Need help finding relay for GLobe CHampion 300. Pics inside

[ke7trp]

The main power relay for my Globe 300 is done.  It no longer pulls in. Checked voltage on coil. 120vac. The manual shows this to be a SPDT meaning it has contacts that pull to make contact on two circiuts.

Can anyone suggest a replacement?  I have no idea the amperage. I have found 3 amp,5amp and 10 amp at various online catalogs. Or if anyone has a new one I would be happy to buy it.

This relay has FOUR contacts on it. Normaly open, Pulls two contacts closed on another set.   Plus it has the two seperate coil contacts on it.

here are the pictures of it.


Thanks

Clark
ke7trp

[W1EUJ]

Is the coil open? Perhaps it can be rewound instead. I've rewound relays, annoying but possible.

Is the spring damaged or corroded? It could be replaced too.

With a little work, you can 'get' an original part that actually fits in the location.

David Goncalves
W1EUJ

[Steve - WB3HUZ]

What size is the fuse on the Champ. If you use that size or larger, your good to go.

[W1EUJ]

Also, try setting your digital camera to MACRO for closeups.

Quit smoking for better health and voice.

[W3RSW]

I wonder what the normally closed (power off) contacts do?

If not much or easily modifiable then an ordinary contactor might work.  Some of the smaller ones might fit and are way beefier in construction.

[W3SLK]

Rick said:

If not much or easily modifiable then an ordinary contactor might work.  Some of the smaller ones might fit and are way beefier in construction.

You can pretty much get a Potter & Brumfield general purpose relays. Cripes I think they are rated 15A at 120VAC.

[Mike/W8BAC]

You can pretty much get a Potter & Brumfield general purpose relays. Cripes I think they are rated 15A at 120VAC.

I agree with Mike'y. Have a look at Mouser stock. I would look for a plug in style and buy a socket for it. That relay looks like a double pole/ double throw, just match up the voltage and current rating and your good. Maybe even pick up a second relay for spare parts. Good luck.

Mike

[ke7trp]

ITs normaly open.  It closes so the HV goes to the PA when you key the transmitter.  Its STUCK closed and welded so the HV is on all the time.

A friend offered up some 10 amp plug in relays.  These are enclosed relays with a tube socket. He has three of them with the sockets. I might try this out. This way, If one failes down the road, I will be able to plug a new one in.  Is 10 amps enough? The manual states that its 700 watts input max on the AC line.  This relay will handle 960 volts. It produces 350 watts input on the RF side.

Clark

[Mike/W8BAC]

Not having a schematic I can't tell you for sure.

 I assume the relay switches the 120 volt AC into the plate transformer?

 And all the contact will see is about 6 amps? (700 watts divided by 120 volts = 5.8 amps)

If that is the case and any other circuits on the other relay contacts are equal to or less than this, than your relay should work fine.

On the other hand, if you are using the relay to switch plate voltage we will need more info.

I think I would look for the welding reason. Watch the contacts of the new relay to see any arcing happens. The schematic should show a capacitor on that switched 120 volt transformer primary. If it's bad you'll have an arc every time it opens as the field collapses.

Mike

[ke7trp]

Here is the Schematic.  Its the Dual pole single throw switch near the 866s. 

This relay is 55 years old and they are known to fail. But any help would be great!!  Here is the schematic for the Globe 300.

Clark

[W1EUJ]

What fails on a relay? Why are you arcing? Did they do that before?

[Mike/W8BAC]

Clark,

I had a look at your schematic. I'm not even going to make a guess. I'll throw it up in the air in hopes someone else here has some experience with this rig. After looking at the schematic I have more questions than answers. I would have to have the radio in front of me to figure it out. I see switches but no relay coils to the right of the 866's. That appears to be a metering switch. I don't see a DPDT relay at all. I might be blind to it but you would do better with something better than a guess.

[W3RSW]

Wow.  I see a four pole single throw.  Three of the contacts in parallel ground the center tap of the lower voltage 5U4 rectifier supply and only one contact controls AC to the primary of the HV transformer and energizes the T/R antenna relay.   Seems like more contacts ought to be dedicated to the HV .  Sure does't seem like a QSK rig. I'd get beefier relay contacts than OEM.   On the other hand perhaps the original lasted for a lot of CB turn-arounds!     (or have you always owned it ?)

[Jim, W5JO]

A relay that will handle 120 V @ 10 amps is adequate.  That relay just puts 120 volts on the primary of the HV transformer.  Use any thing that will fit and you will be fine.

[ke7trp]

Thanks for the help.  This rig was owned by hams. 5 of them total. I traced it back to the original owner. This is the factory relay and it lasted for all these years. Its a trouble spot in the radio.  These relays BUZZ loudly when keyed. When I got the transmitter it would not work at all. I cleaned and lubricated that relay and the radio was back on the air. It spent 7 months on 75 meters without isssue. Then one day the plate current and power where up and down. I found that relay arcing when I modulated the rig. The contacts are Burned again. I could clean it but this time, I would rather just replace it. I have cleaned it already and I think I am past the top coating of the contacts now. In its current condition, the thing is stuck and the relay does not even move when you key the rig. It works based on the carbon built up. I am sure a new relay will fix this radio as its working now.. Just not perfectly. I really dont think something else caused this relay to fail other then thousands of cycles. I guess I will find out when I replace it with the new one!

I am going to install the 10amp Enclosed tube socket type relay tonight or tomorrow. I will let you guys know what I find. I am also going to install different coupling caps and w0VMC is sending me an audio kit to remove that Super tight audio bandpass filter on the schematic. I hope to get a bit wider sound without really making to many changes. Its a strong and great transmitter. I just want it a little better but mainly original. I am going to note all my changes in the manual as the other hams have done since it was new. This way if someone wants it back to original they can change it back.

Thanks for all the help guys.

Clark

[Jim, W5JO]

Clark that thing has the couplates PC 81 and 91 in the audio plus a low pass filter between the 12AX7 and 6AQ5.

This is an easy fix.  Get an old ARRL handbook and look in the Audio Amp section for the chart that gives values for the components to replace those couplates.  The values in the handbook is good from 100 cycles to enough to help.  If you have an RCA receiving tube manual, you can find the same information. 

Should you not have access to the information, email me and I will scan and send it back to you.  One thing I would suggest is put a spark gap across the primary of the modulation transformer.  Also check the leakage of that 3 section can cap in the audio section.  If it leaks enough it will take out the LHV transformer.   
Smoke is smoke.

Jim

[W3SLK]

Clark said:

A friend offered up some 10 amp plug in relays.  These are enclosed relays with a tube socket. He has three of them with the sockets. I might try this out.

Thats the ticket. That relay base will take up probably less room than the OEM relay. A P&B will drop right in the socket. Becareful, there are 8-pin and I think 11-Pin. The 8-pin, DPDT should suit your needs. I'll have to look at my Globe Chump to see what the status is of the relay in it.

[Jim, W5JO]

Hey Mike(y) is your working?

[ke7trp]

A ham came over with a box of 5 PotterB plug in relays. All 117volt AC at 10 amps. He had several sockets and even a right angle bracket that holds the relay socket to the chassis. Perfect.. The relays are new. Later tonight I am going to wire one up and mount it. Should work fine. Cant wait to get it back on the air! 

Clark

[W3SLK]

Jim said:

Hey Mike(y) is your working?

No not yet. I've placed an order for T-2 the LVPS transformer. Jeff should have it to me by next month.

[ke7trp]

This radio is now fixed.

Today, I found the perfect mounting spot for the PB style relay. I mounted it solid and moved all the contacts over. The transmitter is now working 100% again.  Stable power. Full power output. Its back in service now and going to be used on 75meters tonight at 3870 if anyone wants to hear it.

I have one LOUD buzzing relay that is located near the modulator deck. Its a small 117v relay. I tightened the mounting bolts down hard and cleaned its contacts. Its about half the buzz now. It probably needs to be replaced.

Thanks to all for the help!

Clark
ke7trp

[N3DRB The Derb]

some of these relays offa bay look identical to your pictured unit.

http://cgi.ebay.com/Lot-of-Assorted-Relays-Allied-Control-Leach-C-P-Clare_W0QQitemZ160315651530QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item160315651530&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A15%7C39%3A1%7C240%3A1318

may want to buy some anyway.