IBM Thinkvision 6736-HC9 No power

[Davi.p]

Re: IBM Thinkvision 6736-HC9 No power

i am come back to this thread, something in the feedback could be wrong, dismount the optoisolator and test it, one side as a normal led with dmm diode check, for the other as a C-E pin of a bjt transistor, it must read open, then you can connect a 1,5v battery on the led side, the dmm probes on the other on current test mode, if there's a current toggle the battery and the current must fall to 0.

[ank]

Re: IBM Thinkvision 6736-HC9 No power

Has everyone given up on this? I have a similar condition, difference being that I loose power after working ok for several seconds to for ever.

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

Ok in the mean time I will start by check resistance on the small caps and resistors around the IC and see if I come up with anything that looks bad or out of the ordinary.

[budm]

Re: IBM Thinkvision 6736-HC9 No power

I have to do more thinking to see what to check next.

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

After looking at the NEW measurements it looks like nothing has changed. Even though I changed the IC and all the caps except the 2 big filter caps. To me that says theres still a component not doing its job... not sure whats next on the list to check....

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

IC ohm reading with no power
pin 1-22kohms
2-47kohms
3-1kohms
4-ground
5-2kohms
6-304k
7-NA not used no reading
8-500+ kohms

DCV
PIN 8-142-160v
PIN 6-5.5-8.2v

the 3-5v pins going to the logic board were reading about the same as before
about 1.5v

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

OK guys I Finally got time this evening to sit down and desolder and solder the new parts on. Once I got it all together I put it back on and plugged it in and still no power. I will pull it off tomorrow and get voltage and resistance readings with the new parts on. I will be checking the resistance on the IC pins with #4 as ground and also get the voltage on PIN 8 and 6 as well as the 5v pins going to the logic board. also going to check the fuse to make sure it hasn't blown. I will report back asap

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

ok ordered the new caps and IC once they come in and get them replaced I'll post back.

[budm]

Re: IBM Thinkvision 6736-HC9 No power

Get the IC as well.

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

and the IC is ok or should I get one and replace it as well?

[budm]

Re: IBM Thinkvision 6736-HC9 No power

"Pin 6 5.9-8.3dcv it bounced around between these numbers" That VCC voltage for running the IC is too low, and with that fluctuation, it can mean the filter caps (2 small caps) are not doing its job. So at least you will have to replace those two caps.

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

Ok Finally was able to get back to this,

Resistance on Pin 8 with ground on Pin 4 is 850000 Ohms Its probably more than this after holding it for about a min it just kept climbing.

Voltage for Pins 8 & 6
Pin 8 161DCV
Pin 6 5.9-8.3dcv it bounced around between these numbers

Also Heated up the 2 small caps and there's NO Voltage change on the 5v pins going to the logic board...

[budm]

Re: IBM Thinkvision 6736-HC9 No power

OK, they do not look bad, but how about pin 8?

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

"all done with back probe on PIN 4 Ground.
1-004------4000Ohms
2-046------46000Ohms
3-001------1000Ohms
5-002------2000Ohms
6-329------329000 Ohms

Does this look/sound right?

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

Pin 7 is not used or present, pin 8 is the HV pin should have high resistance. You might as well order the IC.
But I will wait for the result of heating the caps with hair dryer first. We still do not know what DC voltage you get at pin 8 (HV) and pin 6 (Vcc) using pin 4 as the ground pin for your DC meter.
Without having the test result of the voltage reading we cannot know what is going on, also still no Ohm, K Ohm on your resistance readings you have posted does not help us out either, that pin 5 reading of 002 in Ohms, K Ohms, M Ohm?
You might as well replacing a set of caps and the IC and hoping that will solve the problem.

I'm sorry I still dont understand the difference between ohms, K Ohms and M ohms and the settings on the DMM. I will google it..... So I know for future reference. I had my DMM set 2000K so I would guess K Ohms.

[budm]

Re: IBM Thinkvision 6736-HC9 No power

Pin 7 is not used or present, pin 8 is the HV pin should have high resistance. You might as well order the IC.
But I will wait for the result of heating the caps with hair dryer first. We still do not know what DC voltage you get at pin 8 (HV) and pin 6 (Vcc) using pin 4 as the ground pin for your DC meter.
Without having the test result of the voltage reading we cannot know what is going on, also still no Ohm, K Ohm on your resistance readings you have posted does not help us out either, that pin 5 reading of 002 in Ohms, K Ohms, M Ohm?
You might as well replacing a set of caps and the IC and hoping that will solve the problem.

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

Ok I will put them on my list of stuff to order. So with not getting a reading on the IC pins 7&8 I as assuming that is bad and needs to be replaced as well? Did you happen to see the pic I posted of it? is the 1203D6 the correct part #?

[budm]

Re: IBM Thinkvision 6736-HC9 No power

OK, at least it is trying to put out something, you may as well replace those two caps,, they are part of the set of caps that should be replaced any way.

[eckertb83]

Re: IBM Thinkvision 6736-HC9 No power

I havent heated up the 2 little caps yet, but did test the voltage going to the logic board and the 3 pins labeled 5v I was getting about a 1v reading. I will heat the 2 small caps up and see if that changes anything

[budm]

Re: IBM Thinkvision 6736-HC9 No power

"all done with back probe on PIN 4 Ground.
1-004
2-046
3-001
5-002
6-329
PIN 7&8 just a 1 one the left no resistance."
So are they in Ohms, K Ohms. If 5 is 2 Ohms, that will be bad for sure.
And how about those two caps and DC voltage readings on the connector on post 36? There are pins with 5V label on them. We are testing the board by itself to make that if there is shorts on the main board that may cause the power supply to be in the shutdown mode, we know that you do not have shorted out MOSFETs which will cause the power supply to be in shutdown as well.