Try the transformer without a load. It could be that the regulator board or the turntable is faulty.
I have this.
I turn it to 1000AC, plug the transformer into the powerline, and try to measure but the line is not even moves.
Two possibilities:
a) If the fuse blew with only the PSU board connected and the power switch was set to 'on', the 8V regulator might have failed s/c.
b) If the power switch was 'off' during your last test, one or more of the rectifier diodes or the parallel snubber capacitors has developed a short.
Check with a multimeter.
Rundmaus
a) If the fuse blew with only the PSU board connected and the power switch was set to 'on', the 8V regulator might have failed s/c.
b) If the power switch was 'off' during your last test, one or more of the rectifier diodes or the parallel snubber capacitors has developed a short.
Check with a multimeter.
Rundmaus
If it is still capable of blowing the 630mA fuse, the transformer is still working. Use a smaller, fast blowing fuse of approx. 200mA if you insist on powered testing.
Please try to answer the following questions without further testing:
1) Was the power switch on during your last test?
2) Where did you try to measure the voltage?
3) Does your meter measure continuity across the filter cap or the rectifier diodes?
Rundmaus
Please try to answer the following questions without further testing:
1) Was the power switch on during your last test?
2) Where did you try to measure the voltage?
3) Does your meter measure continuity across the filter cap or the rectifier diodes?
Rundmaus
I don't have 200mA fuses to try it right now, and it is Sunday 😀
1)The fuse blows only if I turn the on/off button to ON. If I remember right, when I used a new ON/OFF button, when I connected it, while it was still on OFF (I'm not sure if it was off or on), a sound of "blowing" came from the button. After that, everytime I change the fuse, regardless if the button is off or on, it is getting burned.
2) What you mean?
3)I connect the AC to the powerline and then I use the two white cables to measure it. But I don't really understand if it is that what you're asking me.
Sorry, but I have to talk in english for years and now it is a bit difficult for me to talk correctly.
Remove the on/off switch completely. Make sure nothing but the power transformer is connected to the power supply board. Check the board around the switch for short circuits, solder bridges and such. Power on again carefully.
If the fuse doesn't blow, the 8V regulator seems to be the faulty part.
Rundmaus
If the fuse doesn't blow, the 8V regulator seems to be the faulty part.
Rundmaus
Then remove the 8V reg from the board and put a power switch back in. Connect nothing else but the transformer, as before. Check carefully for shorts and solder bridges in the regulator area. Power on carefully.
If the fuse doesn't blow, get a new reg.
Rundmaus
EDIT: Make sure that the pinout of your replacement switch is the same as the original switch! A different pinout might mean that switching it on shorts the rail against ground.
If the fuse doesn't blow, get a new reg.
Rundmaus
EDIT: Make sure that the pinout of your replacement switch is the same as the original switch! A different pinout might mean that switching it on shorts the rail against ground.
Afterwards, use your meter in the 20VDC range and measure across the large cap on the PSU board. You should see approx. 15V there.
IMPORTANT: When measuring the powered unit, do not touch anything. Best to use clip-leads and connect the meter securely before powering on. Then connect mains/power on, read meter, power off. Disconnect meter only *after* disconnecting mains.
IMPORTANT: When measuring the powered unit, do not touch anything. Best to use clip-leads and connect the meter securely before powering on. Then connect mains/power on, read meter, power off. Disconnect meter only *after* disconnecting mains.
@Mooly:
Seems so. Transformer is still capable of blowing the fuse, seems ok. Fuse only blows with power switch on. Doesn't blow with switch removed.
Either a wiring error in the replacement switch or a faulty 8V reg.
Rundmaus
Seems so. Transformer is still capable of blowing the fuse, seems ok. Fuse only blows with power switch on. Doesn't blow with switch removed.
Either a wiring error in the replacement switch or a faulty 8V reg.
Rundmaus
Some of these cheap designs are just designed to fail after a period of time. The regulator may be operating with a minimum heatsink and may be operating close to its SOA (Safe Operating Area).
Its a Philips 🙂 they do.
Actually regulators do fail, I've seen it many times when they have gone down but thinking about that, its usually ones on the end of an SMPS somewhere that fail.
A few logical checks should reveal the problem here.
One way to test the transformer ON LOAD is with an auto bulb. Let's assume that the transformer is 15VA, try soldering a 10W auto lamp across the secondary as check that the lamp illuminates.
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