Hello all
I'm troubleshooting this SWR WorkingPro 10(Fender generation),the complaint was blown fuses every time.I went ahead unplug the TXmer secondary,power it up and fuse flashed.
I'm suspecting a shorted transformer but where do I buy it? online store preferably.Help me.
The dumb question is what is that black round component RT2-STMC30-26,I see those in every amps(in yellow too).Never bothered about it all this time.Its the least suspected villain for this flaw but hey,this is electronics,we can never be to sure.
What is its name?How do we measure it?Which setting on the DMM should we use when doing so?
I'm troubleshooting this SWR WorkingPro 10(Fender generation),the complaint was blown fuses every time.I went ahead unplug the TXmer secondary,power it up and fuse flashed.
I'm suspecting a shorted transformer but where do I buy it? online store preferably.Help me.
The dumb question is what is that black round component RT2-STMC30-26,I see those in every amps(in yellow too).Never bothered about it all this time.Its the least suspected villain for this flaw but hey,this is electronics,we can never be to sure.
What is its name?How do we measure it?Which setting on the DMM should we use when doing so?
If it's connected across the primary, it's a surge suppressor, used to be referred to as an MOV (metal oxide varistor). They're common in electronics and "protected" power distribution. They are effective on fast spikes, but can fail shorted. Check across it with an ohmmeter.
If it's connected in series with the primary, it's possible it's a thermistor or surgistor which limits the inrush current (so the fuse does not blow). These can also fail shorted, so the same check applies. I can't find a schematic which has the transformer connections, just the main circuit board schematic.
The RT designation would lead me to guess it's a thermistor (Resistor, Thermal).
If it's connected in series with the primary, it's possible it's a thermistor or surgistor which limits the inrush current (so the fuse does not blow). These can also fail shorted, so the same check applies. I can't find a schematic which has the transformer connections, just the main circuit board schematic.
The RT designation would lead me to guess it's a thermistor (Resistor, Thermal).
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It is a thermistor, a resistor that lowers its resistance as it warms up. it is used as an inrush limiter when the amp is first powered up with empty caps. fender often includes them in designs. It is not in a position to blow fuses. If it fails open, no power up at all occurs. if it somehow were to fail short, the amp would still function.
Before you commit to a new transformer MAKE SURE the mains connections are right. Your second photo shows them. Flip that board over and look at the copper traces. Then verify that the mains comes in through the thermistor and switch and is across the transformer primary - in other words make sure the wires don't have the switch across the mains.
Here in the USA, I'd just order a new transformer from a Fender parts dealer. Where you are, the Fender part number for the transformer is on the label, upper right where it says "customer ref", the number that follows is the fender part number. You could contact whoever sells fender in your area. But the transformer maker appears to be in Hong Kong, their part number is on it, as well as their web address, so perhaps it could be obtained from Keen Ocean. Just a thought, I don't know if that would work out.
Before you commit to a new transformer MAKE SURE the mains connections are right. Your second photo shows them. Flip that board over and look at the copper traces. Then verify that the mains comes in through the thermistor and switch and is across the transformer primary - in other words make sure the wires don't have the switch across the mains.
Here in the USA, I'd just order a new transformer from a Fender parts dealer. Where you are, the Fender part number for the transformer is on the label, upper right where it says "customer ref", the number that follows is the fender part number. You could contact whoever sells fender in your area. But the transformer maker appears to be in Hong Kong, their part number is on it, as well as their web address, so perhaps it could be obtained from Keen Ocean. Just a thought, I don't know if that would work out.
If the primary has gone short circuit, that was probably caused by a bad mains connection, plug or socket or extension lead.
What Enzo said .
That said, a couple small details:
1) it shows a 230V primary only and you have 220?/240V? mains so there's no "wrong winding selected" possibility, but there may be other wiring errors, I'd fully pull the transformer outside the chassis, simply to make 100% certain, and connect primary only to mains, through the proper fuse .
2) try to go through Fender, even if you have to order from USA and wait.
I very much doubt the HK supplier can sell you one, even if they wish.
They must be a huge OEM supplier, who won a contract, (say 5000 transformers that model for Fender) , delivered them and got to do something else.
It's not a generic part like, say, a 12V 2A transformer which lots of manufacturers buy and which they might supply you by pulling one from another order.
3) if Fender can't help you, *maybe* ANTEK has a suitable one , try Mouser too, or even, gasp!!!! ..... EBay 🙁
4) just as a side note, if Fender says "no" and can't find it anywhere else, you'd be in my situation: here in Argentina even if available in USA, freight for a heavy part is a deal killer, Customs is a mess, etc. , so I'd straight wind my own, period.
Not a toroid, I'm not that equipped, but a conventional EI type: your picture shows you have plenty space for one.
Only possible problem might be height, the EI size for that power is 80mm high.
In a nutshell: try to ask Fender first and foremost, even if paying somewhat high freight (+ tax???) , if impossible try some local transformer winder.
That said, a couple small details:
1) it shows a 230V primary only and you have 220?/240V? mains so there's no "wrong winding selected" possibility, but there may be other wiring errors, I'd fully pull the transformer outside the chassis, simply to make 100% certain, and connect primary only to mains, through the proper fuse .
2) try to go through Fender, even if you have to order from USA and wait.
I very much doubt the HK supplier can sell you one, even if they wish.
They must be a huge OEM supplier, who won a contract, (say 5000 transformers that model for Fender) , delivered them and got to do something else.
It's not a generic part like, say, a 12V 2A transformer which lots of manufacturers buy and which they might supply you by pulling one from another order.
3) if Fender can't help you, *maybe* ANTEK has a suitable one , try Mouser too, or even, gasp!!!! ..... EBay 🙁
4) just as a side note, if Fender says "no" and can't find it anywhere else, you'd be in my situation: here in Argentina even if available in USA, freight for a heavy part is a deal killer, Customs is a mess, etc. , so I'd straight wind my own, period.
Not a toroid, I'm not that equipped, but a conventional EI type: your picture shows you have plenty space for one.
Only possible problem might be height, the EI size for that power is 80mm high.
In a nutshell: try to ask Fender first and foremost, even if paying somewhat high freight (+ tax???) , if impossible try some local transformer winder.
Prove that TX is the problem first. Disconnect the primary of the TX. Try turning on the power to see if the fuse blows. If the fuse blows then the TX may be OK. The AC power distribution of the PCB assy with fastons may be the problem. Try the TX connected using external cord & fuse. Keen Ocean is an OEM Supplier.
The distribution board showed everything snap in accordingly,
I done a continuity test at all secondary out.All the three outlet "ping" with one another.In short all secondary out is shorted.
I'm reluctant to deal with my local FMIC dist.for obvious reason.Prices,birocracy etc..
Hey Mr Enzo,could I order the power transformer through you.Just a thought.
My thanks also to Mr okcrum,jonsnell,JM Fahey,Audio1man and again to Enzo.
I done a continuity test at all secondary out.All the three outlet "ping" with one another.In short all secondary out is shorted.
I'm reluctant to deal with my local FMIC dist.for obvious reason.Prices,birocracy etc..
Hey Mr Enzo,could I order the power transformer through you.Just a thought.
My thanks also to Mr okcrum,jonsnell,JM Fahey,Audio1man and again to Enzo.
Oh, I forgot to mention;
They usually include a small pouch with sweets.
A nice attention of them.
They usually include a small pouch with sweets.
A nice attention of them.
I don't think so. The label on the transformer shows three center-tapped secondaries. Thats nine wires out. On the picture, I see only seven connectors, and the label says "yellow" for the center tap of all three windings.
So it seems that all three secondaries share a common center tap. In this case, the "ping" is to be expected and does not necessarily indicate a fault.
Regards,
Rundmaus
I second the suggestion of disconnecting everything from the transformer, including the mains, then connect mains directly to the primary wires through a fuse. That verifies the transformer as defective or not and eliminates the primary wiring in the amp.
There is a VERY simple tester for transformer shorted windings over at www.geofex.com under tech tips. it is worth putting one together for your bench.
There is a VERY simple tester for transformer shorted windings over at www.geofex.com under tech tips. it is worth putting one together for your bench.
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