I'm guessing that they still sell it. I have a small nipper I bought from Radio Shack that does an excellent job of clipping those loose ends.
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Recapping older radios
- Thread starter KALR 7570
- Start date
Here is a pic of the 2 large caps. Before replaced all I got was loud pops when I turned it on. After the change I got receive and modulation but no power. A cb tech online recommended I check the cap near the final. I checked it, it was bad, I replaced it and I'm on the air. How did I waste my time and money?
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You did not, it was broken and you fixed it.
In well designed consumer equipment where there are not a lot of cost cutting measures most of the time it is not a problem.
However, most CB manufactures are looking for ways to save a penny here and a penny there, this can add up to thousands of dollars over the coarse of production runs on many thousands of units, often they would use a cheaper component that would be considered borderline in meeting the specs ( example using 10 volt caps were a 16 or 20 volt cap really would be a better choice) to save money.
Add to this the common habit of the average CB operator to push things ( clip/peak/tune/overvolt/mod) beyond what the radio would see as working conditions in a normal stock set-up and you see failure sooner than normal.
There are common Caps that are known to go bad in some of these radios.
Many of them are now 30+ years old, live in cars/trucks that sit in the summer time and see 110+ degree temps with the windows rolled up.
Dried out caps in the old Yaesu 101`s, old cobras, old radios shack radios, known caps that dry out in the 1970/80`s designed Uniden 2510/2600/Lincoln/Superstar/Royce/Pace radios, the list goes on.
If they are bad and the radio will not function, no money is wasted in the repair.
If you have an old radio and you want to do everything you can to preserve the longevity of the equipment, replacing caps that are borderline under-rated or just 30+ years old can be a good idea.
I have worked on old AM/Shortwave tube radios that the caps were 50+ years old.....and still work fine, but I also feel that they were built with higher quality materials back then. Another thing to think about is that often these radio are stored for a long time in who knows what kind of storage conditions.
To each his own, some guys would rather just toss a radio that fails to work and get a new one.
Some will pull apart, test, and repair a radio........
73
Jeff
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I used my TRC-428 for about a year before I got a Galaxy 2100. My 428 had been in storage twenty-five years. I hooked up my 428 recently to a dummy load and it shows two watts deadkey and swings to 12 watts(had it peaked 28 yrs. ago). I'm debating on sending it to DTB to go through it and restore to like new performance. The modulation limiter resistors haven't been clipped.
Rather than just change all the caps, why not simply check them out with an ESR meter? You can usually spot a failing cap with an ESR meter before it goes really bad.
The worry about buying caps in bulk to replace all the ones in the radio is that you could be replacing the original with a modern cap that has a higher ESR than the original one even if it is 30years old.
Note that you can often use an ESR meter with the caps still in circuit and still spot a bad capacitor. A good ESR meter will also read out the capacitance as well.
I made my own ESR probe rather than buy one but you can buy a reasonable ESR meter for less than the cost of a CB.
The worry about buying caps in bulk to replace all the ones in the radio is that you could be replacing the original with a modern cap that has a higher ESR than the original one even if it is 30years old.
Note that you can often use an ESR meter with the caps still in circuit and still spot a bad capacitor. A good ESR meter will also read out the capacitance as well.
I made my own ESR probe rather than buy one but you can buy a reasonable ESR meter for less than the cost of a CB.
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I'm looking to get an ESR tester. I really do not like having to recap an entire radio. It is tiresome. Even a bore. I have a couple of radios from local operators that desperately need to have the caps analyzed. This would make it much simpler. However, hunting down the points on the board traces where the caps are - is half the battle to replace them anyway . . .
http://rover.ebay.com/rover/1/711-5...0001&campid=5336136228&icep_item=251205574391
http://www.amazon.com/Peak-Electron...1359921229&sr=8-7&keywords=Anatek+Corporation
http://rover.ebay.com/rover/1/711-5...0001&campid=5336136228&icep_item=251205574391
http://www.amazon.com/Peak-Electron...1359921229&sr=8-7&keywords=Anatek+Corporation
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I've got mixed feelings on this issue:
On the one hand, I'm thinking: "if it ain't broke, don't fix it" along with: "if it works, don't mess with it."
However, on the OTHER hand, the older the rig, and/or the more 'used & abused' it is, or if it was an eBay or garage sale special, sometimes it's worth recapping.
I am also of the opinion that, with electrolytics typically being the chief cause of failure, coupled with the fact that they are relatively inexpensive, it seems to me that for about $18 - 25 to recap an ENTIRE RADIO all in one shot, rather than take the time to individually test each and every cap, seems to make more sense to me, ESPECIALLY if you replace all the 10V caps with 16, 25 or even 35V caps of the same pf/uf values.
While I have scavenged transistors, resistors, pots, LED's, lights, switches, knobs, and button caps from old (donor) radios, the one thing I WON'T reuse is an (old) electrolytic capacitor, no matter how good it looks (or tests.)
Having said that, is there a "LIST" of the most often failed electrolytics, OR, the ones that SHOULD BE CHANGED by radio chassis? For example, WHICH caps should one IMMEDIATELY change when purchasing a used:
- Cobra 148 GTL or Uniden Grant
- Cobra 29 or Uniden PC76
- Cobra 25 or Uniden PC68
- Galaxy/Ranger 3600 chassis
- Galaxy/Ranger 6900 chasis
- President HR2600/2510/Lincoln chassis
- Uniden PC122 / Cobra 146 / Radio Shack TRC-453 / TRC-465 chassis
I know there are recap "kits" out there, but I'm sure that by using the parts list of a Factory Service Manual, and/or, by carefully removing, sorting and then replacing each and every individual capacitor one could actually save some money in the process (especially if you intend to do MORE than 1 individual radio) by buying your electrolytics in "bulk".
Your thoughts?
On the one hand, I'm thinking: "if it ain't broke, don't fix it" along with: "if it works, don't mess with it."
However, on the OTHER hand, the older the rig, and/or the more 'used & abused' it is, or if it was an eBay or garage sale special, sometimes it's worth recapping.
I am also of the opinion that, with electrolytics typically being the chief cause of failure, coupled with the fact that they are relatively inexpensive, it seems to me that for about $18 - 25 to recap an ENTIRE RADIO all in one shot, rather than take the time to individually test each and every cap, seems to make more sense to me, ESPECIALLY if you replace all the 10V caps with 16, 25 or even 35V caps of the same pf/uf values.
While I have scavenged transistors, resistors, pots, LED's, lights, switches, knobs, and button caps from old (donor) radios, the one thing I WON'T reuse is an (old) electrolytic capacitor, no matter how good it looks (or tests.)
Having said that, is there a "LIST" of the most often failed electrolytics, OR, the ones that SHOULD BE CHANGED by radio chassis? For example, WHICH caps should one IMMEDIATELY change when purchasing a used:
- Cobra 148 GTL or Uniden Grant
- Cobra 29 or Uniden PC76
- Cobra 25 or Uniden PC68
- Galaxy/Ranger 3600 chassis
- Galaxy/Ranger 6900 chasis
- President HR2600/2510/Lincoln chassis
- Uniden PC122 / Cobra 146 / Radio Shack TRC-453 / TRC-465 chassis
I know there are recap "kits" out there, but I'm sure that by using the parts list of a Factory Service Manual, and/or, by carefully removing, sorting and then replacing each and every individual capacitor one could actually save some money in the process (especially if you intend to do MORE than 1 individual radio) by buying your electrolytics in "bulk".
Your thoughts?
I do not like to wait for them to fail because thouse 6.3 and 20V tantalum caps usually fail to a short not to an open which can take out an ic or trasnsistor.
After reviewing my comment of a few years ago, I would like to retract this statement. Leaking capacitors are a problem and should be replaced.
I can see it especialy if the the thing is NOS and been sitting in it's box un-used for 25+years. Sitting unused is just as bad for eletronics an engine sitting for 25 idle. THings just dry out. Sure if you have a variac you could try to bring it up slowly reforming the caps but how many people have a variac just sitting around the house? So many IC's are not being made any longer and all it takes is one cap to take something that has no replacement out. Then you are the proud owner of a boat anchor. On top of that when talking about SSB radio sometimes you just can not buy anything remotely as good today. For example an NOS NDI SSB 40CH radio or the nicer RoadTalker 40 SSB base/mobile radio's would easily sell for over $500 if you had to buy one new today retail so what the big deal springing for $180 or less recap, alignment and evaluation? Have yo heard how bad modern SSB sound? Their terrible on receive so full of noise. I normally hate it when people say things like "It is cheap insurance"....but sometimes it does make sense. If you have to take the timing cover off to change a timing belt it makes sense to replace the water pump , tensioners and cam sensors while you are that deep in the engine even if those parts have not failed yet. We call it preventive maintenance. You do not wait often for things to break if you can help in aviation as well you have fixed maintenance based on hours of operation not parts failure or symphony of coming failure. It has been my experience that when something fails often parts farther down from that part will fail as well. It is not that you must it more just about a good practice. If the unit has been used a lot often the caps are fine but sitting for years at a time sure does seem to take it's toll on lytics!
Maybe all the transistirs should be replaced as well since even a tiny switch transistor can fail with drastic results from shorting something to ground.
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Or diodes even . . .
Just kidding. However, these cheaply built radios stored or used in adverse weather conditions (both extremes of heat AND humidity) has both deserved this scrutiny and consideration.
The abundance of 10v caps present. Radios designed with caps that are too close to the margin of practicality for a given circuit because of mfr cost consideration. Some cap kits (like Klondike Mike's) will provide some better deserved, different cap values for some locations that supersede design. Not just upgrading voltage; but more/less capacitance as needed.
PLL/oscillator/clarifier stability is also a huge factor that I've noted.
Then there is abuse by the previous Attila the Hun operator who trounced the radio.
Used and older radios saturate the market from time to time, and buyers wag their heads when the go belly up in a short time and wonder what the remedy may be. Not always; but often enough to be a huge factor in my view and some practical experience.
Tantalums also have a finite life expectancy too; seen some of this recently as well . . .
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I do agree with you Rob. In fact my above post was said in jest. In fact I had to go back and add the smilie I missed.
