HD-10 Keyer

[Joe Hutchens]

Recently, I've started to have a very intermittent problem with my HD-10.   
Sometimes the dots will be sent as dashes.   It's almost as if the dash 
paddle is being hit, but I've monitored the dash paddle with a voltmeter, and 
it is not going to ground.   However, it is dropping about 1 volt.

In the standby mode, the dash paddle is about 12.5 volts.   The dot side is 
11.9 volts.   When the dash paddle is hit, the dash paddle voltage, of 
course, drops to zero and the dot side drops to about .7 volts because of D1.

When the dot paddle is depressed, it goes to zero, and the dash side goes to 
about 8.5.   This voltage drops to about 7.5 when the problem happens.

The problem only occurs when I least expect it, so it's going to be difficult 
to pin down.   It has just failed long enough for me to eliminate RFI, and 
take a few voltage readings.   I suspect maybe Q6 (socket problem) or D1.

Any help would be appreciated.

Thanks,
Joe (  WJ5MH )

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html