This is my first post at HB but I have been a reader here for a while now and thought it was time to give back to this awesome community. I am writing this since I found very scattered info on the Nuova Simonelli (NS) Mac series of machines on the web and even in NS manual - particularly with repair/trouble shooting the single group machine. So here goes to trying to put something in one place based on my experiences for others and the lengthy post (sorry) will probably be most interesting for prospective buyers/current owners.

For reference, my NS Mac Cup V 1gr Volumetric Dose machine was manufactured in mid 1997 and uses a Cubic Ricerca Persal 93 Power Control module and a Perstas 93 dose control panel.

OPINIONS ABOUT THE NS Mac Cup 1gr:

I bought the NS Mac Cup used after seeing it in operation due to the age of the machine and the risk associated with older & costly volumetric dose electronics. In the case of the Mac cup 1 group only, the electronics have been discontinued by NS. I did some poking around with my electronics and will include a small parts list that may be of use for those who are not afraid to use a soldering iron.

This is a plumb in rotary pump HX machine with a 5L boiler that runs on 15a 120v electrical service. While it is a large machine with more of a retro styling, it can fit under a normal counter with overhead cabinets but barely.

Like many commercial plumb in machines, the NS should be run on a in-line water softener and a water line pressure regulator set between 1 to max of 5 bars of pressure (stated on the name plate of the machine). I found this out after buying mine so include this in the cost of ownership of a commercial machine. To protect the electronics - it might not hurt to plug this machine into a power line conditioner.

In terms of performance (with a Compak K6 flat grinder), this is a great home machine that will churn out drinks as good or better than most coffee shops. It will steam milk FAST and recover quickly to allow you to create multiple drinks in a short period of time (small party in a home environment). This thing is way easier/less frustrating to use than the Rancilio Nancy/Silvia - no more uneven extraction or cracked pucks! I think that the slow pressure ramp up with the NS during the 1st sec helps with the extraction process (preinfusion??). The build quality is great and things are well laid out so that even someone who is unfamiliar with the layout can follow the design. With care, this thing should last a long time in a home environment.

When I got the machine, Cafiza was my friend for backflushes and a new shower screen was required. Additionally, some things needed to be worked on/repaired and I learned a few things mostly by trolling HB, Coffee Geek and the site published by Paul Pratt out of HK. These are my experiences that I wanted to share.

GROUPHEAD SEAL CHANGE

Neglected seal baked on from age - removed by carefully putting a small screw into the hardened rubber and pulling out with pliers. Easy fix.

DANCING BREW PRESSURE GAUGE

The needle on the brew/line pressure gauge would shake wildly when the pump engaged. Solution: there is a coiled tube (snubber coil) that attaches to the gauge the had a mix of air/water in it which caused needle fluctuations. Remove it and dry it out with heat then re-attach. Gauge works like new.

DESCALE AND REFILLING BOILER

You can check the boiler for scale by draining the water out of the machine and then remove the boiler element - note the orientation of the heater element before removing the 4 bolts. The NS Mac Cup has a convenient drain valve connected to drain cup underneath the stainless steel drip tray. You will need to use a 17mm wrench to loosen the nut.

The gasket for the boiler on my machine was teflon and I managed to reuse it but you should have one on hand before opening the boiler just in case yours is paper or in bad shape.

When it comes to refilling the machine the NS manual for the Mac Cup is geared mostly for the 2+ grp machines. The one group machine DOES NOT HAVE a manual boiler refill valves as mentioned in the manual. I talked with a NS USA rep from the Seattle office and they told me to run the machine and have the boiler fill for 90 sec which is when the controller will stop the water flow. Shut the machine and start it up again to complete the boiler fill. I was assured the element would not fry out and I have tested this many times personally - that said - your mileage may vary. Oh, there is no audible alarm on my 1 grp machine - it will NEVER beep at you even though the manual refers to an alarm - this is a feature for the 2 grp machine. However, the led lights on the front panel will blink when there are issues.

The descale process has been covered in depth here before so I will not rehash the process other than to say I did the descale by introducing 2tbls/L citric acid solution through the water supply line (citric acid was sourced cheaply from a home wine making supplier) into both the boiler and through the brew path, heating the boiler with the solution and using the drain valve to remove and flush the descaler out.

VOLUMETRIC DOSE CONTROL ISSUES / POWER CONTROL MODULE BLOWING FUSES / FLOWMETER (related issues):

Volumetric dose control stopped working - the water would continue to flow from the grouphead without stopping when appropriate vol was reached and the LED above the Continuous Flow button would start blinking after 3 sec. into the shot. Re-Programming the buttons resulted in no water flow for the button which was reprogrammed and the continuous flow and stop button LEDs would blink. Espresso could still be made using the continuous flow button so I was in no rush to fix the issue. Later the front panel LEDs seemed to randomly light up or lose power since the LEDs would dim out. Finally, the 100ma fuse blew up and the 12v power transformer in the power control module was burning hot to the touch (fuse was in place to prevent the self destruction of the transformer)... Lucky.

I read here that the biggest current draw for the transformer are the flowmeter and the relays on the board. I discovered on Mr Pratt's site that the resistance for a flowmeter between "+" and "O" terminal should be 1.8k to 2.4k ohms. My Gicar flowmeter unit measured 9 ohms which increased the current draw on the transformer that led to a fuse failure, messed with the volumetric dosing operation, and robbed power from the front control panel LEDs. I replaced the electronics on the top of the meter with a Digmesa unit while keeping the original fittings on Gicar body (Gicar and Digmesa flowmeter tops are interchangeable as mounting is the same) and now the machine is working great again! All symptoms have disappeared including a super hot transformer. Oh, the resistance on the new flowmeter was 1.2 KILO ohms not 9ohms.

While ripping apart the Control panel and Power module I replaced the most common things that fail which seem to be the electrolytic capacitors and the voltage regulator. Additionally, I created a small inventory list of parts numbers for the bigger items on each board while I was working on these two devices which I have included below. One should be able to get most items from a larger electronics part suppliers.

Persal 93 Power module:

ERA Transformer: BV 042-5055.0g
Power relay for heating element: Panasonic/Matshusita JM1AN-TMP-DC12v
3 relays for solenoids/pump: Panasonic/Matshusita JW1FSN-DC12v
Voltage regulator: LM7812CT
Electrolytic capacitor: 470 uF 63v
Diodes 1n4007


Perstals93 dose control board - contains one proprietary cubic ricerca IC (if this goes i think the board is toast since you will not be able to replace this ic easily)

3 - Electrolytic capacitors 10uF 63v
1 - Electrolytic capacitor 47uF 35v

Various generic IC chips:
TL7705ACP
93C46CB1
HEF4096UBP
ULN2004A
LM340t5

Overall, I have learned a lot about my commercial HX machine and I am very happy with the coffee that it consistently produces. Thanks for reading my long winded writing I hope that this post will help others just like previous posters on HB have helped me. Thanks.

I really enjoyed reading about your experience with the Mac V - I inherited one from my friend who used to have a coffee shop and it has been wonderful. I have a question for you - I always steam my milk and then draw my espresso - is this what you would recommend? With this machine could I do both processes at the same time? Thanks for the information and taking the time to answer!

I am glad you enjoyed my post, I really wondered if anyone actually would read my extremely long post! To answer your question, it is really a personal preference given that both processes can be completed in a very short order or at the same time if you prefer. From my readings, some people like to steam the milk like you and then let it sit to settle for 30 sec while they pull a shot.

Personally, I pull the shot first since the routine takes me a min or two. (grinding by individual dose/ weighing the grounds/ WDT etc) and then I steam the milk. There seems to be no ill effect to the shots (as long as the cups are pre-warmed) and the latte art is an acceptable work in progress.

Have fun with the MAC Cup ! ... even after a year of ownership with the learnings & sometimes fustrating journey that I had repairing a commercial machine, I still really like the NS as it is a SOLID machine. (admittedly though I did recently think about jumping on a La Marzocco GS3 MP that came up on a classified ad in my Province for a smoking price but SO did not approve so the NS lives on!!)