Yaesu FRG-7700 display ???

[Ken Taylor]

No problems, just thought a clearer version may assist. I don't recall if
Yaesu had a propensity for using IC sockets (I fear not) but you should be
able to pull the segment drive pins down to the reference voltage (pin 1 of
the IC) using, say, a 10k resistor without causing damage. (Is the display
connected via one of those fairly rigid ribbon cable connectors??). Thus you
can light the segments up one by one (for all digits, obviously) to check
operation. OKI made these beasts but don't even list them in the obsolete
components
http://www2.okisemi.com/us/docs/PrdDisplayDocs.html#products.txt1525 but an
e-mail may be rewarded.

www.1sourcecomponents.com claim to have these IC's in stock, but who knows
how much. I think I'm actually looking at one right now on a VFD board from
an ancient satellite dish controller (I'll confirm the part number if it
becomes an issue), but as I'm here in New Zealand it may be of limited use
if you can find one more local to yourself. Let me know though, I can send
it over.

Cheers.

Ken

 

[Mark Zenier]

According to my schematic Q57 and Q58 are drivers for the 2 LEDs used in the
clock mode to indicate AM or PM. Looks like I'm going to get the scope on
the bench and see what happens on the various segment pins. I've not had
much luck finding the data sheet on the MSM5524, anyone have any?

The service manual for the (Trio)Kenwood R-1000 has a lot on it.
Internal block diagram and pinout. I got the pdf from the mods.dk
site.

Mark Zenier [email protected] Washington State resident

 

[Henry Kolesnik]

Thanks Mark I'll go to .dk and get whatever they have.