Marantz 18 transformer

[calman46]

Dead,he ripped it all apart and then told me couldn't rewind it. All I have is the iron

 

[calman46]

If I can get the AC volt values for the secondaries winding's maybe I could make a transformer, remember I have the core . I not sure about the scope winding though .

 

[SidSmith]

Why you just put a new transformer dedicated to the scope like here : http://www.audiovintage.fr/leforum/viewtopic.php?f=76&t=756&start=110

 

[tomqts@]

If I can get the AC volt values for the secondaries winding's maybe I could make a transformer, remember I have the core . I not sure about the scope winding though .

Red to Red 26 VAC CT (GND) 26 VAC support + 36 VDC - 36 VDC
Blue to Blue Estimate 38 VAC CT(GND) 38VAC support - 36VREG after R14 R17 430 Ohm
Grn to Grn Estimate 150 VAC CT (GND) 150 VAC support 200 VDC Stereo Neon lamp.
Red/Grn to CT(GND) 460 VAC support -500VDC for osillocope.
Yel to Yel 6.3 VAC heater oscillocope
Brn to Brn 6.3 VAC for lamps

 

[calman46]

Thank you .

 

[RV59]

Red to Red: 25,5-0-25;5 VAC
Blue to Blue: 51-0-51 VAC
Grn to Grn: 160-0-160 VAC
Red/Grn to CT: 360 VAC .
Yel/Yel 6.3 VAC
Brn/Brn 6.3 VAC

You can check this in the Marantz Model 19 Service Manual, transformer is the same of Model 18.
But the problem is for determinate the intensity of the current for each winding.

 

[calman46]

I haven't look at the 19's paper work yet . Can we ballpark the current draw from the 19's (or18's) schematic and use larger wire gauge to be safe ?

 

[calman46]

I was looking into the transformer winding software online to determine the windings . The program I found won't run on 64 bit system .
It looks like the secondary winding was one coil with taps ,I don't think I could learn all the math to do that .

 

[tomqts@]

I was looking into the transformer winding software online to determine the windings . The program I found won't run on 64 bit system .
It looks like the secondary winding was one coil with taps ,I don't think I could learn all the math do that .

 

[calman46]

Thanks , we're moving forward !

 

[calman46]

Red to Red: 25,5-0-25;5 VAC
Blue to Blue: 51-0-51 VAC
Grn to Grn: 160-0-160 VAC
Red/Grn to CT: 360 VAC .
Yel/Yel 6.3 VAC
Brn/Brn 6.3 VAC

Red to Red is 25.5v -0V- 25.5v
so its red to ct is 25.5v
red to red would be 51V correct ?
The punctuation confused me

 

[calman46]

So the red ,blue , green and red/green windings all share the same CT (red/yel) ?

 

[RV59]

Yes, they are windings at midpoint, this point is connected to ground.

 

[calman46]

but wouldn't the CT be different for each winding

 

[calman46]

So to DIY one these you would have to 4 separate windings each with there own CT then connect them all to to Ground . Does that sound feasible ? The HV scope winding is unique I'm not sure if a separate winding would work.

 

[RV59]

Yes that's right; Unlike the others, the HV winding has no midpoint.

I am not a transformer specialist.
The best would be to find a transformer manufacturer.

 

[RV59]

I advise you to use a separate transformer for HV winding.
I made this transformation for my 3 Model 18.

 

[calman46]

Do you any documentation on how you made your transformer ?
Yes I think a separate transformer is the way to go for the scope .

 

[tomqts@]

Would you post the schematic of the 19 ,so I can calculate the winding for you.
How are the dimentions of your transformer ?

 

[calman46]

I'm back . I bought a junk 18 and the transformer is good .The 360VAC(red/green to CT) is there and so are the other voltages . I'm working on a Pioneer SMB201 now so I can't do the transplant yet .
Why does the scope winding go bad ? Could it be the 10uf/ 575volt cap shorts? Some component(s) on the scope board go south? I wouldn't think it was the winding itself because it would have failed sooner and there would have been a service bulletin about it. Before I install the transformer I'm looking for some options to protect the transformer , a fuse comes to mind . What do you think ?
There was a 20A fuse in the donor unit but the AC cord was cut off ,which may have save the transformer from someone just plugging it in.