Dekatron
 
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,185
Default Re: Mysterious capacitors.

I agree, only producing axial caps (that would not mount easily and remain stable) was the main reason at the time for adding caps (pun intended).
Maarten is offline  
Old 9th Aug 2022, 12:57 pm   #19
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
Default Re: Mysterious capacitors.

I've seen those yellow caps in a Philips transistor radio (which paradoxically was assembled by Plessey).
__________________
I'm the Operator of my Pocket Calculator. -Kraftwerk.
G6Tanuki is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 12:21 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.