bonzoronnie
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| posted on 30/4/17 at 01:14 PM |
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Electronic component id help
Can anyone please help me to identify an electronic component.
Have spent hours searching the net, all to no avail.
 
Boat sender
The component in question is the square silver one in front of the LM340T5 voltage regulator chip .
Only marking on it is 100 - u1 - 100
The u1 could mean that it is some kind of capacitor, possibly 1 micro farad in value ?
That said, I have been unable to find an image of a capacitor that even remotely resembles the component in the picture.
It may help to say that the photograph is the pcb of a simple sender unit that drives 2 gauges.
Any help would be most welcome
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gremlin1234
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| posted on 30/4/17 at 01:50 PM |
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looking at the circuit, its a classic power supply,
I think its a 'polyester film' capacitor
see third one in this pic.
https://en.wikipedia.org/wiki/Capacitor#/media/File:Condensators.JPG
this type tend not to be used much now, I guess they have found even better ones ;-)
edit: see also
https://en.wikipedia.org/wiki/Film_capacitor
[Edited on 30/4/17 by gremlin1234]
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bonzoronnie
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| posted on 30/4/17 at 02:17 PM |
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Thank you so much Gremlin
Looks like you may have nailed it 
Perhaps 1uf - 100v ?
For those that are interested.
The sender unit is from a my brothers boat.
Sends the rudder angle position to 2 gauges.
Removed the entire system ( sender & gauges ) because it was no longer working.
Took it home for a fiddle, as you do 
I hooked it up to a battery & noticed that when I touched the heatsink on the LM340T5 the sender & gauges worked once more.
Quick inspection with a magnifying glass, I noticed that one of the pins of the regulator chip had broken.
For testing purposes I decided to solder the pin back together, in a moment of stupidity I forgot to disconnect the battery
Anyhow once the pin was soldered it no longer worked , guess I must have made soldering iron contact with one of the other pins & fried the
chip.
Have replaced the LM340T5 regulator chip but still nothing so most likely something else is blown.
So few components on that board, I am tempted just to change the lot.
Going to be way cheaper than spending £500 + on a new dual station set up. 
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bonzoronnie
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| posted on 30/4/17 at 03:06 PM |
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Thanks to Gremlins help I have managed to find the component in question
It's a 1uf 100v 5% Stacked Polyester Film Capacitor.
Here is a better picture of the pcb
 
Description
Circa 1980's & no longer in production.
Not a lot of components to justify the huge cost that these things command.
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DW100
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| posted on 30/4/17 at 04:25 PM |
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Looks like the diodes to the right are forming a bridge rectifier that feeds a 5v volt regulator and a 250 Ohm potentiometer in the middle to give the
postion. Nothing that couldn't be make for less than £10
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gremlin1234
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| posted on 30/4/17 at 04:28 PM |
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the most likely element on that circuit to fail would be one or more of the diodes
they would be easy enough to test (buzz out) with a multimeter.
note these look like very small diodes, and if you shorted the regulator positive in, to ground, then that would easily 'blow' them
if they have any markings on them, then you could replace the like for like, or uprate them to the 1n400x series. (the last part of the part number is
the max voltage rating) so I would use 1n4001 if under 50v, else 1n4004 upto mains voltage.
the capacitor in question is likely to be across the input of the regulator, and for testing purposes could be removed.
and if it replacing it, just use a more modern version of similar construction and value
see
http://www.ti.com/lit/gpn/lm340
for typical wiring of the regulator.
edit:
you say that a leg was broken on the reg.
I think it would be worth using some 'hot glue' or similar, to save vibrations causing a similar failure again.
ps Marvin, the paranoid android suffered this type of problem too
"and me with this terrible pain in all the diodes down my left side"
[Edited on 30/4/17 by gremlin1234]
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gremlin1234
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| posted on 30/4/17 at 04:33 PM |
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quote:
Originally posted by DW100
Looks like the diodes to the right are forming a bridge rectifier that feeds a 5v volt regulator and a 250 Ohm potentiometer in the middle to give the
postion. Nothing that couldn't be make for less than £10
yep though there are also a couple of trim pots for fine tuning.
note to OP
don't just replace all the components, else you will loose these trim settings.
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bonzoronnie
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| posted on 30/4/17 at 04:56 PM |
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Thank you chaps.
Gremlin
I am sure you are right & I have fried some or all of those diodes.
If I made contact with the soldering iron it would have been pin 3 to pin 2 , I am guessing that would have shorted out big time.
Damn my silly lapse of concentration.
I can just about see 1N4 marked on the diodes.
Will de-solder 1 so as I can have a better look with my eye glass.
Changing the diodes will be my first priority.
with a little luck, I have not harmed the 250r pot or the 3 trimmer pots.
Soooo wish I went to Radio rentals when I left school ( They were hiring )
Like a dumb ass I choose to become an apprentice Butcher of all things.
Once again, thank you for the help.
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gremlin1234
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| posted on 30/4/17 at 05:21 PM |
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the diodes on there look like 1n4148,
also if you were testing from a dc source, it might just work if your reverse the polarity of the input!
but really just test them with a multimeter
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bonzoronnie
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| posted on 30/4/17 at 05:35 PM |
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I have just tested the diodes with my multi meter, only get a buz from one, looks like the other 3 are dead.
Yes to me they look like 1N4148's.
Will have a root though my electronic components collection for some, failing that I will order some in.
ETA
Yes I would be loathed to change the trimmer pots as I do not have the equipment to re trim new ones.
Very good call on the hot glue idea.
The area where the sender is installed is subject to a fair bit of vibration.
I am honestly surprised that for a marine application, the board is not even conformity coated.
[Edited on 30/4/17 by bonzoronnie]
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rf900rush
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| posted on 30/4/17 at 05:40 PM |
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Hi
u1 is 0.1 micro Farad.
100 would be the maximum working voltage.
u is used as the decimal point
IE 4u7 would be 4.7uf
It is likely to be across pin 1 and 2 or 2 and 3.
It would used as a "Decoupling" capacitor
In reality 0.1 or even 1uf would work.
The number 7805 on the device next to it would indicate a 5volt positive regulator.
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bonzoronnie
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| posted on 30/4/17 at 06:31 PM |
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quote:
Originally posted by rf900rush
Hi
u1 is 0.1 micro Farad.
100 would be the maximum working voltage.
u is used as the decimal point
IE 4u7 would be 4.7uf
It is likely to be across pin 1 and 2 or 2 and 3.
It would used as a "Decoupling" capacitor
In reality 0.1 or even 1uf would work.
The number 7805 on the device next to it would indicate a 5volt positive regulator.
Thank you for the info.
Yes that cap is across pins 2&3 ( Assuming pin 1 is the one with the dot )
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rf900rush
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| posted on 30/4/17 at 07:32 PM |
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Yes Pin one left.
pin 1 is input normally 9v - 30v.
pin2 is 0 volts.
pin3 is output 5v.
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gremlin1234
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| posted on 30/4/17 at 08:22 PM |
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quote:
The number 7805 on the device next to it would indicate a 5volt positive regulator.
its the LM340T5 high accuracy version of the
lm7805
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MikeRJ
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| posted on 1/5/17 at 09:51 AM |
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quote:
Originally posted by gremlin1234
edit:
you say that a leg was broken on the reg.
I think it would be worth using some 'hot glue' or similar, to save vibrations causing a similar failure again.
Having just a plain TO220 package (the regulator) supported only by it's own legs is an absolute no in any situation where it will be exposed to
vibration, but then bolting a heatsink onto it and leaving the legs as long as possible pretty much guarantees the solder joints will fail in short
order. A shocking bit of design really.
Note that hot glue will only be useful if the regulator doesn't get hot enough to soften it in normal operation, hopefully that will be the
case.
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02GF74
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| posted on 2/5/17 at 08:31 PM |
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quote:
Originally posted by gremlin1234
quote:
The number 7805 on the device next to it would indicate a 5volt positive regulator.
its the LM340T5 high accuracy version of the
lm7805
?? lm340t5 is higher current, 1.5 A vs 1.0 A for 7805.
without seeing circuit diagram it is guesswork - the diodes could form ac - dc rectifier for the regulator but is the elecritcs on the boat ac?
connecting circuit to battery, which are ALWAYS dc seems to imply not. Also being signal diodes my guess they are converting the rudder position
signal from ac to dc ....but as said, it is guess work.
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gremlin1234
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| posted on 3/5/17 at 10:38 AM |
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quote:
?? lm340t5 is higher current, 1.5 A vs 1.0 A for 7805.
yea, I think you are right there, its the "A" version that gives the
higher accuracy ;-)
ref:
http://www.ti.com/product/lm340
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bonzoronnie
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| posted on 3/5/17 at 07:28 PM |
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Hi chaps
Replacement diodes arrived today
I also got a new capacitor just in case it is needed.
Will get the soldering iron out as soon as I have a spare moment.
New capacitor was marked u1 -100 the same as the original, so .1uf was the correct value ( Thanks for that )
Yes it is madness to leave that regulator chip & heatsink unsupported , one would expect better from Vetus Marine.
Normal for boat electronic systems to be 12 or 24vdc & this boat is no exception.
All powered by 12v dc.
The sender unit can be powered by 12 or 24v dc, I guess that is why they made use of the LM340T5 regulator chip.
Must save on the production costs of fixed voltage senders.
I must admit, I do not have the electronics knowledge to even pretend I know how the circuit works.
The VDO senders are way more simple, just an oil damped wire wound pot with wiper arm to provide an insulated floating earth signal to the gauge.
Once again, thanks chaps.
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gremlin1234
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| posted on 3/5/17 at 08:24 PM |
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quote:
Here is a better picture of the pcb
Description
Circa 1980's & no longer in production.
the markings on the components (the trim resistors) suggest soon after week 15 of 1993
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David Jenkins
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| posted on 3/5/17 at 09:22 PM |
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What sort of current does this thing have to supply? Or, if you're not sure, what is it driving?
The reason I ask is that these 3-lead voltage regulators are quite inefficient, especially when they have to lose a lot of voltage - e.g. taking 12v
down to 5v at, say, 1 Amp means a lot of heat will be generated. They usually end up too hot to touch.
The alternative is to use a switched-mode power supply like these
sold by Hobbytronics (made by Pololu in the USA). They run near-enough stone cold, even while supplying a lot of power. They are also quite
small - the low-current ones are tiny! I have used them encapsulated in heat-shrink tubing without problems.
Worth looking at, if you're planning to spend money buying components to fix the old one.
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bonzoronnie
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| posted on 4/5/17 at 06:59 PM |
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David.
I do not know what current the sender draws, The output of the regulator chip is 5v dc but I do not know if this is trimmed further by the other
circuit components.
The sender is used to drive 2 simple analog needle gauges.
My guess, low dc voltage & not a lot of current.
The whole system uses 6 core shielded data cable, 2 wires to provide the power & 2 pairs of signal wires.
Thank you for the link, they have some very useful things & will be a handy source for future projects.
Gremlin.
Thank you for that information on component age. 
I had assumed the the gauges were part of the boats original equipment.
The boat was built/launched in 1980.
That data suggests the rudder indicators were manufactured & fitted circa mid 90's ish
Owner will be pleased to know this.
You were spot on with the diodes.
I changed all 4, re tested, the sender & gauges now work as they should.
No other components needed to be changed.
Left the unit on for 5 hours, no real noticeable heat was generated by the regulator, felt quite cool to the touch.
I am sure a wee dab of hot glue will be fine to help prevent future vibration fatigue.
As they say, jobs a good'un
Many, many thanks for your help.
I thought some kit car stuff was expensive, boy, marine instruments take things to a whole new level.
Priced up the latest Vetus rudder gauges.
The gauges are £230 each & the sender unit is £240
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02GF74
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| posted on 4/5/17 at 07:07 PM |
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quote:
Originally posted by bonzoronnie
I do not know what current the sender draws, The output of the regulator chip is 5v dc but I do not know if this is trimmed further by the other
circuit components.
The sender is used to drive 2 simple analog needle gauges.
My guess, low dc voltage & not a lot of current.
concur - probably 1/10 A or less - in case you need anaother in the future, you could always draw out the circuit by looking at the pcb tracks - there
are very few components - a 5 V supply and a ac - dc signal converter is my guess at what it does .
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