Forum Replies Created
-
Great! Your next step is indeed to take all the voltages again, now that’s fixed they’ll all have changed and hopefully they’ll offer some useful insight now.
It’s a common thing to assume the BBD (especially SAD1024) is dead first as it’s the most expensive part but blindly assuming that and replacing it isn’t the way to go and nine out of ten times in my experience (and I know other techs who have had the same experience) it’s not the problem… not chastising you but hope if I say it enough the idea will disappear
except for when it’s SAD512D, they do seem to die more often but that’s neither here nor there.You may indeed bitch about them, they are pretty bad, some more so than others (especially when the wires are wrapped round) you get used to them after a while of working on them but even then a trace still lifts now and then.
That’s fine and you want to convert the power section so it looks like the one in this schematic;
Yes, each pin, numbered like this, notch or dot indicating the top of the chip
Oh wow, that’s a lucky find! I have some limited information on it which sadly doesn’t include the schematic but I think I can help you anyway
Do you have a multi-meter and know how to use it first of all?
Have the voltages changed? On the 324 you should be seeing roughly the same voltage on pins 8 & 9 as you are on pin 10 (it’s a buffer for the reference voltage which should be half supply, pin 10 where the voltage reference enters is a little low but that could just be down to tolerances or value drift) hence why I suggested that cap and the 324 its self.
On your voltages where you list ‘nothing’ on the ICs that’s where the bias voltage should be seen so something is causing an issue there.
Here’s my redraw of the factory schematic for reference;
except for when it’s SAD512D, they do seem to die more often but that’s neither here nor there.
