Data East Power Board Missing -98v

ievans

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Jan 10, 2019
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Can anyone help me diagnose missing -98v on my DE power board (520-5047-01 Rev B)?

on the CN5X6 power out to DMD connector I should get -98v and -110v. I’m actually getting -0.2v and -150v.
before I start working through replacing each of the components, i’m hoping someone who can read schematic properly might help me pinpoint the likeliest candidates.

The caps and resistors all seem to check out fine on a multimeter. Don’t think I can test the diodes and transistors without removing them though.

the board has some corrosion etc but nothing stands out
 

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ievans

Site Supporter
Jan 10, 2019
11
6
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Cardiff
Not yet, been a busy start to the year (i work in health) so working through the pinwiki advice is on the to do list...
 

Moonraker

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Aug 18, 2011
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continuity test the PCB tracks as there could be a break (cap corrosion?)

From your schematic provided components to check are:
C16
TR6
R14
R17
R10
C12
R11
C13
D10
D11
TR4
TR2
R13
R9
Diode under R9 (D8?)
C11