Guitar amp toroidial transformer

[nigelbytes1]

Need some help with an amp i acquired.
Its an old amp and i was told the transformer had blown. I was given a simillar one 12-0-12-0 which i think is the wrong one
Make Sessionette
Model: Sessionette 90
Transformer toroidial.
Can anyone help here as i have a few problems trying to replace the transformer, Easy to source but unsure which one i need i.e. 52-0-52-0v
or 16-0-16-0v,
The original transformer does not say what voltage it is , It only states type and serial number ( no voltages shown)
Heres a schematic of a similar model (sessionette 75) No schematic for the 100 but i guess they are simillar. Can anyone help me here please ?

 

[ericmark]

Only one op-amp seems to need the high voltage so way forward would be to get the info on the op-amp.

Internet comes up with This PDF which has same plan as you show.

Is the company still going? From what it says I don't think OP-Amp is a chip but a collection of parts including two power transistors.

 

[nigelbytes1]

I havent tried to contact Award-session and they do have a website.
http://www.award-session.com/
Circuit diagram SG 75 here
http://www.award-session.com/award-session_manuals.html
Power supply and transformer shown here,
http://www.award-session.com/award-session_accessories.html
Somewhat expensive repair i think.
However, After looking at the The Toroidal transformer i can see the windings are a little burnt and theres a smell (burnt) so i'm guessing its shorted out (1 fuse 800ma on input and 2, 2amp output are blown), I was given a replacement buts its rated at 50kv 12-0-12-0 volts (the guy told me this was the right one) I dont think it is.
I'm sure i can find a replacement at half the cost but unsure of voltage Kv etc

 

[FDJ]

(1 fuse 800ma on input and 2, 2amp output are blown),

The fact that the output fuses are blown points to a fault after the transformer.

The transformer may still be duff but you have another problem.

Looking at the ratings, you need 35-0-35 to give 52c DC.
Power rating for 90w output would be 120VA

Frank

 

[nigelbytes1]

My mistake F1 800ma blown, power to transformer, F2 and F3 2amp from secondary winding going to bridge rectifier, So fault after rectifier ?

 

[FDJ]

My mistake F1 800ma blown, power to transformer, F2 and F3 2amp from secondary winding going to bridge rectifier, So fault after rectifier ?

Can you please clarify exactly which fuses are blown.

Do you have a multimeter?

Frank

 

[nigelbytes1]

800ma mains input blown, transformer output +? -? volts both fuses from secondary output to bridge rectifier blown. As seen in diagram above Top left T2 T3

 

[FDJ]

800ma mains input blown, transformer output +? -? volts both fuses from secondary output to bridge rectifier blown. As seen in diagram above Top left T2 T3

OK, the fault is beyond the two output fuses.

Now you need to get technical.
Replace the 800mA mains fuse and remove the two output fuses.
Power up and check the transformer has the correct output volts and doesn't blow the fuse.

Use a multimeter to check the bridge rectifier.

Check the output amplifier and repair as necessary.

Simples

 

[nigelbytes1]

Transformer is toast , Was smoking according to guy i got it from. It also has broken wires.
Someone bypassed 3 fuses to test
He gave me replacement and told me it was correct one, (RS type) is totally differant, And wrong voltage 0-12-0-12 volts
Amp requires +52 and -52v
I had reply from award session they have correct transformer (at a cost)
But they wont say what correct voltage is, So looks like i have to buy from them.
Meanwhile i need to test J50 and K135 Mosfets (obsolete now) but i found source (cricklewood electronics) 2SJ, 2Sk etc.
I thought this was going to be a simple repair

A nice amp and I don't want to scrap it.

Thanks all.