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Author Topic: Repair of Broken Terminal Strip  (Read 9263 times)
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K4RT
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« on: July 23, 2015, 04:44:08 PM »

Has anyone successfully repaired a cracked solder lug terminal strip using super glue or some other adhesive?  By "successfully" I mean the repair has proved durable.  A five lug strip in my SB-610 cracked resulting in complete separation and I have no spares on hand.  Mouser carries them, but I would like to know if a viable repair is possible.  An image showing the location of the crack or break is attached.  Thanks. 73 Brad.


* 3lugs.jpg (20.62 KB, 540x240 - viewed 410 times.)
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N4zed
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« Reply #1 on: July 23, 2015, 05:35:45 PM »

I have not repaired one but my first attempt would be to use a strip of fiberglass or two or three and resin. Non-conductive, strong and will adhere to most everything...

Ken
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Ken<br />N4zed
KB5MD
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« Reply #2 on: July 23, 2015, 10:27:27 PM »

5 MINUTE EPOXY
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w1vtp
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« Reply #3 on: July 23, 2015, 11:59:44 PM »

5 MINUTE EPOXY

Agree.  Glob it on and keep rotating it until it sets
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KC4VWU
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« Reply #4 on: July 24, 2015, 02:48:56 AM »

Radio shack DID carry five lug strips such as the one you posted. Would it be feasible to just change it out?
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K4RT
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« Reply #5 on: July 24, 2015, 08:31:49 AM »

Thanks. I will try 5 Minute epoxy and see how it goes.  I would like to get it repaired, get new caps and diodes for the HV power supply soldered in, and put the monitor back in the station.

Yes, the strip could be changed out. The two Radio Shacks near my QTH, one just a mile or so away, have closed. Mouser carries a 5-lug  strip for around a buck, so if the epoxy doesn't work, I will order some new strips from Mouser.
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w1vtp
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« Reply #6 on: July 24, 2015, 09:11:37 AM »

Thanks. I will try 5 Minute epoxy and see how it goes.  I would like to get it repaired, get new caps and diodes for the HV power supply soldered in, and put the monitor back in the station.

The two Radio Shacks near my QTH, one just a mile or so away, have closed. Mouser carries a 5-lug  strip for around a buck, so if the epoxy doesn't work, I will order some new strips from Mouser.

OK.  Just be sure it's the clear stuff.  Don't know about that grey stuff put out by JB Weld
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KD6VXI
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« Reply #7 on: July 24, 2015, 12:47:56 PM »

Do NOT use JB weld.   Depending on the formulation,  the amount of metals in it vary.   Ask me how iI know.

Another good  repair formula is Styrofoam cup, melted down with acetone.

Good insulator for high voltage as well.

--Shane
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KA2DZT
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« Reply #8 on: July 24, 2015, 10:12:32 PM »

5 lug terminal strips use to be 12 cents.  Try to glue it with 5 minute epoxy.  They do break easily. I have draws full of those things, some used, most new.  A buck for a new one is OK if you need one.  How much is the shipping? You don't want the 12 cent item end up costing 10 bucks..
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DMOD
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« Reply #9 on: July 27, 2015, 12:20:52 PM »

I have had success using the super glue "gel."

Smear a thin film of the gel on the crack and along the full length of the terminal strip. The thinner the film, the faster the set.

Hold or press until set.  Cheesy

Phil - AC0OB



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WQ9E
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« Reply #10 on: July 28, 2015, 08:02:09 PM »

In most cases a bit of two part epoxy will be all that is needed.  But if there is likely to be stress on the repair OR if serious damage could occur from a break then you want to make a little stronger repair. To make a repair that will easily stand up to the mechanical stress you need to use another small piece of phenolic or a similar plastic like substance to reinforce the cracked part of the terminal strip.  Cut a piece of material that will extend maybe 1/4 inch either side of the crack and drill a hole in this piece to clear the rivet.  Once you epoxy this into place it will be very strong and won't break due to the mechanical stress that often results from temperature cycling during operation.
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Rodger WQ9E
K4RT
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« Reply #11 on: July 30, 2015, 12:30:28 AM »

Alan, Shane, Phil & Rodger,

I bought 5-Minute clear epoxy and I plan to set to work on it this weekend. I do have some phenolic pieces to use for this repair.  Rodger that is a good idea about drilling a small hole to clear the rivet. The affected terminal strip is where the HV AC is connected to the rectifier/voltage doubler so I wouldn't want anything to come loose there.

73,
Brad
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kc4umo
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« Reply #12 on: August 01, 2015, 08:22:12 AM »

I work on a lot of old equipment that has these terminal strips.  And often find them broken. Being vintage I like to keep the original look and not replace stuff with new. I use a glue that is used in the RC airplane builds called Zap. The one I use is for the terminal strips is "Zap-A-Gap".

As long as there are no carbon traces on the strip it works pretty good. I have also cut strips from old circuit boards and made my own.
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K4RT
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« Reply #13 on: August 01, 2015, 09:06:31 AM »

Buddy,

Thanks for the tip. I will keep Zap A Gap in mind for next time.

I had time Friday morning to epoxy the broken strip, using a small piece of phenolic as discussed above. Last night the bond was solid so I wired in & soldered three new caps and diodes. It's a good repair. The CRT is working again and voltages in the HV section look good. Voltage at one of the CRT pins is low but that may be a resistor that has aged out of its spec value, which I will check today. 

Thanks guys.
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Patrick J. / KD5OEI
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« Reply #14 on: August 01, 2015, 09:04:23 PM »

Haha carbon traces. I want to digress a little on that subject. They played a good one on me with a BTA-250. I looked everywhere I could see for a dynamic short on the high voltage. Suspected a bad wire in a cable or maybe a rat-chewed one. The cables in that set run partly inside enclosed areas. Never found the short. B+ is only 1600-1800 in that set.

But I was not alone in missing the problem. A broadcast transmitter repair technician / engineer didn't find the issue either and had spent many hours eliminating things, which was a good start in any case. The station owner didn't want to spend more $ on that old standby rig and I ended up buying it.

I decided not to spend more time on it since I already had one and ended up selling it to a gentleman from AZ, Henry Hurass, AKA Dr. Hankenstein of audiotesla.org.

He decided to do a complete restoration and the TX is just like new. The carbon tracks were under the rectifier sockets..  Duh!! But I'm really glad he has the TX, it couldn't have a better home. Check out his site to see the wonderful job he did on it.
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