[Premium-Rx] Harris RF-590 A12 800khz missing

[thoyer]

Some progress - Turns out that cables on assy A10, J2 and J2 were swapped.
J4 is the 800 kHz from A12.

Guilty party - probably me. I had many of the boards out replacing shorted
tantalums and a couple fried resistors as a consiquence of the shorted caps.
Sometimes I'm my own worst enemy......... I even sketched a picture with the
cable colors on it and still put them back in the wrong place........

Now I'm getting fault A4-01 which I'll dig into tomorrow (After I check the
cables.....).

Tom
W3TA

-----Original Message-----
From: premium-rx-bounces at mailman.qth.net
[mailto:premium-rx-bounces at mailman.qth.net] On Behalf Of Gilbert Harris
Sent: Sunday, July 21, 2019 6:43 PM
To: Premium-Rx at mailman.qth.net
Subject: [Premium-Rx] Harris RF-590 A12 800khz missing

You likely received an A12-2 FAULT indicating bad BITE test located on the
800khz reference. This originates from U5 4mhz reference at pin 5 which is
then divided by 5 at U6 with output at pin 5 (800 khz.)  U5 also provides
4mhz which is divided by U4 for the 1mhz reference output. This is tested
PRIOR to the 800khz during FAULT testing so  the problem is after U5.  Go to
U6 and measure its supply voltage, then if ok press on near by circuit board
for cold solder joint, put oscilloscope on pin 1 ( input 4mhz) and pin
11(output 800mhz).  I'll bet you have done already. I may have a couple
A12/A21 somewhere but can't access for 6 weeks.
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