Unknown part, photo

[alp soandso]

I thought it was a capacitor, now I am not so sure.
Anybody know what this is?

http://members.shaw.ca/alpugh/UnknownPart-s.jpg


Alp

 

[Spehro Pefhany]

On Tue, 27 Sep 2011 04:13:39 GMT, the renowned alp soandso
<alpalpsoandso@gmail.com> wrote:

I thought it was a capacitor, now I am not so sure.
Anybody know what this is?

http://members.shaw.ca/alpugh/UnknownPart-s.jpg


Alp

If memory serves (and it may well not) that's an old 'wet-slug'
tantalum capacitor. If so, corrosive stuff inside.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Franc Zabkar]

On Tue, 27 Sep 2011 02:35:56 -0400, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> put finger to keyboard and
composed:

On Tue, 27 Sep 2011 04:13:39 GMT, the renowned alp soandso
alpalpsoandso@gmail.com> wrote:


I thought it was a capacitor, now I am not so sure.
Anybody know what this is?

http://members.shaw.ca/alpugh/UnknownPart-s.jpg


Alp

If memory serves (and it may well not) that's an old 'wet-slug'
tantalum capacitor. If so, corrosive stuff inside.

It looks like a tantalum to me as well. The date code is suggesting
the parts were made during week 42 of 1994, but I recall seeing these
during the early 1980s. In fact they used to fail catastrophically and
burn holes in the PCB.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[Jamie]

alp soandso wrote:

I thought it was a capacitor, now I am not so sure.
Anybody know what this is?

http://members.shaw.ca/alpugh/UnknownPart-s.jpg


Alp
YEs, that looks like a Cap.

25V, 50uf +/- 10%

I would replace that if it isn't reading, it most likely is
connected to the unijunction oscillator.

btw, those relays are prone to coil burn out. We use a lot of them
in the plant and I've never had one cook a unijunction how ever,
we've had bad caps and bad coils in them.

P.S.
some of ours used an IC, you must have an old type or one that
has a short timing spanned on it.

If you had a scope with isolation or a battery operated scope this
would be much simpler to diagnose. You would read between B1 and B2
of the unijunction of pulsing activity.



Jamie

 

[alp soandso]

Tantalum capacitor.
Thanks gang!

I imagine the red end is the equivalent of the neg marking on an
electrolytic (ie connect to more negative voltage (or gnd)).???

I have now read that reversing the leads can lead to capacitor failure,
I think I messed it up in my testing trying to determine what it was. I
don't think it holds a charge anymore but I was seeing it at one time.

Sad.
Will replace with a modern tantalum.

Alp

 

[ehsjr]

alp soandso wrote:

Tantalum capacitor.
Thanks gang!

I imagine the red end is the equivalent of the neg marking on an
electrolytic (ie connect to more negative voltage (or gnd)).???

Red usually indicates positive.

I have now read that reversing the leads can lead to capacitor failure,
I think I messed it up in my testing trying to determine what it was. I
don't think it holds a charge anymore but I was seeing it at one time.

Sad.
Will replace with a modern tantalum.

You'll likely find 50 uF difficult to get . Use 47 uF instead. If
this is for your Potter Brumfield relay circuit, it is likely that you
don't need a tant - you could probably use an aluminum electrolytic
instead. Generally, tantalums cost more, so at least you could
experiment with cheaper caps and replace with tants after you've
sorted out the polarity issue.

Ed

Alp

 

On Wed, 28 Sep 2011 17:20:15 -0400, ehsjr <ehsjr@nospamverizon.net>
wrote:

alp soandso wrote:
Tantalum capacitor.
Thanks gang!

I imagine the red end is the equivalent of the neg marking on an
electrolytic (ie connect to more negative voltage (or gnd)).???

Red usually indicates positive.


I have now read that reversing the leads can lead to capacitor failure,
I think I messed it up in my testing trying to determine what it was. I
don't think it holds a charge anymore but I was seeing it at one time.

Sad.
Will replace with a modern tantalum.

You'll likely find 50 uF difficult to get . Use 47 uF instead. If
this is for your Potter Brumfield relay circuit, it is likely that you
don't need a tant - you could probably use an aluminum electrolytic
instead. Generally, tantalums cost more, so at least you could
experiment with cheaper caps and replace with tants after you've
sorted out the polarity issue.

Ed


Alp

As for the polarity issue, the negative normally goes to ground, so
determine the ground. However if it's a coupling cap, then your guess
is as good as mine.

BTW: What piece of equipment is this thing in?

 

[alp soandso]

On Wed, 28 Sep 2011 17:20:15 -0400, ehsjr wrote:

Red usually indicates positive.




You'll likely find 50 uF difficult to get . Use 47 uF instead. If this
is for your Potter Brumfield relay circuit, it is likely that you don't
need a tant - you could probably use an aluminum electrolytic instead.

Ed

Well if red is positive that might explain why my part substitution is
not working.
I thought I would put the neg end of an (47 uf) electrolytic cap where
the red end of the tantalium was.
I'll verify on the working "delay/relay timer" which end the red end was
at and try again on the broken one. Might yet get it working.

Alp

 

[alp soandso]

BTW: What piece of equipment is this thing in?

A timer relay. see previous post in this thread for the exact type if you
are interested.

Alp

 

[ehsjr]

alp soandso wrote:

On Wed, 28 Sep 2011 17:20:15 -0400, ehsjr wrote:



Red usually indicates positive.




You'll likely find 50 uF difficult to get . Use 47 uF instead. If this
is for your Potter Brumfield relay circuit, it is likely that you don't
need a tant - you could probably use an aluminum electrolytic instead.


Ed


Well if red is positive that might explain why my part substitution is
not working.
I thought I would put the neg end of an (47 uf) electrolytic cap where
the red end of the tantalium was.
I'll verify on the working "delay/relay timer" which end the red end was
at and try again on the broken one. Might yet get it working.

Alp

Your posts on this, for some reason, made me want to dig a lot deeper,
looking at some of the posts you made elsewhere about this issue. Some
of the information I found was not readily apparent to those who have
responded here, so I'll add it into this post. If I mis-state any
of the findings, please correct the errors. Here's what I've found:

You want to repair a Potter & Brumfield CUF-41-30120 time delay relay.
The exact model of the relay is of critical importance. The datasheet
(referenced below) does not show a CUF-41-30120. It does show a
CUF-41-70120, and it also shows a CUH-41-30120. The reason the exact
model is critical is that the model number indicates the relay coil
voltage, which could be 24 volts DC or 24 volts AC, or 120 volts AC.
Knowing the correct coil voltage is important for us to figure out what
circuit is inside the relay case. It may be that CUF-41-30120 *is*
the correct model and is not shown on the datasheet, but it is worth
double checking.

You have already replaced the relay, which restored your machine to
proper operation, thus proving that the relay is indeed defective. You
want to repair the defective relay for use as a spare, rather than
building an add-on (external to the relay) circuit. Purchasing a new
relay is too costly: ~$200

You suspect two internal components: MSU112-2 which someone told you
is a ujt and the 50uF tantalum capacitors. You say you might have
installed the caps backwards. Both of these issues need to be double
checked. A search for a datasheet for MSU112-2 or MSU 112-2 or MSU112
or MSU 112 does not find one. It may be that the transistor is not a
ujt - without a schematic or a datasheet we can't be sure.

The datasheet for the relay can be found by clicking on
"Compact Time Delay Relay" near the bottom of the page at:
http://relays.te.com/pnb.asp

Per that datasheet, your relay is a "Delay on operate – Delay period
begins when input voltage is applied. At the end of the delay period,
the relay will operate and will not release until input voltage is
removed." (I am assuming the datasheet applies because the model
numbers shown there are *so* close to the model # you posted.)

An adjustable delay on operate timing circuit can be made with 5
components: a transistor, a potentiometer, a resistor, a capacitor
and a zener. (If you don't need an adjustable delay, you don't need
the pot - instead, you use a fixed resistor.) You already have the
pot as part of your existing broken relay. (I'm assuming yours has an
adjustable delay.) The question is: do you have room inside the
relay case for those parts if you remove the existing parts?
The above also assumes that your circuit uses 24 volts DC to energize
the relay.

Ok, please check the model # you have against the datasheet info.
Measure the coil voltage that the machine provides to energize the
relay to see if it is AC or DC, and the voltage level. Examine
your broken relay to see if the parts mentioned above could fit
in the available space. And please post the results.

Regarding your original circuit, the best thing, if possible, is
to repair what you have. We know that the existing components fit
in the available space, and there is no need to create a new circuit
if the defective component(s) can be identified and replaced.
Examine that transistor very closely to see if maybe the part
is labeled something other than MSU 112-2. If it is, please post
the correct number. You mention a diode - are there any numbers
visible on it? Many diodes have part numbers starting with
1N, like 1N4148, IN4001, 1N4746, 1N914 and so forth. See if
you can determine the part number for your diode. Also, in
one of your posts you mentioned that a few parts were connected
inside the relay case. So far, as I recall, you mentioned 2
caps, a diode and a transistor. Are there any other parts that
you didn't mention?

Finally a general comment. The price of time delay relays is really
annoying. Take a 10 dollar relay, and a buck or two worth of parts,
and presto! you've got a $200 relay. :-( From the manufacturer's
point of view I can see it: limited volume, tooling costs, production
time, etc. But from the consumer point of view ... grumble. I
think that may be why I'm so interested in this "saga".

Ed