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465 55v regulated filter cap type.


Dave Peterson
 

What is the type of this capacitor, and what are its appropriate replacement types?

Picture of C1534:
https://groups.io/g/TekScopes/photo/258720/0?p=Created,,,20,2,0,0

Manual calls for: FXD,ELCTLT: 3UF, 20%, 150V.

Plenty of radial electrolytic cap available on Mouser, but no 3uF axial caps.

Suggestions?

Thanks,
Dave


adesilva_1999@...
 

Dave,

The 465 I worked on had that cap leaking and I replaced it with a 4uf/150 volt.

Mouser
#: 75TVA1402
Mfr. #: TVA1402
Desc.: Aluminum Electrolytic Capacitors Axial
Leaded 150V 4.0 uF
Price $2.71 each


Dave Hills
 

That used to be a Sprague 109D, Wet Tantalum capacitor.
I would replace with a 10uF to 15uF 100v to 150v aluminum electrolytic. Or, a 3.3uF
polypropylene film type if it will fit.

Dave


What is the type of this capacitor, and what are its appropriate replacement
types?

Picture of C1534:
https://groups.io/g/TekScopes/photo/258720/0?p=Created,,,20,2,0,0

Manual calls for: FXD,ELCTLT: 3UF, 20%, 150V.

Plenty of radial electrolytic cap available on Mouser, but no 3uF axial caps.

Suggestions?

Thanks,
Dave


Dave Peterson
 

Ah yes, Wet Tantalum.

Any of the Tantalum caps are replaceable with Electrolytic, right? Is the only reason they were used was the size (capacitance, space, money) technology at the time? Are their any other properties about this capacitor's location that are significant in its selection? Why such a leaky mess was used? (Seems very common).

I've added the TVA1402 to my Mouser list for this scope, but will look into Daves recommendation too. Curious to see what comes up for those dimensions.

Thanks guys!
Dave


Dave Wise
 

It depends what the cap is used for.


Tantalum characteristics dear to designers:

1. Low ESR

2. Low leakage (electrical, not chemical!)

3. Stable capacitance


You will not get (3) with an aluminum electrolytic, and you will not find (1) and (2) simultaneously in a single part.

In most reservoir and bypass applications, only (1) is important and a size-upgraded low-ESR aluminum will do.

In timing applications, (2) and (3) are critical and if a film part will fit, that's the way to go.

?I probably haven't covered all the bases.


HTH,

Dave Wise

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dave Peterson via groups.io <davidpinsf=yahoo.com@groups.io>
Sent: Sunday, January 17, 2021 8:24 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 465 55v regulated filter cap type.

Ah yes, Wet Tantalum.

Any of the Tantalum caps are replaceable with Electrolytic, right? Is the only reason they were used was the size (capacitance, space, money) technology at the time? Are their any other properties about this capacitor's location that are significant in its selection? Why such a leaky mess was used? (Seems very common).

I've added the TVA1402 to my Mouser list for this scope, but will look into Daves recommendation too. Curious to see what comes up for those dimensions.

Thanks guys!
Dave


 

This thread is giving me anxiety about my stable of 475s. I've only had one dead electrolytic (that caused an obvious issue), and it only leaked enough to corrode one lead, it didn't even make it down to the pad.

Now I'm thinking that I need to go over each instrument with a magnifier just to be sure that nothing is spreading silent corruption.

-- Jeff Dutky


adesilva_1999@...
 

The space there is very tight. I had to manipulate/bend the leads and put heat shrink on them to get it in there. I doubt an axial cap of sufficient value can be fitted there as it might be too tall. Also, in my case, I had to snip one end and take it out as I did it from the component side. Even the 4 uf I used was a little too big and hence the need to bend the leads and insulate them.

I got rid of the rest of the wet tantalums along with it but did not bother about the dipped tantalums other than the one under the HV shield. I could not get the exact same but went with the nearest in value for the critical caps on the power supply only. I also did not think of increasing the values because of the physical sizes and available space. Below is a list of what I replaced:

Mfr. #: USR1E470MDD1TP
Desc.: Aluminum Electrolytic Capacitors Radial Leaded 47uF 25V 85c 6.3x7 20% 2.5LS
#: 594222213836109 2pcs.

Mfr. #: MAL213836109E3
Desc.: Aluminum Electrolytic Capacitors Axial Leaded 10uF 25V 20%
#: 75TE1504E3 1pc.

Mfr. #: TE1504E3
Desc.: Aluminum Electrolytic Capacitors Axial Leaded 150V 5uF
#: 75TE1500E3 1pc.

Mfr. #: TE1500E3
Desc.: Aluminum Electrolytic Capacitors Axial Leaded 150V 1uF
#: 71RL07S361GTR 1pc.

Mfr. #: TE1208
Desc.: Aluminum Electrolytic Capacitors Axial Leaded 35uF 25volts
#: 594MAL212634102E3 2pcs.

Mfr. #: MAL212634102E3
Desc.: Aluminum Electrolytic Capacitors Axial Leaded 1000uF 10V 10x18
#: 5303AG1.5R 1pc.

Mfr. #: TVA1402
Desc.: Aluminum Electrolytic Capacitors Axial Leaded 150V 4.0 uF
1pc.

Hope this helps.


tedbmoss@...
 

I am just replacing caps on a TDS420 power supply , more than one actually, they looked fine from the top, no corrosion.When I took them off they were all leaking underneath but had not damaged anything yet. The TDS640s I am repairing have massive cap leaks, in the 30's, on the acquisition boards. I just replace them all..


 

I'll second Dave Wise's statements.

My rules-of-thumb for replacing tantalums - in order of preference:

1. Film caps where they will fit - same or slightly higher capacitance, and generously higher voltage - Wima MKS2 is my go-to, large selection at Mouser or Digikey
2. Aluminum Electrolytics - generally 4-5x capacitance, and voltage according to the circuit requirements (+about 20%) - Nichicon KL Low-leakage for 85°C applications, Nichicon HE/PW or Panasonic FS for 105°C applications.

Menahem Yachad
www.condoraudio.com