On Tue, 19 Feb 2008 11:11:21 GMT, Geo
put finger to keyboard and
composed:

On Mon, 18 Feb 2008 15:52:51 -0000, "N Cook" wrote:

or model AD-L528, 2 labels
from cold , a part second, partial feint display on the fluorescent, then
nothing.
All voltages agree with legends of 3.3,5,12,-20V dc and 4.4V ac to the
display. Standby voltage of 2.1V on switching power on.
Anyone know what the RAT of designator RAT5V stands for as it is only 1.4V
on one of the lines to/from? the ps

There is a blcok diagram and a hand-drawn psu circuit (a bit too blurry) at:-
http://www.adl528.com/cyberhome/AD-L...ALD5/index.htm

Geo

It appears that PQ30RV21 (2A LDO regulator) provides the RAT5V rail:
http://sharp-world.com/products/devi.../pq30rv1_e.pdf

AFAICT, the PC5V rail is derived from RAT5V by switching it via Q8
(2SB772) which is in turn controlled by Q7 and the standby signal
(from the decoder board?). So if RAT5V is only 1.4V, then where is the
OP's PC5V coming from? BTW, D15 seems to be drawn with the wrong
polarity.

- Franc Zabkar
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