Senseo coffee maker

Having dismantled and inspected several of this "strange machines" my conclusion is the following:

There is an oscillating-piston pump inside with in- and outlet valve.
It is energized by a microprocessor controlled circuit for a working time depending on the button selected (1 or 2 cups). The pressure and flow are nearly constant for a perfect working pump.
The pod holder restricts the thruput by its central hole. (E.g. you get now an extra pod-holder with a very small hole for expresso type)

So if you don't get enough coffee it may be that
1) the duty-cycle (timing) of the pump has changed.(not often occurring) no repair, you have to undergo electronic and programming work
2) the pump lost efficiency (cylinder of the pump clogged, piston not working with complete stroke, spring force fadening or just one of the 2 valves leaking) ca be "repaired" after dismantling machine ,extracting pump and taking it apart, success not garanteed - grinding valves is already time spending
so my principle before starting this work is to run the machine without the coffee pod to check the water output, use a new holder with clean central hole, if this works it will be nr.
3) the central hole of the holder is clogged, may be not by limestone, but dried coffee extract (grease) clean with needle or even better with micro-drill

There is a way to adjust the volume in the service manual. I can't post a link, but google Philips senseo PDF, and this is the file HD782070.pdf

The relevant section is here:

Volume adjustment
The new PCB circuit board makes it possible to adjust the volume output by means of pushing the one cup and two-cup user controls.
How to adjust the volume output
1. Be sure the boiler is filled properly, other wise perform fill procedure see DFU for instructions.
2. Switch appliance on and wait until the unit is ready to brew.
3. Be sure a pod holder is placed, but without a Coffee POD. Only adjusting with plain water
4. Place a cup on the drip tray cover and push the one cup button.
5. When the appliance has finished it is stabilized to perform the volume adjustment.
6. Empty the cup, podholder and push again for one cup setting, measure the volume output with a graduated beaker. In the table you can find the requirements for the minimum maximum volume output cc mL values depending from the country version

France version
Min. water cc mL 104
Max. water cc mL 120

General version
Min. water cc mL 125
Max. water cc mL 141

7. Unplug the appliance from the mains.
8. Press the 1 and 2 cup button simultaneously and plug the mains on
9. When above step succeeded the LED will turn on continuously.
10. Depending if the volume has to de or increase you have to push the 1 or 2 cup button. Every time you push the 1 or 2 cup button the LED will turn off for 0.5 second feedback to user and the pump time will be shortened or lengthened for 0.5 seconds depending which button was pushed. Pushing 1 cup button pump, time will be shorten with 0.5 sec is approximately minus 3.5 cc mL less coffee Pushing 2 cup button pump, time will be lengthen with 0.5 sec is approximately plus 3.5 cc mL more coffee When the volume has to increase with 10 cc for example, push the 2 cup button 3 times. The new value will be stored when you switch the appliance off by pushing the main switch. LED will turn off
11. Turn appliance on again and brew one cup, measure the volume. In case the volume is not within specification repeat steps 6 to 11.
12. End

How to Fix Low Flow Rate on Philips Senseo Coffee Maker:
A quick and fairly easy way to get your Philips Senseo producing full cups again rather than half a cup.
Usually the problem is the difficult to get to very small filter in the bottom of the pod holder that clogs up with old coffee in the holes and on the underside. Running through descaler is often not that effective at removing the old coffee stuck in the filter since it seems to be coffee bits rather than calcium scale.
See this tip in a youtube video for a quick way to remove and clean it:

https://youtu.be/uhirS92_Lwc

or search on Google for "comeinhandynow Senseo"

This applies to all Senseo coffee machines, so typically the following models, at least:
HD7863, HD7864, HD7857, HD7850, HD7840, HD7827, HD7823, HD7814, HD7816, HD7825, HD7810, HD7820, HD7870, HD7860, HD7824, HD7841, HD7812, HD7830, HD 7815

The pod holder is the problem here. If you finf you are getting a smaller cup of coffee use a nylon kitchen brush and give the gauze hole in the middle a good old scrub. Hey presto! problem solved

Descal with vinger or citric acid, NOT BLEACH, its very bad for you! do it every three months or 200 uses which ever comes first. IT will keep the pumps, valves and tubes clear.

If no good,
Call senseo at 866-4-736-736 866-4-Senseo and describe the problem.if you have purchased or received it as a gift less than two years ago they will send a new one FREE.

I have been fighting this same problem for several months now (my Senseo is about 2 years old) and I was having to run 4 double cycles to get my regular cup filled.

Today, out of desperation I ran 3 loads of half bleach / half water through the machine. You would NOT believe the **** that came out of my Senseo! NASTY! After that I ran about 6 loads of staright water through to flush and I immediately saw a huge difference. It now fills my big mug with 1 double and 1 single brew (just like new).

Try at your own risk, I mean we are talking bleach here. Be careful and good luck!

There isn't a way to adjust it. The senseo is calibrated to make either a 4oz or 8oz cup. Unfortunately, we are so used to buying mugs at the store that are MUCH bigger than this!