Transformer trouble!

rubendelacosta · Joined: Dec 25, 2005 Posts: 153 Location: lisbon

anyone knows any thig about this transformer (MT-TS0302)? I need a similar one for my tama techstar TS 206....but i don't know the "inside" voltage....and the one i have it's broken. I gogled it and nothing..... Crying or Very sad

Help me please!

thanks, ruben.

Uncle Krunkus · Posted: Mon Jun 05, 2006 6:26 am Post subject:

Sorry Ruben,
couldn't find anything.
It's the mains transformer yeah? You need the schematic to check out what the sec voltage is.

rubendelacosta · Joined: Dec 25, 2005 Posts: 153 Location: lisbon

yep, it's the main transformer.
i found this site that says that have the schematic....but i they say i have to pay for that : \ http://www.musicparts.com/products.aspCompany=Tama

In the other hand i found this site whit the schematic from a similar tama module, the ts 305
http://fa.utfs.org/diy/tama305/schem.htm
but the transformer have a diferent name (MP-TS0106) and on the inside runs on 15v and 6v( i think).
It's probably it, because the diference betwin tama TS206 as tama TS305 is that tama TS305 have four more modules than the TS206(and on the outside the modules look just the same)

but i'm not shure, do you think this is the voltage that my TS206 needs?

thank you, ruben.

dnny · Posted: Mon Jun 05, 2006 9:19 am Post subject:

Hi Ruben - what regulators you have on your 206?

7806 ? 7815? or 78xx ?
that will tell us more about the transformer.

daniel

toppobrillo · Posted: Mon Jun 05, 2006 10:03 am Post subject:

what happened to the tranformer?

rubendelacosta · Joined: Dec 25, 2005 Posts: 153 Location: lisbon

The thing is, this machine runs on 120v and i live in portugal so the voltage here is 220. The fuzes blow up and there is no place i can find some 120v fuzes. So my plan is to switch the 120v transformer to a 220v and then i can put some 220v fuzes. The other problem is....my 220v to 120v converter burned weeks ago....and now i can't mesure the voltage(i probably sould buy one...that's right...but right now i'm out of money: \) of the 120v transformer....

rubendelacosta · Joined: Dec 25, 2005 Posts: 153 Location: lisbon

where do i see this "regulators"?

Uncle Krunkus · Posted: Mon Jun 05, 2006 2:14 pm Post subject:

Just want to let you know that you don't need to use 120V fuses. The important thing with fuses is their Current rating (how many Amps or milliamps they can carry before blowing) the voltage rating has more to do with how safely they will blow. So 220V fuses are fine for 120V as they exceed the working voltage rating.
But that still means you need a 220V -> 120V step down transformer.

dnny · Posted: Tue Jun 06, 2006 12:22 am Post subject:

rubendelacosta · Joined: Dec 25, 2005 Posts: 153 Location: lisbon

oh, so that's a regulator Wink

well ther are two regulators and ther names are 7815 and the letters/numbers after are UC8412.

just curiosity....what they "regulate"?

dnny · Posted: Tue Jun 06, 2006 5:57 am Post subject:

rubendelacosta · Joined: Dec 25, 2005 Posts: 153 Location: lisbon

hey! thanks a lot!
you saved my TS206

ruben

dnny · Posted: Tue Jun 06, 2006 9:23 am Post subject:

did you get it working? great! thats good news -
wave

blue hell · Posted: Tue Jun 06, 2006 9:44 am Post subject:

dnny · Posted: Tue Jun 06, 2006 12:15 pm Post subject:

piedwagtail · Posted: Tue Jun 06, 2006 12:27 pm Post subject:

HANG ON!(20-35VAC?why.....what current....how many windings.....2@35 will roast the 7815s and probably the rest of the board)

Please refer to the schematic posted and hyper-check....
I forsee a transformer primary 0-220V 0r 0-115 and 0-115(join 115 and 0 in the middle so the 0-230 appears end to end)
The secondary if you are going to subsitute and your device is anywhere near the TS305 in that schematic...will be simply two 0-15V windings.(unless see BUT..)
15V X 1.4V after full wave rectification(if that is what it uses)will be enough for the 7815 to work.

The device schematic shows two 7815s because 7915s didn't exist.One 7815 regulates as normally seen nowadays and the second regulates earth 15V above the -15 V line.
Due to this factor there are two rectifiers instead of the one we use today with the 7915.
The size of transformer you need depends on the current this thing draws,that will have to estimated and overreached.

BUT....are you looking closely enough?...big style regulator checks are casual compared to how many tracks or wires leave the transformer.....maybe the 7806 is a low current device looking like a transistor and is stuck somewhere else on the board.
Check the TS305 schematic against the 306,look at the secondary connections....Are there 6?are there three fuses?how many rectifiers are traceable from the tranny?

If you only need +/-15V you are in luck...RS or Farnell must service Portugal and these transformers are easy enough to pick up.
http://pt.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=1131504&N=401
(BUT maybe need a bigger transformer)

An additional 6V tap will not be easy to find,you'll need an additional transformer.

So it may be better,considering your inexperience,to simply buy another stepdown tranny.Depends on your price/time ratio,i 'm not being rude,but what i've written above was not learnt overnight.
Some homework needs to be done....

Robert

zipzap · Posted: Tue Jun 06, 2006 2:59 pm Post subject:

15v transformer will work? I´ve learned somewhere, think it was even here, that a 15v transformer is critical, as the mains voltage may/will drop too low from time to time. The Ideal value is supposed to be 18v, thats where you are on the safe side and losses are little. In this case that´ll be 2*18v. If ýou don´t know how much current is needed, again a look at the regulators may help. If they are wearing huge heatsinks i would use a transformer that can supply at least 2,5A (*2). Otherwise 1A is propably more than enough.

piedwagtail · Posted: Tue Jun 06, 2006 3:50 pm Post subject:

Yes,i hadn't considered Portuguese line regulation.....revise to 2@18V on inspection!

blue hell · Posted: Tue Jun 06, 2006 4:16 pm Post subject:

15 Volt is disturbingly low indeed.

78xx volatage regulator have overcurrent protection, for the 7815 it typically kicks in at 1.2 A (after some time, the peak current can be higher). This does not map directly to the current the transformer must be able to supply, but it does approximately so when the output voltage of the transformer is high enough to allow for some drop in voltage due to the peak current.

Exact calculations are pretty involved for this, but an 18 V transformer will have some headroom, so 1.2 A for the transformer seems a reasonable absolute max value.

The maximum heat dissipation for the regulator could then be something like 15 Watt (worst case estimate) for which quite large heatsinks would be needed.

(This is not really much of a problem though, as the regulators not only have over current protection but they are also protected against overheating. What will happen in the case of overheating is that the circuit works until it overheats, it will then shut down and when it cools enough it will start again - a clear sign that larger heatsinks are needed.)

I can't find thermal resistance data for the 78xx devices, but when a small heatsink is mounted a rough estimate would be 500 mA for the transformer.

Another guide could be the size of the transformer, it would have to have roughly the same physical dimensions as the original, preferably not smaller.

And a maximum current rating of a transformer being too high is not really a technical problem, it just costs more than a rightly dimenesioned one (and it will be bigger). When in doubt better too high than too low.