Restoring an old, broken PacoJet 1

One of the pieces of equipment very high up on my bucket list was a PajoJet. It had stood there for years but the buying price, even for a used unit was just too prohibitive.
A new PacoJet will set you back over 4.500 Euro, even a used one is around 2.000 Euro, which is just a little steep for a private household.

For those who haven’t heard of it, a PacoJet is something like the holy grail for Michelin-star chefs to achieve perfect textures for Mousses, Ice Creams, sauces, etc.
So, when I was offered a broken unit that was deemed beyond salvage at a very low price, I thought “challenge accepted” and bought it.
Unfortunately, there aren’t any repair-manuals available. Also PacoJet won’t sell spare parts, so you have to go with what you can salvage. If one of the specific components like the mainboard or the power supply can’t be repaired, you’re stuck.
I do understand their point here though. The unit is rather complicated, computer controlled and involves high-speed components. Nothing you want your fingers caught in.
If you don’t know exactly what you’e doing, you’ll either get electrocuted or you’ll amputate a few fingers in the revolving mechanics.
This is definitely a case of “don’t do this at home”!
Having restored a few cars, I thought “well, it can’t be more complicated than that”. Unfortunately, it was.

Spoiler alert: In the end I managed and I learned a lot in the process but if I calculate all the hours I put into the restoration, this is probably the world’s most expensive PacoJet ever.

When the PacoJet arrived in the original carton and I unpacked it, I immediately understood why it was sold as broken and beyond salvage.
It was dented and scratched plus it was just dead, one light came on when I powered it up but nothing else.

The PacoJet as it looked when I unpacked it. Dented, scratched and lifeless.

So, in order to get to the ground of things, I opened the case and checked the mechanics.
I decided to take a step-by-step approach and to fix one issue after the other.
Opening it, I immediately saw that the unit was absolutely dirty and grimy.
A sticky layer of fat and dirt covered everything inside the unit.
Over 20 years in a restaurant-kitchen take their toll.

The inside of the device. Very dirty and grimy. Notice also the power-switch. This was broken and water could run inside the power-supply. A major safety issue and an accident waiting to happen.

One of the first things I noticed was that the security-switches for the beaker-holder were totally dirty and worn.
These switches ensure that the unit will only power up when a beaker-holder has been inserted properly. Otherwise only the green power light will come on but nothing else will happen.
This was exactly the behaviour the device showed, so I used an Ohm-Meter to check the switches and found one to be faulty.
I then bridged this switch to test if the unit would power up.

The faulty safety-switch with a bridge for testing if this was the cause if the error. Never run the system like this though!

Powering up the unit, the display came on immedately, the “ready”-light was green.
Before going on, I replaced both switches with new ones. Even though one was still ok, it was just a question of time when it would break as well. It’s always better to replace this kind of thing when the unit is open anyway.

The old safety-switches were replaced with brand new ones.

With the new switches in place I then tried to do a function-test of the device.
Unfortunately, it only sprang to life for a split second before going dark again.
Not what you want, but hey, that would have been too eas and nothing better than a good challenge.
I decided to continue my troubleshooting activities by checking the electronics.
All ciruit boards were extremely dirty and impossible to check.

A very, very dirty and sticky Circuit Board

Even with all the dirt on the boards, you could still see that some components were clearly faulty.
If you take a close look at the Siemens-component in the foreground on the picture below, you’ll notice that some of the legs are askew and seem to have been re-soldered after having broken off at some point.
Clearly, whoever had been tring to repair this unit in the past didn’t have a clue what the were doing.

The Siemens TLE4260 in the foreground: The legs were badly soldered on after having broken off and clearl didn’t have a proper contact.

I decided to bathe the circuit boards in alcohol to clean them. Even though this may not sound like a good idea, it actually works. After having bathed the mainboard in alcohol and having carefully removed the dirt with an old toothpaste, it actually looked like new.

Bathing the mainboard in alcohol actually made it look like new.

When I turned the mainboard over to check the rear, some components actually fell out.
These seem to have come loose at some point and were only held by the sticky fat and dirt that had crept everywhere.
The bent transistors on the picture below also caused issues and needed to be replaced.

After cleaning the mainboard, a transistor plus some other components just fell out. They had been held in place only by the dirt on the mainboard.

I decided to do a thorough check of the board to see if there were any other cold soldering points. I found a few.

The rear of the mainboard. The soldering points marked red were cold, i.e. the components werent’s soldered in properly, causing the unit to malfunction.

I decided to replace all components that looked slightly dodgy, especially the Siemens TLE 4260. I found a source that sells this component for less that 4 Euros, so I bought a handfull, in case I break one or it fails some time in the future.
The comparison between new and old is stunning.

The new TLE 4260 versus the old one. 4 missing legs that lost contact whenever the unit moved. No wonder it failed.

I also removed and tested all other transistors on the board. Checking them in a tester showed some of these to be faulty as well.

Removing, checking and replacing all transistors on the mainboard.

Having throroughly checked the electronics one more time I reassembled the unit and again tried to run it.
This time it actually ran, at least for a while.
Something was still wrong though.
Even though the control panel showed that the rotating rod inside the device, to which the blade is fastened, was supposed to move up again after having finished scraping the frozen contents of a beaker, it continued going down at a very low rate.
This pointed to a mechanical issue, so I needed to figure out the principle on which the device actually works.
Originally I thought this was something like a power drill, very simple and easy to understand. The more I learned though, the more I was impressed by the ingenuity of the machine.
Basically, the whole principle is based on the fact that the rod rotates inside an also rotating steel tube. The rod will always rotate in the same direction and at a constant speed of 2,000rpm while the speed of the tube will vary, depending on whether the rod is supposed to go up or down.
Whether it goes up or down and at which speed depends solely on the difference beween the speed of rod and tube.
If the tube rotates faster than the rod, the rod will move up.
If the tube rotates slower than the rod, the rod will move down.
While the rod rotates at a constand speed, the speed of the tube is controlled by a gearbox which contains two electromechanical clutches, one at the top and the other at the bottom.
Having determined that a mechanical issue was be the cause of this problem, I decided to test the gearbox by powering the clutches separately and to see if they engaged properly.
I quickly noticed that, even though both clutches made a loudly audible click when activated, the bottom clutch didn’t actually engage properly.
The top one seemed to move, at least a bit, but I wasn’t sure if it was ok, so I decided to disassemble the gearbox.

The gearbox. On the left and on the right, you can see the two electromechanical clutches

As can be seen in the picture, the gearbox -like everything else inside the unit- was extremely dirty. I therefore decided to clean all components thoroughly.
Especially the clutch on the left seems to have had contact with a liquid which definitely also ran inside the clutch.
Removing the clutches revealed even more dirt in and around them.

One of the two clutches. My hands were actually clean before I removed the parts. These clutches were extremely dirty.

As dirt is never a good thing inside a clutch, I checked if I could find spares online.
I actually found some used ones on eBay. These looked worse than mine though and were still supposed to cost 100 Euro each. As that wasn’t an option, I took the risk, disassembled my old ones, cleaned them until the inside looked like new and then reassembled them. Miraculously, no parts were left over.
Having cleaned and reassembled the gearbox I again tried actuating the clutches. This time they moved significantly stronger than before.

The disassembled gearbox with the equally disassembled top clutch.

I did actually manage to get the whole unit reassembled, redid the cabling of the mainboard, the top board, the power supply and all the sensors in the unit.
I also replaced the power switch to make the unit properly waterproof again.

Now the big moment: Trying if it works.
Power On, select 1 portion, hit “Start”.
Lots of noise, the rod goes down, stops briefly…. and goes up again!

Challenge mastered, goal achieved. The unit that had been declared beyond salvage actually worked.
Now… taking into consideration the dozens and dozens of hours I spent repairing it, even at minimum wage this repair would have been extremely expensive, so I guess it really was beyond salvage if you take into account the labour-costs.
On the other hand, I did this in my spare time, so in the end I got a fully functioning PacoJet for a low three-digit figure.

Now that it worked, I also wanted it to look nice and fit into the kitchen, so I decided to work on the metal case.
First of all, I removed the dents and sanded it down to also get rid of all the scratches.

The outer case after having filled in the dents and having sanded out the scratches.

I then sprayed it in a classic beige tone to give it the retro-look I wanted.
This way it will fit in with my other kitchen appliances.

The case with the first layer of beige paint.

The beige paint was then covered with two layers of high-gloss clear paint.
Finally, I used chrome-letters normally used in the Automotive Industry to put some finishing touches to that retro-look.

Adding a new Overlay for the display as well as chrome letters to the front gave the 25 year old PacoJet a classic look.

With all the work I put into it, the PacoJet now looks brand new and matches the other appliances nicely.

The “new” PacoJet among the other appliances in the kitchen.