The Shop > Electronics & IC Programing
Digital oscilloscope project/kit
John Rudd:
Lyn,
I suspect the scope has suffered a death blow.....your wall wart thing must have too many ziggies coming out......
Things to check:
The voltage at TP 20 needs to be near that indicated on the schematic........
Check the voltages around TP21 and TP23....
Measure the voltages around Q1 and Q2...
John Swift:
check the 3v3 at TP23 this is the reference at one end of R42 (1K)
the junction of R41 and R42 is the feedback voltage going to the V-MON input of U1
an error at V-MON = TP13 = pin 16 affects the actual voltage at TP25 the -8V supply
the actual voltages measured depend on the positive supply at J 9 and J10
I'd expect the voltage on TP13 to be about +2V when the -8V switching supply circuit is working correctly
John Stevenson:
Just got one of the transistor / components checkers delivered from China.
Bought the ready made up on as it was only a quid more than the kit ???
However no paperwork or instructions, anybody got a link to some somewhere ?
kayzed1:
Many thanks all, i will have a play on Friday.
John S, PM me your address i got two sets of destructions in my pack i will stick them int post.
Lyn.
Ow! John R, does that mean ( the high volts ) that the scree will be an EX- screen now?
John Rudd:
Lyn,
Not the ex - parrott sketch.... :lol:
The extent of any overvolts damage cannot be determined without further checks and possible component replacement to resolve the existing problems...
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