What does B.K. capacitor mean ? MS-16 power supply

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AnalogApples

Member
Hi friends! I’m going to recap the power supply of my Tascam ms-16 and the parts list in the manual says the two 4700 uf electrolytic caps (35v and 50v) say (B.K.) in parentheses right after the voltage requirement.

What does (B.K.) mean? And how are you doing today?
 
AnalogApples said:
Hi friends! I’m going to recap the power supply of my Tascam ms-16 and the parts list in the manual says the two 4700 uf electrolytic caps (35v and 50v) say (B.K.) in parentheses right after the voltage requirement.

What does (B.K.) mean? And how are you doing today?
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I'm doing great now thanks! Just found out my daughter who I last saw Sunday does NOT have Covid, just a bad cold and so I do not need to self isolate (like a certain president didn't) for two weeks!

I have waded through Wiki on capacitors for thee and cannot find "B" (*) but "K" I am sure is a tolerance, 10%.

Generally I would not worry about capacitor parameters, so long as you get a quality product from a reputable company. Mouser, Farnell, RS Components you will be fine. If the machine runs hot at all you might like to go for 105C types but all that gives is longer life and I doubt you expect ANOTHER 40 years out of it?

*B seem to be a date code but, = 2011 which is daft!

Forgot, (old, meds y'know) Don't be tempted to fit hugely bigger value capacitors. They will hardly make any difference to the hum levels and 'might' bugger the transformer.

Dave.
 
Doing alright. You?

I have no idea what “B.K.” means, but functionally there is nothing unique about the function of those caps within the context of the assembly. They are primary filter capacitors for a linear power supply. Period. Any good quality modern electrolytic parts will do well there. I prefer caps that are geared for switching power supplies as the tend to be spec’ed for long life, high temp and low ESR...all good things. My go-to for this application is Nichicon PW series caps.
 
sweetbeats said:
Doing alright. You?

I have no idea what “B.K.” means, but functionally there is nothing unique about the function of those caps within the context of the assembly. They are primary filter capacitors for a linear power supply. Period. Any good quality modern electrolytic parts will do well there. I prefer caps that are geared for switching power supplies as the tend to be spec’ed for long life, high temp and low ESR...all good things. My go-to for this application is Nichicon PW series caps.
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Ah! I feel better now knowing YOU don't know either Mr Beats!

Keep well,

Dave.
 
Thanks, guys! May your helpfulness return to you ten fold!

I’m actually upset today because I’m realizing the best job (chauffeur)I’ve ever had may be going bye bye because of Covid. I’m healthy and fed so I won’t complain. Plus there’s 30,000$ (retail value) worth of antique music equipment in my apartment while kids in Nepal have to kick balled trash bags since they can’t afford soccer balls. ?
 
Well that’s not particularly unusual, though generally Teac was smart about their component selections as far as striking a balance between cost, reliability and performance within the market range. The trick is that what was “low ESR” in the mid 1980s is not the same as what is “low ESR” now. There have been improvements. But the fact Teac spelled it out in the MS16 Service Manual indicates they were paying attention to this detail.
 
AnalogApples said:
I’m not looking forward to locating in-stock B.K. caps online. ��. The ones Miroslav posted are all factory order.
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I really wouldn't sweat this component selection, something of this quality:https://uk.farnell.com/vishay/mal225638472e3/cap-4700-f-63v-alu-elec-snap-in/dp/2474588?st=4700 63v is going to be better than the original, probably smaller.

I have not had an elctrolytic capacitor fail in anything in the last 20 years that I can recall.

Dave.
 
A wild ass guess........

Any chance the caps are Nichicon branded? They evidently grade some of their caps for 'sound quality'.

"TYPE-1: The low profile high tone quality grade of the new development
electrolyte adoption.
TYPE-2: The center grade that the best sound is provided electrode foil,
with the multiple use.
TYPE-3: The highest tone quality grade by the low drag the gold plating
terminal adoption."

The AK, BK, and CK are the type designations.
https://www.nichicon.co.jp/english/products/pdfs/e-lkg.pdf

I have come across Nichicon caps occasionally, but don't recall if there was any letter suffix and likely any good quality cap with the same uf and voltage rating would work fine.
 

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AnalogApples said:
I’m not looking forward to locating in-stock B.K. caps online. ��. The ones Miroslav posted are all factory order.
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You are way overthinking this. Miroslav only shared the link to answer the question what does “B.K.” mean. You do not need that specific brand of cap. Just get Nichicon PW series caps...readily available, and affordable...likely spec better than the BK caps...and be done with it.

Are you actually having trouble with your power supply? Have you measured the AC ripple on the rails filtered by those caps?
 
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sweetbeats said:
You are way overthinking this. Miroslav only shared the link to answer the question what does “B.K.” mean. You do not need that specific brand of cap. Just get Nichicon PW series caps...readily available, and affordable...likely spec better than the BK caps...and be done with it.

Are you actually having trouble with your power supply? Have you measured the AC ripple on the rails filtered by those caps?
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+1 There is a thread over at SoS forum where a chap had a problem with hum and it came down to a 15V 4A 'raw' external 50Hz power supply. This WAS the 6800uF filter cap', gone down to 1400uF. He fitted a new, (nothing special but 105C) 10,000uF and all was tickertyboo again.

But! That cap failed because of stupid design, it was placed just mm from the power transformer and therefore got much hotter than it should. Had it been fitted the other side of the PCB carrying the 4 diodes I venture it would have lasted twice as long.
My point in all this waffle is, electrolytic capacitors are MUCH more reliable than many people think given half a chance! Yes, go for a decent brand but don't pay silly money for 'audiophool' types.

Dave.
 
Sweetbeats, no I’m not having trouble with it. My Otari MX-5050 had physically leaking caps, as well as my Tascam 320B mixer. So I guessed I should replace the PS caps in all my old stuff. (Tascam 244, and the MS-16)

Ok, I’ll just order some of those other caps and not worry about it. I’m still learning about circuit repair. I know to discharge capacitors before I work on it, but I am still learning. The support I’m getting on this forum is excellent. You’ve all put a smile on the face on an anonymous Wisconsin dude.
 
AnalogApples said:
Sweetbeats, no I’m not having trouble with it. My Otari MX-5050 had physically leaking caps, as well as my Tascam 320B mixer. So I guessed I should replace the PS caps in all my old stuff. (Tascam 244, and the MS-16)

Ok, I’ll just order some of those other caps and not worry about it. I’m still learning about circuit repair. I know to discharge capacitors before I work on it, but I am still learning. The support I’m getting on this forum is excellent. You’ve all put a smile on the face on an anonymous Wisconsin dude.
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It sounds like, based on your experiences with your Otari tape machine and Tascam mixing console caps it’s pretty understandable why you are considering recapping you’re MS16 power supply. And the power supply is typically the first place to recap. But there’s also nothing wrong with testing things first if there is no physical signs of failure. I’ve done a LOT of preemptive/prophylactic recapping. It’s not a bad idea, but there’s no compelling reason to necessarily be like me and recap the sh1t out of everything just because. I can be a bit obsessive. But it sounds like you’ve got good reasons to do what you are doing, and it sounds like you are on track with what you need. I’ve had good experiences with all the Nichicon caps I’ve used, and the PW series are ideal for your application. I know a number of people way more experienced and intelligent than I am on this stuff that also include Nichicon caps such as the PW series on their list of go-to parts.

Keep us posted!
 
sweetbeats said:
It sounds like, based on your experiences with your Otari tape machine and Tascam mixing console caps it’s pretty understandable why you are considering recapping you’re MS16 power supply. And the power supply is typically the first place to recap. But there’s also nothing wrong with testing things first if there is no physical signs of failure. I’ve done a LOT of preemptive/prophylactic recapping. It’s not a bad idea, but there’s no compelling reason to necessarily be like me and recap the sh1t out of everything just because. I can be a bit obsessive. But it sounds like you’ve got good reasons to do what you are doing, and it sounds like you are on track with what you need. I’ve had good experiences with all the Nichicon caps I’ve used, and the PW series are ideal for your application. I know a number of people way more experienced and intelligent than I am on this stuff that also include Nichicon caps such as the PW series on their list of go-to parts.

Keep us posted!
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My thoughts pretty much. The wholesale diving in and re-capping scenario seems to me a bit of a 'fashion'?

Obviously, IF there is a fault or/and leaking of white ***t can be seen, 'ave'em out but otherwise tests should be done on the LF response and LF distortion, the latter giving the better idea of failing capacitors.

Don't have the means/smarts to do such tests? Maybe should not be messing with complex analogue audio gear?

In CERTAIN circuit situations it is prudent to increase the value of a coupling capacitor as this will reduce LF distortion but the effect is a small one and, WTGR to "Tape Machines" they are not ultra low THD devices to begin with. Any change of value MUST be tested for response.

Power supply caps can usually be changed 'on sight' they have the hardest life and you might increase the value slightly since you will usually find a higher value modern cap the same size or even smaller than the incumbent. But don't go mad! A 50% upscale should be seen as the maximum.

N.B. These are MY thoughts about general electronic equipment. I defer to Sweetbeats in ALL matters tape recorder!

Dave.
 
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