Rebuilding Globe King

[W8UJX]

I am rebuilding an old Globe King 500C.  The rig had a lot of rust so I am removing all parts on the three decks to clean the chassis.

When I rebuild the modulator I am going to use new parts in the speech amp.

My question is:

I wonder if I should retain the two couplets or replace them with discreet components?  The reason I ask this question is that if I ever sell the rig a potential buyer may prefer the couplets???

Any ideas???

Tnx,
Jerry, W8UJX
jk.ashley@earthlink.net

[Steve - WB3HUZ]

Since it's not going to be original (you're doing a chassis up resto), I don't see how not having the couplates would be a problem. If you can save the ones in there now, put them in a bag and keep them. If you get an anal buyer, hand him the bag.

[w1vtp]

Jerry

Are you going to do any "mods" to improve the freq resp?  As I recall, those couplets would have to be replaced anyway to get rid of the yellowy bottom end response.  Save the couplets in a bag as Steve already said and tape it inside the xmtr somewhere.  As long as you do a good job on the parts replacement, I think you are doing a future buyer a favor.  Just be sure to document things well and keep the documentation where you can supply it or refer to it.

Al VTP

[Steve W8TOW]

Yank out the couplets! There are several excellent suggestions on the web for
restoration of the AF section of a GK500. Some even have details on the components
inside the couplets. I personally have restored several and typically gut the AF section,
then rebuild it according to best operating standards.
Good luck es 73
Steve
w8tow

[W9RAN]

Hi Jerry -
If you haven't yet, be sure to check out WA5CMIs resto site:

http://www.qsl.net/wa5cmi/gk500.htm

I saw this GK in K5JWKs garage in San Antonio, and the "before" pics don't begin to do it justice.   Take your time and you'll have similar results!

73, Bob W9RAN

[N2DTS]

You have to ask yourself, do you want it original and a collectors item, or do you want to have fun with the rig and have it work well and sound nice.

I always did and always will modify anything I own, for me, that is the fun part.

If you do change things, be sure to document it though.

Most of the old gear has gotten so expensive that I sold it all off and went home brew.
While the old stuff is expensive now, it might not be forever, once all the people who know how to operate and fix old gear die off. In 20 years, the stuff might be worthless again.

I always think about the 1957 chevy....in 1957 it was a new car, in 1967 it was junk, in 1980 to 1990 it was a hot classic, in 2015 it might just be an unsafe poluting gas hog you cant get parts for.

Homebrew, no matter how well made, is always almost worthless to other people.
There is no guilt about changing anything homebrew!

All those old vintage rigs had serious cost cutting or design problems, poor audio, electrolytic filter caps, drifty VFO's, marginal parts, weak iron, they always cried out (to me) 'fix me'.

Nowdays, if you fix the problems, you ruin the resale value....no fun at all!

Brett
N2DTS


 

[Jim, W5JO]

As others have said replacing the couplates is up to you.  If you have a bridge and can measure the caps in it I would definately do that.  You can measure the resistors with an ohm meter.  If any of them are out of spec, they should be discarded in any event.  If they aren't, then it is up to you.

Somewhere I have a copy of an article out of AM Press Exchange be the venerable K4KYV on modification of the modulator deck.  If you are unable to find anything else and want this, I can scan and email to you.  Send me a PM and I will do that.

It is a straightforward modification that can be copied out of any old handbook if you choose to roll your own. 

[N3DRB The Derb]

or you can pick gear that has next to no "collectable" value as they are, but that can be modified to work for you. otherwise known as sweat equity.    The Gonset 201 amps are good examples. They will never be "collectable" because they're just not worth much money for various reasons.  GK 500's are very collectable, but anyone who is anal enough to care if he F$#* plates are in place I wouldnt want to buy or sell anything from or to anyway.  They would come back in 5 years after the rig  having gave perfect service in that time and demand their money back because a speech amp toob went bad.

I'm not kidding, either....I dont want any "collectable" rigs anymore. They poisoned their own pond with a "collectable" rig  price bubble and now it is going to bite em.

[W1EUJ]

The other side. I'm tired of people wanting market price for radios they heavily modified without documentation or proof that it even works.

[N3DRB The Derb]

yeah, that too.

I have mixed feelings about this. on one hand, the "collectors" made the ham radio I knew unaffordable to me, but that made me build my HB rig. and they dont keep the rigs forever. "estate sale" is the great equalizer. as long as the rigs are saved, it's all good. What sucks is when uncaring family throws everything in a dumpster. "Collector" or not, as long as that is minimized, we on the same team.

[ke7trp]

I am restoring a GK500C also..  Mine is less than a week out. I will let you know if I have the problem about the harmonic.

I would probably leave the couplates in.  I also own a Champion 300 and talk on it daily. I had orginaly planned on removing the Couplates on this transmitter also. But then with the help of Robert he decided that these where not really the limiting factor. Sure, its best to yank them out. However, I dont think its needed. Other mods elsewhere got me the wide audio I was after. Every person on the air as been very happy with the results of bypassing the Filter and coupling to the Driver tube directly. This way, We can switch it back easliy and nothing is removed. THe only thing that was changed permenantly was the Mic lead in resistor. Mine had a 100K and now with a 3 megs installed the D104 is matched much better. Just these simple mods that he helped me with, made a huge tremendous difference in sound without hacking it up.

I wrote in the manuals log what I did and why, just as other hams have done for the past 50 years. THis way, The next owner, can change it back if they wish.

Clark

[WB2RJR]

Jerry,

I've owned a GK500B for 30 years now. Bought it from my cousin WA2LDC for $100. I've kept it on the air all this time, so it's not "original" as I didn't always have the money to exactly replace the original components when they crapped out. Many years ago I replaced the couplets to get the audio to sound good with the mike I was using. I still have them if someone wants them when I'm dead.

My GK, although in excellent physical condition, is not a collectors item. It is just the transmitter I use everyday.

73,

Marty WB2RJR

[W9RAN]

After all this time, hasn't anyone drawn out the schematic of what's in those doggone Couplates?   I figured someone had but can't find it - so I left mine stock.

I got a good deal on this one, as the HV transformer failed and a previous owner threw it away (!), moved the HV transformer from the modulator down to the power supply and cobbled it up to operate as a SSB linear.  Finally got it rewired and restored including a new Peter Dahl transformer for the HV.  Working good now, all stock except SS rectifiers in the HV supply.  Some pics: http://smg.photobucket.com/albums/v652/ranickel/Globe%20King/

73, Bob W9RAN

[Jim, W5JO]

After all this time, hasn't anyone drawn out the schematic of what's in those doggone Couplates?   I figured someone had but can't find it - so I left mine stock.

Try this:
http://www.amwindow.org/tech/htm/couplate.htm

[Van K7VS]

I have no idea where my last message went so will try again!  I would certainy use the couplets that came with the globe king and make sure when you rewire everything on the modulator chassis that the schematic is correct around the 6L6 as there was an error on the original manual schematic for the modulator section in this area, but then again, mine was the GB500A so your schematic may be fine.  Just double check it before pulling the socket off the chassis.

I found the audio reports to be excellant at all times using their original wiring of the modulator chassis using the couplets I puiled off originally.  I would also recommend a D-104 mike.

Regarading what you are doing.  I used a very cheap sand blaster ($20.00 item) from Harbor Freight to take the rust of the chassis' and then purchased a galvanize spray product at Lowes Hardware.  I also reshot the cabinet, front panels and had them silk screened locally for about one hundred bucks.  When finished I ended up with a "NEW" old Globe King all original that works great!

You can go to my call on qrz.com and see a picture of the unit (double click on the image) in the RH corner of the QRZ page when it comes up!   Good luck on the project and let me know if you need any further advice that I might be able to share.

Van, K7VS

[ke7trp]

Nice 500A threre van!   I just got the electrical restoration done on my 500C.  I am going to repaint the cabinet this week to the original Hammer tone.  I will post pics of it when its done.

On the couplates..   My personal advice is to ditch them.  I posted above that I would keep them but after completing the project and using the D104, I ended up with stock audio. If thats what you want, then leave it alone.

In the end, I ditched the couplates and ran everything with the W0VMC mod kit.  Now, I feed outboard audio into the back Patch jack. If I plug a D104 in it, I get stock type tone.  Maybe a bit more low end. With the outboard gear I am now getting 20hz to 12,000hz audio which I enjoy.

So, I guess it comes down to what the goal of the project is.. My goal was to make it perform so I ended up going that route.

Clark