Elo 1525L power board ptb-1218

[PlainBill]

Re: Elo 1525L power board ptb-1218

Removed them again to get actual postable readings out of circuit:

D809 = SF34 Diode and reads on Diode Mode: 441 Black probe on Cathode stripe side... nothing reverse... and nothing either direction on 200, 2k, 200k

D810 = SR360 Diode and reads on Diode Mode: 192 Black probe on Cathode stripe side... nothing reverse... and nothing either direction on 200, 2k, 200k

Are these the values we needed, or did I set the DMM wrong?

Thanks again

nothing meant just a "1" or "l"

Those values indicate the diodes are fine. At this point I'm going back and re-examining my conclusions. Let's try this - use the diode test function to make readings across the leads of Q803.

Alldatasheet.com is having database problems, so we'll have to wing it. Number the pins in any order and measure 1-2 1-3 2-3 2-1 3-1 3-2 (the red probe goes on the first number of each pair).

PlainBill

[BlkSmth]

Re: Elo 1525L power board ptb-1218

Those values indicate the diodes are fine. At this point I'm going back and re-examining my conclusions. Let's try this - use the diode test function to make readings across the leads of Q803.

Alldatasheet.com is having database problems, so we'll have to wing it. Number the pins in any order and measure 1-2 1-3 2-3 2-1 3-1 3-2 (the red probe goes on the first number of each pair).

PlainBill

got them readings. sorry it took o long guys... got a bit busy.
here they are: 512 / 8 /1920+ / 1921+ / 8 / 524
still not understanding why that diode on D806 reads both ways (317) on diode mode.

looks like the acer al502 and the nec 1550me are based on this similar design.. I've scoured the web looking for this Now all I might need is a walk thru to make sure I'm learning to follow these schematics correctly, and get sufficient tools as needed.

links to docs I found:



and especially this one:


note page 40, 88- *, then especially page 130

[PlainBill]

Re: Elo 1525L power board ptb-1218

got them readings. sorry it took o long guys... got a bit busy.
here they are: 512 / 8 /1920+ / 1921+ / 8 / 524
still not understanding why that diode on D806 reads both ways (317) on diode mode.

looks like the acer al502 and the nec 1550me are based on this similar design.. I've scoured the web looking for this Now all I might need is a walk thru to make sure I'm learning to follow these schematics correctly, and get sufficient tools as needed.

links to docs I found:



and especially this one:


note page 40, 88- *, then especially page 130

Don't worry about delays. My wife is on vacation for the summer, so my time is no longer under my control.

Thanks for the links for the schematics; that will make it easier to explain things.

Those numbers suggest something is seriously wrong with the FET. I'd suggest removing it from the board and testing it out of circuit; I've been wrong before. Here's the datasheet.

PlainBill

[BlkSmth]

Re: Elo 1525L power board ptb-1218

Readings just in

Fet removed as request. 538 /8 /1925 / 1925 / 9/ 534

what are the rules with fet for replacement as far as voltage etc.
For example I have a p10nk70zfp from another board that I believe is good.

Data Sheet: http://pdf1.alldatasheet.com/datashe...K70ZFP_07.html

[PlainBill]

Re: Elo 1525L power board ptb-1218

Readings just in

Fet removed as request. 538 /8 /1925 / 1925 / 9/ 534

what are the rules with fet for replacement as far as voltage etc.
For example I have a p10nk70zfp from another board that I believe is good.

Data Sheet: http://pdf1.alldatasheet.com/datashe...K70ZFP_07.html

This is really outside my area of expertise, and I get a queasy feeling whenever I suggest substituting parts. I was hoping someone more knowledgeable would have jumped in here.

The rated voltage and current of your proposed replacement are better than the original. The only area that might be a problem is input capacitance. The proposed replacement has a capacitance 4 time greater than the original. I really can't predict how that will affect performance.

PlainBill

[BlkSmth]

Re: Elo 1525L power board ptb-1218

This is really outside my area of expertise, and I get a queasy feeling whenever I suggest substituting parts. I was hoping someone more knowledgeable would have jumped in here.

The rated voltage and current of your proposed replacement are better than the original. The only area that might be a problem is input capacitance. The proposed replacement has a capacitance 4 time greater than the original. I really can't predict how that will affect performance.

PlainBill

any other takers on this mosfet swap? I dont want to destroy the board
the OEM # was 4N60B, this one is p10nk70zfp

[BlkSmth]

Re: Elo 1525L power board ptb-1218

any other takers on this mosfet swap? I dont want to destroy the board
the OEM # was 4N60B, this one is p10nk70zfp

Ok, I had a p4nk60zfp on another monitor. I thought the specs looks close enough to the s0220 sss4n60b. during removal with desoldering braid I think I ruined it.... The values dont seems to test on diode mode. dam it all again. Anyone got a good source so I can replace both with correct values? Also during that test plainbill had me do while in diode mode, what would the correct value or optimal would have be on the DMM?
Thanks in advance guys...........BlkSmth

the p4nk60zfp readings "Plainbill asked: Number the pins in any order and measure 1-2 1-3 2-3 2-1 3-1 3-2 (the red probe goes on the first number of each pair)" are open all except the last 3-2 which is 546 value.... They where diff before

[BlkSmth]

Re: Elo 1525L power board ptb-1218

cannot see giving up

I found what I think would be a good choice:# SSS4N60B s0220
http://www.mouser.com/Search/Product...y512-FQPF5N60C

Then the other I smoked... STP4NK60ZFP
http://www.mouser.com/Search/Product...11-STP4NK60ZFP

any peeps get a chance to verify that for me, that would be great. The oem datasheets are on links above........

[PlainBill]

Re: Elo 1525L power board ptb-1218

Ok, I had a p4nk60zfp on another monitor. I thought the specs looks close enough to the s0220 sss4n60b. during removal with desoldering braid I think I ruined it.... The values dont seems to test on diode mode. dam it all again. Anyone got a good source so I can replace both with correct values? Also during that test plainbill had me do while in diode mode, what would the correct value or optimal would have be on the DMM?
Thanks in advance guys...........BlkSmth

the p4nk60zfp readings "Plainbill asked: Number the pins in any order and measure 1-2 1-3 2-3 2-1 3-1 3-2 (the red probe goes on the first number of each pair)" are open all except the last 3-2 which is 546 value.... They where diff before

Those numbers are NOT unreasonable for a power FET transistor. Here is the datasheet for the SSS4N60B. Note that the legs are G(ate) D(rain) S(ource) and that there is a diode which will conduct from Source to Drain (in normal operation Drain is positive with respect to Source). If you numbered in order, left to right 1=G, 2=D, 3=S, the results are exactly what I would expect.

Checking the specs, I would say the P4NK60ZPF is a good substitute for the SSS4N60B. It is available from Digi-Key for $1.40 each. Don't delay, they only have 3059 on hand.

PlainBill

[BlkSmth]

Re: Elo 1525L power board ptb-1218

Got my Digikey order today

Replaced the Q803 with p4nk60zfp as a suggested relacement. still the same... pooooooop! Anyone got anymore suggestions? I'm overlooking something here. I would love to win this one. all this by shorting pins 2,3 on this Q803 originally.....

[BlkSmth]

Re: Elo 1525L power board ptb-1218

after replacing the mosfet Q803 I've taken some time to read all resistor values per the schematics link I supplied above.

Plainbill, that R811 is a 1.2ohm 2w colors where Brown, red, gold, gold. I can get nothing but infinite on DMM set on 200,2k,20k... but when I goto 200k I get 20.0 then while holding probes I can set the DMM back to 20k and get 19.98 .....must be bad? I dont have any laying around for subs other than 1.8ohm 3w ww 5% .... not sure them rules for this. Also testing futher indicates that the R814 set DMM on 2k reads 90.7 which should be according to the colors and schematic it should be a 47ohm Yellow, violet, black, gold.

any suggestions for replacements also rules for replacing resistors with larger values? anyone anything? thanks guys! ....Blk

[alexanna]

Re: Elo 1525L power board ptb-1218

Start over, with the DMM on the 200 ohm scale touch the probes together what reading do you get?

[BlkSmth]

Re: Elo 1525L power board ptb-1218

Start over, with the DMM on the 200 ohm scale touch the probes together what reading do you get?

Set DMM on 200, gives reading of 00.5 then goes down to 00.3 while holding for a few seconds

[jetadm123]

Re: Elo 1525L power board ptb-1218

I take it that you're measuring R811 in-circuit? Since other components could be affecting your readings, you'll have to remove it from the board and retake your measurements.

[BlkSmth]

Re: Elo 1525L power board ptb-1218

I take it that you're measuring R811 in-circuit? Since other components could be affecting your readings, you'll have to remove it from the board and retake your measurements.

maybe we have a winner on this one... its infinite all settings on DMM removed from circuit.

what are them rules for resistor replacement?

[BlkSmth]

Re: Elo 1525L power board ptb-1218

ok for replacment I have another similar board that i can rob a White, violet, silver, gold. whick calculates into .97ohm 1w for the R811. This must be better than the other suggestion of 1.8ohm 3w? any help is appreciated.

[BlkSmth]

Re: Elo 1525L power board ptb-1218

replaced the R811 on this thing. value checks at 1.2ohms and replaced the R814 with 47ohm 1/4w (bit larger)

still not working. any other suggestions? top portions of this board not getting power. nothing past the I802, C828

[BlkSmth]

Re: Elo 1525L power board ptb-1218

Here is a schematic for easy following maybe this will someone better than me. I've check every resistor now..all check good

wish I could fire this thing. Shorting Q803 was bad orginally

So far I've replaced Q803, R811, R814

any pointers other than dig a hole are welcome :P

Not sure how to test D806. I have a replacement thats exact if it was proven failed...I'd have to remove it from another board.

[BlkSmth]

Re: Elo 1525L power board ptb-1218

Here is a flowchart troubleshoot that might make things easier for someone to help me

still unsure where I need that black probe set for ground when checking thse values.

and then troubleshooting the d806

[Toasty]

Re: Elo 1525L power board ptb-1218

Voltage across C805? C807?