Repairing a FujitsuSiemens LSL3230T

[killian6pk]

Re: Repairing a FujitsuSiemens LSL3230T

Swapping that cap for a known good one didn't work out - the transformer still ticks. Could the resin inside it be failing?

Take ohms readings on the transformer. Pin 1 to Pin2; Pin 1 to Pin 3 etc. Until you have all the combinations of pin 1. Then start with Pin 2 and do the same and then on to Pin 3 etc. Number them any way you want. Just report back what readings you got. Remember power off.

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

Swapping that cap for a known good one didn't work out - the transformer still ticks. Could the resin inside it be failing?

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

Managed to find a 50V 10uF cap, will need to try that tonight.

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

A month with no ideas... I'm thinking of sourcing a new PSU board.

Regarding that PSU, I'm wondering if I could use a different board - as long as the connectors are the same?

Oh, on other thread, Rusty informed me that the cap is 50V 10uF, but the one I have is 100V - would that matter?

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

I'm beginning to wonder if the transformer itself is faulty - it has markings as follows:

SPW-134 A
E140167
LSE-B3 0839F3

clicking/ticking might be due to failing insulation, so if I was to replace it, what are the specs? Search over the net yielded nada.

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

C806 is 10uF 100V and it's been swapped already...

[Scenic]

Re: Repairing a FujitsuSiemens LSL3230T

Nope. The startup cap is normally a 35-50V 22-47uF electrolytic (somewhere in that range usually).

From the pic of the PSU board in the first post, I'd say the startup cap is C806 (right below the optoisolator and above the little PCB that sticks up)

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

Now, that startup cap - would it be C803 (that yellow rectangular) MPXGMF40/100/21 metal film cap?

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

Nope, I should've done that though. If we start from assumtion that the diodes are indeed broken (again), what would you suggest is busting them?

[retiredcaps]

Re: Repairing a FujitsuSiemens LSL3230T

Did you measure the diodes as I asked in post #18. Did you measure them out of circuit to verify?

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

Well, I find it hard to believe those diodes were faulty after all - replaced them, plugged in, listened to chirping for a while and re-measured those 4 diodes with similar results. Any more ideas? Or should I just go and get a replacement unit if there's one available on eBay...

There was mention about startup cap - also that it rarely goes bad.

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

Indeed - there were 4 faulty ones:
D2: 0,766 V
D4: 0,767 V
D8: 0,767 V
D9: 0,766 V
Going to replace them tomorrow. I think I have a hundred of those (1N4148) stashed or so

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

Have yet to measure them the wrong way round - they do look proper the right way

[retiredcaps]

Re: Repairing a FujitsuSiemens LSL3230T

Here are some measurements I've already done:

To test a diode using the diode test function, you must take 2 readings on the same diode. One reading is with the probes one way and the second reading is with the probes reversed.

A good diode should read between 0.3 to 0.8V and "out of range" the other way.

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

Here are some measurements I've already done:
D2: 0,547 V
D4: 0,546 V
D8: 0,545 V
D9: 0,549 V
ZD801: 0,645 V
D802: 0,474 V
D803: 0,442 V
These were measured with meter set to diode.
D806: ground in the middle, readings 0,337 V left and right (ohms:3,847k right, up to 23k left - stabilizes around 17,5k)
D807: ground in the middle, readings 0,248 V left and right (ohms: 1,927k right, up to 23k left - stabilizes around 18,5k)

Will measure the DC across the big cap later - my kid is still awake...

[Jasgriff]

Re: Repairing a FujitsuSiemens LSL3230T

You need to put your meter on the ohm setting and read then both ways around. Make sure its done with the power off.

You should have a low reading then a high one. If you get 2 very low or very high readings then they have gone.

Let us know your readings.

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

D806 is SRF 10-20 and D807 is SRF 10-10 - how would I measure them? Or rather, what readings they should give without power...

[tom66]

Re: Repairing a FujitsuSiemens LSL3230T

Startup cap or bad diode on secondary.

[DMCrimson]

Re: Repairing a FujitsuSiemens LSL3230T

If you mean by main filter cap that huge one, it had some 300+ volts over it.

[Jasgriff]

Re: Repairing a FujitsuSiemens LSL3230T

I am not massively sure that I am on the right track here but I think it makes a noise when there is not enough power to drive it?

You could try testing the main filter cap and see what voltage you have running across that to see if its right or not.