Some help please....
This is my very first post - so please be gentle with me. Also, if this is in the wrong section then by all means redirect me. So...
I have 3 Musical Fidelity Dr Thomas power amps. I have the second edition ones and they are paired together and have been delivering great service for over 20 years.
A while ago I bought the even earlier one which I suggest is known as the 'shoebox' version. I ran it for a year and then the sound started to tail off.
What was apparent is that one or both of the 22000uf capacitors had decided to give up on life (and leak its insides all over the bottom of the amp - nice!). They were the original LCR caps from back in the day. I spoke with LCR and they clearly said they don't make those any more and all their old stock they sold off years ago to someone they used to deal with, ages ago. They suggested I bought the next nearest thing and installed that.
My question is that on the LCR 22000uf 63v caps it say PLAIN NEG and there is, as far as I can see, no +/- against the terminals. The replacement caps I bought are same rated Kendeil caps but they are identified as + and -.
So, assuming that correct connection is important - how would I go about identifying which way round to connect the caps?
Thanks for your help....
Edward.
This is my very first post - so please be gentle with me. Also, if this is in the wrong section then by all means redirect me. So...
I have 3 Musical Fidelity Dr Thomas power amps. I have the second edition ones and they are paired together and have been delivering great service for over 20 years.
A while ago I bought the even earlier one which I suggest is known as the 'shoebox' version. I ran it for a year and then the sound started to tail off.
What was apparent is that one or both of the 22000uf capacitors had decided to give up on life (and leak its insides all over the bottom of the amp - nice!). They were the original LCR caps from back in the day. I spoke with LCR and they clearly said they don't make those any more and all their old stock they sold off years ago to someone they used to deal with, ages ago. They suggested I bought the next nearest thing and installed that.
My question is that on the LCR 22000uf 63v caps it say PLAIN NEG and there is, as far as I can see, no +/- against the terminals. The replacement caps I bought are same rated Kendeil caps but they are identified as + and -.
So, assuming that correct connection is important - how would I go about identifying which way round to connect the caps?
Thanks for your help....
Edward.
It seems a rude place for new members here, so we'd better be more patience, at least to what the seasoned consider obvious. Once at the top, one can only tumble down. Did you only peek around here for 8 years?
You're right to be cautious, and polarity is important with large (polarised) capacitors.
But pictures of the originals and replacements will help to those who will attritute to your post. I had a nice MF once, but I do not know these MFDT's your mentioning (picture!).
You're right to be cautious, and polarity is important with large (polarised) capacitors.
But pictures of the originals and replacements will help to those who will attritute to your post. I had a nice MF once, but I do not know these MFDT's your mentioning (picture!).
Edward in times gone by the positive was marked by red paint and the negative black .
That changed to an imprint on the solder tags flat surface of a + and the negative --as you say is PLAIN --its an indent so shouldn't rub off .
If that is not the case then Philips capacitors have a 1 representing the positive and a 5 representing the negative .
Again Denon capacitors have a checkered imprint on the POSITIVE flat surface and nothing on the negative .
Yes I know ---confusing.
That changed to an imprint on the solder tags flat surface of a + and the negative --as you say is PLAIN --its an indent so shouldn't rub off .
If that is not the case then Philips capacitors have a 1 representing the positive and a 5 representing the negative .
Again Denon capacitors have a checkered imprint on the POSITIVE flat surface and nothing on the negative .
Yes I know ---confusing.
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You make some good points.
It may not be possibly be my very first post - but I don't post very often. I do visit from time to time and read posts but electronics, volt amps ohms and so on, are so very complex and detailed for me, that......
Someone, many years ago, once told me that if you have nothing intelligent or good to say - the best to say nothing. People may think you are stupid - but there is not point in proving them right by opening your mouth. 🙂
What I will do, or try and do, is gather some photos of the existing, which is all still in place - and the new ones - and then hopefully people can then point me in the right direction. Perhaps in the future I may be able to then share my improved knowledge with future generations. 😀
It may not be possibly be my very first post - but I don't post very often. I do visit from time to time and read posts but electronics, volt amps ohms and so on, are so very complex and detailed for me, that......
Someone, many years ago, once told me that if you have nothing intelligent or good to say - the best to say nothing. People may think you are stupid - but there is not point in proving them right by opening your mouth. 🙂
What I will do, or try and do, is gather some photos of the existing, which is all still in place - and the new ones - and then hopefully people can then point me in the right direction. Perhaps in the future I may be able to then share my improved knowledge with future generations. 😀
Ahh .... Duncan - that is very, very helpful. There is a red marking on the terminals - so that pretty much answers an important question.
You wouldn't believe the original soldering in this item - I am no expert - but it does look like a blind, school child has put this together. I only probably solder things about a dozen times a year - but I reckon I could have produced better solder joints. I guess it was 80's early hifi manufacture - but as with some of the early MF items - it really does look like it was done on a kitchen table - but late at night, on a Friday - after a couple of stiff ones. Grateful for your helpful comment. So red = positive - big thanks.
You wouldn't believe the original soldering in this item - I am no expert - but it does look like a blind, school child has put this together. I only probably solder things about a dozen times a year - but I reckon I could have produced better solder joints. I guess it was 80's early hifi manufacture - but as with some of the early MF items - it really does look like it was done on a kitchen table - but late at night, on a Friday - after a couple of stiff ones. Grateful for your helpful comment. So red = positive - big thanks.
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Duncan,
no I don't think I missed it - but because it is early on in my DiyAudio life - my posts have to be checked initially by a modirator - so that is probably why the post seem slow and out of sequence. I could do the quote thing - but perhaps will do that later on.
Your post was extremely helpful.
Will work out how to put some pictures up - but need to head to bed soon as work in the morning. 🙄
no I don't think I missed it - but because it is early on in my DiyAudio life - my posts have to be checked initially by a modirator - so that is probably why the post seem slow and out of sequence. I could do the quote thing - but perhaps will do that later on.
Your post was extremely helpful.
Will work out how to put some pictures up - but need to head to bed soon as work in the morning. 🙄