Help with my Transformer - vibrating

Brit01 · 25th July 2009, 02:33 AM

Hi guys,

Something strange is happening with my psu

Just stoppped working and blew the fuse on the primary.

I disconnected the psu, replaced the fuse, and placed a light bulb between the connections on the secondary.

Light bulb lit fine.

Now I replaced the rectifier, checked all connections, and then re-attached and powered up. The tranny shakes like a earthquake!! Immediately switched it off, checked everything and tried again. again the same vibration and no B+ voltage.

What's going on?

Brit01 · 25th July 2009, 02:40 AM

Update:

I tried using my SS rectifier with the tranny and still it vibrates like crazy.

What's happening with the tranny? Has it died? Strange that it still illuminates the light bulb.

whitelabrat · 25th July 2009, 12:10 PM

Something is shorted, but I don't think it is the transformer. That's my first guess.

chris661 · 25th July 2009, 12:14 PM

Same problem in the physics lab. The one we were using was very old, so it vibrated itself off the desk.

I'd try a new one.

Chris

Shoog · 25th July 2009, 01:21 PM

Excessive current draw from a short somewhere. If the transformer isn't giving off rank smelling smoke then its probably somewhere else.
Start by looking for blackened resistors - especially cathode resistors.

Shoog

Brit01 · 25th July 2009, 01:39 PM

Had a good night sleep and checked everything in the morning. seems to be my tube power supply.

Tried a new SS power supply and everything works fine.

Very strange, checked everything visually on Bas's psu and everything looks undamaged. Have to do some probing.

Cheers

Brit01 · 25th July 2009, 02:12 PM

Checking the circuitry:

D2 on Bas's psu is reading both ways

Blown diode here?

richwalters · 25th July 2009, 06:29 PM

A shorted diode creating half wave seems a possible cause.
On the otherhand; some years ago I came across a sim problem to find a 110V transformer wired for a 230V supply. Over voltage leading to core-saturation can also cause sim noises. Check primary wiring config.

richy

Brit01 · 25th July 2009, 07:16 PM

Turned out to be one of the diodes! Swapped it and all works fine now

richwalters · 26th July 2009, 04:30 AM

Although you may have found the fault; there may be an underlying reason behind this: It may repeat.
Is surge current (input inrush) into cap input filter too high ?
Too high reverse peak volts for diode? (Vrrm ratings)
Mechanically busted.

An anti surge fuse used in primary ?

richy

25th July 2009, 02:33 AM	#1
Brit01 diyAudio Member Join Date: Jul 2008	Help with my Transformer - vibrating Hi guys, Something strange is happening with my psu Just stoppped working and blew the fuse on the primary. I disconnected the psu, replaced the fuse, and placed a light bulb between the connections on the secondary. Light bulb lit fine. Now I replaced the rectifier, checked all connections, and then re-attached and powered up. The tranny shakes like a earthquake!! Immediately switched it off, checked everything and tried again. again the same vibration and no B+ voltage. What's going on?

25th July 2009, 12:14 PM	#4
chris661 diyAudio Member Join Date: Feb 2008 Location: Lancashire Blog Entries: 7	Same problem in the physics lab. The one we were using was very old, so it vibrated itself off the desk. I'd try a new one. Chris __________________ "Throwing parts at a failure is like throwing sponges at a rainstorm." - Enzo My setup: http://www.diyaudio.com/forums/multi...tang-band.html

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25th July 2009, 02:40 AM	#2
Brit01 diyAudio Member Join Date: Jul 2008	Update: I tried using my SS rectifier with the tranny and still it vibrates like crazy. What's happening with the tranny? Has it died? Strange that it still illuminates the light bulb.

25th July 2009, 12:10 PM	#3
whitelabrat diyAudio Member Join Date: Dec 2006 Location: Maryland	Something is shorted, but I don't think it is the transformer. That's my first guess.

25th July 2009, 01:21 PM	#5
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	Excessive current draw from a short somewhere. If the transformer isn't giving off rank smelling smoke then its probably somewhere else. Start by looking for blackened resistors - especially cathode resistors. Shoog

25th July 2009, 01:39 PM	#6
Brit01 diyAudio Member Join Date: Jul 2008	Had a good night sleep and checked everything in the morning. seems to be my tube power supply. Tried a new SS power supply and everything works fine. Very strange, checked everything visually on Bas's psu and everything looks undamaged. Have to do some probing. Cheers

25th July 2009, 02:12 PM	#7
Brit01 diyAudio Member Join Date: Jul 2008	Checking the circuitry: D2 on Bas's psu is reading both ways Blown diode here?

25th July 2009, 06:29 PM	#8
richwalters diyAudio Member Join Date: Sep 2003 Location: Alps:Tube amp designs over 150W, SMPS guru.	A shorted diode creating half wave seems a possible cause. On the otherhand; some years ago I came across a sim problem to find a 110V transformer wired for a 230V supply. Over voltage leading to core-saturation can also cause sim noises. Check primary wiring config. richy

25th July 2009, 07:16 PM	#9
Brit01 diyAudio Member Join Date: Jul 2008	Turned out to be one of the diodes! Swapped it and all works fine now

26th July 2009, 04:30 AM	#10
richwalters diyAudio Member Join Date: Sep 2003 Location: Alps:Tube amp designs over 150W, SMPS guru.	Although you may have found the fault; there may be an underlying reason behind this: It may repeat. Is surge current (input inrush) into cap input filter too high ? Too high reverse peak volts for diode? (Vrrm ratings) Mechanically busted. An anti surge fuse used in primary ? richy

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