Should a transformer live/neutral pins have continuity?

[mikay786]

Just a quick question.

Was wondering why the two pins on this transformer have continuity between them for live and ground. Is this normal? If not why would it be doing so?

[stj]

Re: Should a transformer live/neutral pins have continuity?

it's not "ground", it's negative.
and it's normal because it's just a long coil of wire inside.

[mikay786]

Re: Should a transformer live/neutral pins have continuity?

Thanks I thought I may have shorted it out somehow.

bought a Sony mini hifi thing today, it all powers up but no sound from speakers. Just trying to figure out what's up with it.

[stj]

Re: Should a transformer live/neutral pins have continuity?

sound from headfones / any audio hum?

[mikay786]

Re: Should a transformer live/neutral pins have continuity?

No hum or hiss, not tried headphones

[mikay786]

Re: Should a transformer live/neutral pins have continuity?

sony mhc-s7av Nice little 4 stack system. Got some goodmans q70 speakers last week which i was hoping to pair with

[stj]

Re: Should a transformer live/neutral pins have continuity?

try with phones incase it's the switch in the socket.

then check all the soldering on sockets,pots etc and anything stuck on a heatsink.

[SteveNielsen]

Re: Should a transformer live/neutral pins have continuity?

Phones will tell you if the preamps and EQ circuits are working in case the problem is in the power amp only. If there's AC hum in the phones could also indicate bad filter caps in the power supply.

[budm]

Re: Should a transformer live/neutral pins have continuity?

Service manual:
http://elektrotanya.com/sony_mhc-sv7.../download.html

[mikay786]

Re: Should a transformer live/neutral pins have continuity?

Just getting a hum in headphones no music. When I push in half way hum in right earbud and when pushed in all way moves over to left ear.

I think ive identified a bad cap also

Rubycon 100v 100uf 85c YK Series - Theres a pair of them side by side located as per pic with red box

Filter caps are the bigs expensive one up front?

Could it be just these rubycon bulgers?

[stj]

Re: Should a transformer live/neutral pins have continuity?

if those are inline with the speaker outputs it could mean there was a bad speaker connected.

[SteveNielsen]

Re: Should a transformer live/neutral pins have continuity?

From the pic I don't see any bulging on the 100uf Rubycons but that doesn't mean they are good or bad. Yes the power supply filters are the big caps at the top of the 2nd pic. I'd test them and the rectifiers, resistors and fuses in the power supply section where the big caps are.

[mikay786]

Re: Should a transformer live/neutral pins have continuity?

They are close to the terminals

behind the heatsink

Would some Panasonic FC series be suitable replacements?

[mikay786]

Re: Should a transformer live/neutral pins have continuity?

Its definitely bulging the 2nd one and has got a little crust on it. Ill try to get a better pic

[mikay786]

Re: Should a transformer live/neutral pins have continuity?

Bulging right in the middle of the K with a small deposit there too on the cap with the red line

[budm]

Re: Should a transformer live/neutral pins have continuity?

You have three speaker relays, do you hear any one of them click on?
Those two caps are for the +/-VCC filter for the preamp of the STK audio IC.

[mikay786]

Re: Should a transformer live/neutral pins have continuity?

When you turn it on it clicks once I think

[budm]

Re: Should a transformer live/neutral pins have continuity?

Did you download the service manuals?

[mikay786]

Re: Should a transformer live/neutral pins have continuity?

Have done now that ive installed chrome.

Removed main board and looks like someones already been in here and made a bit of a mess.

That relay has been wrapped in black tape for some reason plus a bit of a bodge on solder side.

[stj]

Re: Should a transformer live/neutral pins have continuity?

someone probably opened the relay to clean the contacts and broke the clips on the shell.

those coils dont look so good either!