Dwight Elvey
Veteran Member
It will likely work with two 100uf caps, back to back for each. You don't need to be exact.
Dwight
Dwight
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Identifying capacitors on TEAC floppy controller board
- Thread starter GearTechWolf
- Start date
Hugo Holden
Veteran Member
6.8uF bipolar caps are a common garden part, Jaycar has them in stock and you can get them from their mail order division for 55c each:
www.jaycar.com.au
or you could get rid of these, probably what I would do, and replace them with Wima 6.8uF 50V film caps, which are fairly compact for this capacity & voltage if they will fit in the allowed space height wise:
In most of my transistor radio/TV/VDU/computer restorations these days I tend to eliminate the electrolytic caps, when I can in favor of film ones. Generally this is practical, physical size wise, when the values are under 10uF and the voltage ratings below 100v. This way you won't ever find yourself having to replace them again and there are no more leakage issues to worry about.
6.8uF 50V Bipolar Electrolytic Capacitor | Jaycar Electronics
From our range of components and electromechanical semiconductors to suit your circuit.
www.jaycar.com.au
or you could get rid of these, probably what I would do, and replace them with Wima 6.8uF 50V film caps, which are fairly compact for this capacity & voltage if they will fit in the allowed space height wise:
1pcs - WIMA MKS2 6.8uF (6,8µF) 50V 5% pitch:5mm Capacitor MKS2B046801M00JSSD | eBay
âââââMore Item âââââ.
www.ebay.com
In most of my transistor radio/TV/VDU/computer restorations these days I tend to eliminate the electrolytic caps, when I can in favor of film ones. Generally this is practical, physical size wise, when the values are under 10uF and the voltage ratings below 100v. This way you won't ever find yourself having to replace them again and there are no more leakage issues to worry about.
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Chuck(G)
25k Member
I think you added a zero there, Dwight. I read that as 2 10µF caps back to back to substitute for a 6.8µF nonpolar.
bladamson
Veteran Member
Oh right. I was looking at C25, C16, etc in the original pic. Sorry about that.
But the question still remains. *Those* are ceramic caps, right?
But the question still remains. *Those* are ceramic caps, right?
Chuck(G)
25k Member
16 µF caps would probably be closer to the desired value, thinking about it.
Dwight Elvey
Veteran Member
I'm likely wrong but it is hard to see the decimal point in the picture from the lighting. I suspect, as usual, Chuck, you are right. They may be 6.8uf. It is just hard to tell.
16 uf would be closer but 10 uf would be easier to find. One should note that the capacitors will last longer if carefully matched in value. An imbalance will make a stronger back current and shorten their lives. Still I suspect for their intended use, either 16 uf or 10 uf capacitors would be fine.
Dwight
16 uf would be closer but 10 uf would be easier to find. One should note that the capacitors will last longer if carefully matched in value. An imbalance will make a stronger back current and shorten their lives. Still I suspect for their intended use, either 16 uf or 10 uf capacitors would be fine.
Dwight
GearTechWolf
Experienced Member
Yup! 6.8uF 50V. By back-to-back, do you mean parallel or series? My meter will do for measuring 10-16uF so I can match them closely.
Chuck(G)
25k Member
Series--positive-to-positive or negative-to-negative. Like polarities to the circuit. However--
For whatever it's worth, higher-capacitance MLCC radial-lead caps are available example. They're also available in stacked SMT packaging.
Intrinsically non-polar and will probably last longer than you will.
For whatever it's worth, higher-capacitance MLCC radial-lead caps are available example. They're also available in stacked SMT packaging.
Intrinsically non-polar and will probably last longer than you will.
Hugo Holden
Veteran Member
The best capacitors for replacements are the Wima type I put a link to on post #22, they are very well made, quality & reliable 5% film types, and they practically never fail.
GearTechWolf
Experienced Member
Doing some salvage on a junk TV board I found a non-polarized capacitor!
Sadly, it's only 4.7uF and is just a hair too large...
(comparison to a AA battery here)
Sadly, it's only 4.7uF and is just a hair too large...
(comparison to a AA battery here)
Time to find an excuse to buy these caps and other stuff from Digikey. I always use their 1st class USPS option for small items and it works well. Might help I live in their home state.
But the last time I used Mouser's economy shipping option it took 7 weeks to arrive.
mark0x01
Experienced Member
On electrolytics the BP designation is definitely bi-polar aka non-polarised.
They are readily available, but not necessarily in a wide range of values, so you may need to try a close value.
They are readily available, but not necessarily in a wide range of values, so you may need to try a close value.
Hugo Holden
Veteran Member
That sort of large non polarized capcitor is likely not your common garden NP cap. It was probably the yoke coupling capacitor for the Horizontal scan coils. They have an extremely low ESR, usually about 0.15 Ohms, or less. They have to be like this because the peak H scan currents can reach 3Amps. The are well replaced by a film capacitor, or oil filled capacitor, where the construction has the wire leads welded to the foils. You cannot buy that type of NP capacitor from any supplier currently, that is why, when you come to replace them in a VDU, you need a film or oil filled type.