M15Mk1 no voltages...

Hi to all.
This is my second M15 that I've built but in this one there are no voltages from the power supply.
At lugs 8-9 of transformer I've about 270 Vac. At positive lug of rectifier I've 240 Vdc, misured against ground, and about 100 Vac (always against ground). ??? How is it possible?
Finally, when I connect the positive of C21 with the positive of rectifier, the 200mA fuse blown.
Hope that someone help me, thanks....

Re: M15Mk1 no voltages...

News: I've tried with a larger fuse like a 500mA and works done with right voltages. Maybe there is high current flow when C21 charges.
For Martin: Is it not too small 200 mA for this use?

Re: M15Mk1 no voltages...

How can I measure the current? To the positive of rectifier against ground? All the voltages are about +/- 1% to the refer of schematic.
PS:I've tried 2 old and used El84...

Re: M15Mk1 no voltages...

I've checked and rechecked the schematic, but I've not found mistakes...
The 200mA fuse blows when I connect C21 at + of rectifier.
I've used standard 0,5mm2 solid core wire for both primary and secondary side of PT. This may be the only thing that could raise the current, with correct voltages altough...
Is this right? Must I substitute with a 0,75mm2 stranded wire?
(my english is too bad ;D )

Re: M15Mk1 no voltages...

Hi again Martin. This the voltage that I measured:
C21+ about 301V
C22+ about 292V
So the voltage between R33 is 8,6V... What I've to do?
Regards, Tio Pepe

Re: M15Mk1 no voltages...

Yes, Martin. Fuse work only when the bridge rectifier is connected to the secondary of PT.
The starts to blow when I connect the C21 at bridge, with or without tubes.
(I've broked 10 fuses by 200mA :'(, so I've decided to substitute then with 500mA
As I've said, I think that there are too much current flow when the capacitors charges.
All in all, the amp works very great!
Regards

Re: M15Mk1 no voltages...

I'm sorry, but changing the wiring the fuse blows anyway...
I'll try to lowering the capacitance.....maybe.....

Re: M15Mk1 no voltages...

I've tried three capacitors. One of these rated for 350V; the second for 400V and the latter is can cap multiple made by JJ Electronics. The fuse blows anyway. So i'll try wiring the capacitors to calculate the current.
bye

Re: M15Mk1 no voltages...

Sorry...out of town.
Here are two links to pictures of my M15. I've changed little bit the design and capacitors. So the power switch is at the back, and pilot lamp (in parallel with power switch) and standby switch is in front.
In the supply board, the power resistor lies under the capacitor.

[Blockierte Grafik: http://www.free4up.com/view.axd?fn=050164122052110.JPG]
[Blockierte Grafik: http://www.free4up.com/view.axd?fn=230008193037012.JPG]

Regards.

Re: M15Mk1 no voltages...

Hi Martin. This is the power supply of M15.
Regards

[Blockierte Grafik: http://imajr.com/th/powersupply_78324.JPG]