 SmokChsrWho let the magic smoke out?Premium
join:2006-03-17
Saint Augustine, FL | reply to Subaru
Re: Mr. Coffee part 2 Most likely ZD3 is 24V, and should have about 24VDC across it. I asked for the part number since from the picture I couldn't get the last 3 digits to match a 24V zener (that doesn't mean it isn't).
The AC enters and goes through the cap and resistor to drop the voltage and current into the proper working range for the ZD. This is the "inexpensive" way of dropping voltage as oppose to using a transformer, as was normally done in days gone by.
ZD's have a failure normal mode of dropping their voltage, or shorting. This is why you should MEASURE the voltage across that diode. In the olden days typically when the zener failed it would also cook the dropping resistor associated with it. In this circuit that may not be the case, as the cap and resistor are likely rated to handle a dead short.
If the voltage is low across the ZD, it would be my first choice for trouble, but it could be anything else on that circuit loading it down. tread carefully when determining if it's the diode or beyond as there is a tendency to want to pull or open the diode for confirmation. Don't do that! Doing that would remove the voltage regulation (that's what a zener is used for) and could allow the voltage on that line to go up to pretty near line voltage.
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 Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | Let me get you the part number I must of forgot all about doing that given all these projects :P
You know I wonder the real reasoning most all switched away from using a transformer? it seems like the really only coffee makers that last are commercial units.
Anyways time to go heat up the iron |
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 IllIlIlllIllEliteDataPremium
join:2003-07-06
Hampton Bays, NY
kudos:7 | reply to alienware
said by alienware :you need to learn before you are able to diagnose things
give him a break.
thats why he is here, he is learning with the assistance of us helping, even if its just a coffee pot.
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | lol I saw those two posts last night I just chucked then went to bed if the ANON looked at the posts above (I don't think any do here) he would of known that I already checked the thermal fuses.
And when I ordered the relay like 4 MONTHS ago clearly I saw the specs on the mouser website... |
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT
1 edit | reply to Subaru
ZD3 is...
1N4749A607 |
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 SparkChaserPremium
join:2000-06-06
Downingtown, PA
kudos:3 | so there is your 24 v
if you have a supply greater than 24 you could pull it and put it in series with a resistor to test it |
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | I don't have a 24V power supply (never got my adjustable PS) but just wondering I never got any hits with the number but if you drop off "607" I did get something but i never saw any 24V
from what I understand the "49A" means it's 24V? |
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SparkChaserPremium
join:2000-06-06
Downingtown, PA
kudos:3 | »www.futurlec.com/Diodes/1N4749pr.shtml |
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | took the cap out and one resistor under it.
The cap says 155K 250V checking it I get 1.45 uF
the resistor (big one) is 47 ohm and it reads right. |
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | reply to Subaru
I took out the resistor under the larger one if I looked at it right it should be 820 Ohm however reading it with my meter I'm seeing 811 k on the resistor. |
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IllIlIlllIllEliteDataPremium
join:2003-07-06
Hampton Bays, NY
kudos:7 | said by Subaru:I took out the resistor under the larger one if I looked at it right it should be 820 Ohm however reading it with my meter I'm seeing 811 k on the resistor.
its still within tolerance depending on the tolerance color code.
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PS3 Gaming Feed - »www.livestream.com/elitedata |
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | said by IllIlIlllIll:said by Subaru:I took out the resistor under the larger one if I looked at it right it should be 820 Ohm however reading it with my meter I'm seeing 811 k on the resistor.
its still within tolerance depending on the tolerance color code. yeah :-/ |
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | reply to Subaru
I pulled D9 the only markings it has is H48 |
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SparkChaserPremium
join:2000-06-06
Downingtown, PA
kudos:3 | You can try a 470 ohm in place of D3 and see what you get. That should load it down enough for 24 V base on the cap. |
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | said by SparkChaser:You can try a 470 ohm in place of D3 and see what you get. That should load it down enough for 24 V base on the cap.
I got some good and bad news.. going to make a video..
first thing I noticed was the clock display was brighter like when it was new.. 2nd was the green LED that comes on does not dim as soon as the power comes on..
2nd thing is it still did not come on.. however I flicked the relay and it buzzed and the decanter started to get warm however it did not stay.
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It's NOT Ni-kon It's NE-KON!
LG is NOT Lifes Good It's Lucky Goldstar!
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | reply to Subaru
»www.youtube.com/watch?v=gBcGgKbm···youtu.be |
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SparkChaserPremium
join:2000-06-06
Downingtown, PA
kudos:3 Reviews:
 ·Verizon FiOS
| reply to Subaru
said by Subaru:said by SparkChaser:You can try a 470 ohm in place of D3 and see what you get. That should load it down enough for 24 V base on the cap.
I got some good and bad news.. going to make a video.. Did you measure the voltage across the 470 resistor? |
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT
1 edit | the voltage was 14.2 DC I just turned it back on the relay is buzzing but still 14V but the burner plate got hot fast.
hmm..
What about that diode near the coil? |
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SmokChsrWho let the magic smoke out?Premium
join:2006-03-17
Saint Augustine, FL
1 edit | If you removed D3 and the voltage increased.. go no further, Z3 is defective. Until you have the 24V supply up, all other functions are unreliable at best.
As for the diode near the coil, it is a simple reversing diode, ( diode put in opposite polarity to drain the discharge voltage of the coil when deenergized) it's not likely to be bad. A simple diode test will confirm it bad or good with one leg pulled from the board.
Again, what I'm trying to get you in the habit of logical troubleshooting. So logically speaking, until you have the power supplies working, don't worry about other troubles. Since the relay diode is only in the circuit when the relay is energized, it's not going to be the reason that the power supply is not up to voltage when the relay is not energized.
If I've followed what you've done correctly, that you removed D3 and replaced it with a loading resistor, and the voltage increased, from that you would conclude that D3 is BAD. Thus replace D3 before doing anything else.
Edit add
What I'm trying to say is, just follow the yellow brick road, and try to not wander out into the corn fields.  |
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Subaru1-3-2-4Premium
join:2001-05-31
Greenwich, CT | yep as soon as I took it out and put the resistor in I noticed the clock display was brighter.. However just with the resistor 470 Ohm it's still not 24V I wonder should I go and replace those surrounding diodes as well? |
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