CRT vertical deflection -- bad solder joints?

I don't understand how shotgunning can /create/ problems, as long as the replaced components are correct replacements. Unless you mean the customer might get upset.

As an experienced service technician, you know that the cause of a given problem is not always obvious, even after extensive troubleshooting. The customer is paying for your time, often more than what the parts cost. Why burn up the customer's money when replacing a half-dozen parts is likely to fix the thing?

I have seen sets (notably Toshiba and Mitsubishi) where shotgunning was advisable in addition to replacing whichever single cap might have been causing your issue.

Mark Z.

We used to call some of the factory repair 'kits' for certain Panasonic sets "shotgun packs" because of the amount of components included. Some of those even included parts not on the board that were to be added on the solder side.

In article , William Sommerwerck writes

Would you be happy for a car mechanic to shotgun a fault on your car, with you paying for his time and all the parts he is unnecessarily fitting?

Isn't that an unfair comparison?

Yes, if an initial /conscientious/ troubleshoot didn't reveal the problem. I'd rather pay for parts than time.

Of course, you can't draw an exact parallel between cars and electronic equipment. It's easier to "see" what is wrong with mechanical devices, but car parts tend to be more-expensive than electronic parts.

There's also the possibility that a comprehensive makes it possible to offer a "lifetime" warranty on the repair.

It goes without saying that if a service shop claims that lots of things need fixing, it's probably not telling the truth.

Thirty years ago I worked part-time -- at $6/hour -- for Chestnut Hill Audio in Philadelphia. The owner said to me "You're not as fast as the other people I use -- but nothing you repair comes back."

I had a holy horror of callbacks. It costs the business money, and it makes the business and the service tech look bad.

By the way, I never shotgunned anything I repaired there, because nothing seemed to need it.

Every component that is replaced, increases the potential margin for error by the person replacing it. I have had many items cross my bench over the years, which have been 'elsewhere' first, and have seen wrong values fitted, caps in backwards, diodes in backwards, damaged print and so on, amongst the many components that have have obviously been shotgunned, as evidenced by the flux all over their joints. I have also seen unsuitable substitutes fitted, where technicians have had insufficient understanding of the requirements of a circuit's design, and have just put in 'what came to hand' in order to complete their shotgun.

Very occasionally, it is necessary to replace a block of components, when a fault is particularly obscure, but I would never recommend it as an acceptable procedure to anyone who wasn't hugely experienced in the field of service work, and particularly in the case of a simple problem such as the OP has with his TV's field scanning, and which would be easily diagnosed with the use of appropriate test equipment.

Arfa

Occasionally, this is true, but only - for me at least - if the manufacturer has recommended a block of components to be replaced, on the grounds that some or all of the additional ones, may have been unacceptably stressed or damaged, by the primary failure. In these cases, the manufacturer or his spares agent usually supplies 'service kits' of all the necessary components. Often the case with switch mode power supplies.

As in, for instance

Arfa

I'm not at all sure you would say that if one of the incorrectly fitted parts was the EMU, for example. This, and many of the expensive sensors on engines nowadays, are usually 'bonded' parts, and once the box has been opened, the supplier will not accept it back, which leaves you paying for it, when it was not required. A while ago, I had just this problem with my local garage, who replaced a cartload of parts and sensors on my engine, for an idle problem that ultimately turned out to be due to a split in the PCV hose. I argued with them long and hard about having to pay for parts that had been shotgunned due to the fact that the guy doing the job had not correctly diagnosed the problem. I eventually had to settle for a reduced labour bill to offset the unnecessary parts cost, which they were determined were staying on the engine, and that I was going to be paying for (at retail price, just to make it worse)

Arfa

Which is precisely what I'm saying. Yes, there are some items - notably switch mode power supplies - where it is often prudent, or even recommended by the manufacturer, to replace a whole raft of parts, but for most general repairs, the cause of the problem should be correctly diagnosed, and the (usually) one faulty component replaced.

Arfa

"whit3rd" wrote in message news: snipped-for-privacy@glegroupsg2000goo.googlegroups.com...

news: snipped-for-privacy@glegroupsg2000goo.googlegroups.com...

I hear what you're saying, and it does, on paper at least, have some validity. However, my comments are based purely on many many years' experience of doing service work on electronic equipment, from all walks of life from consumer through industrial, and on a daily basis. I replace bad electrolytic caps all the time. Several items every week will require bad caps finding and replacing, and in just about every single case, the ESR meter tells the story. In fact, it is probably the most useful test instrument to live on my bench, and has paid for itself many times over.

Whilst I accept that electrolytics *do* fall in value, I find it actually quite rare. Almost always, if a cap has fallen in value, its ESR will also be out of the window. In my experience though, the reverse is often not true. Having found a bad cap with my ESR meter, I do occasionally check the value on my digital C meter, and for the most part, find it to be well within tolerance.

As to having to remove caps to test them, again this is rare, and quite impractical on complex switchers which may have many electrolytics, and more than one that is faulty. I don't know if you are personally involved in commercial service work, but in today's economic climate, and with the low value of much equipment, the name of the game is quick and accurate diagnosis of a problem, and minimising additional costs of time and materials. I have never been an advocate of 'shotgunning' faults by replacing components which may or may not be faulty. I have had many items pass across my bench over the years which have come from other service outfits who have replaced components 'willy-nilly' that they suspected to be faulty, but without ever getting to the bottom of the original problem, and having compounded that original fault in their efforts. I have had caps fitted backwards, diodes and transistors fitted backwards, wrong value resistors fitted, print damage and so on. So personally, I like to have a bit more than a suspicion that a component is faulty, before replacing it. In the case of electrolytics, my ESR meter, for the most part, does that for me. In saying that, however, I think that I should also say that I fully accept that the use of an ESR meter is as much black magic as science and, although it is a useful instrument when used by its instruction manual, for the professional user, there is also a considerable amount of interpretation and 'feel' involved. In 'casual' hands, an ESR meter may be little better than a multimeter for finding bad caps ...

One place where it can fool you is where an electrolytic has gone short circuit - fairly rare these days, but does happen. In that case, the ESR meter will of course, give a nice low reading that will, initially at least, fool you into thinking that the cap is (probably) good.

Arfa

fitted,

the

hand'

Yes, but you and I don't make such mistakes.

In article , Meat Plow writes

Tell me how. Not being argumentative, I'd be genuinely interested to hear why you think it's unfair.

If the parts are cheap with little or no additional labor, and done to prevent a repeat failure in the near time frame, as is often the case with TV's, then yes, I would be happy, and so are my customers.

Mark Z.