Acer AL1917 giving me hard time

[Agent24]

Re: Acer AL1917 giving me hard time

Have fun! And if worse comes to worse you can always use that sledge hammer

It would probably make more sense to sell it for spare parts and at least maybe get some money back rather than smash it

[greggmh123]

Re: Acer AL1917 giving me hard time

I have a Fluke 88 from my previous life as a Ford tune-up tech, so that should work.

My wife has two of the AL1917 LCDs and her Dad has two...all four are identical, bought at the same time. If it gets to the point of the sledge hammer, I will take my wife's remaining good monitor and give it to her Dad so he can have three identical monitors, and then get her three new ones. Both "only" have two now, but want three. I created a monster (or two!) when I convinced them that they needed two monitors.

I have to keep the wife happy!

[greggmh123]

Re: Acer AL1917 giving me hard time

Hmm, my reply did not show up. Here it is again.

I have a Fluke 88 from my previous life as a Ford tune-up tech, so that should work.

My wife has two of the AL1917 LCDs and her Dad has two...all four are identical, bought at the same time. If it gets to the point of the sledge hammer, I will take my wife's remaining good monitor and give it to her Dad so he can have three identical monitors, and then get her three new ones. Both "only" have two now, but want three. I created a monster (or two!) when I convinced them that they needed two monitors.

I have to keep the wife happy!

[greggmh123]

Re: Acer AL1917 giving me hard time

Agent24,

Well, I wouldn't really smash it. I would probably tinker for the next six months to try to figure it out, and save it for parts for the remaining three.

Gregg

[greggmh123]

Re: Acer AL1917 giving me hard time

In case anyone hasn't figured it out yet from this conversation, the problem still exists.

I will do more testing when the ESR meter gets here. The darn thing will work for hours on end, and then start to turn off and on (power light goes off), finally just going off and requiring removing/reinserting the power cord to get it to come back on. It went a full 24 hours once.

[Agent24]

Re: Acer AL1917 giving me hard time

From some threads I read on here, problems with them going off randomly might be something more than just capacitors.

But, you never said what brand and series you changed the capacitors with, and what they originally were. If you use replacements that are unsuitable you can get issues too.

[greggmh123]

Re: Acer AL1917 giving me hard time

Agent24, et al,

All the old ones on the power board were Hermei. All the old ones on the audio board are Hermei, and have not been changed yet. The ones on the video board are Rubycon, something with a king's crown symbol, TL, and T3(?). NO cap is visibly defective.

I got my ESR 70 meter today and measured all the old caps from the power board (715G1823-2), then the ones still mounted on the audio board (715G1841-1-AC) and video board (715G2227-1-AC). The chart in the ESR 70's manual is nowhere even close to the readings in the charts mentioned here, so I do not trust its figures.

I have an Excel attachment with all the readings.

[greggmh123]

Re: Acer AL1917 giving me hard time

I have pictures in JPG format that are all well under the JPG size limit listed, but are over the pixel limit, so I need to resize them before uploading.

[Rtech]

Re: Acer AL1917 giving me hard time

I have seen a number of 'supposed' ESR values for various meters for various caps, and they differ considerably.I ended up taking sample readings from known good caps, and using those as the criteria.

[Lumberjack777]

Re: Acer AL1917 giving me hard time

Wow. My goodness. I have never seen such detail in a caps result. I'll bet Ford loved you!
Those caps definitely look just fine. By the way, did you buy it built; or put it together yourself?
Basically, after measuring 1000's of caps, it comes down to the fact that most PSU caps that are good read like 0.05, 0.07, etc. The smaller caps will read like 1.2, or even as high as 2.
When you get a "badcap"; it will read like 15. 35. 28. 76. So you can see that readings like 0.07 uF definitely show low ESR, and are good caps.
I think I need to send you a bad cap just so you can see how high the ESR really is
For me it's pretty simple. 0.05, 0.08 uF = Good. ---- 25+ uF = bad. 12+ = bad. OK? You'll get the feel of it after awhile.
So upload some pics of the front and back PSU and mainboard and we'll get that badboy all fixed up.
I see a LOT of potential in you Gregg. You are gonna be really good at electronics diagnostics. Even though I always hated Fords

[greggmh123]

Re: Acer AL1917 giving me hard time

Sometimes I get carried away with documentation! Yes, my service managers did love it, and actually won several court cases because of it, even though my work wasn't why they got sued.

I bought the Peak ESR 70, not the Blue ESR, so it came assembled.

I have some motherboards with bulging caps that I can test to see what to expect.

I am not sure what you mean by "PSU and mainboard." It has three boards: one into which the power cord connects, one with an audio jack, and one with DVI and VGA connectors.

I think the easiest thing at this point is to swap the boards one at a time with the ones from her other monitor. At least then I will know which board is the problem.

[greggmh123]

Re: Acer AL1917 giving me hard time

Here are some pictures. I think D920 on the back looks odd...the solder looks as though it has melted and is more shiny on on side than the other. It is the diode(?) that is screwed to the big heat sink on the front.

The video-connector board has one area that looks odd on the front at U406. There is discoloring of the area.

[Agent24]

Re: Acer AL1917 giving me hard time

The ESR values you measured on the old capacitors are not bad, as already pointed out, and your new capacitors didn't change the problem so I assume they're not it.

It could well be something else that's the problem. Since you have more than 1 monitor of this model, try swapping this PSU with a known good one. If you still get the problem, then it could be the lamps or logic board at fault.

[greggmh123]

Re: Acer AL1917 giving me hard time

Agent24,

It seems like the PSU board has to be the problem, because the screen can work perfectly for hours on end, and then the monitor will turn off completely with no power light at all. The only way to turn it back sometimes is to pull the power cord and wait, then plug it in again. Other times, it will be turned off by using the power switch, then it starts to turn on and off by itself and just keeps doing it until I unplug it.

I'll swap boards this week and see what happens.

[greggmh123]

Re: Acer AL1917 giving me hard time

Well, folks, I finally got time to test both monitors. I took all three boards from the problem monitor and put them into the good monitor and it worked perfectly for days. I took all three of the good monitor's boards and put them into the problem monitor, and it too worked fine.

Finally, I installed the power board from the problem monitor back into it, but used the audio and video boards from the good monitor in that problem monitor. I took the problem monitor's audio and video boads and put them into the good monitor along with its original power board.

Everything has worked fine for a week.

I have no idea why, because when I had the problem monitor with all three of its own boards in it, including the re-capped power board, the problem still existed.

Anyway, your help is greatly appreciated, and I learned a lot. Plus I haev a cool new tool!

[Davi.p]

Re: Acer AL1917 giving me hard time

I'm not expert in troubleshooting but on top of all making other test could take longer, so i will take the thing at the wide, why don't you try to dismount the mon., set up a test bench with pc connected, you switch them on and soon you detach the button board and see if the problem persist?