AMPEG SVT-CL rewiring for 220V and other issues

[GainFreak]

Hi,

A friend of mine recently bought a brand new Ampeg SVT Classic from abroad. It's labeled for 240AC operation. Line voltage here by standard is 220VAC although it's not uncommon in some places to go up to 230V.
I found the AC board schematic for SVT VR (I assume it's the same board) but I don't see a 220V option although it looks like the power transformer has 100 and 120V taps. So I was wondering if it's possible to rewire the amp for 220V operation or I should go for 230V?
Unfortunately there are couple of more issues with this amp. It worked for 20 mins or so and switched itself off. Now upon switching Power on the fault LED immediately starts blinking between red and green. Also the fan is not working. According to the schematic it should start working after Power is switched on. I read somewhere that fan also should be rewired from 100-120V to 220-240V but I don't see anything on the schematic about that.
Any advice would be greatly appreciated.

AC board schematic:

ac.pdf

[J M Fahey]

1) Use 230V, it's close enough
2) *This* schematic says nothing about the fan, search and post one which does.

[GainFreak]

I don't have another schematic of the AC section. I have a file with schematics collected from the net but they're all at least 10 years old.
AFAIK Enzo has the current one I hope he will chime in later.
After some "debugging" on the PT primary taps (according to that schematic and table) I came to this arrangement:



The SVT CL PT has the same colors. If this diagram is correct the PT could be rewired for 220V.

SVT_CL schematics I have:

AMPEG SVT_CL.zip

[MarkusBass]

... I read somewhere that fan also should be rewired from 100-120V to 220-240V but I don't see anything on the schematic about that.

On the schematic you attached there are jumpers J14, J15 and J16 with a text: "FAN" above them. Isn't it information about the fan?
Also the information about rewiring fan is not correct. This is a 117V fan and it cannot be rewired to 240V. In the States it is connected directly to the mains power (117V), and in Europe it is connected to 120V windings of the transformer. So it has to be connected differently but it is still a 117V AC fan.

Mark

[GainFreak]

On the schematic you attached there are jumpers J14, J15 and J16 with a text: "FAN" above them. Isn't it information about the fan?

I saw those but I haven't opened the amp yet. What I can see from behind are two wires going to the fan.

Also the information about rewiring fan is not correct. This is a 117V fan and it cannot be rewired to 240V.

Then I guess when you rewire for different mains voltage it gets rewired "automatically" to stay on the 120V winding. Anyway it's not working now I'll check it out when I open the thing.

[hodgy]

Try this.
Tech Note -- 120V to 230V conversion.pdf

[GainFreak]

Thanks. It looks like the same chart as from SVT VR AC section schematic. Obviously they have the same AC board for all 300W tube SVTs.

[hodgy]

Thanks. It looks like the same chart as from SVT VR AC section schematic. Obviously they have the same AC board for all 300W tube SVTs.

That is correct.