Turntable - Problem with AC Adapter

[GeorgePal]

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]

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]

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]

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

 

[GeorgePal]

The last one is from the turntable.

 

[Mooly]

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]

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]

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]

That should help... thanks.

 

[GeorgePal]

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]

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]

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]

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]

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]

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]

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]

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]

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

 

[GeorgePal]

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

An externally hosted image should be here but it was not working when we last tested it.

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]

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