Turntable - Problem with AC Adapter

GeorgePal · 2013-05-12 7:41 am

Hello!

I have a Philips FP146 turntable from the '90s!
Yesterday I tried to use it after at least a decade. It didn't work. I opened it and I realized that its AC adapter is not working properly.

The name and serial key of its adapter is:
AMC 8549
3111 158 30050

Is there any possibility that I can find its technical info in order to replace it with a new one?
The only informations I can find about on the turntables are:
220V, 50Hz, 14W

Thanks in advance!

Mooly · 2013-05-12 7:47 am

Somewhere on the adapter it should (I would have thought) give the voltage and whether its AC or DC output. The 3111 bit sounds like a Philips part number.

Maybe close up pictures would help.

Are you sure the adapter is faulty ? Maybe a cable break or problem with the connector. Getting a new adapter should be easy as long as we know the voltage, the polarity and whether its AC or DC.

If you don't get much response I can move this over to "power supplies" forum.

GeorgePal · 2013-05-12 7:51 am

Thanks for all of your help Mooly!

I'll post some photos in about an hour because I have a job to do in the next our!

Mooly · 2013-05-12 7:54 am

No problem... I'll be around later if no one else jumps in.

GeorgePal · 2013-05-12 11:31 am

The last one is from the turntable.

Mooly · 2013-05-12 12:26 pm

I was thinking of a little "wall wart" when you said adapter.

That's a simple mains transformer with one secondary. Is it open circuit on the mains input side ? Many have a thermal fuse embedded in the windings. Check the winding on a meter on ohms range, It should read low resistance across the mains input side.

Mooly · 2013-05-12 12:39 pm

More info... if you look where the secondary connects in the TT you will find either a single diode rectifier or a bridge rectifier. Close to this will be a "large" electrolytic capacitor. If you look at the voltage rating of the cap we can work backwards to deduce a reasonable ball park figure for the transformer voltage.

If the thermal fuse is open circuit then there is always the possibility that a fault (such as a shorted rectifier etc has caused the tranny to overheat. It may or may not be just a faulty transformer.

Rundmaus · 2013-05-12 12:49 pm

You can download the service manual at:

70FP146 Service manual

The transformer feeds a very simple power supply consisting of a bridge rectifier and reservoir capacitor. Output voltages are an unregulated 15VDC and 8VDC regulated via a voltage regulator IC.

So any transformer giving approx. 15VDC after rectification will do.

Rundmaus

Mooly · 2013-05-12 1:02 pm

That should help... thanks.

GeorgePal · 2013-05-12 2:43 pm

Thanks for your help!! =)
Can u suggest me a transformer to buy from amazon.co.uk or ebay.co.uk? I don't want to buy a new one which won't work!

Thanks again! =)

Mooly · 2013-05-12 3:09 pm

I'd normally suggest a component retailer (which depends where in the world you are of course).

For example,
CTFC12-9 - CAMDENBOSS - TRANSFORMER, 12VA, 2 X 9V | CPC

My worry is that there is possibly a fault with the turntable that caused failure of the transformer.

Normally some basic tests would be done on the transformer first. Are you 100% its faulty ? and that that alone is the problem ?

I haven't actually downloaded the service manual but based on the 15 volts DC mentioned earlier suggests a transformer of around 9 to 12 volts AC. Small transformers have a poor regulation factor. That means when lightly loaded the output can be considerably higher so a 9 volt tranny could give nearer 10 volts. And its all regulated back down to 8 volts again anyway.

Knowing the approx physical dimensions of your tranny would help too in selecting a replacement. We need as much info as possible to make an informed choice

Mooly · 2013-05-12 3:15 pm

I'm just looking at the manual now... taken at face value I'd say it was a 12 volt tranny.

For example,
CTFC20-12 - CAMDENBOSS - TRANSFORMER, 20VA, 2 X 12V | CPC

KatieandDad · 2013-05-12 3:18 pm

You should be able to get away with any 30 or 50VA 12V transformer.

Toroidals are more common these days..http://www.ebay.co.uk/itm/30VA-2X12...al_Components_Supplies_ET&hash=item2ec76bd67b.. but if you really want an EI type I'm sure they can be had.

Here's one of many.

http://www.ebay.co.uk/itm/30VA-E-Sq...mplifier_Parts_Components&hash=item19cf301262

GeorgePal · 2013-05-12 3:24 pm

Mooly said:
Knowing the approx physical dimensions of your tranny would help too in selecting a replacement. We need as much info as possible to make an informed choice

Here!

Mooly · 2013-05-12 3:25 pm

KatieandDad said:
You should be able to get away with any 30 or 50VA 12V transformer.

Toroidals are more common these days..30VA 2X12V 1.25A Toroidal Transformers | eBay.. but if you really want an EI type I'm sure they can be had.

I've just spotted a 630 ma fuse on the secondary side so its really low powered, probably around 10 to 15 VA.

George... all that means is the transformer can be a small physical size.

KatieandDad · 2013-05-12 3:30 pm

For CPC - look at Farnell element14 | Electronic Component Distributors, CPC are their trade counter suppliers. http://www.rs_online.com also deal with Joe the public and have an enormous range of transformers.

As long as you realise that the minimum (smallest) specification will be about 10VA, anything with a higher VA rating will do the job.

http://www.ebay.co.uk/itm/12V-10VA-...al_Components_Supplies_ET&hash=item2c6ec754c0

Mooly · 2013-05-12 3:30 pm

Would something like this fit. All the dimensions are shown on the product details.
CTFC12-12 - CAMDENBOSS - TRANSFORMER, 12VA, 2 X 12V | CPC

Small toroidals are another option,
MCFM50/12 - MULTICOMP - MINI-TOROIDAL, 5VA 2X 12V | CPC

I'll have to leave it for now... but are you sure the old one is faulty ?

Edit CPC are doing free delivery at the moment... you have to follow the instructions on the main page.

KatieandDad · 2013-05-12 3:42 pm

Mooly, you've gone right down to 5VA with your last post, I think that would be too small.

GeorgePal · 2013-05-12 3:51 pm

Mooly said:
I'll have to leave it for now... but are you sure the old one is faulty ?

I don't know whats its name in English, so I'll post an image.

While I was trying to figure out what caused the problem, I found that this
[IMGDEAD]http://www.markidis.gr/images/products/FAST5X20.gif[/IMGDEAD]
was burnt. So, I changed it and tried to open the Turntable on again, but it burnt the new one too. I disconnected everything from the AC except the ON/OFF board. I changed the on/off button, tried to open it, and I had the same problem. So, what else may cause the problem?

Rundmaus · 2013-05-12 3:56 pm

Don't try any further without a bulb tester, you're risking damage to more components.

I'm looking at the schematic, will report back soon.

Your last attempt was with the PSU board only? Everything else disconnected?

Rundmaus

Turntable - Problem with AC Adapter

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