Mains TX outputs for Line 6 Spider 4 anyone?

[allante666]

Hi
Line 6 Spider 4 75 watt. Primary blown on mains tx and wonder if anyone knows what the voltage should be on the secondary while I'm waiting for a price from Line 6 (who will send it by email in a few minutes... yesterday...)
In case its a ridiculous price I figured I could source one from elsewhere but don't know what the outputs are. It has one centre tapped winding but I suspect the centre tap might not be centre as the resistances measure quite differently each end to centre, unless of course the secondary is dodgy as well.
I cant find a schematic for the 4 which shows the power supply (unless anyone knows differently) and of course Line6 wont send them out to anyone unless you're a authorised Line 6 repairer (or should I say THE authorised repairer as there only seems to be one in the whole UK)

Apparently before this went o/c the amp developed a no audio fault. not sure how its connected but possibly power rail gone haywire somewhere. He said that the mp3 input worked fine but nothing plugged into the guitar socket did nor did the headphones. Im thinking it may be the guitar sense circuit not knowing it has a guitar plugged in? he said the rest of the amp all lit up and worked as normal.
Either way I cant do anything until I sort out power so any help appreciated!

TX part number is 11-30-0006. I know that as i found one for sale by a U.S. company but he said he didn't know what the outputs were! Seems there were a few different ones fitted but that number one is the three wire output. some others have 5.

[g1]

Unfortunately, the schematics do not show the power supply, so no voltages from the transformer.
Full Compass shows the TX at $34US, so I would think you should be able to get it for a reasonable price.
But are you confident there are no other issues? If it gets more major, these amps are probably not a lot of money used.

[allante666]

Hi. No I know, I have the schematics which for some reason don't have the power supply on too. The one at full compass is the one I saw and emailed them but they said they didn't know what the output voltages were.
34 dollars would be fine but I'm in the UK so it will probably be extortionate over here!
No, I'm not 100 percent confident theres no other issues hence why I need a price first. These amps as clean as this one is fetch 75-100 GBP on Fleabay so It might be worth doing. If I could find out the voltages I could cobble something together to power it up to see if there were any other problems.

[g1]

If it only has one center-tapped winding, then there is a main split supply, +/- some voltage that does not exceed the rating of the main supply filter caps. Also check the specs for the output chips, do not exceed their max. supply ratings.
Between the ratings on the main caps and the output IC's, you should be able to power it up (with cobbled supply) to some safe voltage.

[allante666]

Yeah, from memory because I'm at home now, I think the two main smoothing caps are 50 volt but theres what appears to be a smaller supply with I think a 16 volt cap which feeds off one side of the winding and gets half wave rectified through a couple of diodes. Might be wrong but that's how it looks at a glance, hence I think that one side of the winding is a bigger voltage than the other. resistances certainly show that but again I'm not sure if the secondary is ok or not. So yes, I can knock something up to do this I just thought someone might just have a proper schematic so I could not only know for sure and could source an alternate tx if the genuine on turns out too expensive. I bet your 34 dollar one gets at least doubled in price by the time it gets a UK price tag on it!!

[mozwell]

The sch i have for Spider 4 doesn't show the power supply, but spider 3 shows 25V caps in the main power supply & seems to use the same power amp ic TDA2050 as the spider 4.
The parts list for spider 4 calls 2200u 50V caps in the power supply.
30W output, TDA2050 on both, i can guess at approx +/- 22V on the power supply, which means secondary voltage of 16-0-16VAC
The other winding powers the 3.3V supply, so a 5 or 6VAC should be fine for that

Is it not possible to get a replacement transformer from somewhere in europe or the uk, maybe one of the UK service centers ?

Is should be quite safe to use a transformer just for testing to make sure there are no other problems (dead ic, dead power amp ic, shorted component) etc before you shell out for a proper transformer. If you don't run the amp loud during testing, a small transformer (20VA or up) should be sufficient. You will also need another transformer if your amp uses an extra winding for the 3.3V supply....
If the amps is working fine with this temporary setup, then the cost of a "proper" replacement transformer is justified.

[allante666]

hi Mozwell, yes I can get something rigged up ok for testing its just as far as the tx goes and finding a comparable one if it turns out viable to replace it I dont think its a xx-0-xx winding I think its maybe a xx-0-yy. There isnt a separate winding the secondary only has three wires out so im thinking its tapped off centre to give two different voltages. I dont know why there doesn't seem to be any power supply schematics kicking around?
I can get a transformer from the uk from Line6's distributor but Im still waiting for them to get back to me with a price.

[mozwell]

I think its very unlikely you would have a xx - 0 - yy secondary, that's something I have never seen before on a solid state amp (and even on a valve amp we still have xx - yy - 0 - xx where yy is for the bias

So if your amp uses the TDA2050 ic, a 15-0-15VAC transformer should get you up & running enough to test the beat out & work out if there are any other faults. If all is good & you can play at low volume, then order the correct transformer
15-0-15 will give you +/- 22VDC or so at the main filter capacitors, which is then easy enough to reduce down to +/-15V or +/-7.5V or whatever this this uses for op amp rails

[52 Bill]

I think its very unlikely you would have a xx - 0 - yy secondary, that's something I have never seen before on a solid state amp (and even on a valve amp we still have xx - yy - 0 - xx where yy is for the bias

If the secondary windings are not faulty, a quick resistance reading of the windings will tell you if there is a center or off center tap.

There probably is a thermal fuse in the primary winding that has opened up. Worst case would be to open the transformer up and bypass the breaker. Then you can power up the transformer and read the actual ac voltages on the secondaries.

[g1]

It should be fairly easy to trace out the main higher voltage split supply, and which winding of the PT it connects to. If the ground connects to the CT, then the PT must be a balanced winding as the DC split supply has to be balanced + and -
Agree with Mozwell that it is highly unlikely to be an unbalanced winding.
Those diodes going to the LV supply could be zeners to drop voltage from the HV supply. See if those diodes connect to the PT. (the diodes you suspect of being half wave rectifiers for LV supply)

As 52Bill mentioned, if there is a thermal fuse in the primary winding, you can bypass it for testing purposes.

[allante666]

Im gonna have to draw this circuit out on paper to get my head round it! Its on double sided board so is really difficult to follow but its only a basic circuit, dont know why its causing me grief to be honest!! Centre tapping and one end of secondary go to the bridge rectifier, the other end of the secondary goes to these diodes I mentioned. Measuring resistances of the secondary Im getting 1 ohm ct to one end and 11 ohm ct to other end which is why i think its not an even split. either that or the secondary is faulty.
the thermal fuse bypass is an option but depends where it is, Ive done that before and its been sat there on top of the windings staring at me and Ive also had them where its buried in the windings unreachable. Ill keep that as a pretty much last resort.
Ill get t the bottom of it eventually its just annoying when its probably staring you in the face and you cant see it for looking! Its made worse by the fact the audio signals run through the board on their way up to the output chip so theres a load more tracks to follow than just the power. They could have used a ribbon for that and made life a bit easier! and yes, still waiting to hear a price from Line 6. They even sent me a survey asking how good their service had been...

[Jazz P Bass]

The pic of the transformer number, 11-30-0006, shows 5 wires.

Line 6 11 30 0006 Power Transformer for Spider II and IV Amps | Full Compass

[allante666]

The five wires you see in the picture are the primary ones. Its got a double winding for different mains voltages. Theres two connectors on the pcb for the different ones. the secondary is the red yellow and black you see in the pic.

[Jazz P Bass]

I honestly do not see how to get all of the voltages required on a three wire circuit.

Here is the header from the Spider IV

Line 6 Spider IV 3012 PS Header.pdf

And the power supply from the 212

Spider 212 Pwr S.pdf

[52 Bill]

I've seen a single secondary used to supply two separate half wave supplies one pos and one neg. Not real elegant, but I guess it could work.

Alante666, you need to reverse engineer the basic supply circuit to figure this out.