Re: SG 503 Display Problem


Albert <aodiversen@...>
 

Hi Mark,

The manual and my board are correct. I checked the schematics and boards of a 7A15 which has lots of 151-0402-00 transistors. The order is definitively CBE (left to right, bottom view, flat face up). That would be TO92 order (A) in the cross reference page 9-5. The cross reference should have mentioned case TO92A then in stead of case TO92.
So I guess your Q320 was not mounted backward after all?

Albert

Yeah, the U530 was a typo. But, I was getting all 8's and 0's on all
frequency selections until I changed the resistor and cap connection to
the collector on the transistor, rather than the emitter. So, I
wonder. Is the schematic incorrect, or the layout picture?

The display isn't doing the overload blink, which according to the
manual, has a .25 second power off. The display character segments just
kind of flicker between 8's and 0's when the frequency is above 1 MHz
while tuning the variable frequency knob. They settle down to a solid
display character when not turning the knob, but the display characters
are either 8's or 0's. When the frequency is below 1 MHz, I get real
numbers on the display.

Mark

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