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Need help identifying and replacing a capatitor. Condenser Microphones
Old 10th September 2011
  #1
Gear Maniac
 

Need help identifying and replacing a capatitor.

Hi all!

I need to replace a capacitor that was sitting in an old Tandberg reel to reel deck model 64 from 1963. Apparently this was powering the outputs as i hear almost nothing now. It's 8cm high and has a diameter of 3.5cm.

So what does these colors mean? The red was going to ground i know anyway.

Can i replace this with a two leg capacitor? And if so, how do i connect it?

And what does the text on the capacitor actually mean?


Many thanks in advance!

/R
Attached Thumbnails
Need help identifying and replacing a capatitor.-p1010020.jpg   Need help identifying and replacing a capatitor.-p1010030.jpg  
Old 10th September 2011
  #2
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Mylithra's Avatar
 

I believe thats a can cap that has 2 sections of 1000uf a piece at 35v. You would need 2 x 1000uf caps to replace it. Can Caps are still made and sold but most Ive seen are made for Tube amps so I dont know where you can get this particular value. As far as replacing, I dont know the deck and would be very hesitant to advise you on how to go about replacing it for many reasons.. not least of which is not wanting to be the cause of you shocking the ever loving crap out of yourself. (kind of hard to do at 35v I know but again, I dont know the deck and dont know what kind of voltage is flying around in there).
Old 11th September 2011
  #3
Gear Maniac
 

You seem to be right about two caps in one according to the schematic (C616 and C617, or maybe C9 and C12?). The Tandberg is all tube actually so you were right there too

Here is a link to the schematic:
http://personal.inet.fi/koti/mieite/...berg62-64x.gif

Looks like theres a resistor between them also.

But where do i connect the ground if i should use two caps? And what is (+) and (-) on this one?


Would replacing it affect the sound and perhaps the noise? I really don't know how these old caps sounds in comparison to the newer ones. The tandberg has too much noise for any serious usage :(
/R
Old 11th September 2011
  #4
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djmukilteo's Avatar
I'm pretty sure those are the power supply filter caps that come off the 25VDC side of that lower diode bridge which are C9/C12.
That cap is a dual multi-section can style capacitor.
Two caps in one can each section is [email protected]
The green wire shown on the schematic should be going to all the tube heaters (V1A - V8A). It is also providing 25VDC to the center channel amp and the oscillator board (23.5VDC)
The ground wire (black?) is ground (negative) for both caps within the can and the (tan??) wire should be going to the lower bridge diode rectifier. Check that and make sure that's what it is wired to. That 5ohm resistor is just indicating the tie between the two caps inside the can. (strap).
This cap has nothing to do with the audio path or "sound" or "noise" in the audio path of the tape deck. It's just the power supply.
If you put a scope or meter on the 25VDC output (green wire) and there is little or no DC ripple and the voltage is close to 25VDC, it's fine. There would be no reason to replace it. If there is a large amount of DC ripple or if they don't measure out to be 1000uF or the power supply doesn't read 25VDC and 23.5VDC where indicated on the schematic then you might want to replace it....but it probably isn't worth doing that for an old tube tape recorder, unless your into restoring it for nostalgic reasons.
You might find someone selling those type of can capacitors somewhere in the vintage tape deck realm...
If you really need to or want to replace it with newer cap(s) you could find the same dual cap can type that will fit in that clip or mount (2) 1000uF 35V electrolytic caps in parallel across the output of that diode bridge to ground.
Take both positive sides of the 2 caps to both the green wire and tan wire and the two negative side of the caps to that black ground wire.
....just be careful when you have it powered up and exposed....there is 245VAC running around those motors and 310VDC around those tubes!
Hope that helps!
Old 11th September 2011
  #5
Gear Maniac
 

Thanks for the info! The thing is that when i got it, the motor wasnt working, so i thought that "maybe" this capacitor was involved in some way. The voltages of it was: Green cable=24VDC, Black cable=27VDC, Brown cable=0VDC. And i thought that maybe putting the back cable on the back leg would solve at least something. So i switched the black and brown cable and the thing started up without any problem, but the motor was still dead. And stupid as i am i forgot to switch them back :( So after a while there was a small "poff" and there was a little tiny hole in the center of the pins. I thought that the cap now was dead. But i tested it now again and i got the same values as last time. So "maybe" it still works? Or is there a way to determine that both caps in the can is ok? Oh, and when all the cabels are connected to the capacitor there is a short between every leg. But not when they are disconnected.

The black is going to the power supply's ground. But maybe this is correct? It says on the can that "outer sect red" and the black cable is wired to the "red" leg. I have never encountered these types of capacitors before so im a bit novice in this area Well, in many areas actually, but particularly in this

Maybe this info helps a bit?

/R
Old 11th September 2011
  #6
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djmukilteo's Avatar
Quote:
Originally Posted by Rymdis View Post
Thanks for the info! The thing is that when i got it, the motor wasnt working, so i thought that "maybe" this capacitor was involved in some way. The voltages of it was: Green cable=24VDC, Black cable=27VDC, Brown cable=0VDC. And i thought that maybe putting the back cable on the back leg would solve at least something. So i switched the black and brown cable and the thing started up without any problem, but the motor was still dead. And stupid as i am i forgot to switch them back :( So after a while there was a small "poff" and there was a little tiny hole in the center of the pins. I thought that the cap now was dead. But i tested it now again and i got the same values as last time. So "maybe" it still works? Or is there a way to determine that both caps in the can is ok? Oh, and when all the cabels are connected to the capacitor there is a short between every leg. But not when they are disconnected.

The black is going to the power supply's ground. But maybe this is correct? It says on the can that "outer sect red" and the black cable is wired to the "red" leg. I have never encountered these types of capacitors before so im a bit novice in this area Well, in many areas actually, but particularly in this

Maybe this info helps a bit?

/R
Well for starters the motor is powered right off the transformer on that 250VAC tap so that cap has nothing to do with the motor not starting or running. That would be something in the motor circuit or maybe one of those two micro-switches.
Think of that canned capacitor as (2) 1000uF caps in parallel. They are connected internally. The schematic shows "green" labeled on the top of the wire line where it says "25V". If you didn't change anything on the top of the capacitor in your photo the green wire is soldered to the "gold" looking terminal.
The black terminal should be ground or (-) and the red (+) coming from the diode bridge. That terminal would probably measure 27V to ground coming into the cap and you get 25V out with no ripple (filtered). You could only see the ripple using a scope. If you used an analog meter movement sometimes you will see the needle bouncing up and down a little...which is the ripple.
So not being able to see in the photo or trace those wires back to what they're connected to....I would "guess" the green wire (gold terminal) is going to C9 (+25V), the black wire (red terminal) is going from C12 (+) to the diode bridge (+C) and the tan wire (black terminal) is going to ground (-).
Now if you changed the wiring around and the cap "poofed" when you powered it up then you popped that cap and it's gone now. It's very possible things would still work but that cap isn't doing any filtering anymore. And that 25V side will be more like pulsating DC rather than flat straight line DC.
SO....if you go get a 2000uF electrolytic cap 35-50VDC "working voltage" (WVDC) you could tie the two wires that go to the "tube heaters" and the "diode bridge" together and connect those to the (+) side of the new cap and connect the ground wire to the (-) side of that new cap, you will have the same thing as had before. You'll have to figure out a way to mount the new cap in place there. That clip might hold the new cap if you get one close to the same diameter with screw terminals or solder tabs on top.

BTW...If your trying to improve the "noise" and think the audio path caps are old or bad those would be all the smaller caps on the audio channel boards. If you put a signal into the audio path you can take a new cap of the same value and voltage and temporarily "clip" it (or connect it) right across the existing cap in the circuit. If that existing cap is bad or in poor condition there will be an improvement you will hear or you will not. It's an easy quick way to find a bad cap in a circuit without guessing which one is good or bad...
Another way of doing this is of course using a scope where you can trace through the circuit path and actually "see" where the noise is and make any improvement if there actually is any to be made.
Bad tubes can also cause all of those problems as well though....so just be forewarned!
Good luck...hope that helps
Old 11th September 2011
  #7
Old 12th September 2011
  #8
Gear Maniac
 

Quote:
Originally Posted by djmukilteo View Post
Well for starters the motor is powered right off the transformer on that 250VAC tap so that cap has nothing to do with the motor not starting or running. That would be something in the motor circuit or maybe one of those two micro-switches.
Think of that canned capacitor as (2) 1000uF caps in parallel. They are connected internally. The schematic shows "green" labeled on the top of the wire line where it says "25V". If you didn't change anything on the top of the capacitor in your photo the green wire is soldered to the "gold" looking terminal.
The black terminal should be ground or (-) and the red (+) coming from the diode bridge. That terminal would probably measure 27V to ground coming into the cap and you get 25V out with no ripple (filtered). You could only see the ripple using a scope. If you used an analog meter movement sometimes you will see the needle bouncing up and down a little...which is the ripple.
So not being able to see in the photo or trace those wires back to what they're connected to....I would "guess" the green wire (gold terminal) is going to C9 (+25V), the black wire (red terminal) is going from C12 (+) to the diode bridge (+C) and the tan wire (black terminal) is going to ground (-).
Now if you changed the wiring around and the cap "poofed" when you powered it up then you popped that cap and it's gone now. It's very possible things would still work but that cap isn't doing any filtering anymore. And that 25V side will be more like pulsating DC rather than flat straight line DC.
SO....if you go get a 2000uF electrolytic cap 35-50VDC "working voltage" (WVDC) you could tie the two wires that go to the "tube heaters" and the "diode bridge" together and connect those to the (+) side of the new cap and connect the ground wire to the (-) side of that new cap, you will have the same thing as had before. You'll have to figure out a way to mount the new cap in place there. That clip might hold the new cap if you get one close to the same diameter with screw terminals or solder tabs on top.

BTW...If your trying to improve the "noise" and think the audio path caps are old or bad those would be all the smaller caps on the audio channel boards. If you put a signal into the audio path you can take a new cap of the same value and voltage and temporarily "clip" it (or connect it) right across the existing cap in the circuit. If that existing cap is bad or in poor condition there will be an improvement you will hear or you will not. It's an easy quick way to find a bad cap in a circuit without guessing which one is good or bad...
Another way of doing this is of course using a scope where you can trace through the circuit path and actually "see" where the noise is and make any improvement if there actually is any to be made.
Bad tubes can also cause all of those problems as well though....so just be forewarned!
Good luck...hope that helps
Very interesting! But how do i connect the wires to the cap? there are 3 wires but only two legs. will the 25VDC and 27VDC go to the positive leg and then ground to the negative?

Yeah, i've heard about this with testing caps as you suggested. But i have never understood what it actually does? Will not the current go through the old cap as well when "clipping in" the new one? And i see that most caps are non-polarity caps. Not sure what to do with these. I attach a picture of the board. There are some strange high metallic caps as you can see

Thanks again for taking time! Really appreciate it! And sorry for stupid questions, but as were in the Geek section, maybe its ok?

/R
Attached Thumbnails
Need help identifying and replacing a capatitor.-tandberg1.jpg   Need help identifying and replacing a capatitor.-tandberg2.jpg   Need help identifying and replacing a capatitor.-tandberg3.jpg  
Old 12th September 2011
  #9
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djmukilteo's Avatar
Quote:
Originally Posted by Rymdis View Post
Very interesting! But how do i connect the wires to the cap? there are 3 wires but only two legs. will the 25VDC and 27VDC go to the positive leg and then ground to the negative?

Yeah, i've heard about this with testing caps as you suggested. But i have never understood what it actually does? Will not the current go through the old cap as well when "clipping in" the new one? And i see that most caps are non-polarity caps. Not sure what to do with these. I attach a picture of the board. There are some strange high metallic caps as you can see

Thanks again for taking time!

/R
Yes those two wires together to the positive and the ground wire to the negative.

If you have a bad cap and you put a good cap in parallel with it you are adding capacitance. So if the bad cap is open your good cap should "replace" the bad cap in the circuit and show a difference and typically "fix" the problem. Not always and noticeable though...using an oscilloscope is the best way to check this.
Non polarized caps are just that...they don't care which direction they go in.
Those other big can capacitors are listed in your schematic and again are part of the power supply rails for the tubes...they are probably fine just test the voltage test points indicated on the schematic and make sure they are the correct voltage (+/- 2-3volts) and not dead or way off.
You can take them out of the circuit and test them with a capacitance meter also. Most of those are just rolled up paper and foil layers. The most common problem is the can leaks air in there and the dielectric paper or plastic gets dry.
As paper or dielectric gets old it has a harder time keeping (separating) voltage away from the foil layers it is isolating and it "burns" a tiny hole through the dielectric material which typically causes the cap to go open. Sometimes the cap will short through the dielectric allowing the foil layers to connect with each other and they fuse together.
That case typically causes other parts around it to fail as well.

The most common caps that affect "noise" in the audio path are the small .01uF bypass caps (small round flat disc shape usually yellow in color) that are tied between the circuit and the ground plane. They are all over the place in many different locations on the circuit board.
The other type of caps are the audio signal isolation caps between different audio path stages. These are typically in series with the audio path. If they fail the audio path will either be dead on the output side.... or the signal will find some feedback path around the bad cap and sound pretty crappy. Those can usually be tested using a scope on either side of the cap and checking your sine wave test signal through the circuit looking for distortion or loss of signal. You can easily do that by injecting your sine wave set to a known value (like 1Vp-p @1Khz) into one of the input channels and then following the path through the circuit path touching your scope probe along the way per the schematic...you should be able to operate any level knobs, EQ etc and watch that sine wave change level to confirm everything is working properly. If you see clipping or distortion of the sine wave you know there is a problem with that stage of the circuit...having a proper signal generator, meter and a decent scope is really the only way to fix this kind of stuff properly....a lot of people on here always think just replacing caps is all that it takes to fix these things....LOL....it's a very common misconception and approach. And caps are cheap....Hope that helps! and good luck!
Old 12th September 2011
  #10
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2N1305's Avatar
 

I'm sorry to say this but, lol, you wrote capatitor.

And yes it is a multi section cap, and no, you don't need to replace it with a multi-section cap because, as stated, these are very hard to find.
You can substitute as many individual caps as you have section sin the cap, using a working voltage of at least what was rated. Also consider a temperature of at least 105°C not the standard 85°C, as that will not be sufficient in a closed area where there are many tubes, especially output tubes.
check out www.tubesandmore.com you might get lucky and find a substitute. If you've never done this ror worked with high voltage, do not attempt to do it yourself...

Cheers, (and be careful!)
Old 12th September 2011
  #11
Gear Maniac
 

Oops, well i cant change that now

Another thing crossed my mind, it was when i connected the black wire to ground that the big capacitor broke down. I switched the black and brown cable. So is it really smart to do this again?

And i asked a friend about the 5 ohm resistor and he said that the 5 Ohm resistor serves two purposes - one is to act as a filter resistor, second is a heat fuse : When it get's too hot, a finger goes loose and disrupts the circuit. That type of resistor is often seen in tube based equipment. And using one single cap would nog be appropriate in this case. Not sure now what to think

Another one said that i should try to locate the 5 ohm resistor. So apparently its not "in" the cap...?

I really hate when getting mixed answers

/R
Old 12th September 2011
  #12
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2N1305's Avatar
 

short answer because I have no time now: don't change or cut anything else. If posssible try to locate a schematic. It will be much easier to understand where those voltages are going and how they relate(ed) to the caps.

cheers!

2N
Old 12th September 2011
  #13
Gear Maniac
 

There is a link to the schematics in my second post. But i don't understand everything

/R
Old 13th September 2011
  #14
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djmukilteo's Avatar
Quote:
Originally Posted by Rymdis View Post
There is a link to the schematics in my second post. But i don't understand everything

/R

LOL
Maybe you should have someone repair it for you if you really think it's worth fixing? You've already changed wires around on something you had no idea what it was and blown that up?....????...that's kind of crazy if you don't know what you're doing don't you think! Especially with high voltage stuff with tubes...why not just stick your hands and switch wires around in your electrical panel and see what happens....seriously
What was your intended reason for repairing or using this thing in the first place? It's not like this it's anything close to a decent tape deck
It's old and noisy and has tubes in it?

Tandberg Model 64 X | Johan's Old Radios

You'll just hurt yourself!
Don't play around with electricity or electronics if you don't anything about it!
Darwin award!
Old 13th September 2011
  #15
Gear Maniac
 

It actually has a beautiful sound, when working Ive had one in the past, but sold it for some reason.

But i agree that switching cables was really stupid of me :( Normally i ask an old friend of mine for advices, but it was late in the night so....maybe i wasnt thinking clearly.

But if everybody suggest that the back wire "should" go to ground, i guess that i wasnt that far off anyway
(I have actually managed to repair a few amplifiers, power supplies and other various stuff, believe it or not )

But as im uncertain now i ask, which i should have been doing in the first place instead of playing around. But i have respect for electricity, and as ive had a few shocks i now what it feels like, and thats something im trying to avoid. At least i try to have one hand isolated all the time when working with current.

But your right! Foolish, stupid and dangerous making decisions not knowing what will happen.

So before i do anything, i must be certain that the thing doesnt blow up or something. Thats why i ask maybe stupid questions. Im done with taking chances.

But you dont have any suggestions instead of criticize me?

/R
Old 13th September 2011
  #16
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djmukilteo's Avatar
Quote:
Originally Posted by Rymdis View Post
It actually has a beautiful sound, when working Ive had one in the past, but sold it for some reason.

But i agree that switching cables was really stupid of me :( Normally i ask an old friend of mine for advices, but it was late in the night so....maybe i wasnt thinking clearly.

But if everybody suggest that the back wire "should" go to ground, i guess that i wasnt that far off anyway
(I have actually managed to repair a few amplifiers, power supplies and other various stuff, believe it or not )

But as im uncertain now i ask, which i should have been doing in the first place instead of playing around. But i have respect for electricity, and as ive had a few shocks i now what it feels like, and thats something im trying to avoid. At least i try to have one hand isolated all the time when working with current.

But your right! Foolish, stupid and dangerous making decisions not knowing what will happen.

So before i do anything, i must be certain that the thing doesnt blow up or something. Thats why i ask maybe stupid questions. Im done with taking chances.

/R
Sorry that probably was a little condescending, but I just felt it had to be said....there are sooo many people who think all this stuff is somehow magical audio equipment that will write them a hit sound or something just by replacing a few caps or something along those lines....it's just amazing how so many have no idea and yet leap in with some duct tape and wire cutters. LOL
As far as those wires are concerned if you didn't change the other ends then just trace them back to what went to ground, which one to the bridge and which one to the tube heater connection (which was labeled "green" BTW on the schematic). The voltage off that bridge is only 27VDC so putting a good 50V 2000uF cap in place will certainly not hurt anything.
Old 13th September 2011
  #17
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2N1305's Avatar
 

Quote:
Originally Posted by Rymdis View Post
There is a link to the schematics in my second post. But i don't understand everything

/R
Ah, sorry, I was going too fast, I read your first post then jumped to an answer because you said capatitor (still find that funnyheh), then I HAD to say something smart.
So without further wait, I will look at the schematic. And also, it seems you are a bit new to electronics so BE CAREFUL! Do not touch anything with your bare fingers, if those caps are still charged (and they are!) and you short the terminals, you will get a serious (life-threatening) shock...
Old 13th September 2011
  #18
Gear Maniac
 

Quote:
Originally Posted by djmukilteo View Post
Sorry that probably was a little condescending, but I just felt it had to be said....there are sooo many people who think all this stuff is somehow magical audio equipment that will write them a hit sound or something just by replacing a few caps or something along those lines....it's just amazing how so many have no idea and yet leap in with some duct tape and wire cutters. LOL
As far as those wires are concerned if you didn't change the other ends then just trace them back to what went to ground, which one to the bridge and which one to the tube heater connection (which was labeled "green" BTW on the schematic). The voltage off that bridge is only 27VDC so putting a good 50V 2000uF cap in place will certainly not hurt anything.
Couldnt agree more on that! It's not the wand at the end, it's the wizard Sure, tubes and all kind of old stuff "could" mean something for your music, but it will not stand between you and that hit record. If it does then its probably something wrong with your whole mix.

Well, i will use it to play tapes, and "maybe" route some sounds through it just to see what it does to it. But it looks cool, and it has tubes, so what more could you want?

well, the brown cable was going to ground before i switched it with the black cable. The black cable had a 27VDC and the green 24VDC whilst the brown had 0VDC. I think that was what made me switching the brown with the black cable. Just seemed logic at the time that ground should have 0VDC instead of 27VDC. I never changed the other ends of the cables and the black cable is actually going to ground. Checked that with my multimeter. Yep, i have one, believe it or not So right now i have no idea what to think actually :(

have to investigate where the other ends are going. But it looked like nobody had resoldered the wires on the cap. The thing that made me open the deck was that the motor didnt run. So i thought that maybe this capacitor had something to do with it. But maybe it was all fine and the motor just had burned or something? Strange though that the black cable has a 27VDC going to ground, to me anyway.

/R
Old 13th September 2011
  #19
Gear Maniac
 

Quote:
Originally Posted by 2N1305 View Post
Ah, sorry, I was going too fast, I read your first post then jumped to an answer because you said capatitor (still find that funnyheh), then I HAD to say something smart.
So without further wait, I will look at the schematic. And also, it seems you are a bit new to electronics so BE CAREFUL! Do not touch anything with your bare fingers, if those caps are still charged (and they are!) and you short the terminals, you will get a serious (life-threatening) shock...
yeah, who spells wrong in the title?

I have it powered off until i know what to do with it. Im usually very careful measuring anything before i touch it and so on. It's a pity that i havent learned to read schematics properly :( Thats a BIG problem actually. But somehow i usually get most things fixed anyway...i measure and just use logic sense i think....not always that good apparently

So why not use the best forums if they are available? Now that would be real stupid!

/R
Old 13th September 2011
  #20
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2N1305's Avatar
 

Okay here's what you have to do:
1- Replace the cap that went "poff" ( I believe this is the motor cap, C14, and should be marked 1,5uF) It should be a 300V cap or more!
2- Once that is replaced, check the wiring to make sure you have it connected like it was before
3- Measure the voltages, only at this spot.

Very odd that the motor runs off 245V, I've never seen this before.

I do not know if you touched anything else in the wiring, but if so you should tell us.

Do the tubes light up? Is there sound?

awaiting response...
Old 13th September 2011
  #21
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2N1305's Avatar
 

Quote:
Originally Posted by Rymdis View Post
yeah, who spells wrong in the title?

I have it powered off until i know what to do with it. Im usually very careful measuring anything before i touch it and so on. It's a pity that i havent learned to read schematics properly :( Thats a BIG problem actually. But somehow i usually get most things fixed anyway...i measure and just use logic sense i think....not always that good apparently

So why not use the best forums if they are available? Now that would be real stupid!

/R
Yes, we are all geniuses here.
We can most definitively, without a doubt, quite possibly, probably, maybe, there's a slim chance we can help you out
alright time out for me for an hour

cheers

ps: tell me three things that confuse you when you read schematics. Don't be afraid, I will not make fun of you. I was nto always a super intelligent geek, you know... (I'm still not!)
Old 13th September 2011
  #22
Gear Maniac
 

Quote:
Originally Posted by 2N1305 View Post
Okay here's what you have to do:
1- Replace the cap that went "poff" ( I believe this is the motor cap, C14, and should be marked 1,5uF) It should be a 300V cap or more!
2- Once that is replaced, check the wiring to make sure you have it connected like it was before
3- Measure the voltages, only at this spot.

Very odd that the motor runs off 245V, I've never seen this before.

I do not know if you touched anything else in the wiring, but if so you should tell us.

Do the tubes light up? Is there sound?

awaiting response...
Maybe i was just lucky fixing the stuff i did....Im not smart, if i were then i wouldnt had to ask about everything But this is the Geek section, so maybe im forgiven?

Nah, the motorcap is 1.5uF and is intact it seems. It was the C9/C12 that blew up on me. I havent touched anything else. Even though there was a tiny hole on the cap it still provided enough power for the amp so that i could hear something. I tested with it dismounted and there was almost silence. But i dont know if its totally "intact" as of the "pooff" Maybe one cap in the can is still ok?

I have to get back to you on what i find hard reading on schematics

/R
Old 13th September 2011
  #23
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djmukilteo's Avatar
Ok....Well if you can fix the 25VDC power supply side back up the way it was....then look at the schematic where the motor is and be careful with the voltage there (it's 245VAC!) and check the motor gets turned on via that microswitch. Take a measurement with your meter at C13 where it connects to the switch and motor and C14 where it connects to the motor and transformer (AC scale 300-500V range if your meter has that) and make sure the motor is getting power and if it is.....then there's a problem with the motor.

Best to clip your meter leads onto those spots first UNPOWERED, then don't be touching anything and turn it on....AND...make sure your meter is capable of measuring 250+volts of AC before doing that!

Doing things like this on a forum seems like trying to tell a person how to load a gun with the safety off......f***king crazy.....

There's an old adage/saying out there in the electrician's world.
If you meet an electrician who has all of his digits and is a walking breathing talking human...just remember
"There's no such thing as a dumb Electrician".
"A dumb electrician is a dead electrician"
...and that's why there is no such thing as a dumb electrician
Old 13th September 2011
  #24
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2N1305's Avatar
 

Quote:
Originally Posted by djmukilteo View Post
Doing things like this on a forum seems like trying to tell a person how to load a gun with the safety off......f***king crazy.....

There's an old adage/saying out there in the electrician's world.
If you meet an electrician who has all of his digits and is a walking breathing talking human...just remember
"There's no such thing as a dumb Electrician".
"A dumb electrician is a dead electrician"
...and that's why there is no such thing as a dumb electrician

F***ing right! lol

It is dangerous, and by golly I'd prefer it if he'd just hand if off to a repair tech. BUT, that being said, I didn't learn anything about taking chances by not getting electrocuted about a dozen times...
Rather, you have to take chances some times.

Rymdis,

Just remember those voltages can KILL
if you know where not to put your fingers then proceed with caution. By the way, exploding caps can ruin your face, I was lucky once... The force with which those things explode is equivalent to a small firecracker, sometimes a big firecracker...
Take the damaged Cap (C9&C10) out of there and replace it with ANY other cap rated higher than 25volts. The damaged cap can still cause problems. It can ONLY degrade and cause more problems.
Old 13th September 2011
  #25
Lives for gear
 

Quote:
Originally Posted by 2N1305 View Post
exploding caps can ruin your face, I was lucky once... The force with which those things explode is equivalent to a small firecracker, sometimes a big firecracker...
and people always laugh at me when I use an long extension lead and power things up from the other side of the room, with something over the changed caps.
Old 13th September 2011
  #26
Lives for gear
 
djmukilteo's Avatar
Quote:
Originally Posted by oxide54 View Post
and people always laugh at me when I use an long extension lead and power things up from the other side of the room, with something over the changed caps.
They laugh because they do not understand and it's funny and strange to them...Tesla used to entertain guests in his lab all the time!
I like safety glasses, double insulated tools and gloves! LOL!
Old 13th September 2011
  #27
Gear Maniac
 

I'll do some measures and post them back here later on today. I saw on the schamatic that at least one place on the center channel amp board had 500V, that's rather high

/R
Old 13th September 2011
  #28
Gear Maniac
 

I checked the 3 cables going to the motor. The first is 172VDC and 142VAC, the next is 172VDC and 142VAC and the third i couldnt get a stable DC voltage on as it jumped bigtime, but it had a a stable 144VAC.


Also checked the cables.
The brown cable is going from the can to the b30c1000 and the green cable is going from the can to one side of the 5 ohm resistor. The back cable is going from the can to the power supply, then continues to the other side of the 5 ohm resistor. So the 5 ohm resistor is NOT in the can But my friend was pretty sure when i asked him about it so....too bad he's busy all the time :/ 76 years old and still hired by companies holding lectures and educations

Maybe this info helps?

/R
Old 14th September 2011
  #29
Gear Maniac
 

Apparently the wiring to the "can" is ok. Just need to switch it for another one.

Is it ok to use two 1000uF 200V caps? I only have 200V at home right now so...will this lead to "any" degration or something? Ive read that you should use as low voltage as you can get away with...but i guess that's in the audio path?

And still have no clue why the motor isnt running either


/R
Old 14th September 2011
  #30
Lives for gear
 
2N1305's Avatar
 

if you want to replace the 35V cap with a 200V cap, that's fine. Nothing "audio" will be affected by this change.

also, do you have tape thread on your machine? Did you notice the two switches near the motor (on the schematic), they make the motor run, if they are closed only.
this is probably why the motor does not work.
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