Change the control board! Change the control board!

[paulg]

Just a personal observation...
For years I have seen many a technician replace control boards (aka computer boards, microprocessor boards etc.) on devices unnecessarily. I call it “throwing parts at a unit”. I do wish the trend would end.
It seems that if a tech cannot determine what is wrong, then it HAS to be the control board! Yeesh!
I remember years ago getting a call from a tech who had a convection microwave that would not reach preheat temperature. “ I replaced the thermistor, control board, fan, heating element and CHECKED EVERYTHING! Your product is bad!!! “
Yikes!
The fella was in the home.
“Did you check the line voltage while the oven was operating?” I asked.
“Uh, no.”
“Check it now with the oven running. What is the reading?”
“Uh, 90 VAC”
Y’all know the rest of that story.
After some calls like the above I changed the first questions I would ask a tech having oven performance issues:
“Is the oven in a mobile home or yacht?”
The techs would laugh but you would be surprised at the crazy issues that resulted when the “home” was being powered by virtual extension cord.
I actually wanted to ramp up the microwave oven control board exchange program as I would have bet a buck that at least half were still good. Still it wasn’t a good idea economically.
This forum really leads the techs in the right direction which saves a lot of boards and tech’s monies.
Comments? How do you get your newbie techs to stop throwing control boards at every repair? I remember one tech admitting that he ordered a control board for every repair as he didn’t want to find out it was bad after replacing some other part. Yikes.

 

[toploader55]

Isn't terrible when you can diagnose the problem but the tech can't ?

Being in the restaurant biz for years you get a trained ear for different machinery noises. When I would put in a work order I would tell them what I thought the problem is and to bring specific parts just in case.

I had about 80% accuracy on my diagnoses and the techs were always happy I could save them a bit of time.

 

[rp2813]

What a sad, sad commentary.

 

[qsd-dan]

Troubleshooting is a skill that is quickly disappearing.

 

[rp2813]

Troubleshooting

Dan, I tend to think it has already vanished. 

 

"Progress" has become quite a debatable term anymore.  There are way too many lame aspects to the corporate world and its bean counters' interpretations of it.

 

[lorainfurniture]

Modern appliances are more computer than mechanical. If you can’t read a wiring diagram your sunk

 

[gizmo]

Fisher and Paykel Smart Drive service manual used to say that over half of the control boards returned under their exchange program had nothing wrong with them.

 

[panthera]

Part of it is conditioning -

Early appliance electronics (consumer and pro) were AWFUL.

Worse than that, actually - they were designed to be the weak point. Super expensive to replace, consumers would just by a new appliance.

Today, the quality of the rest of the appliances has fallen whilst the boards' quality has, incredibly, improved markedly. Still, always, the most expensive component and, frequently, the easiest repair.

 

Sadly, the brilliant man who used to repair used appliances here in Cheyenne has retired and now we're stuck with the yank and replace youngster who took it over.

 

[perc-o-prince]

Miele

Our training was very thorough; it centered on theory of operation and finding what was wrong with the sequence to pinpoint the issue.

Unfortunately, the newest member of the service team in New England was a millennial whose father owned an all-brands repair company. Add on to that that between the time I was trained and he was trained, they'd shortened the program and omitted some of the finer points. He'd call his father for help and was becoming a parts-swapper. He didn't like it when he'd call me and I'd stop him from ordering a list of parts, and make him think about the issue using theory of operation. More often than not, it was either something very simple and relatively inexpensive, vs. a control board, or there was nothing wrong. He believed that if the customer thought something was wrong, there must be something wrong.

I remember being told that we spend a lot of time on calls "fixing the customer" rather than the appliance, but this was not done with his group. I spoke to the "master trainer" who said he needed to follow the new training schedule and they didn't go over that point in detail any more. Sheesh!

Chuck

 

[paulg]

Early days were tough

Part of my being persnickety about troubleshooting had a lot to do with my early days in a TV shop. I was told on the first day to never replace any more than was necessary AND be able to prove what you replace was faulty. All faulty parts were always returned to the customer. All warranty parts were held for 90 days. You were not hired to rebuild every set. Whatever came into the shop probably worked yesterday. Just find what is wrong today and repair it.
On top of that, it was very common for TV stations to send rigged TVs and other devices to shops to see what the shop replaced. We passed scrutiny in each rigged repair. However other neighborhood shops were a little overzealous with replacing parts and they ended up on TV with a big black eye to their reputation.
We had to be very careful. To this day - even when working on units in the house or for a hobby repair, I find the (usually one) faulty component first and then decide what optional maintenance or parts replacement I find prudent.

 

[gizmo]

fixing the customer

what a good expression!

I often find that, even where there is a genuine fault, it was caused by misuse.

I am an amateur and generally I am repairing gadgets for my friends so I am careful not to offend, but I often have to tell people that they are doing it all wrong...

 

[d-jones]

As an aircraft mechanic the term we use to describe replacing parts until the problem goes away is "shotgunning." Aircraft parts are extremely expensive, so the practice is severely frowned upon. For example, an alternator for a Challenger 601 was $79,000 back in 2006 or 7. I'm sure it's gone up in price since then. Anyways, as a lead mechanic at a corporate aircraft maintenance facility at the Van Nuys Airport I had to know which of my guys were capable of properly troubleshooting and which guys weren't, then assign the work accordingly. It sounds a bit harsh, but I've seen things go catastrophically wrong because the wrong guy was given a task that was over his head. Some guys reach the limit of their capabilities changing parts, and surprisingly some will even screw that up.

 

[statomatic]

This sound familar

I'm HVAC tech for maintenance & commissioning, I see that almost everyday.

Commissioned a split high wall ac unit and got called back by the contractor after three months, asking to replace the control board of the unit and check the refrigerant charge as it didn't reach the temperature.
I've opened the unit and seen the filters heavily clogged by fluff and dust, of course the unit worked fine after cleaning.

Also found a funny issue on a VRF system with 9 indoor units and a main remote controller, the system works fine except the main remote controller.
The contractor has replaced the main remote control without success, another guy replaced the nine indoor unit boards and the outdoor unit communication board without success.
So they gave up then I came, inverted the two communication wires on the main remote controller and now it works...

 

[paulg]

Nine PWBs plus remote control?

That must be a record for misdiagnosis. Had I been the manufacturer and I found out about that, I would have suspended their authorization until their techs attended factory training again!

 

[paulg]

Similarly: Change all the capacitors! Change them all!

Similarly, I see a lot of novice techs picking up vintage equipment and chopping out all the capacitors as if it is the smart thing to do in all cases.
Yes, I understand the mortality of wax and older capacitors. But doesn’t anybody do troubleshooting anymore?
Two of my case histories. As a hobby I fix vintage stuff for my own fun.

1968 Admiral stereo. Hum in audio:
Picked up this nice bookshelf stereo. Works fine, but low-level hum in audio. If I went to the internet they would think I was nuts for NOT chopping out EVERY capacitor and replacing it.
And so I put the unit on the bench.
One wire in the audio path was immediately next to the AC line to the power switch. Moved the audio wire, hum goes away. Place wire back into original position, hum returns. Redress wire, replace two lightbulbs and two years later, my new den stereo hasn’t skipped a beat.

Case history #2. 1966 Admiral stereo (Chicago is Admiral territory)
Believe it or not I picked this up as a virtual new-old-stock unit. Estate sale. Unit looks new. Cord still coiled. A relative of the estate says it never worked right so it was just put away. I bought it.
One channel is dead. If I went to the internet they would think I was nuts for NOT chopping out EVERY capacitor and replacing it.
Was the problem a capacitor?
Yes.
Would mass replacement of every capacitor have fixed it?
No!
Why?
Because Admiral never installed the capacitor. It was left out. The unit never worked. I installed the missing capacitor and the unit worked perfectly.
My rant is over. I hope trade schools become popular again so kids get the training they need.

 

[cornutt]

The rot has been setting in for a while. Back in the '90s, I had a furnace issue. I had to call several techs to find one that could fix it. One tech literally said "You need a new unit" as he was getting out of the truck. I invited him to get right back in the truck and leave. (One thing I learned from that experience is that a lot of the "techs" in the HVAC business are strictly installers. Doing cookie-cutter installs of new units is the only thing they are trained on. If they have to look at an existing unit, or figure out an atypical situation in an install, they're lost.)

 

[gizmo]

A week ago I rescued a well-known-brand upright vacuum cleaner from the skip behind a shop. It had been replaced under warranty (there was a sticker on it that said "faulty,discard when replacement arrives." The suction was fine but the brush roll didn't turn. (separate switch for brush which lit up but brush didn't turn.)

The base of the machine has a complicated circuit board with some sort of small IC, lots of surface mount components and some other stuff like a diode bridge, a triac and some resistors. It all seems unnecessary to me, it only controls a light and the brush motor, and both functions are "on" or "off", no speed control. So a sensible design would have the switch directly powering the brush motor, but no it had a couple of dozen tiny components in the circuit. I could see the triac supplied power to the rectifier that fed the motor (rectifier converts the 240 volt AC to DC for the little permag motor) so started checking for power. even touching the circuit with my multi meter probes caused the motor to briefly spark to life, it turned out a tiny resistor that turns on the triac was stuffed. I had a suitable resistor on hand (not identical but close enough) so the vac is now fixed. Part worth 20 cents or less. vac works great on carpet but useless on hard floors. It's not a keeper (cheap junk really) but I will find it a home.

 

[vacerator]

Gizmo,

would that brand name vac be an Electrolux, or a Miele product?

 

[perc-o-prince]

Mike,

I don't know that anyone would call Miele vacs "cheap junk" and wouldn't consider it a "keeper." They get incredible reviews and are considered one of the best machines for the money on the market (though I can't speak for the robot or stick styles). Even the upright, fairly new to the market for Miele, has shown very well.

Now Bissel, Shark, Hoover...

Chuck