[Elecraft] Fw: No power, No audio

[Tom Hammond NØSS]

Hi Tom:

> > I am working on the Alignment & Test Part 2.  I have been
> > reading countless emails in the archives on the elecraft
> > website and did the "Cheap 'N Dirty" signal tracing except
> > I used a Heathkit IG-102 Signal Generator over the past
> > week trying to find the problem.  The 13 test points checked
> > out okay.

So what is the specific problem to begin with? I don't see a problem 
mentioned, so I'm not sure what it is that you're trying to fix.

Never mind... I now see the problem stated below... guess I should have 
read a bit further first...

> > With my Heathkit T-4 Signal Tracer I have been able to
> > listen on the RF board to U11 (Tx Mixer/product detector)
> > pins 4 & 8 to cw on 40 meters, so it does receive.  I have
> > no audio.

Using your signal tracer (assuming it works at AUDIO frequencies as well as 
at RF), what do you hear at the output of the product detector, pin 4 or 5 
of RF Board U11 (RF U11-4 or RF U11-5)? If you get signal here, then you 
have signal passing completely thru the IF.

This being the case:

1) Perform a MENU | ST L to confirm that you CAN (or cannot) hear the 
sidetone. If you CAN hear the sidetone, you know that CTRL U9 (AF Amp) is 
working (go to step 2). If you CANNOT, then check the AF AMP and the 
voltages to it as well.

2) Confirm that you have installed the solid wire jumpers at CTRL-R18 & 
CTRL-R19.

3) Using your signal tracer, check for signal at pins 2 & 3 of CTRL-U9 (AF 
AMP). If you have AUDIO input to these points, then you should have 
received signal out. If you have audio at step 2 above, but not here, then 
check for the presence of CTRL-R17. One builder recently installed CTRL-R17 
into a couple holes just BELOW where it was actually supposed to be 
installed. This caused the MUTE line to go permanently LOW, thus turning 
off all received audio to the AF Amp. The sidetone still worked, but no 
RECEIVED signal came thru.

> >I did get the 080 info message one time and went through the
> > reset.  The display is all zeros, the voltmeter quit working
> > and the Lo Batt message pops up periodically although I have
> > it on a power supply.

The Lo Bat message does not display all the time, about once every 3 
minutes, if I recall... it's more of a periodic warning that things are 
slowly approaching a point where action should be considered, rather than a 
notice of pending failure.

This having been said, the implication may be that you have S1 (the 
voltmeter switch on the Control Board set to EXT(ernal) instead of 
INT(ernal) which is required to monitor the voltage from the power supply. 
The EXTernal position allows you to use the internal DVM as a voltmeter via 
a probe, but it also keeps the K2 from monitoring it's internal supply 
voltage. As a result, you'll see a LO bAtt warning periodically. 
Additionally, when you have the meter switch to EXTernal, the display WILL 
read all zeros, since it's telling you that you have not voltage at the 
probe (which you've probably not even built or used). Just slide the switch 
to INTernal and you'll be good to go again.

> > The voltage very rarely drops below 5 volts when switching
> > with the relays.

Measured at what point(s)?

> > Doing some voltage checks I found that 3 pins on U8 (quad),
> > U6 (MCU), & U7 (EEPROM) should be 5 volts but are zero and
> > a pin each on U8 & U7 should be zero volts but is 5 volts.

Which pin on U7 & U8? And U7 & U8 on WHICH PC board? Elecraft used the same 
component numbering on EACH PC board, so you have to specify which PC board 
you are referring to, in order for the reader to know what's what. It's 
common to the nomenclature I used above (e.g. CTRL U7-x) when referring to 
a particular pin on a certain device on a certain PC board.  Use FP for 
Front Panel PCB, CTRL for Control PCB, and RF for RF PCB. For the time 
being, I'll assume you're referring to the Control Board, because U6 on the 
Ctrl Board is the MCU.

Hope this helps a bit.

73,

Tom Hammond   N0SS