Follow Up: Heath HW-8 Final Problem

[Joe Y]

A follow up to what I discovered was causing my
recently aquired HW-8  to transmit and show output
indication in receive mode as an FYI to those working
with HW-8's.
I picked up an NTE 159 replacement for the suspect
keying transitor Q11. Upon removing Q11 and preparing
the new device I noticed the D shaped outline of the
device printed on the pcb did not correspond to the
lead orientation, so if you are following the book
building the rig you want to naturally match the pcb 
silk screening, doing this results in the device being
installed with the collector and emitter swapped.

The device had to be turned 180 degrees to be
installed properly.

The rig was like this from the day it was built as the
Q11 I pulled was the original marked with the Heath
part number. Package was even marked EBC but still
installed wrong. 

I wonder if anyone has seen this? Could this be an
early HW-8? Something to watch for.


I performed a completed the alignment and it plays
like a champ, I like it. It is a shame the original
builder never picked up on the problem.
73,

Joe


Hello all,
I picked up an HW-8 and noticed it has some strange
issues and I need some ideas and also transistor part
numbers if anyone can help for Q9 the final, Q11
Keying transistor and Q8 Driver.

When I powered the rig on for the first time since
receiving it I noticed it to be down a bit in
sensitivity. The main thing I noticed is that the
meter was showing output in the receive mode and
adjusting the loading control changed the level on the
meter. In adition the rig seemed very microphonic and
would howl and oscillate with changes to the preselect
control.

This effect occurs on all bands. Intertestingly the
rig does key up and transmit with good output.

I removed the final transistor and the sensitivity
restored and output indication disappeared.

I then checked the keying transsitor Q11 and on RX it
is showing 6.5 volts where it should be 0 volts. 

I reinstalled the final and pulled Q11 to see the
effect, I found that with the final in the circuit the
RX is poor almost like its pulling it down, however
with Q11 removed the rig doesnt show output indication
on the meter in RX

My feeling is that the final is bad and Q11 is
suspect?

Tia for any assistance,

73 

Joe 




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