[Boatanchors] TR-7 Digital Display Is Intermittent ???

[Revcom Electronics]

Bill.
As with many electroflourescent displays, they are plagued 
with "cold" solder connections on the PC board.

Most equipment built in the 80's and early 90's with flow 
soldering techniques suffer from this, especially when there
is heat involved in the circuit.  The unit merely warms up,
and the joint seperates.   

Need a good magnifying glass, small tip solder station and 
reflow ALL suspect looking PC connections.  Do it about 
every day here on both commercial two-way, industrial
electronics.  Often the crack is so subtle it can hardly been
seen around the leads. 

Kenwood 820's suffer from this as well as MANY early ICOM
rigs. 

Rod
K0EQH

----- Original Message ----- 
From: <w0ng at comcast.net>
To: <drake at mailman.qth.net>; <boatanchors at mailman.qth.net>
Sent: Sunday, June 24, 2007 6:29 PM
Subject: [Boatanchors] TR-7 Digital Display Is Intermittent ???


> As a long time ham but first-time owner of a TR-7 (and new to this 
> list) I'm hoping one of you veteran TR-7 folks might be able to tell me 
> why my otherwise fine working TR-7 (built in Feb 1980) looses it's DR-7 
> digital display after the rig is on for an hour or so. When the digital 
> display goes out, the rig is otherwise not affected. Everything else 
> works fine just no digital display. 
> 
> Turning off the power to the rig and turning it back on does not 
> restore the digital display. There is no obvious pattern as to when it 
> goes out. Sometimes at power up it is out and other times after the rig 
> is warmed-up is goes out. No smoke, no weird sounds, no loose 
> connections, no outward signs of any kind that it is going out.
> 
> Any help someone could offer would be greatly appreciated. I don't yet 
> have the skills to troubleshoot the DR-7 board (or any of the digital 
> circuits) yet. I'm hoping it is a simple fix one of you has used 
> before. Thanks in advance. 73, Bill, w0ng
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