SMR-4 Mk II Power Test Problems

Hello Shruthi people…
I’ve got to the first testing stage on the filter board and hit some problems.
With 7.5v in, I get +2.27v at the red points and -2.11v at the green points.
With 9v in, I get +3.52v and -3.25v.
The 5v rail gives +2.27v at 7.5v in, and +3.52v at 9v in.

Pin 5 on the LT1054 chip gives +2.37v at 7.5v in, and +3.52v at 9v in.
I tried replacing the LT1054 with no result and I’ve checked the soldering, which is OK (I think…)
Also carefully rechecked component positions.

Power Supply Specs. : PRI: 100v-240v ~ 60/50Hz 550mA
SEC: 7.5/9/12v —2250mA

Please Help!

What do you get straight out of the PSU? could be a dud.

Hi 6581punk.
I’m getting 8v and 9.15v directly from the PSU.

I seem to remember some earlier thread where a similar problem turned out to be that the 7805 and 7905 power regulators were mixed up…

This is indeed what I’ve done. Off to practice my desoldering technique now… I’ll let you know soon. Many Thanks.