SVT-II-P dead...

[boroman]

AFAIR your mains voltage is 230V.
For 230V the 2 primaries of the PT are wired in series via switch S5, connecting pins 2 and 3.
Means that there must be continuity between pin 1 and pin 4 and the DCR should be the sum of the two primary windings.

As you don't have continuity, there's no primary current and no secondary voltage.
Check switch S5 and its wiring.

On the 115V setting I have continuity between 1+3 and 2+4
On the 230V setting I have continutiy only between 2+3

[Helmholtz]

On the 115V setting I have continuity between 1+3 and 2+4
On the 230V setting I have continutiy only between 2+3

Correct.

Now if 2+3 are connected with 230V setting, you should be able to measure a resistance between 1+4 corresponding to the sum of the resistances between 1+2 and 3+4.

[boroman]

Correct.

Now if 2+3 are connected with 230V setting, you should be able to measure a resistance between 1+4 corresponding to the sum of the resistances between 1+2 and 3+4.

No resistance ("OL" on the meter).
230V AC betwen 1+4 when connected to mains

[Helmholtz]

No resistance ("OL" on the meter).

That's not consistent with your measuements from post #10.
Measure again between 1+2 and 3+4 and check for bad solder connections or broken traces around the switch.

[boroman]

That's not consistent with your measuements from post #10.
Measure again between 1+2 and 3+4 and check for bad solder connections or broken traces around the switch.

OK. I messed.. sorry

at 120V switch setting:
Reading approx 1-2 ohm between 1+3 and 2+4 (also, continuity between those points)

at 230V switch setting:
Reading approx 1-2 ohms between 2+3 (also, continuity between those points)

[Helmholtz]

Oh well...

With S5 set to 115V the primaries are wired in parallel and set to 230V the windings are in series.

If your wall voltage is 230V (?), set the switch to 230V and leave it there.

What are resistances between PT primary pins 1+2, 3+4, 2+3 and 1+4? Make sure your Ohmmeter is calibrated.

[boroman]

Oh well...

With S5 set to 115V the primaries are wired in parallel and set to 230V the windings are in series.

If your wall voltage is 230V (?), set the switch to 230V and leave it there.

What are resistances between PT primary pins 1+2, 3+4, 2+3 and 1+4? Make sure your Ohmmeter is calibrated.

Hey Helmholtz - I just wrote it above

It's 1-2 ohms between 2+3
(No other readings between other points)

[g1]

What are resistances between PT primary pins 1+2, 3+4, 2+3 and 1+4? Make sure your Ohmmeter is calibrated.

Hey Helmholtz - I just wrote it above

It's 1-2 ohms between 2+3
(No other readings between other points)

Please double check ALL the readings he asked for. Dig your probes in. It's not possible for you to have resistance readings different at 1-2, 3-4 since post #10. Unless the readings in post #10 were a mistake.

[boroman]

Please double check ALL the readings he asked for. Dig your probes in. It's not possible for you to have resistance readings different at 1-2, 3-4 since post #10. Unless the readings in post #10 were a mistake.

Hey, I covered it on #20 post and explained the mistake, why we get to this for the second time? (those reading from post #10 were with switch set to 120V)



So these are all right, double checked, as stated above:

at 120V switch setting:
Reading approx 1-2 ohm between 1+3 and 2+4 (also, continuity between those points)

at 230V switch setting:
Reading approx 1-2 ohms between 2+3 (also, continuity between those points)

[Helmholtz]

Point is your readings don't make sense.

If both primaries are open you shouldn't have a low resistance between 1+3 (or 2+4) in 120V setting. Look at the schematic.

With 230V setting, 2+3 are connected by the switch, so should measure close to zero Ohm.
What does your Ohmmeter read with shorted leads?

[g1]

Hey, I covered it on #20 post and explained the mistake, why we get to this for the second time? (those reading from post #10 were with switch set to 120V)



So these are all right, double checked, as stated above:

at 120V switch setting:
Reading approx 1-2 ohm between 1+3 and 2+4 (also, continuity between those points)

at 230V switch setting:
Reading approx 1-2 ohms between 2+3 (also, continuity between those points)

So you have no resistance readings ( OL ) between 1&2 or 3&4 with switch in 240V position? But continuity between those same points with switch in 120V position?
The only way that would be possible is if C53 was shorted. Remove it and check those readings again.

[boroman]

Point is your readings don't make sense.

If both primaries are open you shouldn't have a low resistance between 1+3 (or 2+4) in 120V setting. Look at the schematic.

With 230V setting, 2+3 are connected by the switch, so should measure close to zero Ohm.
What does your Ohmmeter read with shorted leads?

So you have no resistance readings ( OL ) between 1&2 or 3&4 with switch in 240V position? But continuity between those same points with switch in 120V position?
The only way that would be possible is if C53 was shorted. Remove it and check those readings again.

C53 & C54 looking good around 3NF measured. With unsoldered I dont see any change at all

BUT with 230V voltage connected (and switch at 230V of course)
I have continuity betweem 2+3 and 1+4 (230V only between 1+4)
Without voltage, continuity is only between 2+3.



Strange...


Anyway, maybe I could connect IEC socket straight to the PT, without S5 in the chain?

[Helmholtz]

Never ever try to measure resistance or continuity in a powered circuit.
It doesn't make sense, won't give useful results and is likely to damage the meter.

It seems both PT primaries are open, probably because someone connected to 230V in 115V setting.
In your picture the PT shows signs of overheating.
So you need a new PT.