I just got my hands on a TI Silent 700 model 707, but it's missing the external power transformer. Unlike similar Silent 700 models, this features an optional battery pack which complicates things beyond my understanding.

Normally I would just look at the back to see how many volts to whack in but it looks like this thing wants AC power, which I haven't seen before at non-mains levels. the back

Mildly confused I looked into the datasheet to become more confused because this seems to contradict the block diagram which claims 28V:

enter image description here

Lucky for us, the schematics for the thing are available in the maintenance manual in this PDF on page 90 which I have reproduced here:

Power Supply Schematic

So, how do I power this thing? Given it accepts battery power, I'm inclined to use a 16V DC source directly into where the battery plugs are (they are readily exposed), but I'm not certain this won't cause any issues. Alternatively, assuming the 20VAC number is correct, I can purchase a mains to 20VAC wall adapter such as the WAU20-2000 from Triad Magnetics.

P.S. Does anybody know what kind of connector this is? I wasn't able to find any reference to it's type in the manual. connector

EDIT: After more snooping I have confirmed the AC adapter is indeed 20VAC

  • 1
    \$\begingroup\$ Either go with the 16VDC to the battery connectors, or replace the AC connector with something current and use the adaptor. I can't honestly see why you're even asking. The AC specs are clearly stated on the label, and 16V DC is just that. Either should work. \$\endgroup\$
    – SiHa
    Feb 5, 2021 at 8:00
  • \$\begingroup\$ Looks like it uses a std IEC power plug used by PC’s \$\endgroup\$ Feb 5, 2021 at 8:32

1 Answer 1


/ WATTS 150 W 120V. Standard IEC Plug

enter image description here

Is this your model? I suppose the isolation transformer is necessary for preventing 0Vdc from being offset from Neutral or miswired Hot to neutral swaps.

Yes I would use a 65W min 16V universal power supply. It has a non isolated DC to Dc converter, so other than possible EMI crosstalk, and charging up 3.3mF cap on startup before turning ON pwr switch, it should work...

The 150W AC rating is generous for power on surge and charger losses.

  • 2
    \$\begingroup\$ This is a different model, looks like the 745. It has a standard power connector unlike the 707. \$\endgroup\$
    – Ben Longo
    Feb 5, 2021 at 14:53

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