Polysix Rebuild

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Re: Polysix Rebuild

Post by jjlonbass »

If you can't find an original transformer, my best guess from looking at the service manual would be that one with 15V-0-15V secondary rated at 30VA or above should do the job; 50VA would be better if it will fit. This is based on the fact that the stated mains power consumption is 25W and that the highest voltage regulated DC rails at the output of the power supply are +15V and -15V. The unregulated outputs from the bridge rectifier and smoothing capacitors will be around +21V and -21V in this case.

You'll need to perform the power supply voltage adjustment procedures after replacing the transformer - I'd recommend doing this even if you fit an original replacement.

Using an external DC supply to replace the missing transformer won't be feasible.

John
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Re: Polysix Rebuild

Post by nickle15 »

BJG145 wrote:
nickle15 wrote:Right now we're still stuck looking for a transformer. Not much else we can do until we solve that.

There's one on eBay currently; they might accept an offer.

Thanks - I tried a couple of weeks ago but they rejected what I was willing to pay.
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Re: Polysix Rebuild

Post by ajay_m »

Looks very much like a standard 15-0-15 VAC transformer (sometimes referred to as 30V CT) and it is probably 30VA or so and the full power supply schematic and service manual appears to be at the link below. The fuses are rated 1A so that would confirm that a 30VA unit ought to be about right. The original transformer may have had 115V and 230V primary windings but you do not require them both, obviously, you just want a unit suitable for whatever your mains voltage is (sorry, not sure if you are in the US or not).

http://www.oldcrows.net/~oldcrow/synth/ ... iserv.html

A transformer that size ought to cost about £20 or thereabouts and is a stock voltage.
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Re: Polysix Rebuild

Post by nickle15 »

ajay_m wrote:Looks very much like a standard 15-0-15 VAC transformer (sometimes referred to as 30V CT) and it is probably 30VA or so and the full power supply schematic and service manual appears to be at the link below. The fuses are rated 1A so that would confirm that a 30VA unit ought to be about right. The original transformer may have had 115V and 230V primary windings but you do not require them both, obviously, you just want a unit suitable for whatever your mains voltage is (sorry, not sure if you are in the US or not).

http://www.oldcrows.net/~oldcrow/synth/ ... iserv.html

A transformer that size ought to cost about £20 or thereabouts and is a stock voltage.

Thanks for the advice! I appreciate it.
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