Maker Pro
Maker Pro

help repair router adapter

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
Ok, so you've given me the resistance of those diodes one way, what about with the multimeter leads reversed
overload it give me 1 which mean overload

Do you have a 15W bulb? Try that. I'm pretty sure a wattage lower than 100W was recommenced. If not, it should have been
will try one although the fuse says 250 V fuse

While you're making those measurements, also read the resistance both ways from each mains input pin to each leg of the capacitor that's failing. This should be 8 measurements. List them in a table where you show the mains input connection (call them 1 and 2), the pin if the capacitor (+ or -), and the two readings. List the reading with the red lead on the capacitor first

ok will check that and get the result
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
use a bulb with a voltage rating the same as your mains voltage.

Excellent information about the diodes.

looking forward to the other measurements. please use the ohms range on your meter for these.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
I note that Edd is now suggesting a resistor rather than a bulb, that's ok too :). But if you go back to a bulb, use a lower wattage one.
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
Then pull the BROWN AC line HOT input wire from the PCB and solder connect one of the lamps RED wires to where you just removed the BROWN wire. The other now loose RED wire of the lamp gets connected to the BROWN HOT AC wire

well you know the brown doesn't have to be the positive hot line evey time since it could be connected to the (-) ~AC power supply which is 220 ~V in Cairo
so you want me to

1- connect the lamp between the brown wire and the board any way?
2- connect the lamp between whatever wire blue or brown that is going to be in the (+) ~AC power supply?

as i said i changed the D9 to new diode that i don't know it's number ...should i re-change it with RL207 one?
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
can you check the 4 diodes near C1 and make sure they have a resistance significantly different when you swap the leads around

i measured them on the Diode scale inmy multi-meter not with ohms scale

do you want me to measure them on ohms scale ?
 

73's de Edd

Aug 21, 2015
3,613
Joined
Aug 21, 2015
Messages
3,613
Sir pharaon . . . . . . .

I only specified that BROWN wire, because I can see that one is coming in and connecting directly to the fuse on the PC board.
Therefore we would have AC line power coming in, to initially pass through your incandescent lamp, and then the output wire of the lamp then passes its power on to the mentioned resistor that is being subbed in for the fuse.

1- connect the lamp between the brown wire and the board any way?
2- connect the lamp between whatever wire blue or brown that is going to be in the (+) ~AC power supply?

Do connection #1.

As far as that prior pulled D5 diode, I do not really suspicion fault with it at all . . . . you might do a diode test evaluation on it and see if its Vf is any where between 500-700 millivolts and shows infinity on the reverse probes test, then why not reinstall it ?


73's de Edd
 
Last edited by a moderator:

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
While you're making those measurements, also read the resistance both ways from each mains input pin to each leg of the capacitor that's failing. This should be 8 measurements. List them in a table where you show the mains input connection (call them 1 and 2), the pin if the capacitor (+ or -), and the two readings. List the reading with the red lead on the capacitor first

1 is brown , 2 is blue
red lead on the capacitor first

ohms scale 2M
+ 2 = 1.3
+ 1 = overload
- 2 = 0.7
- 1 = overload

red lead on mains input
2 + = 0.6
2 - = 1.17
1 + = overload
1 - = overload
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
DSC_2693.jpg


D7 give me those readings both way on diode scale in multimeter

1360 red for cathode
650 black for cathode

didnt try yet sir 73's de Edd changes

will do it in while and see what will happen
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
sir 73's de Edd

there's something i would like to take you opinion about
D7 and D9 both are 1n5819 diode
D7 was giving me like ± 300 on diode scale so i change it
but i changed it to regular 1 amp diode
and now i learned that 1n5819 is a schottky diode
do you think the new regular diode is responsible for what happening to C1?

the issue is i can't find schottky diode in my area no 1n5817 or 5818 or 5819
the only diode i can find is 1n4007 and RL207
do you think any of them can be a replacement for 1n5819?
 
Last edited:

davenn

Moderator
Sep 5, 2009
14,254
Joined
Sep 5, 2009
Messages
14,254
the issue is i can't find schottky diode in my area no 1n5817 or 5818 or 5819
the only diode i can find is 1n4007 and RL207
do you think any of them can be a replacement for 1n5819?

no, Schottky diodes and that one in particular are "special diodes"
if you think it is faulty, it WILL need the same or similar part #

the 1N400x series diodes are not fast switching types and will fail if used in that position


Dave
 
Last edited:

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
I found pr1004
Will that be good replace for 1n5819
 

73's de Edd

Aug 21, 2015
3,613
Joined
Aug 21, 2015
Messages
3,613
Sir pharaon . . . . . . .

All of our prior attention was directed to the 4 FWB diodes, now in moving to the D5, D7 and D9 units, I have already explained the D5 circuit function.

I reworked the foil path portion of the board just below, in denoting the positions of the D7 and D9 diodes, the terminals of the power switching transistor .
If things have not changed, I am seeing the solder joints of D7 as having never been touched.
On D9, its visually being a different story.
I think where a mistake was made, is if the D9 diode was tested and found with its lower Vf junction reading being in the 400 millivolt range.
That tended to made you condemn it, because you are probably used to finding higher Vf's than that.
This can be attributed to to ones not fully knowing that Vf specifications can have variances between different types and families of diodes.
In the case of Schottly diodes , they don't come in too high of voltage ranges, but exhibit VERY fast switching rates and different current capabilities, of which, I have seen their Vf (low voltage drop) go down to as low as 200 millivolts on higher power rectifier function units,
In the case of D9 here , note that its function here is to provide a one way path from the emitter of the power transistor to ground.
And I am asuming that you were able to read the original D7 and D9 diodes markings and confirm that both were being 1N5819's.
Those two diodes fully meet the needed requirements of:
High Current Capability, Low Forward Voltage Drop and High Frequency / Fast Switching Rate capabilities.

Possible ERROR 1:

If you sub in a 1N4007, you still squeak by on the = < 1 amp current need and are making the circuit 50% worse on the voltage drop, but the largest error is in its switching speed capabilities.
If you had 50 ~ AC line power being involved, that s l o w switching time is taking f o r e v e r. . . .and EASILY handled .
BUT, in this power transistors case, you have switching times in the order 50,0000 . .or . .100,000 . . or. . .250,000 changes PER second.
That is where the shortcoming in the use of the 4007 is, as its specification for its STOPPING conduction or turnoff is so long that some of the then reversed polarity voltages, rush backwards through the still conducting junction.
The diode is conducting in ONE direction, while its the SLOW cutoff time characteristic, when being challenged by too high of a frequency
input, is the equivalency of a shunting resistor, which is letting both directions / polarities of + - voltages then pass through.
The diode revolts by running hot and the power transistor revolts by not operating normally / optimally due to that impending circuit deficiency.

Possible ERROR 2:

Your last possibility would be the use of a fast switching diode in that application . . . .which would be that newly found PR1004 diode.
If you sub in a PR1004, you still squeak by on the = < 1 amp current need, this unit will meet the switching speed capabilities, but its SHORTCOMING is its greater Vf specification, in its creating a GREATER voltage drop.

Soooo the proper candidates will be those 1N5819's which were in the circuits initially.
If you will test them again and find the Vf being in the 400mv range and swap the leads and get your "1" reading, by all means re install them, as I believe that they are telling you that they are good.

Pilot to ground control . . . . .over and out .....

Foil Side Drawing Rework:
( Mainly Pink and Red add ons)

FRyCMlt.jpg





73's de Edd
 
Last edited:

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
As far as that prior pulled D5 diode, I do not really suspicion fault with it at all . . . . you might do a diode test evaluation on it and see if its Vf is any where between 500-700 millivolts and shows infinity on the reverse probes test, then why not reinstall it ?
it's test were 192....in your last pic you send in reply #54 D5 is D9

I would now suggest the replacement of the fuse where we now have the lamp connected, with an ~ 47 through 100 ohm resistor at 1 watt
done that

Then pull the BROWN AC line HOT input wire from the PCB and solder connect one of the lamps RED wires to where you just removed the BROWN wire. The other now loose RED wire of the lamp gets connected to the BROWN HOT AC wire.
done that still no glow when i connect the power

You want to initially leave that bad C1 position without any capacitor there at all.
Then you power up the system and see if C2 accumulates a charge and does not "blow up" like C1 did.
If it runs give us the DC voltage measured being across C2. ( ? about 340 Vdc ? )
done it work fine without heating or blow up and the DC voltage measured being across C2 is 294 Vdc

As I would expect at least a short dim glow on initial turn on, with those initially fully discharged electrolytic caps pulling a bit of power.
nothing no glow a all
I'm stopping now . . .to see how it goes
it work fine C2 didn't fail or get hot

If things have not changed, I am seeing the solder joints of D7 as having never been touched.
On D9, its visually being a different story
its D5 Not D9

Soooo the proper candidates will be those 1N5819's which were in the circuits initially.
If you will test them again and find the Vf being in the 400mv range and swap the leads and get your "1" reading, by all means re install them, as I believe that they are telling you that they are good.
it was 192 and i reconnect it and the circuit work fine

now i'll try to connect new C1 and see what will happen
 

pharaon

Oct 28, 2014
439
Joined
Oct 28, 2014
Messages
439
now it's working fine i connect new C1 it didnt fail or get hot..i think it all was because i used wrong D5 when i used the original 1N5819 now every thing working fine

i really learned a lot from this project about the used diode and how this circuit work
a lot of thanks for every one who help me and guide me throw the fixing process

i'll start repairing project soon for linksys router hope you will help me with it too

thanks a lot I'm grateful for all what you taught me
 
Top