SR failed in PTT. Globe champion. questions

[Gito]

HI

In transmit mode the B+ from 5U4 and HV voltage from 866 is always on,so RL2 and RL3 is not used.

in PTT switch the ground connection of the B+ is off(LV voltage) ,only grounded when relay 3 closes ,also the high voltage transformer is off and switch on by RL3.
So when Relay 3 is activated ,the L.V and HV voltage is on.
That means the LV and HV voltage is switch on and off by the PTT switch ,that activated RL2 ,RL 2 activated RL3 than LV and HV voltage is on.

There's a big difference ,
On Transmit mode the inrush current only happen when the transmit switch  is activated,and stay so/all the time even when We keyed the transmitter since all the RL3 contact point is bypassed  with the transmit Switch.Even it clicks when the PTT switch is used (RL2 and RL 3 is still working but has no influence/no use on the transmit mode)

In PTT mode the LV and HF  on/of is operated  by the PTT switch.
Each time You key the PTT ,There's a inrush current ,because the switching in and of  for the LV and HV power supply.

I still believed there's a voltage drop  on the voltage input of RL 3(110VAC),so the relay won't closed maximally at the moment the PTT is switch  on.(caused by in rush current) or RL3 is changed /defective and needs more voltage to activate it,or  a bad contact points in RL3

Gito

[Jim, W5JO]

As Gitgo says, change RL 3 and if that doesn't fix it change RL 2.  I am betting on the relay that controls 115 V to the HV transformer now that you have definately eliminated the PTT relay.

[ke7trp]

Champ is all done.  Changed relays. Still chattered once in a while.  Got fed up, Put the thing back in its case and hauled it back into the shack. Now on 115 volt 22 amp variac, There is no chatter, I guess 128 volts I have at the line in the workshop is just to much. 

Upgrades: 

Added 100UF cap to VFO B+input side.  Stopped all FMing.. Clean and clear, no Freq Drift.
Installed new VFO Bulb thanks to W7TFO.  This is a bulb used in "exit" signs.
Removed Failed SR recitifier, Installed 1amp 1000V diode, New 500UF cap and 47K resistor (half wave rectifier on PTT).
Changed main plate Relay.
Lubricated and Cleaned Fan.
Replaced Two soft Preamp tubes.
Went back to new RCA 866 rectifiers instead of plug in diodes.

Loads up clean to 210 watts AM on Bird 43P meter. 650 watts PEP.

The champ pulls alot of power. When run on a 20 amp houshold line, I got 7 volts of AC Drop when modulated. Now running it on 30 amp Seperate line with 22 amp variac.  1.5 volts AC Drop. 

If you have this problem.. Try a VARIAC before wasting a few weeks trying to stop the chatter!

Thanks to everyone for the lessons and help!

Clark

[N2DTS]

Its hard to see such a slight voltage increase causing a relay to chatter.
As an experiment, turn the variac up to the 128 volts and see if the chatter comes back.

Any idea why the peak power is down?
You should be getting almost 200 watts more....

Brett

[ke7trp]

Yep.. It chatters when I plug it into the wall directly.  This is adding ALOT of voltage inside.   At 115 input, No chatter.

I dont think a Champion will ever do 850 pep.  I can remember this one doing a bit more peak with the solid state diodes and at 128 volts in.. But at 115 volts and 866s, Maybe it did 800. It talks around 600 to 650.. Maybe my finals are getting weak after 55 years. 

I just tried it with the variac up.. I am showing 700 straight up on the bird.. But I have to put the Grid at the max setting of 15.  I just dont like pushing this old champ

I decided to go back to 866s and to lower Grid down to the middle range.. Back off on the old girl and enjoy it. If that transformer goes, I am in big trouble.  Also,The Oil can is 1000v unit and with the plug in diodes, i was way over that rating. 


C

 

[Gito]

Hi Carl

Logically when You put a higher DC voltage on a DC relay it won't chatter./maybe it will burnt
I have a different opinion,its not only DC voltage on the relay that goes up but also all LV and HV  power supply goes up,and the transformer are made for 115 VAC right.That makes the AC current in this transformer higher than it supposed to be(using 128 volt,the coil winding/turns is design for 115 VAC).

So the chatter must come from the point contacts of RL3 ,maybe not having the amperage needed at switching on(cause the higher current/inrush current needed using 128VAC in the transformers ),and stop chattering  when the smoothing capacitors is charged(less current flow)

When using the normal voltage (115 VAC) all the current flowing in the transformers /circuit is normal as it is design.
It's just my opinion.

Gito

[ke7trp]

I agree Gito.  I just put it on a variac on a stiff AC line and no more chatter. 

I used the radio last night for 2 hours. No issues.

C

[N2DTS]

No, I dont think I would push that trans hard.
What happens if you load it a little lighter, does the positive mod come up?

Brett

[ke7trp]

Yes. If I load it by the book at 330ma.  It talks about 550 to 600 peak.  If I load it down to 280 to 290, it talks up around 700.

I decided to load it about 290.  Then the plate meter wiggles and does not yank back.


C

[N2DTS]

I sounds like it wants to run about 250 ma.
The difference in power out would not show on anyones S meter...

Fairly rare radio, no?
I had the opertunity to buy one about 20 years ago but passed as it was over priced and broken.
Neat little rig though, the one I looked at had round corners?
I know they made a lot of different versions of most stuff they built.

Brett

[ke7trp]

250 might be a little light.    I like to get the Current up. Dont want any arcs in the Mod trans.  I just cruise it around 290 to 300 MA. 

Here is a picture of mine. Now used with an SP600..

Before this line they made a Champion 150 but it was rack mount and plug in coil.

They made this one that I have.. the standard 300.  Then the 300A, Then the 350. 
They all had the same tubes and looked very close to the same.  Its a heavy radio at 120 lbs.  But its really not that bad considering its as powerfull as the GLobe King 400 and that was large and rack mounted with plug in coils. 

I see 1 to 2 a year on ebay.  I missed out on a MINT one.  Lots of them where converted to a single 7094 or other tube Since the AX9909 Amperex finals are like hens teeth.

CLark

[N2DTS]

That looks like the one I looked at.
I like the globe king 400, at least the RF deck, a well working rig, the power supply and modulator needed a lot of help...but the rf deck seemed fine.

Brett