Inconsistancies In Manufacturing

[phrunt]

A guy I know repairs Minelab detectors in South America, he's currently working on four GPZ's that have faults and showed me a photo of them on his workbench.  The immediate thing I noticed is the differences in construction, notably how random the glue is on the PCB.  The hot glue/RTV silicone is often used on PCB's to help with vibration where they haven't used any sort of mechanical fixing, more of a cheap way to do it really,  If you think about it tall heavy capacitors are only held on by little leads into solder pads so having some mechanical fixing helps prevent vibration and stress failure especially on something like a metal detector that has a pretty hard life being bumped around and dropped.

Sometimes it's used to shield components from the one next to them to help with preventing heat transfer or just keeping components separated.  In very high density PCB's its often used for electrical clearance ensuring components are kept apart, an example is if a high voltage mosfet is too close to another component the glue helps prevent arcing between the mosfet and nearby components.

All four GPZ's are relatively modern versions, the newest one in the far right being a couple of years old, the others are 3-5 years old, all four are revision 3 PCB's, take note of that, it means there was a Revision 1 and 2 PCB so over the lifecycle of the GPZ there have been changes to the PCB since the original release, anyone wondering if the first GPZ is the same as the modern ones, it's not, perhaps in performance it is but they've felt the need to change the PCB 3 times since the first production run, sometimes this is due to components being discontinued or it's because they've found problems and resolved them on later PCB's, this is certainly not unusual and detectors on the market for a long time end up with many PCB revisions, for example here is my Gold Bug Pro, it's a revision 6 PCB as evident in the top right corner of the photo, they maybe even higher now, mines a 2017 model.

The Gold Bug Pro

The GPZ, all 4 are the same revision.

So without further ado, here are some photos of the 4 GPZ's.

I've chopped up the photo to individuals so you can look at the differences better and blanked out serial numbers for privacy reasons.

You'll see just how different they are, some are well glued, some have no glue at all, it's all very random,  I was so surprised by this inconsistency on such an expensive electronic product.  It's not even put on well either, in some cases it virtually misses its target and isn't providing much support at all.   This is not what you'd call quality work.  The glue is likely hand done, in some cases it can be done by machine but with how random and inconsistent it is this is very much done by hand, and not done even remotely well at all.  Doesn't give you a lot of confidence in build quality does it.

[MSC]

Sure hope mine is glued up well. 

[Don71]

The newer 7000's definitely perform better than the older units. I tested a January 2022 unit vs a June 2016 unit. The newer version was quieter and deeper. I could get an extra 2-3 inches depth on most targets on the new unit. And the new one was so much smoother!

This worries me for the GPZ 8000. It's always good to wait to buy for the bugs to get worked out on these expensive machines. But impatience takes over!  I hope Minelab does a good job and irons out all the problems before release.

-Don

[phrunt]

1 hour ago, Don71 said:

The newer 7000's definitely perform better than the older units. I tested a January 2022 unit vs a June 2016 unit. The newer version was quieter and deeper. I could get an extra 2-3 inches depth on most targets on the new unit. And the new one was so much smoother!

It's funny you should say that, JW had the main PCB replaced in his GPZ, it was quite an early model one, obviously the new PCB was the latest model and he noticed his detector was different when he got it back, I can't recall exactly what he thought was different but he knew the detector like his own right hand as he used it so much so he noticed the change in it after the repair.  I'll have to ask what if he can recall what he noticed different.

[mn90403]

Is there any way to know 'sales of units' by year?  or total units sold of any model?

[phrunt]

2 hours ago, mn90403 said:

Is there any way to know 'sales of units' by year?  or total units sold of any model?

I'd guess they'll keep that information very confidential.  They sure don't tell shareholders.

[kac]

The hot glue is used quite a bit to keep trim pots from moving as well as keeping connectors from working loose. You will probably see more variations between machines because the components have a tolerance +/- and lower grade components will have a higher percentage.

Newer models should be better than old if the manufacturer updates the pcb and any chips with improved circuits.

[okara gold]

Are these all manufactured in Malasia?

If so, who knows what the instructions are to the final assemblers / inspectors.

Put a dab of glue on anything that moves or wiggles?

[phrunt]

Yes, they're all Malaysian, ideally If it were me I'd be adding the glue to everything I've circled in this photo, and if you look at all of the different boards they all have these things glued on at least one of the PCB's, it's just missed on many of them, this one is quite funny the person adding the glue virtually completely missed their target in the top right corner, they have a little line of glue running off the capacitor barely touching it.   More often that not they're just applying glue to one side too which isn't ideal especially when if you look how they've done it they've got minimal contact on many of the components they're applying the glue to.  It's just a real messy job and they clearly take no pride in their work.

The bottom left black wire looks like it has such a bad solder contact on it's pad, I will get the guy repairing them to check that as it may be his fault, this PCB was turning on and reporting the battery dead (when its not) and turning off.    It's hard to see things when all you've got is photos, I've already zoomed them as much as I can without stuffing up the image too much.

You'll likely have to click on the photo and click the + sign a couple of times to get the full zoom to see things properly.

They've done a better job on this GPX 6000 PCB, I remember old 4500 board photos where the work was very well done with the glue.  I can't find a photo at the moment.

Norvic some time ago put up a photo of his SDC 2300 guts, it looks pretty tidy on the glue.

 

[okara gold]

 It sure looks like quality control isn't a top priority. And by the looks of the external pod seam on the Manticore, the "glue" is a messy job too. And like the old cliche... An ounce of prevention is worth a pound of cure.