Hi Gang...

Decided to get my HF station back on the air. I have a heathkit apache
xmtr that was working the last time i used it (about 10 yrs agao!).
Plugged it in and turned it on. Lights go on.

Heres the problem:
Switching it to Transmit from standby.

The Red Transmit light comes on.
The TR relay switches over
I get HV
but no Plate or Grid current

Any ideas. I have not yet located my copy of the manual.

Is this a common problem ? A bad tube or tubes.

Does this indicate bad finas (2 6146Bs)

Any help out there ?

Thanks,
Joe
WB2JQT, Newark Valley, NY

On Wed, 12 Nov 2003 05:37:31 UTC, dada wrote:


Hi Gang...

Decided to get my HF station back on the air. I have a heathkit apache
xmtr that was working the last time i used it (about 10 yrs agao!).
Plugged it in and turned it on. Lights go on.

Heres the problem:
Switching it to Transmit from standby.

The Red Transmit light comes on.
The TR relay switches over
I get HV
but no Plate or Grid current

Any ideas. I have not yet located my copy of the manual.

Is this a common problem ? A bad tube or tubes.

Does this indicate bad finas (2 6146Bs)

Any help out there ?

Thanks,
Joe
WB2JQT, Newark Valley, NY


I doubt that it's the tubes. Might be an electrolytic cap or a
carbon resistor in the bias circuit. I've seen carbon resistors
with waaaaay off values.

I don't know exactly why resistors go bad but they do.

Another likely suspect is the relay or switch contacts. It could
either be a thin insulating layer on the contact itself or some
dust.

As a precaution.

Vacuum all the dust out.

De-ox-id the switches.

Work all the switches and relays.

Look for bulging or leaking electrolytics and replace them. Don't
bother to measure or test them. If they look funny, out they go.

Get a manual or schematic from one of the free download websites
or buy the Heathkit CD, link to the vendor is on my page at
http://www.kiyoinc.com/heathstuff.html

Measure the voltages at the powersupply. Anything close should be
good enough to get it working.

The tubes don't go bad with time. These are industrial materials,
tungsten, steel, stored in a hard vacuum. You can put a tube on a
shelf and if left undisturbed, it should work fine after 1,000
years.

de ah6gi/4

"No Spam (ckh)" wrote:

Switching it to Transmit from standby.

The Red Transmit light comes on.
The TR relay switches over
I get HV
but no Plate or Grid current

Any ideas. I have not yet located my copy of the manual.

Joe
WB2JQT, Newark Valley, NY


I doubt that it's the tubes. Might be an electrolytic cap or a
carbon resistor in the bias circuit. I've seen carbon resistors
with waaaaay off values.

I don't know exactly why resistors go bad but they do.

Another likely suspect is the relay or switch contacts. It could
either be a thin insulating layer on the contact itself or some
dust.

As a precaution.

Vacuum all the dust out.

De-ox-id the switches.

Work all the switches and relays.

Look for bulging or leaking electrolytics and replace them. Don't
bother to measure or test them. If they look funny, out they go.

Get a manual or schematic from one of the free download websites
or buy the Heathkit CD, link to the vendor is on my page at
http://www.kiyoinc.com/heathstuff.html

Measure the voltages at the powersupply. Anything close should be
good enough to get it working.

The tubes don't go bad with time. These are industrial materials,
tungsten, steel, stored in a hard vacuum. You can put a tube on a
shelf and if left undisturbed, it should work fine after 1,000
years.

de ah6gi/4

Thanks Cory.

I'll give that a shot.
Joe
Wb2JQT