G4/214 Geloso problems

[fr...@notvalid.it]

Hi all, I'm repairing an old Geloso G4/214 receiver.
I checked and subsituted (only the ones checking bad) capacitors, resistors
and solid state diodes.
All tubes have been tested with an emission tube tester.
Potentiometers and switches have been cleaned.

The set appears to have been tweaked by someone else so the repair doesn't
seem easy at a first glance.
However here're the symptoms, I think they are unrelated but I can't be very
sure anyway.

1) no reception on any band, there's not the slightest crack or change of
background noise even when touching the antenna connectors.
2) USB and LSB positions give a loud AC noise on the speaker but the AM
position gives "normal" background hiss and not the slightest hint of AC
noise.

Next step will be injecting a signal on the antenna socket and try to follow
it through the various stages but I ask here anyway if these symptoms ring
the experts a bell maybe.

Thanks in advance and best regards.

Frank IZ8DWF

[w4...@cox.net]

Frank,that is a nice looking receiver,,,It is double conversion..Two
6BE6 tubes in mixers. your problem could be one of the oscillators
not running...If you have a scope or counter ,probe pin 1 on both 6BE6
's should show a healthy osc signal on both..If no scope or counter,
you can use an auxillary receiver to tune to osc freqs,the manual
may show these freqs..On this old stuff it`s good idea to test all
tubes ,make sure that they are good..Good Luck 73 Harold W4PQW

[fr...@notvalid.it]

w4...@cox.net <w4...@cox.net> wrote:
>
> Frank,that is a nice looking receiver,,,It is double conversion..Two
> 6BE6 tubes in mixers. your problem could be one of the oscillators

indeed it was, during the resistor check & replacement I had made a bad
solder join to the first mixer's LO input... soldering back that connection
solved pretty much all of the problems.
The receiver is however quite deaf by today's standards even after a full
realignment.

> not running...If you have a scope or counter ,probe pin 1 on both 6BE6
> 's should show a healthy osc signal on both..If no scope or counter,
> you can use an auxillary receiver to tune to osc freqs,the manual
> may show these freqs..On this old stuff it`s good idea to test all
> tubes ,make sure that they are good..Good Luck 73 Harold W4PQW

Yes I have some test equipment, I just started to scope around for signals
and found the missing first LO signal. It seems to me that the xtal
oscillators for the second conversion have a bit low signal output. Maybe
bad tube?

Thanks a lot
Frank IZ8DWF

[Manuel Alberto Marques]

[Manuel Alberto Marques]

Hi Frank
I'm also restoring my old G4/214 (from my dad)
I think i'm almost there ...
Finally I got the Transformer rewound, after Burnt out primary winding
I already put the transformer and connected the ends in the circuit-
In the end there was no smoke and everything looked normal.
I have reception, but the audio is too low.
I noticed that the 11-valve audio amplifier (12AX7) is working very poorly (the tube is NEW) and the V8 BFO (also the 12AX7 is new) will not turn on.
I measured the voltage and it's about 5,2.Volts,. I measured with the analog multimeter the electrolytic capacitor 25uF 30 volts and it seemed good
Is it possible to make any suggestion where i should work?
Thanks for your help
Marq CT1BWW

[Manuel Alberto Marques]

Hi all, I'm repairing an old Geloso G4/214 receiver.(from my dad)
I think i' almost there...
Finally I got the Transformer rewound, afert Burnt out primary winding

I already put the transformer and connected the ends in the circuit-
In the end there was no smoke and everything looked normal.
I have reception, but the audio is too low.
I noticed that the 11-valve audio amplifier (12AX7) is working very poorly (the tube is NEW) and the V8 BFO (also the 12AX7 is new) will not turn on.

I measured the voltage and it's about 5.2 Volts, I measured with the analog multimeter the electrolytic capacitor 25uF 30 volts and it seemed good
Is it possible to make a suggestion wherw i shoulkd work?
Thanks in advance and Kind Regards

Marq CT1BWW

[Scott Dorsey]

Manuel Alberto Marques <ct1...@gmail.com> wrote:
>I'm also restoring my old G4/214 (from my dad)
>I think i'm almost there ...
>Finally I got the Transformer rewound, after Burnt out primary winding
>I already put the transformer and connected the ends in the circuit-
>In the end there was no smoke and everything looked normal.
>I have reception, but the audio is too low.

>I noticed that the 11-valve audio amplifier (12AX7) is working very poorly =

>(the tube is NEW) and the V8 BFO (also the 12AX7 is new) will not turn on.

>I measured the voltage and it's about 5,2.Volts,. I measured with the analo=

>g multimeter the electrolytic capacitor 25uF 30 volts and it seemed good
>Is it possible to make any suggestion where i should work?
>Thanks for your help

Cathode bypass electrolytics are almost always bad... just replace it, and
then check the cathode and grid voltages. If the grid voltage is in any way
above ground, also suspect the coupling capacitor driving it.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[i3hev, mario]

+1

Moreover, deep clean and check all switches - they are likely culprits
too :)

'73
i3hev, mario



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