need a schematic not user manual for a "Furman AR-1220"

[M Philbrook]

Like it states.. I've reversed engineered som of the board but it would
be nice if I had an offical schematic to this Furman AR-1220 120V like
regulalor...

Currently what I have found it the control transformer to P3 plug seems
not correct to me.... It is using a 230v primary in a 120 V system and
is part of the supply rails for the 5, 15+ and 15- post regulators..

Its only getting to 10VDC after the bridge on the average and of course
that isn't enough for proper reg..

I put in a temp transformer that would deliver the correct amount but
then it places the unit into EVS mode (Extreme Voltage Shutdown) and
never comes out of it, yet it seems to appear to operate with rails
saging on the 15 volt supplies.. These supplies are to take care of the
TLO84 quod opamp and thus the way they are now tells me the 15 volt regs
are nothing more than limiters not regulators...

So does anyone have a source to the schematic ?

[Phil Allison]

M Philbrook wrote:
>
> Like it states.. I've reversed engineered some of the board but it would
> be nice if I had an official schematic to this Furman AR-1220 120V like
> regulator...

>
> Currently what I have found it the control transformer to P3 plug seems
> not correct to me.... It is using a 230v primary in a 120 V system and
> is part of the supply rails for the 5, 15+ and 15- post regulators..
>

** That tranny HAS to be 240V rated so it can cope with accidental ues with 240VAC power.

https://www.sweetwater.com/store/detail/AR1220--furman-ar-1220-ac-line-voltage-regulator

> Its only getting to 10VDC after the bridge on the average and of course
> that isn't enough for proper reg..
>

** May not matter, TL084s have a wide operating voltage range.

> I put in a temp transformer that would deliver the correct amount but
> then it places the unit into EVS mode (Extreme Voltage Shutdown) and
> never comes out of it, yet it seems to appear to operate with rails

> sagging on the 15 volt supplies.. These supplies are to take care of the
> TLO84 quod op-amp and thus the way they are now tells me the 15 volt regs

> are nothing more than limiters not regulators...
>

** That is likely exactly how it works.



.... Phil

[Dave M]

Have you tried contacting the manufacturer yet? Drop them an email
(in...@furmansound.com) and ask for a copy of the schematic. Some companies
still provide real customer service - you just have to ask for it.

Cheers,

Dave M

[Phil Allison]

Dave M wrote:

>
>
> M Philbrook wrote:
>
> > So does anyone have a source to the schematic ?
>
>
> Have you tried contacting the manufacturer yet?
>

** I think Philbrook has twigged.

The Furman works fine despite his objections to the unconventional use of IC regs a voltage limiters.



.... Phil