hello again Frank,
as there is no indication in the documentation of what is the normal output
power of the vfo,maybe it would be useful to use new 6cl6 and 5763,also an
indication of grid excitation is useful,on my set the excitation
potentiometer is about 1/4 turn to get the 3.5 ma required on 80M
with the driver tuning condenser correctly tuned,this can be checked in
RECEIVE position of the transmit/receive switch(but this has maybe been
modified in your set
) AND the am/vfo-beat/cw switch in vfo-beat:this powers up only the vfo,not
the
pa ,this is used to tune the tx to the rx frequency(heterodyne).In this
condition you can get an indication of the excitation,without using the
pa,you should not have hv
so no risk for the pa tube,but I am just wondering
what are exactly the modifications don on your tx...
-why not try to put it back in its original condition by removing all those
relays
Hope this helps
73 alain F1gqb
thanks for your suggestions for the rx,I already dit it :-(((


--
Alain Nierveze
www.radio-astronomie.com

a écrit dans le message de news:
...
nierveze wrote:
hello
I also have a g222 tr first generation ,that has no problem for now...(I
touch my wooden head!!)
It seems that you have an excessive dissipation of your 6146.
What is the current of plate?

unfortunately I didn't pay attention to the value as I was paying
attention
on the plate colour and other sign of problem, like smoke somewhere. It
was
on the very first TX tests and the final tube lasted too short a time.

Check the vfo,does if give enought power,does the small variable
condenser
at its output work?

yes the driver tuning condenser work, but what's "enough" output?
I can measure the RF voltage at the grid of the 6146 but how can I tell
what is supposed to be the right drive voltage?

Do you have enought excitation on the grid?

on the service information I haven't seen any indication on what's enough
excitation voltage. I'll try to realign the VFO again for maximum output
on
all bands


What is the voltage of the G2 of the 6146?

it's 210V at no load
Can you check what DC voltage you have on the 6146 G1 when TX in AM mode?
Can you confirm G1 bias is -50V in CW mode?

On the first version of the transmitter it is provided by a small
separate
transformer and power supply,this small power supply is used for the vfo
,the two first tubes on the modulator and the G2 of the 6146 .Also
change
this rectifier (tubular one,black) I did the same modifications than you
replaced chimical condensers and rectifiers,for the rectifiers I used
small
'bridges 'with 1N4007.

yes, I also used 1N4007.

I am not a specialist of those machines...it is just the first tx I knew
45
years ago at my grand father's station...
it is just some ideas.
Also a way to save your pa tubes until you find the problem would be to
decrease the hv ,so decrease the plate dissipation ,I have used a variac
to
underpower the transformer,not standard but it helped me.

well yes, good suggestion. I didn't expect the tube to die so quickly. I
once repaired an old Yaesu FT-101E that had a failure in the 6JS6C grid
bias
circuit and basicly it had no negative bias on control grid, so as soon as
the
heather was switched on, the tubes would start drawing a large amount of
current and the plates were glowing bright red. I of course switched off
the set as soon as I saw the plates glowing but I think the owner didn't
realize wath was going on since most of the wires around the power
transformer
were carbonized. It's amazing that the power transformer itself survived
and what was amazing too is that those tubes still were putting 50-60% of
their rated output power after the problem was fixed and many wires were
changed.

73 F1GQB
It is my turn to ask a question ,I also have a geloso g209 receiver that
has
some problems:from times to times one of two second lo stops (the one
used
on am,and usb,the one used in lsb works),it seems a thermal problem,I
used
antioxidation produtcs,I reshaped the contacts,I resoldered everything,It
continues,
what can it be????

if it has two separate xtals for USB and LSB, check the xtal socket and
the tuning of the oscillator. Try gently moving the USB xtal and see if
RX come back again.

Thanks and 73
Frank IZ8DWF